David Mackay, the Cambridge University physicist, has published a really nice quantitative exposition of the sustainable energy problem. http://www.withouthota

David Mackay, the Cambridge University physicist, has published a really nice quantitative exposition of the sustainable energy problem. http://www.withouthotair.com/ http://www.withouthotair.com/ The chapter on renewable energy considers current technology, breeder reactors, and extraction of uranium from saltwater. His basic conclusion is that we have at least hundreds of years of Uranium at near-current consumption levels... which is probably enough time to develop fusion.