The energy input of solar (sourcing and extracting the rare earths, the manufacturing process, installing and maintaining them in situ) is non-zero, and solar panels have a finite lifespan. These variables are often not well understood, nor factored into discussions of solar as "renewable". I don't believe there exists an end-to-end solar operation, i.e. the entire supply chain solar powered by its own products. So solar is only cheap because its inputs are cheap, and they are cheap because they are powered by cheap oil.