When you start looking for solar panels, you want to choose the best and most efficient ones. But what does solar panel efficiency mean and is it that important? Let's get to the bottom of it in our article.
Key takeaways
Solar panel efficiency measures how much sunlight a solar panel converts into electricity. It is expressed as a percentage. For example, a solar panel with an efficiency of 20% converts 20% of the sunlight that hits it. The remaining 80% is either absorbed as heat or reflected.
Efficiency = [Power output / (Area of panel x 1000 W/m²)] x 100%
Solar panels have made significant strides in recent years. Their average efficiency has risen from 15% to 20%, with some high-performance models reaching 25%. As new technologies appear, this figure keeps growing.
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The efficiency of most panels is roughly the same, so in most cases, it’s not a parameter you need to chase. Yet there are situations where it can make a difference.
First, if your roof space is limited. Higher-efficiency solar panels generate more power from the same area. In other words, the more efficient your panels are, the less installation space your system will demand. That is especially important if you have space constraints but still want to generate big amounts of electricity.
Second, if you live in a cloudy area. Efficient modules are better at capturing diffuse sunlight scattered in the atmosphere. For this reason, they are invaluable in low-light conditions, such as on cloudy days or in the early morning and late evening. This extended operating window increases overall energy production, especially in regions where the sun is a rare visitor.
Aiko is a Chinese photovoltaic company, one of the world's largest manufacturers of photovoltaic cells and solar modules and a Tier 1 manufacturer by Bloomberg. It was founded in 1996 and is headquartered in Shanghai. Aiko’s all-back-contact modules efficiency exceeds 24%, while cell efficiency is over 26.5%
Maxeon began as a division of SunPower, a once famous American solar panel manufacturer, until it spun off as a separate company in 2020. With shingled solar panel design and interdigitated-back-contact cells, Maxeon’s home solar panels boast some of the highest conversion rates available today, reaching over 24% efficiency.
RECOM is a leading European solar module manufacturer and a comprehensive solar solutions provider founded in 2007. RECOM uses N-type cell technology and a back-contact connection. As a result, their panels achieve over 24% efficiency.
LONGi Solar was founded in 2000 in China and is one of the world’s largest solar manufacturers. LONGi Solar uses the latest technologies such as multi busbars, half-cut cells, PERCs and N-type cells and their panels show good efficiency and reach over 23% conversion rate.
AEG is Germany’s largest electrical engineering company, founded in 1887. And that’s not a typo. The company produces literally everything from solar light bulbs to power plants, including solar panels. With a combination of N-type and back-contact cells and shingle technology, AEG solar module’s efficiency goes up to 24% and higher.
Founded in 2001 in Canada, Canadian Solar is the only non-Asian brand in the world’s Top 10. The company uses N-type cells and TOPCon technology to make their modules more than 23% efficient. Being from the North, these modules do very well even in bad weather, low light and winter.
Founded in July 2020, Huasun Solar is a Chinese technological innovation company specializing in high-efficiency N-type silicon heterojunction solar wafers, cells and modules. The company produces modules with efficiency almost reaching 24% and is not going to stop at that.
Jinko Solar, founded in 2006 in China, is the world’s largest solar manufacturer. The company’s engineers do not shy away from trying out all the latest technologies in their panels and constantly come up with new ones. The efficiency of their modules reaches 23% and is considered one of the highest on the market.
Winaico is a Taiwanese solar panel manufacturer operating since 2008. Their company offers one of the best product warranties on the market – 30 years – proving that they are absolutely sure in their product’s quality. The efficiency is also great – up to 23%.
If you want to get the most out of your panels, you need to understand what factors affect their efficiency and take them into account whenever possible. Here are some of them:
The material composition of a solar panel significantly impacts its efficiency. Silicon, in its various forms, is the most commonly used material. Monocrystalline silicon, with its pure and uniform structure, offers the highest efficiency.
Thin-film solar cells, made from materials like amorphous silicon, cadmium telluride, or copper indium gallium selenide, are known for their flexibility and versatility. Yet they generally have lower efficiency compared to crystalline silicon cells.
Emerging technologies like perovskite solar cells show immense promise due to their potential for high efficiency and low cost. These materials are still in the research and development stage, but they could revolutionize the solar industry in the future.
While solar panels are designed to absorb sunlight, excessive heat is the worst enemy of their efficiency. Most panels operate optimally at cooler temperatures; as the temperature rises, efficiency declines. Additionally, climate factors such as humidity and air quality can influence how much sunlight reaches the panels. Clear, sunny days are ideal for solar energy production, while overcast conditions can diminish output.
The ability of solar cells to absorb different wavelengths of light also affects efficiency. Solar cells typically convert only specific wavelengths of sunlight into electricity. If a panel reflects too much light instead of absorbing it, energy is wasted. Anti-reflective coatings and textured surfaces can help minimize reflection and maximize absorption, allowing more sunlight to be converted into usable energy.
The efficiency of the wiring and inverter system is another critical factor in overall solar panel performance. The wiring connects the solar panels to the inverter, which converts the direct current generated by the panels into alternating current used by most household appliances. Any resistance in the wiring can lead to energy loss, and the inverter itself has a conversion efficiency rating that affects how much of the generated energy is usable. Choosing high-quality components can enhance overall system efficiency.
Finally, the positioning. Panels should ideally be installed in a location that receives direct sunlight for most of the day, typically facing south in the Northern Hemisphere at an optimal angle. Shading from trees, buildings, or other obstacles can dramatically reduce a panel’s energy output.
Solar panels can work in various weather conditions. Though their efficiency may be affected by different weather types, they can still generate electricity even on cloudy days or in rain.
While solar panels produce more electricity in summer due to longer days and more direct sunlight, in fact, cold, sunny days are even better for them. Colder temperatures can slightly increase their efficiency, while wind helps clear dust that can hinder performance.
To ensure a consistent energy supply, even during cloudy periods or winter storms, pair solar panels with battery energy storage systems. This allows you to store excess solar power for use during off-peak hours or when the grid is unreliable.
Another common question about solar panels is whether they can work in the rain. The answer is yes, but their efficiency can vary depending on the intensity of the rain and cloud cover.
Solar panels convert sunlight into energy, not heat. Even on cloudy days, some light penetrates the clouds and reaches the earth's surface. Although heavy rain and thick clouds can reduce the amount of direct sunlight reaching the panels, they can still generate electricity from the available light.
Surprisingly, rain can actually benefit solar panels by washing away dust and dirt that can accumulate on their surfaces and hinder performance. This cleansing effect can contribute to improved efficiency.
Ready to take the next step? A1 SolarStore is your one-stop shop for top-quality solar panels and equipment. With our extensive selection, expert guidance, and competitive pricing, we would be delighted to help you make the most of solar energy.
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