What’s this book about?

I’m concerned about cutting UK emissions of twaddle – twaddle about sustainable energy. Everyone says getting off fossil fuels is important, and we’re all encouraged to “make a difference,” but many of the things that allegedly make a difference don’t add up.

Twaddle emissions are high at the moment because people get emotional (for example about wind farms or nuclear power) and no-one talks about numbers. Or if they do mention numbers, they select them to sound big, to make an impression, and to score points in arguments, rather than to aid thoughtful discussion.

This is a straight-talking book about the numbers. The aim is to guide the reader around the claptrap to actions that really make a difference and to policies that add up.

This is a free book

I didn’t write this book to make money. I wrote it because sustainable energy is important. If you would like to have the book for free for your own use, please help yourself: it’s on the internet at

This is a free book in a second sense: you are free to use all the material in this book, except for the cartoons and the photos with a named photographer, under the Creative Commons Attribution-Non-Commercial-ShareAlike 2.0 UK: England & Wales Licence. (The cartoons and photos are excepted because the authors have generally given me permission only to include their work, not to share it under a Creative Commons license.) You are especially welcome to use my materials for educational purposes. My website includes separate high-quality files for each of the figures in the book.

How to operate this book

Some chapters begin with a quotation. Please don’t assume that my quoting someone means that I agree with them; think of these quotes as provocations, as hypotheses to be critically assessed.

Many of the early chapters (numbered 1, 2, 3, …) have longer technical chapters (A, B, C, …) associated with them. These technical chapters comprise Part III.

At the end of each chapter are further notes and pointers to sources and references. I find footnote marks distracting if they litter the main text of a book, so the printed book had no footnote marks. Discrete end-note marks have been added to this ebook to allow easy referencing.

The text also contains pointers to web resources. When a web-pointer is monstrously long, I’ve used the TinyURL ervice, and put the tiny code in the text like this – [yh8xse] – which is shorthand for a tiny URL, in this case: A complete list of all the URLs in this book is provided at

I welcome feedback and corrections. I am aware that I sometimes make booboos, and in earlier drafts of this book some of my numbers were off by a factor of two. While I hope that the errors that remain are smaller than that, I expect to further update some of the numbers in this book as I continue to learn about sustainable energy.

How to cite this book:

David J.C. MacKay. Sustainable Energy – without the hot air.

UIT Cambridge, 2008. ISBN 978-0-9544529-3-3. Available free online from