[beerandt]

But endless fields of solar panels and wind turbines is?

That seems like a somewhat arbitrary, fine line to walk.

[sigstoat]

neither of them strike me as great but taking down the solar farm is probably cheaper and easier than rebuilding a mountain.

[dahfizz]

Those sources of energy are both renewable and can be deconstructed with no permanent environmental impact, which makes them "clean" in my mind but I agree it's an ambiguous word.