Considering solar panels, the first thing people usually look at is the modules’ efficiency. The reason is simple – this number will directly affect the amount of energy you’ll be getting, making your return on investment higher or lower. However, the efficiency you eventually get isn’t solely determined by the percentage specified by the manufacturer. Read on to learn about the various factors affecting performance and how to make your solar panels more efficient.
What is the efficiency of solar panels?
In a narrower sense of the word, it is a percentage a manufacturer puts on modules after testing solar panels in the lab. Since these conditions adhere to a single standard, it is a good reference point for determining which panels will output more electricity for a certain quantity of sunlight.
However, the number won’t be of much use if the panels don’t perform as expected under the conditions in your area. So, in a wider sense of the word the efficiency of solar panels can refer to how well they do their job right there on your roof. In the first case, it is simply a predetermined number you can’t do much about. But in the second, numerous factors come into play to contribute to the overall performance of your system. You have the power to mitigate the bad ones and reinforce the good, thus increasing solar panel efficiency.
Tips to maximize solar panel efficiency
Even a tiny efficiency improvement can add up to significant savings over a PV system’s lifespan. The following tips will help you gather as many of these little improvements as possible. They apply to all kinds of solar panels, regardless of the brand, type or rated efficiency.
- If bad, cloudy weather is a frequent guest in your state, consider panels designed with these conditions in mind. The manufacturers always mention good performance under low-light conditions and you won’t miss it if you read the panel’s description. If you want more specific data, look for low irradiance test results in the datasheet. This seemingly small detail may lead up to a 10% difference in annual energy yields.
- If some segments of your PV array, however small, are shaded on a regular basis, they may cause all panels to perform worse than you would expect. There are various solutions to minimize the impact of shading, like power optimizers, microinverters or panels with multiple bypass diodes.
- Regular maintenance can also increase efficiency. Clean solar panels will convert light into electricity better and will serve you longer.
- Smart positioning can make the panels perform significantly better. To get the best results, face them south in the northern hemisphere and vice versa. Second best options are east and west, but you can lose up to 15% of your solar harvest. The angle also matters a lot: an ideal inclination should be equal to your latitude.
- All solar panels are covered by protective glass, which inevitably reflects some of the light back. Anti-reflective coatings deal with this problem, making your panels a bit more efficient.
- PV modules don’t absorb all the light the Sun is throwing their way. However, there are solutions for that too. PERC cells have an additional reflective layer that allows them to perform 6 to 12% better. There are also bifacial modules that absorb light from both sides at once, increasing the output by up to 30%.