You just stated it. Solar energy is free. The earth is bombarded witrh free energy to the tune of;
1,749,229,032,802 Solar energy striking Earth [today] (MWh)
The sun is the perfect energy producer. It is responsible for ALL flora (life) on earth and keeps any nuclear waste to itself.
For the earth and its inhabitants, trees are the perfect energy conversion machine. They scrub the air from CO2 and produce oxygen , while providing an almost infinite variety of food for the animals on earth.
As to using artificial energy processors, there needs not be any bad side-effects .
The earth has managed to use raw solar energy without polluting side-effects.
There is no reason why humans could not copy natural means to convert raw energy into usable power.
It will require a different “mindset” of our mindscape and the application of not-for-profit conversion mechanics so that maximum efficiency with least amount of waste becomes the standard, not the rare exception.