These lectures will review the challenges facing energy policy, the outlook for different sources of primary energy (fossil and renewable), how energy is used, and prospects for improved energy efficiency. A colloquium ‘Can Future Energy Needs be Met Sustainably?’, that I will be giving on Tuesday 15 September at 16:30, is part of this course – see separate Abstract for a summary. The lectures will provide more details and address topics that will only be mentioned in passing in the colloquium.