Solar power is terrific, but unfortunately the sun does not shine at night. In addition to solar arrays you need either some way to store energy or generate it at night. That's called "the base load" in the energy industry. An idea that's not bad is to pump water to a high reservoir when you have excess power and then run it to a lower reservoir through dynamos when you need power. The industry does do that in the few places that can accommodate that topographically. Another idea is batteries, but they are horribly inefficient, expensive, and require a lot of maintenance and replacement.

So how do you solve the base load problem? The greenest way would be the new nuclear reactor designs. They use very abundant input materials, are safe by design, produce little waste, and don't make stuff for building bombs. The Thorium Molten Salt design uses the Thorium we have by the megaton in mine tailings. The standing wave design uses the depleted Uranium we also have in the megatons from enriching Uranium for reactors and bombs for the last 75 years. So they actually consume radioactive waste. They are like building reactors that run on poop. Something we already have and wish we didn't.