Comment by gnramires

Virtually all energy on available on Earth is Solar-derived. Plants all use solar power, carbon sources are all ancient stores of solar power. There's enough solar energy for several of our civilizations (4-5 orders of magnitude more, by a napkin calculation). Roughly 1/50,000 of Earth's surface covered in solar panels would suffice.

> do they still require fossil fuel energy to create, not to mention maintain and rebuild

That's not really particularly relevant. What is crucial is that they produce more energy than they consume. This is an important figure, EROI (Energy Return on Energy invested), which should be >1

https://en.wikipedia.org/wiki/Energy_return_on_investment#Ph...

Photovoltaics generally have been well over 1. There are still sustainability challenges with the technology, but I think they're minor (relative to current alternatives and carbon technology).