Solar Panel History, Efficiency, Technology, Installation and Cost

A solar panel or photovoltaic (PV) module is a technology that converts sunlight into electricity. The term “photovoltaic" (PV) comes from the process of converting light (photons) to electricity (voltage), and is a word commonly used within the solar industry. For example, the photovoltaic effect describes the phenomenon whereby semiconductor materials, like silicon, produce electrical current upon contact with sunlight. The photovoltaic effect is a scientific term that refers to the potential of sunlight to produce electricity. 

It was discovered by Alexandre Edmond Becquerel in 1839, kickstarting an almost 200-year evolution of solar technology. In 1883, Charles Fritts invented the world's first functioning solar panel, using selenium as a semiconductor. However, Fritt’s panel only produced around 1% efficiency.

The first solar panel fit for practical application was created by Bell Labs much later in 1954, producing around 6% efficiency, using silicon. Silicon is as a semiconductor material, meaning it switches between being an insulator and a conductor depending on the presence of light. The silicon atoms are essentially knocked free by photons, or light particles, creating an electrical current. To this day, most solar panels are made from silicon.

There are four main solar panel types: monocrystalline, polycrystalline, and thin-film PERC (Passivated Emitter and Rear Contact) panels. The two most common solar panel types, monocrystalline and polycrystalline, are both made from silicon. Monocrystalline panels, made from a single silicon crystal structure, offer higher efficiency but come at a higher cost due to their complex manufacturing requirements. Polycrystalline panels, made from melted fragments of silicon, are more affordable but slightly less efficient than monocrystalline cells.

PERC cells are similar to monocrystalline but typically have an additional rear surface layer that allows an added solar reflection, which increases overall efficiency by up to 3%. Lastly, thin-film panels are the most affordable and come in various sizes and shapes, but generally have the lowest efficiency of all types.

That being said, thin-film solar panels are innovative, and some experiments have produced efficiencies of up to 30% using concentrated light. As research and development within the solar sector develops, solar panel efficiency continues to climb closer to the 30-33% Shockley–Queisser limit, which represents the theoretical maximum efficiency for a solar cell.

The average price per kilowatt-hour (kWh) for solar energy has significantly decreased over the years, making it a highly competitive and feasible option for renewable energy sourcing. In the USA, residential solar panel costs typically range from $0.75 to $3.60 per watt. Monocrystalline panels are the most expensive, costing around $1 to $1.50 per watt, while polycrystalline panels range from $0.75 to $1.50 per watt.

Thin-film solar panels are the cheapest at $0.50 to $1.00 per watt, but they are less efficient than monocrystalline and polycrystalline panels. Several factors determine the cost of a solar system, including its size (measured in kW), quality of components, complexity of installation, and battery storage.

Solar panel systems contain many essential parts for converting sunlight into electricity. At their core are solar cells (photovoltaic cells) that capture sunlight and produce direct current (DC) electricity. Solar inverters then convert this into alternating current (AC) for home and appliance use. Solar racking securely mounts panels, net meters credit surplus energy, and performance monitoring optimizes solar output. Solar batteries store excess energy, charge controllers regulate voltage, and protective materials enhance durability.

Together, these components enable solar panels to efficiently harness clean and renewable energy. A solar panel system, particularly a residential solar array, usually includes solar panels, an inverter, a solar battery for energy storage, and possibly solar monitoring to track energy production.

The installation necessities for a solar panel system depend on several factors. These include the geographical location, the amount of direct sunlight, the size of the roof, the direction the roof faces, and local permits. Solar panel installation should always be done by a licensed professional to ensure safety and efficiency.

What is a Solar Panel?

A solar panel is a collection of solar cells mounted within a framework and used to generate electricity from sunlight. Solar panels are known by various names including solar cell panels, solar electric panels, solar modules, photovoltaic modules, or photovoltaic panels. Solar panels are most commonly installed on rooftops to provide power to residential and commercial buildings. However, they are usually able to be placed anywhere that has sufficient space and provides an optimal amount of sunlight.

Throughout history, there have been many pivotal steps leading to the invention of the solar panel. The potential to harness solar power was first discovered in 1839 when French scientist Edmond Becquerel observed that light produces an electric current when it interacts with certain materials. Bequerel’s groundbreaking discovery of what he called the photovoltaic effect influenced American inventor Charles Fritts to invent the first solar panel in 1883.

The four main types of solar panels are monocrystalline, polycrystalline, thin-film, and passivated emitter and rear cell (PERC) panels. Monocrystalline is the most common solar panel type, followed by polycrystalline. Monocrystalline and polycrystalline solar panels have been on the market for decades and are relied on in the commercial solar industry for their efficiency, durability, and low cost. Thin-film panels, known for their flexibility and lightweight design, are the least expensive solar panel type. PERC panels, which are up to 3% more efficient than conventional panels and work well in low-light conditions, are the most expensive solar panel type.

The working principle behind solar panels is a scientific phenomenon known as the photovoltaic effect, where certain semiconductor materials (like silicon) generate an electric current when exposed to sunlight. Around 95% of modern solar panels employ silicon for its high conductivity and efficiency. These solar cells are layered with a positive and negative film to create an electric field.

When sunlight strikes the cells, the electrons become active, causing them to move and create an electric current. This direct current (DC) is then passed through an inverter, which converts it into alternating current (AC) suitable for household electricity usage. The entire process is silent, free from moving parts, and entirely dependent on the abundant, renewable energy provided by the sun.

Solar panel materials vary according to solar panel type. Most solar panels today are made from silicon in various forms. For example, monocrystalline panels are made from a single silicon crystal, while polycrystalline panels are made from polysilicon, which is less pure. Thin-film solar panels are sometimes made using amorphous silicon but are commonly made from cadmium telluride or copper indium gallium selenide as well. PERC panels are made with modified silicon cells, which have an additional layer on the back to increase their efficiency. Other materials commonly used within solar panels are glass, polymer, ethylene-vinyl acetate (EVA), copper, and aluminum, which are used for various panel components such as wires, frames, and encapsulation.

Solar panels have a wide range of applications, many of which contribute to the overall production of clean, renewable energy. Solar panels are most commonly used to power homes and businesses. Other common applications of solar panels include heating water, operating irrigation pumps, water purification, and powering lights and small devices.

What is the History of Solar Panels?

The history of solar panels dates back to 1839 when French scientist Edmond Becquerel discovered the photovoltaic effect, a process where exposure to light generates an electrical current. Initially, this discovery had limited practical applications beyond light measurement for some decades until Willoughby Smith discovered the photoconductivity of selenium in 1873. This then led to experiments by William Grylls Adams and Richard Evans Day in 1876, which showed that exposing the element selenium to light produced electricity without heat or moving parts. These discoveries laid the groundwork for the discovery of the solar panel.

In 1883, Charles Fritts created the first solar cell, using selenium coated with a thin layer of gold. Fritts proposed rooftop solar installations to maximize sunlight conversion. In 1884, the first rooftop solar system was installed in New York City. However, Fritts’ selenium cells were only about 1-2% efficient, limiting solar energy's practicality.

In 1954, a significant milestone occurred when Daryl Chapin, Calvin Fuller, and Gerald Pearson from Bell Laboratories developed the first practical silicon photovoltaic cell, marking the birth of modern solar panels. Silicon cells became popular due to their reliability, although their high purity made them expensive.

One notable development during this period was the use of solar panels in space exploration. In 1958, the Vanguard 1 satellite became the first spacecraft to use solar cells to generate electricity in orbit. This marked a pivotal moment in the history of solar technology, as it demonstrated the reliability and effectiveness of solar panels in extreme conditions.

The 1960s and 1970s witnessed the mass production of solar panels, although they remained relatively expensive for mainstream consumers. During this time period, solar panels were mainly used for niche applications like powering satellites and remote communication equipment. The 1973 oil crisis brought international focus on renewable energy and solar power as nations sought alternatives to fossil fuels. This led to greater investment in research and development within the solar industry.

In 1995, the US National Renewable Energy Laboratory (NREL) introduced “thin-film” solar cells, which were cheaper to manufacture than silicon cells. While less efficient, they gained popularity for their affordability and became the third most common panel type globally. This development allowed for the broader adoption of solar panels in various applications, including remote power generation and grid-tied solar installations.

As the 21st century began, solar energy continued to gain momentum. Governments worldwide introduced incentives and subsidies to promote the adoption of solar panels, further driving research and development efforts. Solar panel efficiency improved steadily, with new technologies like concentrator photovoltaics and advanced tracking systems enhancing their energy capture capabilities.

In recent years, researchers have explored innovative materials and designs, such as perovskite solar cells, which promise to revolutionize the industry by combining high efficiency with lower production costs. Additionally, advances in energy storage solutions, like lithium-ion batteries, have complemented solar panel installations, enabling the storage of excess energy for use during periods of low sunlight.

Today, solar energy has become a mainstream source of renewable power, with widespread residential and commercial solar panel installations. The cost of solar panels has significantly decreased, making them a financially attractive option for many consumers. Continued advancements in technology, including paper-thin solar cells and nanomaterials that convert heat into electricity without sunlight, promise to further enhance the efficiency and versatility of solar panels.

These ongoing developments indicate a bright future for the renewable energy industry, with solar power playing a crucial role in reducing our dependence on fossil fuels and mitigating climate change.

Who Invented Solar Panels?

American inventor Charles Fritts invented the first working solar panel in 1883, which he did by coating the element selenium with a thin layer of gold. In 1884, Fritts had his solar cells placed on rooftops in New York City, though they produced only about 1-2% efficiency, making them unviable for widespread adoption (especially given the high cost of selenium).

Beyond scientific curiosity, Fritts’ invention was motivated by a desire to present an alternative to Thomas Edison’s electricity-producing coal plants, built only three years earlier. Another party sometimes credited with the invention of solar panels is Daryl Chapin, Calvin Fuller, and Gerald Pearson from Bell Laboratories, who created the first practically viable solar panel in 1954. The Bell Laboratories team used silicon as the semiconductor instead of selenium, which improved its efficiency to around 4-6%.

The work of both Fritts and the Bell Laboratories team would not have been possible without Edmond Becquerel's discovery of the photovoltaic effect in 1938. Becquerel showed that semiconductor materials produced an electric current when exposed to light. Other important contributors to the invention of solar panels include Willoughby Smith and Russel Ohl.

What are the Types of Solar Panels?

There are four main types of solar panels: Monocrystalline, Polycrystalline, Thin-Film, and Passivated Emitter and Rear Cell (PERC).

Monocrystalline solar panels are constructed from a single pure silicon crystal split into several wafers. An advantage of mono panels is that they are more space-efficient and longer-lasting compared to polycrystalline or thin-film panels due to the high grade of silicon used. The complex manufacturing process makes mono panels more expensive than the other main panel types but cheaper than PERC modules.

Polycrystalline Solar Panels contain multiple silicon crystals within a single cell, providing a balance between cost and efficiency. The manufacturing process of polycrystalline panels is less energy-intensive than monocrystalline panels, resulting in reduced manufacturing costs.

These panels are used in various applications, including residential arrays, commercial setups, and campervans. Polycrystalline cells convert sunlight into electricity at an efficiency rate of 13-16%. However, while they offer affordability and reduced waste, they require more space and have slightly lower efficiency compared to monocrystalline panels. With an average price of around $0.75-$1.50 per watt, they are a budget-friendly option for renewable energy production.

Thin-Film Solar Panels have a thin layer of photovoltaic material bonded onto a glass, plastic, or metal back sheet. The unique advantage of thin film is that the panel does not require a frame backing, making it the cheapest, lightest, and easiest to install of all main solar panel types. The rigidity and flexibility of thin-film modules allow better solar generation integration into products and buildings than crystalline silicon used for mono and poly panels. 

However, thin-film solar panels are generally the least efficient of all four solar panel types. Some thin-film panel types, such as CIGS (Copper Indium Copper Gallium Selenide), have produced exceptional efficiencies under lab conditions. That being said, thin-film panels are not yet widely used or available on the commercial solar market.

PERC (Passivated Emitter and Rear Cell) Solar Panels are an advanced version of monocrystalline and polycrystalline panels. PERC cells use additional layers on the cell's rear side to capture around 1-3% energy than other solar panel types. The overall production per unit area is higher, making them the most space and energy-efficient type. The extra cost of using passivated layers in PERC modules makes them the most expensive solar panel type. However, due to their higher efficiency, PERC solar modules will produce more electricity in the same area than other panels, making them the most cost-effective solar panel type in the long run.

What are the Types of Solar Panels by Application?

The four types of solar panels according to their various applications are Outdoor, Indoor, Vehicle, and Plane.

Outdoor Solar Panels are the most common application type, specifically designed for outdoor use to efficiently capture sunlight. Typically installed on rooftops and solar farms, outdoor solar panels are designed to efficiently capture large amounts of sunlight in various environmental conditions, making them typically more physically resilient than the other solar panel application types. However, they are similar to Vehicle Solar Panels and Solar-Powered Planes in that they must adequately withstand weather conditions.

Indoor Solar Panels are the best for powering small devices, such as calculators, watches, and weight scales. Unlike outdoor solar panels, indoor panels are optimized to collect low-intensity light and are usually used for less demanding applications compared to other panel types.

Vehicle Solar Panels are self-contained solar cells intended for use on vehicles like cars, buses, or camper vans (RVs). Vehicle Solar Panels are the most mobile of common solar application types and must withstand movement similar to solar planes. Unlike indoor solar panels, Vehicle Solar Panels are typically installed on the vehicle's roof, much like outdoor solar panels, in to capture maximum light. Solar vehicles offer sustainable and efficient transportation options, as demonstrated by solar-electric hybrid vehicles like the Toyota Prius and the Lightyear 0.

Solar-powered planes are the most experimental and least common application of solar panels, having been tested on both manned and unmanned large-scale aircraft, primarily for military and defense purposes. Examples include the Gossamer Penguin, the Solar Challenger, and the Solar Impulse, showcasing the potential of solar power for long-range flight, aiming to reduce carbon emissions and provide sustainable flight options for the future. However, widespread use of solar-powered passenger aircraft remains distant, with hydrogen power emerging as an alternative for sustainable air travel.

What is the Cost of a Solar Panel?

In the US, residential solar panel costs typically range from $0.75 to $3.60 per watt. Monocrystalline panels are generally the most expensive type, costing around $1 to $1.50 per watt, while polycrystalline panels are slightly less expensive, ranging from $0.75 to $1.50 per watt. Thin-film solar panels are the cheapest option, priced at $0.50 to $1.00 per watt, but they are also less efficient compared to monocrystalline and polycrystalline panels.

Prices of solar panels for residential or commercial use have decreased significantly over the past decade, thanks to technological advancements and increased market competition. However, the cost of solar panels varies widely depending on factors such as geographical location, the chosen solar installer, available incentives, and the type and brand of panels used.

The total cost of a solar panel system depends on various factors, including the number of panels needed, the brand and type of panels used, and the complexity of the installation. Additionally, incentives such as the Federal Tax Credit can significantly reduce the overall cost of installing solar panels, making them a more affordable option for many homeowners and businesses.

What are the price categories for Solar Panels?

Solar panel prices in the United States are effectively categorized into three distinct ranges to cater to different buyer types. These are mid-range, industrial, and small-quantity buyers.

For mid-range solar buyers, typically consuming up to 10 megawatts (MW) of electricity annually, solar panel costs fall within a moderate pricing band. These buyers often seek a balance between quality and affordability, focusing on reliable brands that offer efficient panels at reasonable rates. Residential solar PV systems for residential homes in the US typically cost $18,000 on average for a regular-sized system of 6 kW and around $30,000 for a 10 kW one (before federal tax credits).

Industrial buyers procuring large quantities benefit from economies of scale. Despite the high initial costs of industrial-grade panels, the unit price drops significantly with bulk purchases, leading to substantial long-term savings. These buyers primarily give precedence to the longevity and efficiency of panels over the upfront cost. Industrial buyers of large solar systems of 30 kW usually pay $300,000.

Lastly, individual small-quantity buyers generally have budget constraints, hence they tend toward less expensive options. While these panels lack the advanced features found in premium range panels, they still provide a substantial portion of a household's energy needs. In terms of system size and cost, complete RV solar systems range from around $600 for the simplest, smallest set-up to upwards of $2,000. Adding additional panels and batteries is likely to increase that cost.

Why is the Solar Panel Price Going Down?

Solar panel prices have been going down over the last 20 years due to two main factors: technological advancements and economies of scale. Solar panel technology has become increasingly efficient in recent years, which allows solar panels to generate more electricity from the same amount of sunlight, for a lower cost. Furthermore, as demand for solar energy increases, prices drop due to economies of scale. Economies of scale refer to the cost efficiencies that become available at larger production levels. 

As of 2024, solar module prices are continuing to fall sharply due to an oversupply of modules stemming from increased production capacities, a shift in technology, and a slowdown in demand. In the Covid years, manufacturers expanded their production in response to high demand and prices, but now face a surplus of modules, according to PV magazine’s article “Solar module price falling, with no end in sight”. Market conditions, including the end of pandemic-related supply shortages and economic uncertainties, have contributed to lower demand, prompting manufacturers to lower prices to stimulate sales and compete for market share.

What is the average cost per kWh produced for solar panels?

The average cost for solar electricity produced in the US lies around $0.06 and $0.08 per kWh. This price criterion is crucial to calculating the Levelized Cost of Energy (LCOE), which is a useful metric for assessing the value of a solar installation. LCOE quantifies the cost of the electricity produced by your solar installation over its lifetime. LCOE, which is presented in $/kWh, is a particularly helpful piece of data because it allows consumers to directly compare the price of solar energy to what a local utility company would charge for grid-based electricity. This calculation is useful to look at when comparing financing options before buying and installing a solar system at home.

How did the Average Cost for Solar Panels change over the past 10 years?

Over the past decade, the average cost of solar panels in the United States has rapidly decreased. Between 2010 and 2021, there was a marked reduction in the cost of residential, commercial rooftop, and utility-scale photovoltaic (PV) systems. Specifically, the cost of residential PV systems saw a 64% price reduction, commercial rooftop systems experienced a 69% decrease, and utility-scale PV systems saw the most significant drop at 82%. This reduction in costs is largely attributed to increased module efficiency, lower hardware and inverter costs, and significant decreases in the price of PV modules themselves. A decade ago, the module cost alone was around $2.50 per watt, but by 2021, the cost for an entire utility-scale PV system had fallen to around $1 per watt​​.

Reflecting on the broader historical context, a decade prior to 2022, residential photovoltaic systems cost upwards of $50,000. However, prices dropped more than 70% in subsequent years, with the average upfront cost for a 6 kW system ranging between $15,400 and $18,800. This price reduction trend was consistent with a 5% drop in the price per watt of solar energy noted in 2018 alone​​.

As of 2024, the average cost for residential solar panel installations ranges between $18,000 and $20,000 before applying any tax credits or other incentives. This translates to about $2.75 to $3.35 per watt, depending on various factors such as location and equipment brands used. To give you a more detailed insight into how solar panel costs vary across the US nowadays, here's a breakdown of the average cost of a 6 kW solar system by state, after tax credits:

• Alabama: $10,290
• California: $11,256
• Florida: $10,836
• New York: $12,012
• Texas: $11,634

These figures demonstrate the variability of solar installation costs across different states, influenced by local competition among installers, job volumes, cost of business overhead, labor costs, and differing state and local policies.​

What is the Cost of Solar Panels for Home Use?

The cost of a standard 6 kW Solar PV System typically costs around $12,000-$18,000 in most American states. This cost varies widely based on factors such as the quality of solar panels, type of solar inverter, location and installation costs.

The cost of premium solar panels ranges from approximately $400 to $550 per panel. On the other hand, the cheapest solar panels available cost as low as $100-$300 each. Cheaper solar panels are associated with lower power output, so in most cases investing in high efficiency modules is a better choice for a long term solar investment.

Meeting the average household's electrical needs in the United States typically requires 15 to 25 solar panels, with the most common system sizes being 5kW and 6.6 kW (kilowatts). In comparison, larger residences with higher energy demands typically need a larger system of around 10 kW with up to 35 panels. Larger systems generally cost more upfront but provide a better cost-to-output ratio, potentially resulting in a faster payback period.

To calculate the total cost of your solar panel system, multiply the estimated system size (in kW) by the cost per watt of the panels. Then, additional expenses such as inverters, mounting hardware, and installation fees are added to reach an approximate overall cost. Remember to factor in any incentives such as the Federal Tax credit or state-based rebates. Solar installers typically include other components like racking, wiring, and inverters in the total cost when providing a quote.

What are the price factors for Solar Panels?

The main price factors for solar panels typically include the type of panels used, the materials used within cells of the panels, the number of panels used, the choice of inverter and whether solar batteries are installed, and the availability of rebates.

The most important solar panel cost factor from a technical point of view is solar panel type. Monocrystalline panels are both the most common and most expensive residential solar panel type. Polycrystalline panels are cheaper than monocrystalline but not as efficient. Thin-film solar panels are more or less expensive than traditional silicon panels depending on the material used and the scale of production.

Different types of solar panels use different materials and manufacturing processes, which determine their cost. The choice of material within a solar panel is a key determining factor of the overall cost of a solar module. For example, monocrystalline panels are more expensive than polycrystalline panels because they are made using a single crystal of silicon, which is costly to achieve but provides a higher level of overall efficiency.

Polycrystalline panels are made from multiple fragments of silicon cells and can even be made from “wasted” silicon material from the monocrystalline manufacturing process. However, while polycrystalline cells are cheaper to produce, the integration of fragmented silicon cells leads to lower sunlight conversion efficiency. This is because the fragments create boundaries within the crystal structure that affect electron flow.

The cost of thin-film panel types varies widely depending on the choice of material used. In some cases, thin-film types like cadmium telluride (CdTe) are quite inexpensive to make, whereas other innovative forms of thin-film solar cells like CIGS (Copper Indium Gallium Selenide ) are costly to produce. Many thin-film solar cells are produced in lab conditions only, rather than being produced for the mass commercial market at scale, which results in much higher costs compared to residential solar types like monocrystalline.

When installing solar panels, the number of panels used within the overall system is a fundamental contributor to the cost outcome. For example, a larger residential solar system size of 10kW (kilowatts) and above is likely to require 22 or more solar panels. A small system size of 3kW is likely to need less than 10 panels. The number of panels needed typically depends on the size of the household or building and the amount of energy required or desired. For example, a household looking to go “off the grid” will require more solar panels to become totally self-sufficient, compared to a household wanting to supplement electricity from the grid.

Beyond the panels themselves, other components of a photovoltaic (PV) system like the inverter and optional solar batteries further influence the cost. Inverters typically vary in cost anywhere between $2000 and $6000, depending on the quality, type, brand and size chosen.

Most PV systems are grid-tied, meaning that rather than store the electricity generated from solar, the excess power is fed back onto the grid in return for credits from the utility company. However, some solar consumers choose to install solar batteries, which add a significant cost of anywhere from $12,000 to $20,000 to the overall system. The advantages of battery storage are that it reduces reliance on grid electricity, provides "free" electricity even when sunlight is low, and allows for backup power during outages.

Another factor that influences the cost of solar panels is the availability of rebates and tax incentives. In the US, the federal Investment Tax Credit (ITC) allows homeowners to receive a discount of up to 30% for installing solar. There are a number of state and local government rebates as well, which provide an additional incentive for installing solar and further reduces the costs of solar installation. Usually these rebates are applied for on your behalf by your local installer.

Does the Cost of Solar Panels vary based on type?

Yes, solar panel costs vary based on the type of panel. Monocrystalline and Passivated Emitter and Rear Contact (PERC) panels, both of which contain crystalline silicon, are the most expensive types of solar panels. Monocrystalline solar panels cost an average of $1 to $1.50 per watt. Comparatively, polycrystalline panels contain multiple silicon crystals and have a lower average price of $0.75–$1.50 per watt. That being said, polycrystalline solar panels are less efficient than monocrystalline ones, requiring more panels to generate the same amount of energy.

PERC cells seem cost-effective per watt since they require fewer solar cells thanks to an additional rear layer. Nevertheless, the advanced technology utilized in manufacturing PERC solar cells contributes to a comparatively higher price compared to other cell types.

Polycrystalline panels use a mixture of crystalline silicon (c-Si) and cheaper types of silicon, making them cheaper than monocrystalline panels but pricier than thin-film panels. Thin-film panels are the cheapest type of solar panels because they contain no crystalline (c-Si), making thin-film panels the most affordable solar panel type.

How does a Solar Panel Work?

The working principle of solar panels is the photovoltaic (PV) effect, a natural phenomenon that allows electricity to be generated from sunlight. The photovoltaic effect operates by automatically producing an electric current when light makes contact with the semiconductor material within a solar cell. When sunlight strikes the solar panel, the semiconductor material absorbs the energy carried by photons, facilitating the movement of electrons within the cell. These liberated electrons form a direct current (DC), characterized by a unidirectional flow of electrical charge. However, most household appliances and electrical systems operate on alternating current (AC), which flows in both directions.

To understand how a solar panel works, you must know that a solar inverter is essential in the entire process, transforming the DC electricity into the AC power needed for common household use.

Solar panels contain a multitude of cells which are wired together, and which generate electricity within a collection of solar panels known as a solar panel system, PV system or solar array. These systems allow enough electricity to be generated to power homes, business and solar farms. Solar panels are typically installed on rooftops and areas exposed to direct sunlight in order to maximise power generation.

The process of how a solar panel system works comprises four essential steps. Firstly, the panel's photovoltaic cells capture photons from sunlight, creating an electrical current. Next, this electricity flows through a conductive wire, which connects all the solar panels in the array either in a “series” or “parallel” formation. Thirdly, the electricity flows through a solar inverter. Lastly, the inverter converts the generated direct current (DC) into alternating current (AC) so that it can be used to power electrical devices in homes, businesses, and other applications.

What are the Parts of a Solar Panel?

Solar panels consist of a number of parts vital for converting sunlight into electricity. The main parts of a solar panel include solar cells (photovoltaic cells), solar inverters, solar racking, net meters, solar battery storage systems, and charge controllers. At the core of a solar panel are solar cells, which capture sunlight and generate direct current (DC) electricity through the photovoltaic effect. To make this electricity usable, solar inverters convert it into alternating current (AC), suitable for powering homes and appliances.

Solar racking provides stability by securely mounting panels on various surfaces, while net meters facilitate surplus energy crediting. Performance monitoring ensures optimal panel output, and solar battery storage stores excess energy for nighttime or power outages. Charge controllers regulate voltage, and protective materials like EVA, back sheets, aluminum frames, interconnectors, and silicone glue enhance durability and protect against environmental factors. Collectively, these parts of solar panels enable solar panels to harness clean and renewable energy efficiently.

The cost of solar panel parts depends on various factors, including the type of solar cells used and system capacity. Solar inverters, racking systems, monitoring equipment, and energy storage devices contribute to the cost. Additionally, charge controllers and protective materials play crucial roles in the solar panel system's functionality and resilience, impacting both performance and durability but further adding to solar system installation costs.

What is a Smart Solar Module?

A smart solar module is a solar panel with a built-in power optimizer such as MPPT (Maximum Power Point Tracking) that helps each module maximize its output, regardless of the production of other modules in the PV system. Smart solar modules are often compared to microinverters because they isolate each panel to improve the system’s overall output. They are most commonly purchased for solar systems with a string inverter. Smart solar modules allow owners individual solar panel performance without the installation and equipment costs associated with microinverters. A smart solar module typically costs around $250 - $400 more than a regular solar panel.

What is a Concentrator?

A solar panel concentrator is a photovoltaic technology that increases a solar panel’s efficiency and output by utilizing curved mirrors to concentrate light. Solar panel concentrators work by directing a large amount of sunlight into a specific area. It’s rare to find these in residential systems, due to the degree of complexity and cost involved. For this reason, concentrated photovoltaics are better suited to industrial applications like solar farms.

What is a PV Module?

A photovoltaic (PV) module, commonly known as a solar panel, is a device commonly used on rooftops to capture sunlight and convert it into usable electricity for homes and businesses. PV modules function by harnessing sunlight, which essentially energizes the photovoltaic cells they contain. Within each cell, there are semiconductors, including p-type (positively charged) and n-type (negatively charged) silicon. When sunlight is absorbed by the photovoltaic module, it triggers the movement of electrons between the p-type and n-type layers, generating an electric field and producing usable electricity. The cost of each PV module depends on several factors, such as the type and brand, but usually costs between $250-$750 each.

What is a Solar Panel Battery?

A solar panel battery (solar battery) is a device for storing the excess electricity generated by solar panels. PV (photovoltaic) systems often create more power than a household requires, depending on sunlight availability and household energy usage. This stored power is then available for use when the household's electricity demand exceeds the amount of electricity generated by the PV system at a given time. Some of the main benefits of a solar panel battery include access to solar power when there is little to no sunlight, financial savings due to reduced reliance on the grid, and sustained power during blackouts.

How are Solar Panels Installed?

In general, solar panels are typically installed by certified solar installers. Solar panel installation is complex in that it involves working at heights on roofs, connecting electrical wiring, and mounting systems like batteries and inverters. For this reason, it's best to leave the solar installation to professional installation companies unless you have experience and electrical expertise.

If you would like to learn how to install solar panels yourself, the following steps will help you get your system up and running. First, establish a sturdy base framework for your solar array, either on the ground or roof. Next, install solar panel mounts, including roof attachments, clamps, and rails, securing them properly. 

Consider incorporating solar trackers to optimize solar exposure. Then, carefully position the solar panels onto the mounts, taking caution due to varying weights. Subsequently, wire the panels in either series or parallel configurations to ensure the electricity flows correctly. The next thing to understand about how to install a solar panel involves the solar panel system as a whole, including the integration of inverters and batteries. 

An inverter is required to convert the DC (Direct Current) electricity generated by solar panels into Alternating Current (AC). While batteries are an optional component that facilitates energy storage. Once the main solar panel components are in place, connect the entire system to the main power supply. Finally, it's crucial to conduct thorough testing of various electrical aspects of your solar panel system.

Other factors to consider when installing solar panels include budget, location, tools, equipment, and safety precautions, each of which plays a significant role in ensuring a successful and efficient solar panel system installation. The costs associated with installation vary based on factors such as system size, location, complexity, and roof type, with regional norms influencing expenses. In the United States, you usually need to spend an extra 25% of the total installation cost for labor.

Why Should Solar Panels in the United States Face South?

It’s generally best for a solar panel's orientation to face south in the US and other northern hemisphere locations. This is because a south-facing orientation aligns with the sun's predominantly southern path across the sky. The ideal tilt angle for solar panels should match your home’s latitude (usually 30°- 45°). By orienting panels according to the correct solar panel angle and orientation, they receive the maximum possible sunlight throughout the day and produce more electricity as a result.

Solar panel trackers are devices designed to continually adjust the angle of solar panels to maintain optimal alignment with the sun. This process, sometimes called sun tracking, ensures that the panels are always positioned to capture the most sunlight. While solar panel trackers are more commonly used in ground-mounted solar systems, advancements in technology have made roof-mounted solar trackers increasingly viable. That being said, for residential purposes, a tracker is not usually required, given the expense involved.

What are Solar Panel Mounts?

Solar panel mounts, or solar panel racks, are structures used to secure solar panels on surfaces like roofs, building facades, or the ground. Mounting the panels ensures their stability during operation. Solar mounts are lightweight and adjustable, allowing panels to be tilted to the optimal angle for harnessing renewable energy. Adjustable solar panel mounts enhance energy output by adapting to the sun's movement.

There are numerous types of solar panel mounts, including rooftop mounts that utilize existing building structures, ground mounts for optimal sunlight exposure, carport mounts that serve a dual purpose, and pole mounts that are beneficial for uneven terrain. Solar racking is usually made from stainless steel or aluminum, which provides enhanced durability and resistance to corrosion and adverse weather events.

It's essential to consider legal restrictions, roof integrity, and orientation when mounting solar panels. Additionally, while DIY mounting is possible, it is risky due to potential hazards such as electrocution, falls, and fires. For this reason, it is often best to leave installation to licensed professionals for those without electrical expertise. Precautions such as guarding against electric shocks, ensuring structural integrity, and addressing arc faults and falls must be taken during solar panel mounting and installation.

What is a Solar Panel Tracker?

A solar panel tracker is a device that maximizes the production of solar panels by aligning them with the sun's movement. As the sun moves throughout the day, a solar panel tracker continually reorients the solar panels towards it, allowing for greater sunlight absorption. Solar panel trackers came about in the 1960s. The first tracker was invented by C Finster in 1962 and operated purely based on mechanics. In subsequent years, solar panel trackers were further developed and improved. There are two main types of solar trackers: dual-axis and single-axis. Dual-axis trackers meticulously follow both vertical and horizontal sun paths, offering up to 40% greater energy yield compared to stationary setups. Single-axis trackers are less complex but still enhance solar energy output by up to 30%.

Solar trackers are expensive, which is why they are less commonly used in residential solar systems compared to previous decades. While solar panel trackers are useful for producing more electricity from a photovoltaic system, they are expensive. With the ever-decreasing cost of solar panels, it is usually cheaper nowadays to increase the power generation of an existing system by adding additional solar panels rather than installing a solar tracker. While solar panel trackers offer many advantages, such as increased energy yield, better sunlight exposure, reduced land use, and grid stabilization, they come with considerations like higher upfront costs, increased maintenance requirements, and limited suitability for smaller rooftop areas.

What affects the Duration of Solar Panel Installation?

The time it takes to succesfully install solar panels is affected by 10 main factors, which are installer availability, roof condition, roof type, number of roof faces, roof pitch, building height, system size, switchboard conidtion, distance between solar panel components and number of installers.

Below is more information on each of the ten factors that affect the duration of solar panel installation.

• Installer availability: Solar panels must be installed by a qualified electrician. Electricians are employed by solar installation companies to ensure the panels are safely and efficiently. However, in certain periods of high demand, it’s not uncommon to wait for up to 3 months. This draws out the time it takes to get your photovoltaic (PV) system up and running. Issues with supply chains and solar panel availability sometimes cause delays on the part of installers as well.
• Roof condition: Solar panels place additional weight on your roof, which is why solar installation requires a roof that is in good condition. It may be necessary to repair or replace your roof if it’s in poor condition and cannot carry the extra weight of a photovoltaic (PV) system. The roof repair increases the duration of solar panel installation.
• Roof type: Roofs are made of different materials, including tin, corrugated iron, tiles, shingles, and Colorbond steel. Whilst solar panels can usually be installed on most roof types, some roofing materials are better suited for solar panel installation than others, making installation easier and faster. For example, tin roofing offers straightforward installation, whereas tile roofs pose a few problems and make installation longer. For example, roofing tiles crack easily when drilling through them. To drill mounting brackets into the roof rafters, you often need to remove tiles and put them back after installation, increasing installation time. The best roof type for solar panel installation is composite shingles because they are highly common, and most installers have the necessary expertise and equipment to complete the installation quickly.
• The number of roof faces: The number of roof faces matters in solar panel installations; in the United States, south-facing roofs capture the most sunlight, followed by east and west-facing roofs, and when installing panels on different roof faces, the greater the number of roof faces involved, the more complex and time-consuming the installation becomes.
• The roof pitch (slant angle): Rooftop installation is easy and quick if the slant angle of the roof matches the optimal tilt angle for solar panels. Solar panel installation usually takes longer if the roof is not sloped at the optimal angle, requiring tilt adjustment which makes it take longer.
• The height of the building: Solar panels work better at high elevations, but the higher your roof, the longer installation takes. For example, the higher the number of stories, the more difficult it is to get the solar panels to the rooftop.
• The size of the system: The larger your solar system, the more solar panels you usually need, and the longer their installation takes. More solar panels increase installation duration for different reasons. Firstly, you need roof repairs or replacement to handle the increased weight or more panels. Secondly, the more your solar panels, the longer it takes to carry them to the roof.
• The condition of the switchboard: You need a space on your switchboard for your solar system. A new switchboard is usually required if your switchboard doesn’t have the required room. Older switchboards do not have safety switches, and these need to be updated to make your installation safe, as this increases installation time.
• The distance between components: The distance between the solar panels and the inverter, as well as the distance between the inverter and the meter, affects installation time. This is because longer distances require more work to wire solar panels, including running the wiring, hiding it from view, and securing it.
• The number of people working: The more people installing your solar panels, the faster it takes. Having more hands quickens installation.

Should I install solar panels by myself? Generally, it is not a good idea to install solar panels yourself. DIY solar panel installation requires an electrician to safely wire the system - expertise that even the handiest homeowners are unlikely to have. Solar installers usually take about 4-6 hours to complete the installation of rooftop solar panels. Most residential solar systems require at most a single day to install. 

Solar panel installation sometimes takes longer if unexpected structural modifications are needed. This includes tasks like reinforcing the roof, updating electrical infrastructure, or making alterations to accommodate the solar panel system. Such unanticipated modifications can extend the installation timeline and should be addressed with careful planning and professional guidance to ensure the safety and effectiveness of the solar installation.

Beyond that, while self-installation is technically possible in the US, solar panel systems must meet specific electrical codes and safety standards. Professional installers are knowledgeable about these requirements and ensure compliance, which is crucial for eligibility for rebates and incentives.

How do Solar Panels Maximize Energy Production?

Solar panels are used to convert sunlight into electricity. Solar panels maximize energy production by placing solar panels on rooftops or in areas of direct sun, allowing panels to capture as much sunlight as possible. The larger the surface area of the panels and the higher the solar panel efficiency, the better the panels are able to maximize electricity production. The efficient and optimal conversion of sunlight into usable electricity is what underpins solar panel efficiency.

Different types of solar panels employ various methods to provide maximum production of energy. For instance, monocrystalline and polycrystalline panels optimize energy conversion by utilizing high-quality silicon cells, while thin-film panels maximize surface area coverage. Tracking systems, such as dual-axis trackers, rotate panels to face the sun directly, ensuring constant exposure to sunlight. Other enhancements, like anti-reflective coatings and bifacial technology, reduce energy loss by enhancing light absorption.

What is the Maximum Power Point in Solar Panels?

The Maximum Power Point (MPP) refers to the highest power output of a solar panel, as represented on a current-voltage (I-V) curve. The MPP is the ideal balance of voltage and current in a PV system, which constantly adjusts itself based on changing conditions like irradiance (sunlight intensity), temperature, and battery charge. Achieving and maintaining the Maximum Power Point is crucial in optimizing the efficiency and energy yield of solar panels. When a solar panel operates at its MPP, it generates the maximum possible electricity for a given set of environmental conditions, ensuring that the system is operating at peak performance. 

To understand this concept better, it's essential to delve into the intricacies of the I-V curve. This curve typically exhibits a distinctive "knee point," which represents the MPP. At this specific combination of voltage and current, the solar panel produces its highest output. Consequently, various technologies, such as Maximum Power Point Tracking (MPPT) controllers, are employed in solar installations to optimize the operating voltage and current of solar panels. 

Using Maximum Power Point Tracking (MPPT) ensures that the power input remains in the optimal range, neither excessively high, leading to energy loss, nor too low, preventing the batteries from reaching full charge. This maximizes the efficiency of solar systems and ensures optimal power utilization.

What is VMP?

Voltage at Maximum Power (VMP or VPM) refers to the voltage level at which a solar panel or module operates at its peak performance output under standard test conditions (STC) when connected to a load. This is the voltage that results in the highest power output from the solar panel.

VMP is a critical parameter listed on a solar panel's specification sheet and sticker. When a solar panel operates at its maximum power voltage, it produces the maximum electrical power it is capable of delivering. It is an essential parameter for ensuring that solar panels are connected to the right load to maximize their power output.

Why do Solar Panels need Inverters to Maximize the Energy Output?

Solar panels need inverters to maximize energy output because solar power is generated as direct current (DC), whereas alternating current (AC) electricity is required for everyday use in homes and businesses. One way to maximize the energy production of solar panel inverters is through a process called 'inverter oversizing,' which involves installing a solar array with a higher capacity than the rated size of the inverter. By installing more solar panels than the solar inverter is meant to handle, the system produces a higher energy yield throughout the day and generates more energy than if the inverter had not been oversized.

Inverters can be oversized by 133%, meaning a 5 kilowatt (kW) inverter is able to process energy from up to 6.6 kW of solar panels. By adding 5 extra solar panels, the system has the potential to significantly increase its energy output. Oversizing a solar array with a 5kw inverter results in a 28% increase in annual energy yield, with a total annual energy yield of 10,624 kWh (compared with 8260 for an inverter that wasn’t oversized).

How is a Solar Panel wired to Inverters?

Wiring solar panels to inverters is a fundamental aspect of setting up a solar power system. In the United States, a licensed electrical technician is recommended to install a solar panel system, including the wiring of the panels to the inverter.

There are three main ways to wire, or “string”, a solar panel to an inverter: in series, in parallel, or a combination of both.

Below is more information on the three main ways to string solar panels to an inverter.

• Series wiring. Series wiring is the most common method of wiring solar panels because it increases the voltage output. It is best suited to full-sun conditions and low-amperage systems. Series wiring involves connecting the positive terminal of one panel to the negative terminal of another panel. When two or more solar panels are connected in series, they become a PV source circuit.
• Parallel wiring. Parallel wiring is when the positive terminal from one panel is connected to the positive terminal of another panel, and the negative terminals of both panels are connected together. When panels are wired together in this way it creates a PV output circuit.Parallel wiring is best used in mixed-light conditions. If shade covers one or two panels, the remaining panels will continue to generate power. Parallel circuits are ideal in low-voltage systems.
• A combination of both series and parallel wiring. A combination of both methods is used in applications where the owner wants to double the level of the voltage, as well as the current from the solar panel to the batteries and other load points. The combination is best suited to commercial and larger applications, as small residential applications do not require a power output of this size. A higher voltage grid-connected system calls for a series-parallel combination, depending on the number of solar panels used in the system.

What is the difference between a Parallel or Series connection from Solar Panel to Inverter?

The main difference between parallel or series connections between an inverter and solar panels is how they affect voltage and current. When solar panels are connected in series, their combined output voltage increases, maintaining a consistent output current (amperage). Conversely, when solar panels are wired in parallel, their combined output current rises (amperage increases), while the output voltage remains constant.

Other differences between series and parallel wiring include their suitability for different lighting conditions and their impact on energy efficiency and cost.

Series circuits are best used in full-sun conditions, whereas parallel circuits are best suited under fluctuating irradiance levels. In a series circuit, solar panels are connected end-to-end, creating a single pathway for the current to flow, which is advantageous for maximizing voltage output in full-sun conditions. In contrast, parallel circuits involve connecting solar panels side by side, allowing each panel to operate independently, making them more resilient to shading and mixed light conditions, as they don't affect the performance of the entire system.

Parallel and series connections produce different levels of energy efficiency. Wiring in series will increase the voltage of a circuit, while wiring in parallel will increase the amperage of a circuit. Both voltage and amperage need to be considered when designing a solar system, especially when it comes to selecting a suitable inverter for the system.

Wiring a solar panel to an inverter in parallel is more expensive than using a series connection. Connecting panels in parallel requires heavier wire than connecting in series, because it needs to handle the higher current generated. The installation process is more complex, and therefore more costly as well compared to series wiring.

Whether it’s better to opt for a parallel or series connection when wiring an inverter to a solar panel system depends largely on the requirements of the system. A series connection is a more common choice in the United States for those looking to maximize the overall efficiency of the PV system, whereas a parallel connection helps bolster the performance of the entire system in shadier conditions.

Why is a Micro-inverter Better for Maximizing Energy in Solar Panels?

A micro-inverter is a device that converts the Direct Current (DC) electricity produced by solar panels into Alternating Current (AC) electricity. Unlike other inverter types, micro-inverters control the output of a single solar panel, which allows individual panels to be monitored independently. Microinverters are better than other solar panel types when it comes to maximizing energy because they enable each panel to operate independently, preventing one shaded or underperforming panel from negatively impacting the overall energy production of the system. Using microinverters generally results in higher efficiency and energy generation compared to standard string inverters.

In addition to panel-level monitoring, micro-inverters offer several other advantages in comparison to string inverters. For example, they support system expansion, allowing homeowners to add more panels easily without purchasing new equipment like an inverter or having to rewire the system, which is often expensive. They allow more flexibility than string inverters in terms of the layout, making it possible to place panels across different roof sections or in non-standard formations. Additionally, micro-inverters often come with a longer 25-year warranty. 

However, when comparing a Micro-inverter vs a String Inverter, it’s important to consider some of the drawbacks, such as the higher initial cost of microinverters, the greater number of potential points of failure, troubleshooting complexities, and susceptibility to lightning damage. In contrast, String Inverters are less expensive but lack the efficiency and flexibility of Micro-inverters, making the choice dependent on specific solar system requirements.

What is a Connector for a Solar Panel?

A connector for a solar panel is a connection cable that attaches different solar components to create a safe flow of electricity across the solar panel system. The most common connector type for solar panels is the MC4 connector. Four other solar panel connectors and cables include the MC3, Radox, SolarLok, and Helios HA solar panel connectors. The MC4 Connector has largely superseded its predecessor, the MC3, as the main solar connector used on the market because they are more waterproof and dustproof.

A solar panel connector helps to safely prevent misconnection within a solar panel system. Solar panel connectors attach the different solar components together using “male” and “female” connector types. The “male” connector refers to the positive lead (+), whilst the “female” refers to the negative lead (-).

Why is an MC4 Connector used for Outdoor Solar Panels?

An outdoor solar panel is a panel that is designed to be durable and withstand diverse weather conditions. MC4 Connectors are most commonly used for outdoor solar panels because they are extremely weather-resistant and are able to handle high currents associated with direct sunlight exposure. Alternative connector types for an outdoor solar panel are the MC3, Radox, SolarLok, and Helios HA solar panel connectors. Installing an outdoor solar panel using an MC4 connector enhances the energy production of the solar panel system compared to other connector types.

What connector do Automobile Solar Panels use?

A car solar panel is a solar device installed on a car’s roof or exterior that converts sunlight into electric energy. Automobile solar panels primarily use an SAE Battery Connector, which is a hermaphrodite two-conductor DC (Direct Current) connector. Solar electricity on a vehicle is mainly used to power the air conditioning, radio, and lights of the car or motorbike.

The primary alternative to the SAE Battery Connector for automobiles is the MC4 Connector; however, the MC4 Connector is primarily used in multi-panel installations in homes, sheds, or offices. The SAE Connector is a common choice for automobile solar panels because it is easy to use, affordable, readily available, and safe. It has a wiring harness that allows you to use and/or charge electronic accessories such as smartphones and GoPro batteries. The SAE Connector uses an SPT-2, 16AWG/2C cable, measures 1.2 Feet, and is heavy-duty, flexible and durable.

What connector do Indoor Solar Panels use?

An Indoor Solar Panel is a panel installed inside and used to generate electricity from ambient light. Typically found inside houses or sheds, indoor solar panels mainly use an MC4 Connector because they are reliable, durable, and weather-resistant. Indoor solar panels mainly power solar indoor lights, solar shed lights, solar camping lights, and solar garden lights. The power generated from indoor solar panels using an MC4 Connector maximizes energy production and ensures the solar panel system is dustproof and safe.

What is the Average Lifespan of a Solar Panel?

The average lifespan of a solar panel is 25-30 years, which is the industry-standard warranty length provided by solar panel manufacturers. The warranty guarantees solar panel energy output of at least 80% of its stated output after this lifespan period.

Solar panels experience a natural performance drop over their lifespan. This averages 0.5-0.8 percent annual output decline, according to a 2012 study by Dirk C. Jordan and Sarah R. Kurtz at the US National Renewable Energy Laboratory (NREL) on "Photovoltaic Degradation Rates — An Analytical Review," published in the journal Progress in Photovoltaics: Research and Applications.

Six main factors determine a solar panel’s lifespan. These factors include location, quantity of sunlight, the amount of sunlight (solar irradiation) received in the panel installation area, the solar panel system type and materials utilized in its production, how often the panel is used, and whether the solar panel was installed correctly. The question of how long solar panels last depends largely on these six factors. Another factor is the manufacturer of the panels and their overall manufacturing quality.

Solar panels are used to generate electricity for powering homes, schools, farms, factories, and vehicles, including motorcycles. The best indicators for determining solar panel lifespan are the panel performance and the product warranty length that solar manufacturers include with their photovoltaic (PV) panels. The standard performance warranty offered by top-tier solar manufacturers such as REC, Hanwha Q-Cells, and Sunpower promises 25 years of energy production at 80% or higher of the peak output.

How to Increase the Lifespan of a Solar Panel?

Solar panels are expected to last for 20-30 years and more. To increase the lifespan of solar panels, conduct a routine check on your solar panels to identify issues hindering their performance, keep your solar panels away from debris, shading, and other harmful materials to prevent damage, and routinely clean your solar panels to eliminate dust and dirt, constantly check the temperature of your solar panels to avoid overheating. Other key ways to ensure your solar panels last include fixing any noticeable damage on your solar panel immediately to avoid further degradation, studying the terms and conditions contained in the warranty, and ensuring proper installation of your solar panels.

Three of the best ways to increase solar panel lifespan include conducting routine checks on your solar panels, keeping solar panels away from debris and shading, and ensuring proper installation. As a key maintenance procedure, routine checks ensure that your solar panels are working efficiently and effectively, which ultimately aids an increase in the lifespan of your panels. If any major issues are identified as a result of routine checks, understanding how to repair a solar panel is crucial for extending a module's lifespan. Solar panel repairs can extend a solar panel's lifespan by avoiding removing and replacing a damaged panel.

Keeping your solar panels away from debris, shading, and other harmful materials is important to help to prevent significant damage. Ensuring proper installation of your solar panels is another important way to increase the lifespan of your PV panels. From mounting to configuring the panels, orientation, and alignment, you must ensure that your solar panels are correctly installed. Proper installation enhances the structure's integrity, preventing it from being affected by external stressors such as high wind, temperatures, and snow loads.

Should you Call an Expert to examine your old Solar Panel?

Yes, it’s a good idea to call a solar installer if you are the owner of an old solar panel. Like all technology, solar panels encounter problems that degrade performance or even pose safety risks. Whilst some problems, such as inefficiency caused by dirt buildup, are able to be handled by homeowners, others require the services of a certified repair technician. Common issues that create that require solar repairs include rusty connectors, micro-cracks, and hot spots, Potential-Induced Degradation (PID), loose wiring and connections, and inner and external solar module damages. 

A standard solar panel service costs between $150-$400, depending on the size of the solar system, but additional costs sometimes occur if repairs are required. Most solar panels have a warrantied lifespan of 25–30 years, which means that they’ll need five to six services during the main period of use. This means that solar maintenance is likely to cost about $2,000 over the lifetime of your system if done every five years.

Calling an expert to examine your old solar panels gives you peace of mind regarding their efficient and safe use. Professional solar technicians and installers know how to repair a solar panel and minimize electrical fire risks from badly fitted or improperly wired panels, which carry a risk of causing property damage or even loss of life as a result of electrical hazards or fire.

Should You Clean Solar Panels?

Yes, cleaning solar panels once or twice each year is important for the proper maintenance of your system. While regular rainfall is sometimes enough to keep solar panels free from dust and debris, cleaning a solar panel every 6-12 months is recommended for totally eliminating dust and dirt build-up that occurs over time, hindering solar panel efficiency.

Solar panels are typically located outside on rooftops, making them susceptible to dust and debris. In addition, vermin, bird droppings, seepage of water and moisture, hail, wind, and sunlight are all potential causes of damage or deterioration to your system. Solar panel cleaning or maintenance is typically required about one to two times per year. Professional cleaning is recommended when the panels are unreachable from the ground or when soil levels obscure the panel face.

Neglecting to clean panels impacted by soiling results in efficiency losses averaging 0.051% per day, according to a 2013 study by Felipe A.Mejia and Jan Kleissl from the University of California on “Soiling Losses for Solar Photovoltaic Systems in California” published in the journal Solar Energy. Regularly cleaning a solar panel gives it the best chance to operate at maximum efficiency.

How is the Efficiency of a Solar Panel Tested?

A solar panel's efficiency is primarily tested using Standard Test Conditions (STC), which are a set of standardized conditions used in the solar industry for evaluating and comparing the performance and efficiency of solar panels. The other four methods for testing solar panel efficiency are Normal Operating Cell Temperature (NOCT), Low Irradiance Conditions (LIC), High-Temperature (HTC), and Low-Temperature (LTC). There is an additional PV-USA Test Condition (PTC) unique to the United States.

The parameters of Standard Test Conditions (STC) include a solar irradiation of approximately 1000 W/m2, a module temperature of 77 degrees Fahrenheit, and an air mass (AM) of 1.5.

The main advantage of testing solar panel efficiency under Standard Test Conditions is that it creates uniform test conditions, allowing for consistent comparisons of PV modules by different manufacturers. STC measures variable conditions such as solar cell temperature, irradiance, and air mass for solar panel owners to benchmark against their unit’s efficiency ratings. The main disadvantage of STC is that these laboratory-based measurements are different from the realistic conditions solar panels endure on rooftops or mounting frames. However, most manufacturers apply Standard Test Conditions when communicating product data to consumers.

In addition to Standard Test Conditions (STC), several other testing methods are employed to evaluate solar panel efficiency. Normal Operating Cell Temperature (NOCT) replicates real-world conditions, including criteria such as 800 W/m² irradiance and 68°F air temperature, aiming to calculate wattage on an average day. Low Irradiance Conditions (LIC) assess performance at higher latitudes and during winter, while High-Temperature Conditions (HTC) and Low-Temperature Conditions (LTC) examine output at elevated and lower temperatures, respectively. The PV-USA Test Condition (PTC), exclusive to the United States, strives to measure actual performance under real-world conditions.

While these methods provide valuable insights into solar panel performance, it's essential to note that STC and PTC often yield higher wattage values than real-world scenarios due to their controlled environments and standard temperature references. Therefore, users should consider these factors when evaluating solar panel efficiency.

What is the Watt Range of a Solar Panel?

The watt range of a solar panel typically falls between 250 to 400 watts per hour when exposed to direct sunlight. This range is influenced by various factors, including solar panel efficiency, the number of solar cells, and environmental conditions.

Solar panel efficiency is a crucial factor when it comes to watt range. Most silicon-based solar cells convert roughly 20 percent of their sunlight into usable solar energy. This efficiency level leads to some panels generating in excess of 400 watts of power. Higher efficiency panels such as monocrystalline generate 5 – 7% more power than polycrystalline or thin-film cells. Their pure silicon crystal strain boasts higher semiconductivity than the other types, resulting in higher energy conversion rates.

The number of solar cells impacts the watt range of PV modules as well. PV modules tend to be made up of either 60 or 72 cells. A 60-cell panel is typically smaller, with an output of 270 to 300 watts, making it suitable for residential installations. In contrast, 72-cell solar panels, larger due to an extra row of cells, typically range from 350 to 400 watts and are preferred for commercial settings.

Environmental conditions like shading, panel orientation, and hours of direct sunlight directly impact a solar panel's watt range. More information on each of these conditions is given below.

• Shading: Shading caused by obstructions blocking sunlight sometimes leads to a significant reduction in panel output, with studies showing up to a 30-40% drop with 20-30% shading. Optimized panel orientation has the potential to result in 7-8% greater efficiency gains. Additionally, more hours of direct sunlight increase a panel's watt range, with a minimum of four hours typically required for effective performance. Cloudy days reduce gains by up to 50%.
• Orientation: Solar panel orientation is the tilt angle at which horizontal panels face the sun. It varies between 20 – 60 degrees, depending on the season. Optimized solar panels experience 7–8% greater efficiency gains than non-optimized panels, according to a 2020 analysis by M.K. Sharma et al. at Panjab University, India on “Optimal Tilt Angle Determination for PV Panels Using Real-Time Data Acquisition,” published in the August 2020 edition of Global Challenges.
• Direct Sunlight: The hours of direct sunlight are the amount of time per day (or year) the panels receive direct sunlight. The watt range of a solar panel increases the more hours of direct sunlight the panels experience, with four hours being the minimum. Solar panels absorb solar energy during cloudy weather, but with up to 50% reduced gains compared to sunny days, based on 2009 research by Nelson A. Kelly and Thomas L. Gibson at General Motors R&D Center on “Increasing the Solar Photovoltaic Energy Capture on Sunny and Cloudy Days,” published in the January 2011 edition of Solar Energy.

How does the Area of a Module affect the Solar Panel Efficiency?

The area of a module affects solar panel efficiency by directly impacting how much sunlight it is able to capture. In general, the larger the surface area of your solar panels, the greater the efficiency and output of the photovoltaic (PV) system. An area of about 215 square feet to 380 square feet is required for a 5KW solar panel system, one of the most common sizes in the world.

The formula for the Area of a Module is defined as Length x Width. The resulting area is usually measured in square feet (ft²) and quantifies the extent of the panel's surface available for capturing sunlight and directly affects its efficiency in generating electricity. For home solar panels, the typical size is around 66x40 inches per panel, with the frame measuring approximately 1.25x1.6 inches. The average weight of each panel is roughly 42 pounds.

Given that solar PV systems consist of multiple interconnected panels, the cumulative area of all panels is what truly matters for system efficiency. In any residential solar PV system, around 14-21 panels are required for enough sunlight to be captured.

To calculate the roof area needed for your PV system, multiply the area of each solar panel by the number of panels, factoring in a gap of about 4-7 inches between each panel. For instance, with 15 panels (each around 18.3 square feet) and a 4-inch spacing between them, you'd require about 296 square feet of roof space for a 5KW system.

The specific roof space needed depends on the size and number of solar panels used, with larger systems typically requiring more space for optimal efficiency. Below are the average area sizes for various standard PV system sizes in square feet.

• 5KW: 269-377 square feet
• 6KW: 301-463 square feet
• 6.6KW: 334-463 square feet
• 10KW: 538-861 square feet

Why is the Current Curve compared to the Voltage Curve for Electrical Performance of a Solar Panel?

Comparing the Current Curve of a solar panel to its Voltage Curve is a common way to determine its electrical performance, typically illustrated as a graph. The Current-Voltage (I-V) Curve of a solar panel is essential because it measures the relationship between current and voltage, providing critical insights into the panel's behavior under different conditions.

Specifically, a current-voltage curve measures the current versus voltage from a photovoltaic module as the electrical load increases from the short-circuit (no load) state to the open-circuit (maximum voltage) state. This curve is crucial for assessing the panel's overall electrical performance, helping to determine factors like its efficiency, the location of the Maximum Power Point (MPP), and how well it converts sunlight into electricity.

The formula to calculate a photovoltaic system’s electrical performance is E = A * r * H * PR.

E = Energy (kWh)

A = Total solar panel area (m²)

r = solar panel efficiency (%)

H = Annual average solar radiation on tilted panels (excluding shading)

PR = Performance ratio coefficient for losses (ranging between 0.5 and 0.9, with a default value of 0.75).

Estimating the electrical performance of a solar panel using this formula helps to identify significant energy losses, such as inverter losses, temperature losses, and shading losses.

What are the Electrical Parameters of Photovoltaic Modules?

A photovoltaic (PV) module, or solar panel, is a group of connected solar cells that produce electricity from sunlight. In the solar industry, electrical parameters are measurements used to assess the efficiency and performance of the module. Electrical parameters measure key aspects of solar module performance, like their peak power output, voltage and current levels, and efficiency. These measurements are taken under Standard Test Conditions (STC), which include a temperature of 25°C (77°F), an irradiance level of 1000 W/m^2, and an air mass (AM) of 1.5.

The six main electrical parameters for measuring solar panel performance are Maximum Power Point (MPP), Open-Circuit Voltage (VOC), Short-Circuit Current (ISC), Voltage at Maximum Power Point (VM), Current at Maximum Power Point (IM), and Efficiency. A brief summary of these parameters is given below.

• Maximum Power Point (MPP): The maximum power point (MPP) is the point on the solar cell's current-voltage response curve that generates maximum electrical power output, calculated by multiplying current (I) times voltage (V).
• Open Circuit Voltage (VOC): The open circuit voltage (Voc) is the maximum voltage available from a solar cell when the circuit is open and no external load is connected.
• Short Circuit Current (I_SC): The short circuit current (I_SC) is the maximum current that flows from a solar cell when the voltage across the cell is zero
• Voltage at Maximum Power Point (VM): The voltage at maximum power point (VMPP) is the output voltage from the solar cell corresponding to the peak power point along the IV curve.
• Current at Maximum Power Point (Impp)): The current at the maximum power point (Impp) is the current (amps) generated by the solar cell at the voltage value corresponding to peak power output on the IV curve.
• Efficiency (%): Solar efficiency reflects the proportion of solar energy effectively converted into usable electrical energy. Efficiency is the most commonly referred to as solar cell parameter.

Manufacturers use these parameters to design solar panels, aiming to accurately represent their performance and allow consumers to compare competing solutions on the market.

What is a Photovoltaic Cell for a Solar Panel?

A photovoltaic (PV) cell, or solar cell, is a device that converts light to electricity via the photovoltaic effect. PV cells are the smallest component of a solar panel and consist of a semiconductor material (usually silicon) that produces an electric current when exposed to light. A solar panel is usually made up of about 60-72 interconnected cells.

90-95% of solar cells on the market today are silicon-based. Silicon is the solar industry standard for photovoltaic (PV) cells because of its reliability, efficiency, and durability as a semiconductor material. The most common residential solar cells, monocrystalline and polycrystalline, both use crystalline silicon as a semiconductor. Some thin-film solar cells, such as amorphous silicon (a-Si) cells, are silicon-based as well. Other thin-film cells use alternative materials, such as Cadmium Telluride (CdTe) and Copper Indium Gallium Selenide (CIGS). There are more than 24 other solar cell types, which have a range of applications such as spacecraft (Multi-junction solar cell), solar-water splitting (Photoelectrochemical cell), and use in remote locations like Antarctica (Copper Zinc Tin Sulfide cell).

One of the main differences between the three main PV cell types (monocrystalline, polycrystalline, thin-film) lies in their silicon crystal purity. Monocrystalline cells comprise single crystalline silicon and are the most efficient (15-25%) of the main cell types. Polycrystalline cells, which use multiple melted silicon fragments, are less efficient (13-17%) but cheaper than monocrystalline cells but cost less. Thin-film cells are the least efficient of the three main PV cell types but are the cheapest. PERC (Passivated Emitter and Rear Contact) is an additional PV cell type that uses additional layers on the rear side of the cell. This extra layer improves the efficiency of the cells by reflecting unabsorbed light back into the silicon layer, allowing for greater energy capture.

Some of the less common solar cell types, like Concentrator Photovoltaics (CPV), present distinct advantages in contrast to the standard solar cell models. For example, CPV has an efficiency of 30-40%, almost double that of commercially-available solar panels. However, the downside is that these advanced solar cells are often much more complex to produce and therefore more expensive.

What is a Multi-junction Solar Cell?

A multi-junction solar cell is a solar cell with multiple positive and negative (p-n) junctions. These junctions are designed to enhance the efficiency of the solar cell by allowing it to absorb different wavelengths of incoming sunlight through the use of different layers.

Multi-junction solar cells use three separate semiconductor materials, including gallium indium phosphide (GaInP), indium gallium arsenide (InGaAs), and germanium (Ge). This gives them superior efficiency compared to more conventional (single-junction) solar cells like Monocrystalline and Polycrystalline. Utilizing three semiconductor materials instead of one boosts solar panel electrical generation by 28.9%, according to a 2007 study by M. Yamaguchi et al. at the Toyota Technological Institute on “Novel Materials for High-efficiency III–V Multi-junction Solar Cells,” published in the February 2008 edition of Solar Energy.

Multi-junction cells are by far the most efficient solar cell type. In fact, a team of researchers at the National Renewable Energy Laboratory (NREL) (Colorado, USA) achieved a world record for solar cell efficiency of 47.1% using multi-junction solar cells, under a concentrated illumination equivalent to 143 suns, according to the paper “Six-junction III-V solar cells with 47.1% conversion efficiency under 143 suns concentration” in the April 2020 edition of Nature Energy co-authored by John Geisz, principal scientist in the High-Efficiency Crystalline Photovoltaics Group.

What is a Third Generation Solar Cell?

A third-generation solar cell refers to a type of photovoltaic (PV) cell that holds the potential to surpass the efficiency limitations of previous generations. The aim of third-generation cells, like Perovskite and dye-sensitized solar cells, is to provide high-power conversion while maintaining cost-effectiveness.

Third-generation solar cells are sometimes referred to as "emerging solar modules'', as they’re experimental, still being developed and researched, and are not yet commonly found on the market. Third-generation cells offer promising advancements in efficiency and are touted to exceed the theoretical 33.7% limit for single-cell solar efficiency, known as the Shockley-Queisser limit. 

Examples of third-generation solar technologies include perovskite solar cells, organic photovoltaics, dye-sensitized solar cells (DSSCs), quantum dot-sensitized solar cells (QDSSCs), multi-junction photovoltaic (PV) cells, tandem cells, and nanostructured cells. Each of these cell types varies in terms of efficiency, cost, and application. Many third-generation solar cells cater to applications in specialized industries and environments such as solar vehicles, aerospace, and wearable technologies.

Many of the third-generation solar cells, like the perovskite solar cell, have gained significant attention due to their innovative approaches. Perovskite solar cells stand out for their unique crystal structure and use of graphene as an electrode, offering high transparency, conductivity, and the potential for cost-effective production compared to traditional PV technologies. Their semi-transparent nature allows them to absorb sunlight from both sides, making them ideal for integration into various applications, including windows, facades, and rooftops, thereby increasing energy absorption surface area. 

Recent research, such as the 2020 MIT study on multilayer chemical vapor deposition graphene and the 2014 study by Y. Zhao et al. on solid-state mesostructured perovskite, has demonstrated advancements that could lead to improved solar panel efficiency, higher energy yields, and the possibility of mass production methods like printing or roll-to-roll process. This has the potential to reduce panel costs and foster broader adoption in the renewable energy sector.

What are the Efficiency Factors of Solar Panels?

Solar panel efficiency is affected by factors such as the wavelengths of light solar panels receive, the type of solar panel used, the tilt and orientation of the panels, and the inverter efficiency. Expressed as a percentage (%), solar efficiency quantifies the amount of sunlight that can be transformed into usable electrical power by the panel under controlled laboratory conditions (Standard Test Conditions).

The efficiency of solar panels is significantly impacted by the wavelengths of light they receive. Red light, which falls within the visible spectrum, has the greatest influence on the performance of solar photovoltaic modules compared to other colors, according to a research paper entitled “Investigating the Wavelength of Light and Its Effects on the Performance of a Solar Photovoltaic Module, by researchers Ogherohwo, Barnabas and Alafiatayo from the International Journal of Innovative Research in Computer Science & Technology.

There are other key factors that influence solar panel efficiency in a more practical sense. These factors include the type of solar panel used, the tilt and orientation of the panel, the inverter efficiency, and the sunshine hours received in the location. By considering the importance of solar panel efficiency, homeowners and businesses are able to ensure they get optimal performance from their PV systems.

How do Aluminum Nanocylinders help the Efficiency of Solar Panels?

An aluminum nanocylinder is a nano-sized cylinder comprised of aluminum that improves efficiency in solar panels by increasing absorption layer permeability. These nano-sized cylinders (or studs) form an array on top of the solar cell's absorbing layer in the solar panel.

In the context of solar cells, the absorbing layer represents a significant portion of manufacturing costs. This layer is where incoming photons interact with the atoms in the structure, causing the release of electrons, which generate an electric current, ultimately producing electricity in the solar panel. Aluminum studs improve the chance of light hitting this absorption layer. Whilst still an experimental technology, the use of aluminum nanocylinders in the top layer of solar cells has the potential to boost efficiency by 22%, according to researchers at Imperial College London in a 2013 study.

Aluminum offers a number of potential benefits for solar technology, including cost-effectiveness and abundance compared to materials like gold or silver. It excels at reflecting and scattering light, enhancing photon travel through the absorption layer of solar cells. Its exceptionally low density (2.7 g/cm³) reduces panel weight, and it provides twice the electrical conductivity of copper. Aluminum's thermal conductivity is beneficial, with applications in heat dissipation. In solar cells, an array of nanocylinders is typically depicted in diagrams, and aluminum is readily available in minerals like bauxite and cryolite. Ongoing research explores aluminum's potential in solar panels, offering a lightweight, flexible, corrosion-resistant, conductive, and recyclable alternative to gold, silver, or copper, which could lead to more cost-effective, efficient, and lighter solar cells as manufacturers seek to reduce costs while maintaining high efficiency.

Which materials are used in Solar Panels?

The most commonly used material in solar panels is silicon, which is found in 90-95% of solar panels currently found on the market. Silicon comes in two main types: monocrystalline and polycrystalline. Monocrystalline panels are made from single-crystal silicon, while polycrystalline panels are made from multiple silicon crystals. Beyond silicon, a variety of materials contribute to the construction and efficiency of solar panels.

Below is a list of ten materials commonly used in solar panels:

• Monocrystalline Silicon: Monocrystalline silicon, with its single-crystal structure, results in higher efficiency panels compared to other materials. These panels convert a greater percentage of sunlight into electricity, making them a popular choice for applications with limited space.
• Polycrystalline Silicon: Polycrystalline silicon panels are slightly less efficient than monocrystalline panels. They require more surface area to generate the same amount of electricity and are cost-effective.
• Amorphous Silicon (a-Si): Amorphous silicon, often used in thin-film panels, has lower efficiency compared to crystalline silicon panels. They are flexible and lightweight, suitable for installations where space and weight are considerations.
• Cadmium Telluride (CdTe): CdTe thin-film panels offer good efficiency and cost-effectiveness. They do not achieve the same efficiency as monocrystalline silicon but provide a competitive alternative.
• Copper Indium Gallium Selenide (CIGS): CIGS thin-film panels have variable efficiency depending on the specific composition and manufacturing process. They are known for their flexibility and achieve moderate to high-efficiency levels.
• Ethylene-Vinyl Acetate (EVA): EVA encapsulation layers are crucial for protecting the solar cells and maintaining efficiency over the panel's lifespan.
• Thermoplastic Polyurethane (TPU): TPU encapsulation layers contribute to panel durability and longevity, supporting overall efficiency.
• Polyester: Polyester used in the back sheet does not directly influence efficiency but is essential for protecting the panel's rear side from environmental factors.
• Fluoropolymer: Fluoropolymer back sheet materials contribute to panel durability and longevity without a direct impact on efficiency.
• Aluminum: Aluminum frames provide structural support and ensure the panels remain in optimal orientation for sunlight capture, indirectly supporting overall efficiency.

Why is Multicrystalline silicon used in Solar Panels?

Multicrystalline is used in solar panels to produce cost-effective, reliable solar modules for commercial and utility-scale solar energy projects. Multicrystalline (Polycrystalline) panels feature fragments of silicon melted together to form solar panel wafers. This process produces a square shape and shiny blue hue. Unlike monocrystalline panels, multi-crystalline solar panels do not require a single silicon crystal but rather melt down multiple silicon fragments.

Using multicrystalline solar cells in solar panel technology has two main advantages for the manufacturer and user, which are outlined below.

• Lowers production costs. Multicrystalline solar panels do not employ the expensive Czochralski method used in making monocrystalline panels. The Czochralski method is a time-consuming and costly process used to grow single crystals, used to create solar cells of very high efficiency. Multicrystalline panels avoid this method by melting silicon fragments together, which is a less costly process but does slightly impact efficiency due to the impurities which result in the cell structure. Multicrystalline panels are typically 13-16% efficient compared to monocrystalline at 20-24%.
• Benefits the environment. Some manufacturers, such as Mitsubishi Electric, have developed innovative technologies that eliminate costly soldering processes in their multicrystalline panels. These soldering processes often contain lead, and their removal contributes to environmental protection.

Using multicrystalline cells in solar panel technology has four main disadvantages, which are listed below.

• Reduces efficiency. Multicrystalline panels typically have lower efficiency ratings, ranging from 13% to 16%, which is below the 20-24% efficiency threshold commonly seen in monocrystalline panels. This lower efficiency is primarily due to how electrons move within the solar cell. Multicrystalline cells, with multiple silicon grains, impede the movement of electrons, reducing overall panel efficiency.
• Limits rooftop space. Since multicrystalline solar panels are less efficient, they require more panels to achieve the same power output as monocrystalline panels. This is a possible limitation for urban homeowners with limited rooftop space.
• Decreases panel heat tolerance. Multicrystalline panels generally have lower heat tolerance compared to monocrystalline panels, which impacts their performance in high-temperature environments and sometimes leads to a shorter lifespan.
• Limits aesthetic appeal. The manufacturing process of multi-crystalline panels results in cells with a distinctive blue, marbled appearance. Each panel looks significantly different from its neighbors, which is not always visually appealing to some homeowners.

Why is Monocrystalline silicon used in Solar Panels?

Monocrystalline silicon is used in solar panels as a photovoltaic (PV) material to produce high-quality, efficient solar modules. Monocrystalline panels have a uniform black color since the single crystal structure is created from high-grade silicon. They are currently the most popular solar modules on the market, occupying over 90% of the solar panel market.

The five advantages of using monocrystalline silicon in solar panel manufacturing are shown below.

• High-efficiency levels. Monocrystalline solar cells have fewer imperfections due to their pure composition. This arrangement makes them more efficient at converting sunlight into electrical energy.
• Suitable for smaller rooftops. Each cell in a monocrystalline panel is almost equivalent to an entire multicrystalline panel. As such, they require less space while guaranteeing the same output level.
• Better performance. Monocrystalline cells perform better under high temperatures and adverse weather conditions. The large gaps in a single-crystal design mean they release heat more easily than multi-crystal cells, which require more cooling.
• High silicon purity. Silicon quality varies, with the highest grade being monocrystalline. Hence, the highest quality of silicon is used to construct monocrystalline solar cells.
• Longer lifespan. Monocrystalline solar cells are less likely to break due to their sturdier construction from larger amounts of silicon. They require less protection from the elements, making them easier to maintain while providing greater longevity.

As a solar cell type, monocrystalline has almost no disadvantages besides cost. This is why monocrystalline solar panels are less popular than multicrystalline solar panels for large-scale commercial projects. They are more expensive to produce, with the manufacturer passing on this increased price to consumers.

Which material for Solar Panels is more popular, Multicrystalline or Monocrystalline?

Monocrystalline and Multicrystalline (Polycrystalline) Solar Panels are both popular solar panel types for both residential and commercial installations. However, monocrystalline is more popular than multicrystalline for solar panels due to their aesthetic appearance and high efficiency, despite the fact they are more costly.

Below is a side-by-side comparison of monocrystalline and polycrystalline solar panels based on aesthetics, efficiency, and cost.

• Aesthetics: Multicrystalline solar panels feature a blue hue, while monocrystalline panels have a near-black aesthetic. Both monocrystalline and polycrystalline panels are fashioned from crystalline silicon, but many consumers prefer the uniform color of monocrystalline panels for their rooftop, as it blends in with black rooftop shingles more easily. This aesthetic appeal contributes to their popularity.
• Efficiency: Panels using monocrystalline cells usually outperform and outlast panels using polycrystalline cells when it comes to efficiency due to lower rates of light-induced degradation (LID), a process that degrades cell performance over time. Monocrystalline panels are more efficient than multi-crystalline panels, offering an efficiency rate of 15-30% compared to polycrystalline, which have lower efficiency rates of 13%–17%. This key difference in performance efficiency makes multicrystalline panels more popular amongst solar installers as well, who are more likely to recommend them to consumers for this reason.
• Cost: Monocrystalline solar panels are generally more expensive than multicrystalline ones and yet are the more popular choice amongst consumers. As manufacturing processes and solar panel technology continue to improve, the price differences between monocrystalline and polycrystalline panels have decreased. Monocrystalline solar panels now sell for just about $0.05 per watt higher than polycrystalline modules, according to a 2019 report by G. Barbose et al. at the Lawrence Berkeley National Laboratory, called “Tracking the Sun: Pricing and Design Trends for Distributed Photovoltaic Systems in the United States-2019 edition. The fact that monocrystalline is more widely adopted than multicrystalline despite being more expensive is a testament to its popularity as a solar panel type.

The market for monocrystalline panel variants is expected to grow tenfold over the next decade, according to a September 2019 outlook by Wood Mackenzie Power & Renewables, entitled “Bifacial market to grow tenfold by 2024,” published on its main website. This puts the multicrystalline vs monocrystalline debate in favor of monocrystalline panels.

Why is Thin-Film used in Solar Panels?

Thin film is used in solar panels as a photovoltaic (PV) material to generate sunlight. A thin-film solar cell comprises thin films of semiconductors layered on glass, plastic, or metal. These have light-absorbing layers up to 300 times smaller than a traditional silicon solar panel, making thin-film solar cells the most flexible and lightweight solar modules on the market.

Thin-film solar panels have four advantages over traditional solar panels, each of which is outlined below.

• Lightweight: The panels sandwich themselves between glass without a frame, leading to a lightweight design.
• Affordable cost: Thin-film panels cost less than traditional solar panels because they are easier to install and require less equipment.
• Environmentally friendly: These solar cells have a reduced environmental impact as a result of using less silicon.
• Easy installation: Installation costs are generally lower due to straightforward installation and reduced labor costs.

Thin-film solar cells have four major disadvantages for manufacturers and users, as below.

• Toxic material: One thin-film cell substrate includes cadmium telluride (CdTe). CdTe contains a large amount of Cadmium, a toxic element that negatively impacts the environment.
• Lower efficiency: They are more inefficient than traditional solar cells for residential use. Traditional PVs range between 13-19 percent efficiency, and thin-film panels average between 4-12 percent efficiency.
• High space requirements: Up to 50 percent more installation space is required for thin-film solar panels, depending on solar project size.
• Panel degradation: Thin-film cells degrade much faster than other panel types. Installers must replace them more often, leading to increased long-term recurring costs.

What is a Flexible Thin Film Cell?

A flexible thin-film cell is a solar cell constructed from ultra-thin silicon wafers that convert sunlight into electricity via the photovoltaic effect. The photovoltaic effect is the phenomenon by which solar cells are able to produce direct current (DC) electricity when exposed to sunlight.

Flexible thin-film solar cells in solar panels offer three key advantages. Firstly, they exhibit versatility by being capable of physically bending and adapting to various surfaces and installation types. These cells are able to be easily installed on building facades and seamlessly integrated into textiles, such as outdoor fashion items and backpacks. 

Secondly, the design of flexible thin-film solar cells differs from traditional solar panels in that they are lightweight and aesthetic, which makes them ideal for applications requiring a level of aesthetic appeal. Lastly, the flexibility of flexible thin-film cells enables easy movement, storage, and reinstallation due to their lightweight nature, setting them apart from heavier traditional solar panels like polycrystalline. 

Flexible thin-film solar cells come with three primary disadvantages. Firstly, they tend to have lower efficiency compared to traditional solar panels. However, ongoing research and development in organic cell technology offers potential prospects for improved efficiency over time. Secondly, flexible thin-film cells have a shorter lifespan, as they are more susceptible to long-term environmental impacts, necessitating more frequent replacements and maintenance. Lastly, due to their thin layers, flexible solar panels require a larger surface area to generate the same amount of energy as their traditional counterparts, making them less suitable for installations with limited space or where space is at a premium.

Why is Laminating used for Thin-film Material in Solar Panels?

Laminating is used in thin-film solar panels to reduce weather-induced degradation in solar cells. Laminating pumps air out of the solar panel layers in a vacuum chamber, heating the layers to melt the encapsulant and pressing them with a flexible diaphragm to embed the solar cells in the encapsulant between the front and back sheets.

Laminating as part of the solar encapsulation process places two layers of ethylene-vinyl acetate (EVA) in a laminating machine to seal the solar cells. 

The solar cell circuits float between the EVA and non-ethylene vinyl acetates, softening the effects of any external shocks or vibrations. This makes thin-film PV solar laminates lightweight and easy to install, and by using a novel peel-and-stick method, they can be easily attached to standing seam panels.

EVA solar encapsulation has grown in recent years due to its excellent defense against corrosion and delamination. The EVA solar encapsulation materials industry is expected to grow at a CAGR (Compound annual growth rate) of 8% to 9% during 2022-2032, according to a 2022 market research report by the Future Market Insights firm on the “Solar Encapsulation Materials Market.”

Lamination protects the solar cells for at least 25 years, reducing the need for warranty claims and interruptions to solar system output. Encapsulated solar cells help improve solar module efficiency and durability due to their excellent barrier protection against humidity and UV radiations, according to R. Steim et al. in their 2015 study, “Laminated Fabric as Top Electrode for Organic Photovoltaics,” published in the May 2015 edition of Applied Physics Letters.

Why is Cadmium Telluride used in Solar Panels?

Cadmium telluride (CdTe) is used as a manufacturing substrate for thin-film solar panels. It is the most popular variant of thin-film solar technology, comprising 50 percent of the market share of all thin-film substrates. Cadmium Telluride modules have one main energy-producing layer from the cadmium telluride compound and surrounding layers for electricity conduction and absorption.

Cadmium telluride thin-film solar technology was introduced to the world in 1972 by D. Bonnet and H. Rabenhorst with an initial 6% efficiency rating. This technology currently has 5.1% of the global market share, second only to crystalline silicon solar panels’ 90.9% of the market. Cadmium telluride (CdTe) is a common substrate in thin-film solar panels, offering two primary advantages in solar applications. 

Firstly, CdTe panels boast a high-efficiency rate, surpassing traditional silicon panels by capturing shorter wavelengths of sunlight, with individual cell efficiencies reaching up to 22.1%, as demonstrated in a 2021 study by A. Romeo and E. Artegiani at the University of Verona.

Secondly, they have low production costs, thanks to a simplified manufacturing process and reduced material requirements, making them particularly suitable for large-scale solar projects. Nevertheless, there are two notable disadvantages associated with CdTe panels. First, cadmium telluride has toxic properties, according to G. Genchi et al. in their 2020 study, “The Effects of Cadmium Toxicity,” published in the January 2020 edition of the International Journal of Environmental Research and Public Health.

Why is Copper Indium Gallium Selenide used in Solar Panels?

Copper indium gallium selenide (CIGS) is used in solar panels as a semiconductor material in the absorption layer of flexible thin-film module substrates. This technology is common in utility-scale installations, Building-Integrated Photovoltaics (BIPV), PV rooftops, and flexible thin-film solar panels.

Copper indium gallium selenide solar cells are designed by depositing a thin layer of copper, indium, gallium, and selenide on a glass or plastic backing. Electrodes are placed on the front and back to amass current. CIGS cells have a much thinner film than other semiconductor materials like crystalline silicon cells. As a result, they have a high absorption coefficient and absorb sunlight easily. These copper indium gallium selenide solar panels first entered the market in Germany in 2011 and have since become available in the United States and China, with a real-world efficiency rating of 10-12 percent.

Copper indium gallium selenide (CIGS) solar cells offer several advantages for solar energy production, including affordable installation due to their versatility in integration, high efficiency in sunlight absorption, and long-term stability without degradation. However, CIGS cells have drawbacks as well, including moderate environmental and health concerns compared to some alternatives like CdTe modules and a need for more space in installations, making them better suited for industrial rather than residential applications.

How to Buy a Solar Panel?

To buy a solar panel, it’s important to follow a few simple steps to ensure a smooth process and satisfaction over the long lifespan of your PV system. Solar panels are purchased singularly or in a comprehensive system. In the United States, it is common to buy solar panels as part of a solar system that includes an inverter and installation.

Begin by calculating your energy needs, which involves determining your average monthly energy consumption using a Solar Panel Cost Calculator and your monthly energy bills. This step ensures you select the right-sized solar panel system for your requirements.

Next, embark on thorough online research to explore various solar panel options available in the market, including different brands, types, and models. Compare and contrast solar panel installers in order to find the most reputable and experienced professionals in your area. Look for customer reviews and testimonials to gauge their reliability and quality of service. This ensures that you’ve done the right research on how to buy a solar panel for your residential or commercial needs.

After narrowing down your choices, reach out to multiple solar panel installers for quotes and consultations. During these consultations, ask detailed questions about their installation process, warranties, and any potential maintenance requirements. This will help you make an informed decision and ensure you choose a reliable installer.

When making your selection, prioritize quality by investing in the highest quality solar panels that fit your budget. Quality panels tend to offer better efficiency, durability, and longevity. Customer reviews are often invaluable in assessing their performance and suitability for your specific location's weather conditions.

Lastly, consider the financing options available for your solar panel installation, such as government incentives and green financing plans. Evaluating the financial aspects helps determine the long-term cost-effectiveness of your solar panel system.

Following these steps is helpful for confidently knowing how to buy a solar panel for your needs, ensuring optimal performance and a strong return on your investment.

What are the Advantages of Solar Panels?

There are seven main advantages of solar panels. Firstly, they are a reliable source of renewable energy, converting sunlight into electricity through photovoltaic (PV) cells. These cells absorb sunlight, generating an electric current.

Secondly, solar panels reduce energy costs by allowing homeowners to save on electricity bills. Factors like panel type, location, and usage influence savings, with a 5kW system saving up to $2000 per year or more. Additionally, solar panels have low maintenance costs, averaging between $150 to $350 annually. Regular maintenance ensures efficiency and longevity.

Despite this, compared to other energy systems, solar panels have relatively low maintenance requirements, making them cost-effective and sustainable. 

Some of the key advantages of a solar panel for homeowners are that it increases home value, facilitates energy savings from tax credits like the Federal Solar Investment Tax Credit (ITC), and provides backup storage for solar systems equipped with batteries. 

Lastly, solar technology is consistently improving thanks to investment, increased research and development, and improvements in manufacturing and scaled production.

Are Solar Panels a good investment?

Yes, solar panels represent a sound financial investment in many countries, including the United States. Although there are initial expenses involved in purchasing and installing a solar panel system, these costs are often recouped within a 5-7 year payback period. This leaves about 20-25 years of the system's lifespan for homeowners to reap substantial savings, which significantly offsets their electricity bills.

In the U.S., the annual savings from a solar panel (PV) system are estimated to be about $600 per kilowatt (kW). Therefore, a 5kW PV system could save homeowners around $3,000 annually. Considering the cost of a 5kW system in the U.S. ranges from $12,000 to $18,000, the return on investment (ROI) over a 25-30 year period is projected to be between $75,000 and $90,000. This makes solar panels an environmentally friendly choice and one that is financially savvy for American homeowners.

However, bear in mind that the exact Return on investment (ROI) for solar panels varies based on factors such as local electricity rates, system size, and available incentives. Many regions offer enticing incentives, with governments actively incentivizing solar panel purchases through the use of incentives, including solar rebates and credits. Lastly, solar panels have the potential to raise the resale value of the homeowner's property, especially as the popularity of solar energy continues to grow.

Do Solar Panels help save money?

Yes, solar panels are a great way to save money for both homeowners and businesses. Typically, consumers have to pay a substantial amount for the energy supplied by the grid, making it one of the largest expenses for many households. Solar panels have the potential to yield annual savings in the thousands of dollars by tapping into a readily available and “free” renewable energy source. While the initial costs include purchasing the solar panels and installation, these expenses are recouped over time through these substantial savings. Once the solar system is paid off, all the savings generated are pure profit.

On average, Americans are able to save around $3000 on their energy bills per year from solar panels, depending on the size of the PV system, household energy consumption, and usage habits. In most cases, the cost of installing a PV system is recouped after less than 7 years. This payback period has reduced over time thanks to advances in technology and government incentives.

The cost savings for solar panel use depends on factors such as the size of the solar system, the amount of sunlight available in your area, the current cost of your electricity bills, the solar rebates available, and the amount of energy you use in your household.

Are there any financial incentives or credits available for Solar Panels?

Yes, there are a number of incentives and credits available for purchasing and installing solar panels. In the United States, incentives and credits for solar panels include the Federal Tax Credit, state-specific tax credits and rebates, utility company rebates, and net metering, which credits excess energy sent to the grid, reducing electricity bills. Incentives are designed to promote the adoption of solar energy and make renewable energy solutions more affordable for households and businesses.

More information on the four main forms of financial incentives or credits for solar panels in the US is listed below.

• Federal Tax Credit: Homeowners receive a tax credit amounting to 30% of their solar installation costs. This credit is set to decrease to 30% in 2033, 22% in 2034, and then drop to a permanent 10% for commercial installations from 2035, with the elimination of the credit for residential installations.
• State Tax Credits: In addition to the federal credit, several states offer their own tax credits for solar power. These credits, which vary by state, are applied against state income tax and range from $500 to $5,000.
• Solar Panel Rebates: Provided by states, utility companies, and manufacturers, these rebates directly reduce the installation cost. They are typically applied at the point of sale and are passed on as savings to the consumer.
• Net Metering: This is a significant benefit for homeowners with solar panels. It allows the electricity generated by the panels to offset the household’s electricity consumption on a one-to-one basis. Excess energy produced and sent to the grid is credited to the homeowner, effectively reducing the electricity bill.

These incentives collectively make solar panel installation more accessible and financially viable for homeowners across the country.

Is there such a thing as Solar Panel Insurance?

No, there isn’t a specific thing called solar panel insurance. Solar panels are usually covered by home insurance in the United States, though this typically involves paying a higher premium.

Insurance companies categorize solar panels as part of the building structure, which means they are included in your home insurance policy. Home insurance typically offers coverage for solar panels in the event of external damage, such as damage caused by severe weather conditions. However, it's important to note that home insurance generally does not cover the risk of electrical faults within the solar panels. Instead, these electrical faults are typically covered by the manufacturer's solar panel warranty as long as the warranty is still valid.

Is it possible to finance Solar Panels?

Yes, it’s possible to finance solar panels to buy solar panels. A number of solar loan types exist which potentially mitigate the expensive upfront cost of installing a photovoltaic (PV) system. There are four popular types of solar loans accessible to homeowners for purchasing solar. These are green loans, no-interest payment plans, personal loans, and power purchase agreements.

More information on the four main solar financing loans is below.

• Green Loan: A Green Loan, sometimes called Green Financing or a Green Lending option, is a type of personal loan used to finance the purchase or installation of clean energy products, including solar products like solar panels, inverters, batteries, and lighting. Whilst the general concept of green loans is that interest is paid as a percentage on the loan, the specific green loan terms for solar vary from lender to lender, with options including secured and unsecured, short-term or long-term, and with fixed or variable interest rates applied. Some major banks offer Green Loans for customers who already have an eligible home loan. This particular variant is sometimes called a Green Home Loan, offering benefits like a fixed low interest rate and minimal fees.
• No Interest Payment Plan: A no interest payment Plan, sometimes called a Zero (0%) Interest Payment Plan (ZIPP), or interest-free payment plan, is a financing option designed for individuals wanting to invest in green energy products, like solar. The benefit of a No Interest Payment Plan is that it allows you to borrow money for solar equipment like panels, batteries, heaters, and inverters, without paying any monthly interest. Instead, borrowers are charged a fixed flat fee in addition to their regular loan repayments. This flat fee covers the borrowing cost and remains constant throughout the loan term, making it easier to know exactly how much you will pay.
• Personal Loan: A personal loan is a standard form of loan that can be applied to the purchase of PV systems and other solar equipment like inverters and batteries. Sometimes referred to as a Personal Loan for Solar when used or marketed for this purpose, Personal Loans are available from a wide variety of financial institutions, from banks to online lenders. The advantage of choosing a Personal Loan when purchasing solar panels is that lenders are more available, and a wider variety when it comes to the financial terms offered.
• Power Purchase Agreements: A Power Purchase Agreement (PPA) is a financial arrangement commonly used in the solar industry. In a PPA, a solar company assumes the role of providing, installing, and maintaining a solar panel system, while the customer, often referred to as the 'off-taker,' agrees to purchase the energy generated by the system at a predetermined price over a fixed term, typically around 10 years. PPAs are becoming increasingly popular among American businesses, offering several key advantages, including potentially lower electricity prices, the ability to meet sustainability targets, access to preferential treatment via buyer groups, price certainty over the long term, and improved environmental reputation.

Are Solar Panels Environmentally Friendly?

Yes, solar panels are environmentally friendly because they do not emit greenhouse gasses or air pollution, unlike traditional energy sources such as coal or gas. Solar panels create electricity from sunlight, which is a clean and renewable energy source. This limits solar’s impact on the environment compared to fossil fuels like coal and gas, which emit greenhouse gasses and air pollutants when used for electricity production. While solar is seen as a positive green energy alternative that reduces dependence on the grid, it's important to note that PV systems do still have some environmental impact due to their manufacturing processes and the waste issues caused by their end-of-life disposal. The renewable energy sector is constantly improving technologies and practices to reduce the environmental impact of solar panels.

Is it possible to Recycle a Solar Panel?

Yes, it’s possible to recycle solar panels, as they are largely made from recyclable materials such as glass, aluminum frames, and silver. However, solar panel recycling is not yet common due to the logistical complexities required and the lack of financial incentives. Since solar panels have a long lifespan, the volume of panels reaching end-of-life for recycling is still relatively low, resulting in limited demand for recycled materials. Additionally, the lack of standardized processes and infrastructure for collecting and recycling panels adds to the logistical challenges.

Firstly, the logistical requirements for recycling, such as separating materials without contamination or loss, are challenging. Since solar panels contain various materials like glass, aluminum, and silicon, each with different recycling processes, ensuring that these materials are effectively separated and processed requires specialized facilities and expertise. The lack of standardized recycling processes adds to the complexity, making it challenging to scale up recycling operations efficiently.

Secondly, there is a lack of financial incentive for individuals and businesses to recycle solar panels, as the effort required is extensive and often not reimbursed. This is partly due to the complex nature of solar panels, which require specialized equipment and processes for dismantling and separating the various components. Without significant advancements in recycling technology and economies of scale, the cost of recycling is likely to remain high compared to the production of new panels.

Despite these challenges, the need to recycle solar panels is a significant focus of the solar industry, particularly as the use of solar panels continues to increase. For example, a typical solar panel takes around 25-30 years to reach "end-of-life." Widespread adoption could lead to a substantial accumulation of discarded panels in landfills, posing environmental concerns.

The growing need to find a way to efficiently and cost-effectively recycle solar panels is a strong focus of the solar industry, especially as the uptake of solar panels continues to climb. Solar panels take around 25-30 years to reach "end-of-life," meaning that the wide uptake of solar panels could result in a substantial accumulation of discarded panels in landfills in coming years, posing a significant environmental concern. Countries like Germany and the Netherlands are great examples of countries currently leading the charge towards better solar panel recycling, a process that requires specialized technology.

How to Calculate the Solar Panel Requirements for Powering a Home?

Calculating the solar energy requirement for your household or business is an important step in purchasing a photovoltaic (PV) system. Follow the steps below to calculate the size of the solar panel system you need. Alternatively, using an accurate solar panel cost calculator can be a convenient way to get an immediate estimate of the cost of solar panels and the potential savings associated with solar panel installation.

Begin by assessing your current energy usage. This is easily achieved by looking at your energy bills for the last year. Obtain your average monthly electricity consumption in kWh (kilowatt-hours) by adding up last year’s usage data and dividing by 12.

Secondly, research the peak sun hours for your location, as this plays an important role in how much solar energy meets your needs. The amount of sunlight varies by region and time of year, affecting how efficiently your panels generate energy. Areas with more sunlight have greater peak sun hours, so it's important to factor this into the equation. Using online tools or irradiance maps is ideal for understanding how much sun is received in a specific location.

Next, consider solar panel output. Solar panels come in various sizes and efficiencies, with output ranging from 110 to 400 watts per panel. The number of panels you need depends on your daily usage requirements and the output of each panel. Higher-efficiency panels generate more electricity from the same amount of sunlight compared to lower-efficiency panels.

Different solar panel types have varying efficiency, which affects their output and cost. Monocrystalline panels are the most efficient of the main solar panel types, but they are more expensive than polycrystalline or thin-film panels. Knowing how many watts a solar panel produces is important in working out your solar panel requirements. To obtain this figure and compare the output of various solar panel types and models, talk to your solar panel installer.

Finally, calculate your system size. Having obtained the relevant usage, sunshine hours, and panel output, the final step is to perform the calculations to understand the size of the PV system required. Using a solar panel calculator is a handy way to do this, or follow our instructions below for working out your required system size:

To calculate your required PV system size, follow the three steps below.

1. Convert your daily kWh usage into watts by multiplying it by 1,000 (1 kWh = 1,000 watts). For example, for a daily usage of 30 kWh, the equivalent in watts is 30,000 watt-hours per day.
2. Divide the watt-hours by your peak sunlight hours to find the total daily wattage needed. For example, if you have 30,000 watt-hours and six hours of peak sunlight, your solar panel system should be able to generate 5,000 watts per day.
3. Lastly, divide the total daily wattage by the wattage per panel in your system. For instance, if each panel generates 250 watts, you would need 20 panels to meet your daily energy requirements. If the panels produce 200 watts each, you would need 25 panels for the same output.

Remember, it's important to plan for future energy needs when sizing your solar system. Factors like working from home, adding electric vehicles, or other appliances inevitably influence your long-term energy requirements. 

How are Solar Panels Manufactured?

To manufacture solar panels, crystalline silicon is sliced into wafer-thin pieces to form solar cells, which are then assembled into panels and secured with a back sheet and front glass, all housed within a sturdy aluminum frame. This comprehensive process is achieved with robotic equipment in highly automated factories.

Firstly, the process begins by building solar silicon cells, which are either p-type (positively charged) or n-type (negatively charged). Secondly, these solar cells are assembled together using solder, with each panel typically consisting of 60 to 72 cells. 

Next, a back sheet is installed to cover the bottoms of the solar cells, providing protection and insulation. The third step of making a solar panel is carefully placing the front glass later over the solar cells to shield them from environmental elements while allowing sunlight to pass through. 

Next, a sturdy metal frame is sealed around the edges to provide structural support and protection to the solar panel assembly. A junction box is installed after that to facilitate electrical connections and monitoring. Lastly, in the seventh step of how solar panels are made, rigorous testing procedures are implemented to ensure the solar panel's functionality and performance meet the required standards.

How Have Manufacturers Decreased the Cost of Solar Panels?

Manufacturers have decreased the overall cost of solar panels primarily by scaling production and increasing solar module efficiency, according to a study by a team at MIT in the Institute for Data, Systems, and Society published in 2018. According to the study, published in Energy Policy, a number of low-level and high-level factors contributed to the decline in solar panel manufacturing cost between 1980 and 2012.

Low-level factors, which directly relate to the manufacturing process, included things like efficiency improvements in solar cells and modules, reduced costs of non-silicon materials, the reduction in the price of silicon, and an increase in the size of manufacturing plants have played a significant role.

High-level factors, which relate to broad influencing mechanisms, included research and development, learning-by-doing, and economies of scale. These factors have allowed solar installers to purchase PV panels from manufacturers at a cheaper overall price.

How do Solar Panel Manufacturers follow the International Energy Agency?

Solar panel manufacturers follow the International Energy Agency by monitoring its industry analyses and following its policy guidelines. The International Energy Agency (IEA) is an autonomous intergovernmental organization providing authoritative analysis, data, and policy recommendations for the enhanced reliability, affordability, and sustainability of energy.

The International Energy Agency has 31 member countries and eleven association countries. IEA membership grants access to cooperation in energy security, data and statistics, policy analysis, energy efficiency, and the adoption of clean energy technologies like solar.

Solar manufacturers follow the International Energy Agency for the two reasons listed below.

• The IEA produces annual reports on the renewable energy sector, which include data on companies investing in distributed solar installations and corporate power purchase agreements (PPAs). This helps solar manufacturers identify market trends and expansion opportunities.
• The IEA advocates for public R&D research in renewable energy, such as utility-scale systems, smarter inverters, and cost reductions in balance-of-system components. Solar manufacturers get to apply for subsidies and tax relief offered by member countries investing in these areas.

The possible penalties for a solar manufacturer ignoring IEA guidelines include the risk of negative exposure and subsequent revenue loss should they be exposed for malpractice. The IEA is an intergovernmental body, meaning any policies it states are followed by its members. Solar manufacturers are often fined or even blacklisted for breaking agreed-upon industry best practices.

What is the Growth for Solar PV Installations Yearly?

The growth for solar photovoltaic (PV) installations yearly in the United States is predicted to occur at a CAGR (Compound Annual Growth Rate) of 17.32% between 2022-2027. CAGR (Compound Annual Growth Rate) measures growth rate over time, including compounding by comparing past performance of investments or estimates to expected future returns. In the last decade, the solar PV industry saw a remarkable average annual growth rate of 22% over the past decade. 

This historical data indicates that the projected growth for 2022-2027 is even more rapid, with 17.32% growth in 5 years against a 22% growth in 10 years. It represents a slight deceleration from the previous decade's rapid expansion. However, this growth still underscores the increasing adoption and significant potential of solar energy across the nation.​

The United States’ solar photovoltaic PV industry is expected to grow for four main reasons: growing accessibility, maturing solar markets, favorable government policies, and increasing numbers of residential PV systems.

Below is more information on the four factors which influence the growth of annual solar PV installations.

• Growing accessibility. In the last decade, the average annual growth rate for US solar was 42%. Solar installations in the country have since grown 30-fold. The total installed capacity in the US reached 96.18 GW in 2020, an increase of about 26% compared to 2019, according to a 2021 report by market research firm Mordor Intelligence on the “United States Solar Energy Market - Growth, Trends, COVID-19 Impact, and Forecast (2022 - 2027)”.
• Maturing solar markets. The US solar energy markets are maturing rapidly, as solar electricity is becoming economically competitive with traditional energy sources in several states, including California, Minnesota, and Hawaii.
• Favorable government policies. The solar PV market in the US is strongly driven by federal policies such as the Solar Investment Tax Credit (ITC), swiftly declining costs, and growing demand for clean electricity across the private and public sectors.
• Increasing numbers of residential PV systems. Solar energy accounted for 43% of all new electricity-generating capacity added to the grid in the US in 2020. At the end of the year, there were roughly 2.7 million residential PV systems in the United States, according to a September 2022 report by the Solar Energy Industries Association (SEIA) on “U.S. Solar Market Insight.”

What are the Top Solar Panel Manufacturers?

The three top solar panel manufacturers are SunPower Corporation, Hanwha Qcells, and Trina Solar.

SunPower Corporation, founded in 1985, is a prominent American energy company specializing in high-efficiency solar panels and photovoltaic cells made of crystalline silicon. It was established to commercialize solar cell technology developed at Stanford University, eventually breaking the 20% efficiency barrier for commercially available solar cells. SunPower has experienced significant growth and progress in its global presence, producing $1.74 billion U.S. dollars of revenue in 2023 and making it one of the best solar panel manufacturers in the world.

Hanwha QCells, founded in 1999 in South Korea, is a leading solar company known for its high-quality solar cells and modules. With headquarters in Seoul, South Korea, and Thalheim, Germany, the company has a strong presence in the US, offering innovative solar solutions for residential, commercial, and utility-scale projects. In 2022, QCells had an operating profit of more than $250 billion US dollars.

Trina Solar is a Chinese solar manufacturer founded in 1997 by Jifan Gao and listed on the New York Stock Exchange in 2006. Its headquarters are in Changzhou, Jiangsu Province, China. Trina Solar manufactures crystalline silicon PV modules and system integration. The company had revenues of $6.15 billion USD, based on its full-year 2021 financial reports.Other top worldwide manufacturers of solar panels include Jinko Solar, Canadian Solar and REC Group.

What are the Standards of Solar Panels?

The standards of solar panels are set by the International Electrotechnical Commission (IEC), a not-for-profit organization providing guidance for solar manufacturers and installers. The IEC sets six main standards for solar photovoltaic (PV) systems, which are IEC61215, IEC61646, IEC 61730 / EN 61730, IEC 60364-4-41, IEC 62108, and IEC 61701. A consensus of 20,000 international experts from industry, government, and testing laboratories determine these standards.

More information on each of the six main standards for solar panels is supplied below.

• IEC61215: The solar panel standard known as “IEC61215” covers the factors affecting the aging of crystalline PV modules. These factors include all weather conditions and forces of nature, such as sunlight, climate (temperature change, coldness, warmth, humidity), and mechanical load (hail, wind suction, wind pressure, and snow).
• IEC61646: The solar panel standard known as “IEC61646” applies to thin-film (amorphous) PV modules as a counterpart to the standard IEC 61215 for crystalline modules. An extra test assesses the degradation behavior of amorphous silicon due to temperature and irradiance exposure.
• IEC 61730 / EN 61730: The “IEC / EN 61730” solar standard consists of two parts. The first part states the construction requirements, mandatory design characteristics, and testing parameters for solar panels. The second part defines three different application classes for a module design: type specifications, related qualification tests, and the resulting safety class modifications.
• IEC 60364-4-41: The solar panel standard known as “IEC 60364-4-41” concerns personal safety measures against electric shock for low-voltage electrical installations. It proposes total insulation for PV systems, requiring special insulation of PV modules based on durability, high dielectric strength, mechanical stability, and sufficient insulation thickness and distances.
• IEC 62108: The “IEC 62108” solar panel standard defines the criteria for the design qualification and type approval of concentrator PV modules and assemblies appropriate for long-term operation in open-air climates. A special certification for these modules is needed due to high solar irradiance concentration through lenses or mirrors that place higher stress on the equipment. The world's first IEC 62108 certificate was issued in June 2009 to California solar technology company SolFocus.
• IEC 61701: The solar panel standard “IEC 61701” sets the resistance standards of solar PV modules against salt mist corrosion. Solar installers operating in highly corrosive atmospheres, such as near the sea, must check the resistance of PV panels against any corrosive effects. It is essential to use PV modules tested against this salt mist corrosion so that the modules are able to be safely installed near coasts or used for maritime applications.

Why are there Standards for Solar Panels?

Standards for solar panels ensure reliable performance, safety, and quality across different types of solar PV modules. These standards, such as IEC 61215, IEC 61646, and IEC 61730, cover everything from manufacturing and performance testing to safety and environmental resistance, helping to instill consumer confidence and facilitate global market access for solar energy products. They are crucial for assessing solar panel efficiency, durability, and integration into existing power systems.

For performance, IEC61215 ensures crystalline PV modules withstand weather conditions, affecting their aging and performance. For safety, IEC 61730 details safety requirements, including design and construction, to prevent accidents. For quality, IEC 61646 addresses thin-film PV modules' quality, specifically assessing how amorphous silicon degrades under temperature and irradiance. These standards, among others, ensure solar panels meet consistent, high-quality performance, safety, and manufacturing benchmarks.

What are the Uses for Solar Panels?

The five most common use areas for solar panels are solar electricity, solar heating, solar-powered transportation, solar lighting, and agriculture. More detail on each of the five most common usages of solar panels are outlined below.

• Solar Electricity: Powering households and buildings is the most common application of solar panels. The panels react to sunlight by creating electrical discharge when connected to a roof, or on open land facing the sun. As the sunlight converts to electricity via the photovoltaic effect, the Direct Current (DC) it produces goes through an inverter, converting it to Alternating Current (AC). This AC electricity feeds into the main electrical service panel, where it powers all types of household utilities, such as lighting, entertainment systems, and air conditioners. Any excess electricity generated is either fed back onto the grid (usually in exchange for credits on your electricity bill) or stored in batteries if there is a battery system attached. With sufficient solar panels and a large solar battery, a home is able to go "off-the-grid", which is ideal for use when the sun isn’t shining (such as overcast days) or if there is a power back. This backup energy reduces the need for homeowners to rely exclusively on grid-based electricity.
• Solar Heating: Solar heating systems use solar collector panels to replace household water heaters, providing hot water to faucets. The panels heat water circulating through tubing lacing via the panels. This hot water travels through piping that provides energy to radiators or radiant flooring tubing throughout the household. These solar heating systems are typically either passive or active. Passive systems use natural circulation, while active systems utilize pumps to circulate water and generate heat. Passive heating systems are more effective at heat generation than active ones, according to a study published in 2006 in Renewable Energy by a team at the Candida Oancea Institute of Solar Energy, Bucharest. The study was titled "Renewable Energy for Passive House Heating: Model of the Active Solar Heating System.”
• Solar-powered Transportation: Solar panels are able to power cars and planes, railroads, and buses. Solar-powered transit is becoming a trend in the renewable energy sector, as solar panels are placed on the vehicle's exterior to generate power. Solar-powered transportation is in its emerging phase but shows promise. Solar buses power public buses in China, reducing their carbon footprint while providing efficient mass transit in densely populated cities such as Beijing. Solar planes such as the Solar Impulse 2 and solar cars like the SolarSpirit model are gaining mainstream recognition.
• Solar Lighting: Outdoor solar lighting is able to improve home efficiency and doesn't require a complicated setup like standard exterior models. The lights are wireless and harness sunlight during the day to avoid the need for grid-supplied electricity at night. Solar lights are quickly joining LED light bulbs and smart home thermostats as inexpensive products that reduce electric bills and improve household efficiency. The availability and affordability of these products are a primary reason why it's common to spot solar-powered street lights.
• Agriculture: Solar panels used in agriculture generate electricity to pump water, run machinery, and store power. Solar energy is one of the oldest and most extensively employed practices in agricultural activities for drying crops and grains. Agricultural uses for solar panels include solar dryers made from screened drying trays or racks, as well as a solar collector and enclosure. The modules heat buildings and water, which is useful for dairy operations and modern poultry farms, and raise animals in enclosed buildings where temperature and air quality control are vital.

What are the usage statistics of Solar Panels?

In the United States, the landscape of solar panel installations varies by state, with each region contributing differently to the country's solar energy capacity. As of 2023, the U.S. has seen a significant increase in solar installations, reaching a record number of nearly 33 gigawatts in that year alone. This growth has been led predominantly by utility-scale installations, with the solar sector being the fastest-growing source of electricity in the country.

A state-by-state breakdown of solar installations reveals interesting trends and leading regions in solar energy. For example, California, known for its long-standing leadership in solar power, has a cumulative solar capacity of 31,873 Megawatts (MW), enough to power over 8.5 million homes. Texas, another major player, has a solar capacity of 9,311 MW, providing energy for approximately 1.08 million homes. Other states like North Carolina, Florida, and Arizona contribute significantly, each with thousands of MW in solar capacity and powering hundreds of thousands of homes.

Florida, in particular, has shown remarkable growth, nearly doubling its total solar capacity since the beginning of 2020. This rapid expansion is often attributed to the state's sunny climate, favorable policies, and increasing adoption of solar technology.

States like Massachusetts and New Jersey, despite being smaller and having less natural sunshine, have emerged as unexpected leaders in solar installations. This shift highlights the importance of state policies and economic factors in driving solar adoption.

For detailed information on solar installations by state in the U.S., refer to the State-By-State Map on SEIA​​. Below are more specific numbers for solar installations in various states across the U.S. as of 2023.

• California: Leading the nation, California has a cumulative solar capacity of 31,873 Megawatts (MW), capable of powering 8,548,370 homes.
• Texas: Texas holds a significant solar capacity of 9,311 MW, providing energy for 1,082,407 homes.
• North Carolina: With a solar capacity of 7,132 MW, North Carolina powers 859,707 homes.
• Florida: Florida's solar capacity stands at 7,074 MW, enough to supply electricity to 842,897 homes.
• Arizona: Arizona has installed solar panels with a capacity of 5,247 MW, serving 810,751 homes.
• Nevada: In Nevada, the solar capacity is 3,904 MW, powering 672,707 homes.
• New Jersey: With a solar capacity of 3,653 MW, New Jersey provides energy to 586,709 homes.
• Massachusetts: Massachusetts has a solar capacity of 3,263 MW, capable of powering 545,258 homes.
• Georgia: Georgia's solar capacity is 3,069 MW, supplying electricity to 359,160 homes.
• New York: New York has a solar capacity of 2,840 MW, powering 474,848 homes.

Are Solar Vehicles costlier?

Yes, solar vehicles are generally more costly than petrol-powered vehicles. Solar vehicles, such as solar-powered cars, currently require a separate battery for power storage. This creates higher upfront costs and space restrictions due to limitations of existing solar technology, which is primarily optimized for fixed placement in houses and other buildings rather than mobile vehicles.

For example, solar batteries currently range from $8,500 to $10,000 (excluding installation), making them extremely costly attachments to a solar vehicle. Solar vehicles are unlikely to enjoy life spans as long as rooftop PV systems and the panels add considerable weight to the vehicle. This makes the heavy upfront cost of solar vehicle panels untenable for most buyers, as current PV panels are primarily designed for fixed installations, such as houses.

Are Solar Planes faster?

No, solar planes are not faster than regular aeroplanes. Solar planes, like the Solar Impulse, face limitations in power and consistency due to variable solar panel performance and onboard battery requirements, which restrict their speed and practicality.

The amount of sunlight emitted by solar planes changes depending on time zones. This inconsistency in solar output prevents solar planes from achieving speeds comparable to regular planes powered by fuel. For instance, the Solar Impulse took 16 months to circumnavigate the globe, while a commercial Airbus A220 achieves the same distance in about 51 hours. The current models of solar planes are usually single-seater and are unable to match the 100+ passenger load of jet planes.

Are Rooftop Solar PV Systems getting popular?

Yes, rooftop solar photovoltaic (PV) systems are gaining popularity in the United States, particularly in the residential market. In 2023, the market for rooftop solar PV systems in US households included 1,832 megawatts of direct current (MWdc) in the third quarter, marking a 12% increase year-over-year.

This growth is part of a broader trend in the U.S. solar industry (which includes commercial and large-scale solar projects). Only in the first half of 2023, 11.2 gigawatts of alternating current (GWac) of PV were installed, representing a 44% increase year-over-year. This surge in solar installations is driven by a variety of factors, including technological advancements, environmental benefits, and financial incentives.

What are the disadvantages of a Solar Panel?

The five main disadvantages of solar panels are pollution, high upfront costs, expensive storage, sunlight dependency, and large installation areas. More information on the five disadvantages of solar panels is below.

• Pollution: Whilst solar power itself is a clean and renewable form of energy, the manufacturing process produces greenhouse gases in the form of CO2. The amount produced is lower than other forms of energy like natural gas (12 times less) and coal (20 times less), according to the United Nations IPCC (Intergovernmental Panel on Climate Change). Additionally, solar panels contain hazardous chemicals like lead and cadmium, which have the potential to seep into the ground in small amounts, especially in underdeveloped countries with inadequate environmental practices. Another concern regarding solar panels is the pollution that results at the end of their life, which is predicted to reach as much as 78 million tonnes by the year 2050, according to a June 2016 report by the International Renewable Energy Agency (IRENA) on “End-of-life Management: Solar Photovoltaic Panels." This increases the need to develop means of recycling solar panels efficiently.
• High Upfront Costs: One of the drawbacks of solar panels is the high upfront cost, which requires a significant initial investment. This includes the cost of the panels, the inverter, batteries, wiring, and the installation process. The expenses for installing rooftop solar panels vary from $16,000 to $35,000. Although the price of solar panels has notably decreased over recent decades, the initial outlay remains substantial, influenced by factors such as panel type, roof condition, and location. Homeowners often opt for monocrystalline solar panels, priced between $1 and $1.50 per watt, while polycrystalline panels, though less efficient, are generally cheaper at $0.75 per watt. Roof condition may elevate costs if repairs or modifications are necessary, and geographical location significantly impacts both system size and upfront costs based on sunlight availability.
• Expensive Storage: Some consumers opt to store the energy generated from solar panels instead of selling the excess electricity immediately back to the grid. Unfortunately, the cost of solar batteries is very high, costing between $5,000-24,000 depending on the size of the battery. This price does not include the cost of the solar panel system, the inverter, or installation. The expensive costs associated with solar storage are a disadvantage of solar panels, reducing the ability of solar panels to provide savings to the consumer because the return on investment takes much longer.
• Sunlight Dependency: Solar panels require direct sunlight to produce usable electricity. The efficiency of a PV system declines on days with cloud cover or inclement weather, such as storms. Solar panels are of limited use for households experiencing minimal sunshine year-round, or in areas that do not receive adequate sunlight. This dependency of solar panels on sunlight is a drawback particularly in regions affected by low sunlight or rainy weather, as the panels aren’t able to collect sufficient energy to power a household.
• Large Installation Area: A large installation area is usually required for solar panels to be installed properly, which is why solar panels are generally placed on rooftops. However, this is a disadvantage for those with an unusual roof shape or structure or those who live in dense areas with insufficient roof space. The average solar PV system in the United States is 5KW or 6.6KW and comprises 15 to 25 solar panels. As such, households in the inner city or with limited space must either invest in compact, higher-cost panels or limit their solar system size.

Why is the lack of a 2-way Electricity network a disadvantage for Solar Panels?

A two-way electricity network, or smart grid, describes the relationship between solar panel owners, who generate electricity locally, and the electrical grid. Traditionally, the grid infrastructure has supported a unidirectional flow of electricity from generators to consumers, whereas solar panels have opened up the possibility for homeowners to produce their own energy and sell it back to the grid, requiring 2-way electricity networks.

The absence of a two-way electricity network is a disadvantage for solar panels because it means that the energy generated by solar panels across the country isn’t able to be exported onto the grid. This leads to energy wastage and the reduction of the efficacy of solar power as a viable energy source for the future.

Why doesn't a Solar Panel continue to work when power goes out?

A solar panel stops working during a power outage because the solar inverter is designed to shut off when the electrical grid experiences an outage. This shutdown is a safety measure intended to protect maintenance and repair personnel from the risk of electric shock caused by any solar energy being fed back into the grid.

The purpose of deactivating a solar panel system during blackouts is that solar panels are typically connected to the electrical grid. A grid-tied solar panel system means that excess electricity generated by solar panels is fed back onto the grid via net metering. This process must be shut off during power outages to ensure electrical workers fixing grid issues are not electrocuted. So, do solar panels work during blackouts & power outages? It depends.

PV systems are sometimes able to continue supplying power to homes during an outage if they are equipped with a solar battery. For this to work, the battery must be in "blackout protection mode," which isolates it from the grid.

In the United States, the electrical safety standards for solar inverters are primarily established by the Underwriters Laboratories (UL) and the Institute of Electrical and Electronics Engineers (IEEE), which state that inverters must not allow a solar power system to generate power if the electrical grid suffers a blackout or power outage. The inverters are linked to the grid network and receive a code when there's an issue, swiftly deactivating them if the grid goes down.

Are Solar Panels Dangerous?

No, solar panels are generally not considered dangerous. When fitted by a trained professional, in compliance with regulations, and consistently serviced thereafter, solar panels pose minimal danger. So, what are the dangers of solar panels? Under certain circumstances, such as improper installation, solar panels do pose dangers, such as electrical hazards and fire risks. By using a licensed electrician and conducting regular maintenance, consumers are able to mitigate the dangers of solar panels.

The electrical hazards associated with solar panels are caused by dangers like faulty installation, improper wiring, and incompatibility of the PV system with existing circuitry. The fire risks involved with solar panels are often the result of improper grounding, which is when electrical currents are not properly diverted to the earth in the case of surges or faults, leading to fire. Do not install solar panels yourself or hire someone who is not professionally qualified to do so.

Whilst solar panels are a form of renewable energy and a safe form of household or commercial equipment, they do carry some potential to damage the environment. For example, the solar panel manufacturing process involves the use of harmful chemicals and creates greenhouse gasses that are dangerous to the environment. In certain situations, solar panels are a danger to living creatures, like birds, where the reflective surfaces either cause collision or attract the birds to land, burning their feet.

How to write and pronounce Solar Panel Correctly?

The correct way to write and pronounce solar panel is “solar (pronounced: ‘sow·luhr) panel (pa·nuhl).” The noun 'panel' typically describes a rectangular section of a surface, such as a covering or a wall. Standard solar panels are rectangular because they are easier to manufacture and present the most efficient use of space. The term solar ‘pannel' is an obsolete synonym of panel.