Optimal would therefore be to use everything yourself completely and not draw anything from the grid. But that is illusory. In summer, you have an enormous surplus because you usually consume little electricity. And in winter, you don't get enough from the roof to cover your high electricity consumption.
But isn't it true that photovoltaics, as long as they are not covered with snow, actually yield more on a nice winter day than at 35 degrees in summer? My electrician explained to me that the modules heat up so much in summer that the output decreases.
But isn't it the case that photovoltaic systems, as long as they are not covered with snow, actually produce more yield on a nice winter day than at 35 degrees in summer? My electrician explained to me that the modules heat up so much in summer that the performance decreases.
The modules themselves would indeed produce more at freezing temperatures. But in winter, the sun is lower in the sky. Then it depends on the angle of the modules. And the day is simply not as long in winter. A sunny summer day with -20°C would be good, but unfortunately impossible.
In winter (Dec and Jan), you get about 10% of the yield that comes down in summer (June/July). I once saw an evaluation of a large system over several years; that's pretty depressing. With 8.7kwp at 70% efficiency, it would roughly cover the base load with hot water without heating, without an electric car for me.