My question about pv panel output power Many sources on the internet says that in reality PV panels can not reach OR exceed STC nameplate values consequently Array-to-Inverter ratio should be always more than 100% to ensure that inveters will work on high capacity Other sources said that panel output power will exceed peak (STC) power frequently and that is require inverter oversizing NOT array oversizing i need to know the which is the right concept??
Submitted
8 years 3 months ago
Comments
Haitham,
Both are correct. A module can certainly have output higher than its STC rating. The primary cause is lower than test condition temperatures.
On the other hand, when temperatures are above this the output is lower than STC.
I do recommend a higher DC to AC ratio with inverters to ensure a efficient system and do not often recommend going below this unless you intend to add on to the system later.
I hope that helps answer your question.
Adam
I noticed that the PVWatts program does not account for snow in its projection of solar radiation. We receive several feet of snow in an average winter and it may hold onto the panels for weeks, or slide off in a day. It turns out that my June production equals Nov-Jan due to the snow blanket on the panels.