How much land mass would renewables need to power a nation like the UK? In this pragmatic talk from TEDxWarwick, David MacKay tours the basic mathematics that show worrying limitations on our sustainable energy options and explains why we should pursue them anyway. He included biomass crops in his calculations, if he had left this option out, the talk would have been much more favorable to renewables.

David MacKay is a professor of Natural Philosophy in the Physics department at the University of Cambridge and chief scientific adviser to the UK Department of Energy and Climate Change. He received a degree in Experimental and Theoretical Physics from Trinity College and a PhD. in Computation and Neural Systems as a Fulbright Scholar at Caltech. In 1992, MacKay was made the Royal Society Smithson Research Fellow at Darwin College at University of Cambridge and was elected a Fellow of the Royal Society in May 2009. He has also taught at the African Institute for Mathematical Sciences in Cape Town. In 2003, his book Information Theory, Inference, and Learning Algorithms was published and, in 2008, he self-published Sustainable Energy — Without the Hot Air. Both books are fully available for free online.