Bill Gates speaks at the TED conference on February 12. This is the audio of the video, combined with his interview from livestream.com answering a couple of Twitter questions and a Scientific American 60 second commentary on geoengineering.
TED conference and Scientific American
More info about this here: http://www.fastcompany.com/1553683/bill-gates-at-ted-we-need-an-energy-miracle-video. Gates is promoting nuclear power and not just any nuclear power but specifically, a "traveling wave" type of nuclear power, which is being developed by a company called TerraPower. More info on them here: http://earth2tech.com/2010/02/15/terrapower-how-the-travelling-wave-nuclear-reactor-works/