It’s the middle of summer. It’s hot. Solar radiation is at it’s peak, but your solar panels are not quite performing at their peak. If you’re wondering what could be going on, our tech team are here to explain.
PV cells work mostly on the visible spectrum, the irradiance is what is important and the heat works against us reducing efficiency.
Panels are tested at 1000 W/m2 at 25ºC to determine peak power rating. Each degree above this rating affects the panel output performance by 0.38% on average (check your panel spec sheet for the exact figure for your panel). Monthly average temperature variations can result in fluctuations in panel performance.
If you want to know how much of a fluctuation is possible check out image 2. You can see that the percentage loss due to summer temperatures is way higher than winter.
Even though the power yield is higher in summer, this is also true for inefficiencies.
Even though the power yield is higher in summer, this is also true for inefficiencies.
