Solar Panel Efficiency: what you need to know !Michael Kibirige
Solar panel efficiency is a measurement of a solar panel’s ability to convert sunlight into usable electricity. Given the same amount of sunlight shining for the same time on two solar panels with different efficiency ratings, the more efficient panel will produce more electricity than the less efficient panel. Solar panel efficiency is determined by the production of electricity by solar cells, which is in turn influenced by the cells’ composition, electrical configuration, surrounding components, and more.
How efficient are solar panels?
Most solar panels are between 15% and 20% efficient, with outliers on either side of the range. High-quality solar panels can exceed 22% efficiency in some cases (and almost reach 23%!), but the majority of photovoltaic panels available are not above 20% efficiency.
How solar panel efficiency differs by product
Given the same amount of sunlight shining for the same time on two solar panels with different efficiency ratings, the more efficient panel will produce more electricity than the less efficient panel. Solar panel efficiency is determined by the production of electricity by solar cells, which are in turn influenced by composition, electrical configuration, surrounding components, and more.
In practical terms, for two solar panels of the same physical size, if one has a 21% efficiency rating and the other has a 14% efficiency rating, the 21% efficient panel will produce 50% more kilowatt-hours (kWh) of electricity under the same conditions as the 14% efficient panel. Thus, maximizing energy use and bill savings heavily rely on top-tier solar panel efficiency.
What determines solar panel efficiency?
Several factors determine how efficient a solar panel is. At its core, solar panel efficiency is determined by how much incoming sunlight the solar panel can convert into usable electricity. But what factors into that end conversion rate? There are several items that solar cell researchers and manufacturers consider when designing and producing efficient solar panels:
- Material – the type of material (monocrystalline silicon, polycrystalline silicon, cadmium telluride, etc.) impacts how light converts to electricity
- Wiring and busing – the organization of wires and “busbars” on a solar panel that capture and transfer electricity impacts efficiency
- Reflection – if the light is reflected away from a solar panel, its efficiency may be lowered. This is why the glass layer on top of silicon solar cells is so important.
Additionally, factors like being able to absorb light on both sides of a cell (bifacial solar panels) and being able to absorb variable wavelengths of light (multijunction solar pan.0els) change the efficiency equation for solar panels. All in all, there is a multitude of levers that scientists and researchers can pull when working on improving solar panel efficiency. Ultimately, it’s all about converting more incoming sunlight into electricity.