Sustainable Energy without the Hot Air (Revised, Community Edition)

David MacKay’s Sustainable Energy - Without the Hot Air ( Reusable and revised.

More on why we are creating this version.


Table of Contents

Sustainable Energy without the Hot Air (2008 Edition)

to those who will not have the benefit of two billion years’ accumulated energy reserves

Part I: Numbers, not adjectives

Part II: Making a difference

Part III: Technical chapters


Why this project

David MacKay tragically passed away in 2016. His wonderful book (and website) were first published in 2008. The material is still of great value. However, is has not been updated since publication and now won’t be (at least by David). David made his book available in machine readable formats and licensed the book (semi-)openly meaning it can be modified and redistributed.

The book remains a go-to reference and extremely useful. However it is getting out of date — e.g. solar situation in 2020 is dramatically different from a decade earlier.1 Its current format is not easily editable nor is in a repository where it can be collaboratively worked on. Finally, there is the risk the book and site could one day disappear.

In this project we have:

  • Created a source form in markdown which is much easier to edit, reuse and publish
  • Put it in a public git(hub) repo which makes it easy for others to collaborate
  • Archived original material so that it is preserved

What this makes possible

  • Creating a revised edition collaboratively to bring it up to date
  • Easier reuse and referencing by others
  • Adding additional functionality (e.g. annotation, search etc)


  • Suggest or make an edit: Open an issue or edit the text directly (coming soon)
  • Make this site better / prettier etc: fork and pull on the repo or get in touch

Full source plus README plus more in the the open github repository here:


Original text is copyright Professor David JC MacKay FRS (Professor of Natural Philosophy, Department of Physics, University of Cambridge) and licensed under a Creative Commons Attribution-Non-Commercial-Share-Alike 2.0 UK: England & Wales Licence. See

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 to any of the electronic versions on this website. There’s pdf and html versions (thanks to William Sigmund!); we are working on other formats.

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-Share-Alike 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. This website includes links to separate high-quality files for each of the figures in the book.

Additions and modifications by other authors are dual-licensed under a Creative Commons Attribution License v4 (unported) and Creative Commons Attribution-Non-Commercial-Share-Alike 2.0 UK (as required by the Share-Alike license).

  1. See this 2017 article on Carbon Commentary with concrete suggestions and associated thread on ycombinator: