Looking at Solar, Grid, and House Load for the Summer Solstice June 20, 2025 and Winter Solstice December 21, 2025. Looking at a month gives a 30-31 day sample for each month. SOLAR 460.7 kWh vs 222.7 kWh - 683.4 kWh 67.4% = 460.7 / 683.4 32.6% = 222.8 / 683.4 Longest Summer is ~2x the Shortest Winter (including one extra day) GRID 195 kWh vs 603.5 kWh - 798.5 kWh 24.4% = 195/798.5 75.6% = 603.5/798.5 About a 3 to 1 ratio in grid power needed in winter An extended power outage required 2.3 kWh from the emergency generator Grid electrons cost ~$0.12 / kWh HOUSE LOAD 883.4 kWh vs 947.7 kWh - almost identical electrical load June or December CONCLUSION The Summer or Winter electrical loads were nearly identical. The solar production significantly avoided grid load in the Summer and still helped in the Winter. This suggests that adding roof-top, wind powered generator(s) might significantly improve year round performance. Bob Wilson
My location has a far more pronounced PV seasonal production difference: (The 2025 summer spikes are from a couple microinverters having communication problems, delaying some reports until the next day or so.) The seasonal differences here are a combination of the northerly latitude, the local climate zone having much more cloudcover in winter than summer, and tree shade being worse in winter when more neighbors' tree shadows reach my system.
