Interesting, one question i had, was hydroelectric due to mountains/hills glaciation or in the sea like the UK. I googled it, it seems like the former.

Geothermal always seemed to me, it's a pretty difficult source of energy to extract for factories n stuff. Like, a factory can melt steel, but no one wants the ground he stands on to melt as well.

Hydroelectric is a much easier source to work with. Humans have used rivers as a source of energy for thousands of years.