If God had wanted us to have nearly unlimited clean energy, He would have placed a fusion reactor into the sky.
(europe.pub)
0 and 40 depending on location? We get 6Wh per W installed per day annual average here. We couldn't get that is 40% was the max. We get 1 to 3Wh/Wi/d in winter and 6 to 12Wh/Wi/d in summer
At midday on a cold sunny spring day we'll get 105% the nameplate power
Wh/Wi/day is Watt hours per Watt installed per day