Climate change and energy is a regular topic here. Here is an excellent reference (free ebook) that goes through the physics of energy need vs. amount we can get from alternative energy sources. Questions like can plains be more energy efficient or will the ground freeze if everyone would use ground heat pumps. It is all there.
I had to read the whole thing in one sitting. Never found any physics book so captivating...
http://www.withouthotair.com/download.html