One guy from Poland posted a video in polish on YT where he calculated that his roof solar in last 10 years of operation provided significantly less RoI than if he simply bought gold at market price 10 years ago and sold it now.

This is a freaking scam over here. We need power mostly in winter, especially with the push to install more heat pumps. Solar is not working in the winter here, people literally got scammed by government that subsidized solar and heat pumps installations for lower income families on the condition that they remove coal or wood powered heating. Now they can’t afford to run those heat pumps!