About this edition

This is not the official edition. David MacKay's original book and website live at withouthotair.com. This is a community edition: the same text, converted to an editable, open format, so that it can be corrected, extended and eventually brought up to date by whoever wants to help.

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, it 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 However it is getting out of date — the solar situation today is dramatically different from that of 2008.¹ Its original format is not easily editable, nor is it in a repository where it can be collaboratively worked on. Finally, there is the risk the book and site could one day disappear.

So this project does three things:

Converts the book into markdown — a source form that is much easier to edit, reuse and publish
Opens it, in a public git repository, so anyone can propose a correction or an update
Preserves it, archiving the original material alongside the converted text

What this makes possible

A revised edition, built collaboratively, bringing the numbers up to date
Easier reuse and citation by others
Additional functionality over time — annotation, search, better navigation

What we have not done

We have deliberately not changed MacKay's text. Every chapter here is his, as published in 2008. Where the numbers have dated — and in energy, many have — they are still his numbers, not ours. Revising them is the work ahead, and when it happens it should be visible and attributed, not smuggled in.

That is also why the figures, the arithmetic and the arguments are left intact even where a modern reader would quibble. The value of the book was always the method: work it out yourself, in units you can hold in your head. That survives the numbers going stale.

How to help

Spot an error, or a number that has dated? Use the Edit this page link at the bottom of the page — it opens that chapter's markdown on GitHub, ready to edit, and turns your change into a pull request.
Rather discuss it first? Open an issue, or get in touch.
Working on something bigger? The whole book is markdown in the repo; clone it and send a pull request.

Credits and licensing

The original text is copyright Professor David JC MacKay FRS and licensed under a Creative Commons Attribution-Non-Commercial-Share-Alike 2.0 UK: England & Wales Licence. The cartoons and the photographs with a named photographer are excluded — MacKay had permission to include them, not to relicense them.

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 the Share-Alike licence requires.

Credit is also due to Tito Jankowski, who did a first pass at getting the book into source form in 2017; this work started as a fork of his.

This edition is maintained as part of Life Itself's climate inquiry.

See this 2017 article on Carbon Commentary with concrete suggestions https://www.carboncommentary.com/blog/2017/3/30/l6qcqgoedse1wmjjz87t09usoq6jva and the associated thread on Hacker News: https://news.ycombinator.com/item?id=14009057 ↩