“Sustainable Energy – without the hot air” at Caltech by Prof David MacKay FRS, Chief Scientific Adviser to the UK Department of Energy and Climate Change (2009-2014). Close-captioning kindly provided by CMU. 5-April-2010. See www.withouthotair.com for free book. David MacKay was a PhD student at Caltech from 1988 to 1991. In 2010 he was a Professor in the Department of Physics at the University of Cambridge.