Posted by: JohnnyRook | December 28, 2008

Brilliant New Book Teaches You How to Evaluate Sustainable Energy Claims

Everybody who is paying attention knows that Climaticide is the most pressing problem that we face. They also know that in order to avoid climate catastrophe we have to find a way to ween ourselves from our dependence on fossil fuels. Unfortunately, that is about as far as the consensus goes.

When it comes to deciding how we will replace fossil fuels and with what, the disagreements are serious and the debates passionate and, all too often, vitriolic. We meet proponents of wind (onshore and offshore), of solar (and its various subcategories), of nuclear (and its various subcategories), of geothermal, of wave, of carbon capture and storage for coal, etc.

How is one to reconcile all these various claims? Well, David MacKay’s new book, is a good place to start.

Unsettlingly, usually, these discussions involve more strong opinions than data. Some people believe that one of these alternative (they are not all sustainable) energy options is the silver bullet that will solve both the climate and the energy crisis. Other argue that there is no silver bullet and that what is required are a variety of silver BB’s: a mixture of technologies, along with greater energy efficiency and preservation of habitat (forests). Do we really just need to build huge number of nuclear plants or wind farms to solve the problem? If, instead, we are going to use a mix of alternative energy sources, which ones should we use and in what quantities?

Rarely does anyone attempt to answer these questions, which is why Cambridge University physicist, David JC MacKay’s new book: Sustainable Energy–Without the Hot Air is so welcome. Although MacKay’s focus is principally on the UK, (the book does have two short section in which he suggests energy plans for the United States and for the world as a whole) the principles and techniques he describes are applicable anywhere. The book will not be published in the US until April, but a PDF version is available for free download here.

Sustainable Energy–Without the Hot Air, is not a book about global warming. MacKay only briefly discusses the climate crisis in his first chapter, Motivations. His purpose, rather, is to bring the discussion about whether it is possible to create a viable non-fossil fuel economy down to earth by actually doing the calculations, albeit in rough, general terms, both from the demand and supply side. The result is very enlightening indeed.

MacKay explains that he wrote the book because:

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

I cannot praise this book too highly. Everyone who is interested in Climaticide and sustainable energy should own a copy. In easy to understand and, often, witty prose, MacKay leads the reader through an examination of all sorts of energy related questions. You can get a sense of the topics covered from the Table of Contents, which I have reproduced below.

As you can see the book is divided into four sections.

In Section 1 MacKay alternates calculations of UK energy use with calculations of energy production from various sustainable sources in an attempt to see if it would be possible to live on renewables alone. He illustrates this graphically by creating two stacks of boxes.

One stack contains boxes with values in kWh/d (kilowatt hours/day–a term he clearly explains in an early chapter) for the ways the British consume energy (transport, heating, etc.). The other stack contains boxes with values in kWh/d for the potential sources of renewable energy in the UK (wind, solar, wave, etc.) As he stacks the boxes one gets a visual impression of whether it will be possible to meet UK energy needs solely with renewables.

In Section II, he considers factors other than renewable energy sources that need to be considered as we decide how we can end our use of fossil fuels. These include, but are not limited to, energy efficiency, electrification of transport, nuclear power and the importation of renewable energy (principally solar) from other countries.

Section III is composed of technical chapters where MacKay explains in greater detail the various physics formulas and calculations that he has used to draw his conclusions. Although this is the section with the most math, MacKay claims that it should be intelligible to anyone with a solid high school background in science and math. I should add that it is not necessary to read Section III in order to understand MacKay’s arguments in the rest of the book.

Finally, Section IV contains useful quick reference tools, such as explanation of units, conversion charts, GHG emissions by country, etc.

MacKay is not preachy. He does not presume to tell us which plan to adopt in order to get off fossil fuels. In the book he presents a number of plans, which the reader is free to adopt, reject or modify as he chooses. What he does insist on though is that any plan be realistic, that the numbers add up. This insistence on constant reality checks may dampen the spirits of some, but I found it invigorating. I have known and written for quite a while now that the solutions to our Climaticide problem were going to have to be big. After reading MacKay’s book I now have a much clearer idea of just how big and why.

Near the end of Section I MacKay draws an important conclusion from the calculations he has made in the previous chapters.

For any renewable facility to make a contribution comparable to our current consumption, it has to be country-sized. To get a big contribution from wind, we used wind farms with the area of Wales. To get a big contribution from solar photovoltaics, we required half the area of Wales. To get a big contribution from waves, we imagined wave farms covering 500 km of coastline. To make energy crops with a big contribution, we took 75% of the whole country. p. 112

Sustainable Energy–Without All the Hot Air is a great book precisely because it is so sobering. If you read it, you may be forced to revise some of your opinions about renewable energy. But that is good. It will mean that you have a better grasp of the facts and of how truly monumental are the changes that we need to bring about.

Sustainable Energy–Without All the Hot Air is a great book precisely because it is so sobering. At first, you may feel disheartened because MacKay does not minimize the magnitude nor the difficulty of achieving the solutions necessary to stop Climaticide. Later, however, after you have got over the initial shock, I think you’ll find yourself encouraged, because MacKay’s hard-headed approach and his insistence on looking at the numbers show that, despite the difficulties, it is possible to create a world in which there is a sufficient supply of energy for everyone without the use of fossil fuels.

This book is full of useful facts and insightful analysis. It is written with panache and illustrates its many points with copious helpful images, graphs and charts. Download a copy and read it. You’ll be glad you did.



  1. Johnny Rook:
    Just found your interesting website while searching for information on the TVA Tennessee coal ash sludge spill. If ok by you, I will place a CC link in my sidebar.


    • John,
      I’m glad you found the site useful. And, of course, it’s okay if you put a link into your sidebar. Thanks. JR

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