February 7, Sunday afternoon
Groton Local Energy Group is sponsoring a book discussion on Sunday,
February 7, 2:00pm  to 4:00pm, at Groton Public Library (Sibley Hall), 99 Main
Street, Groton, MA.  On review will be Sustainable Energy - without the
hot air by David J.C. Mackay.  The author is a professor of Physics at the
University of Cambridge in the UK and brings a physicist’s perspective to
understanding our energy systems – renewable and otherwise.  You can
download the book from the author's website or purchase it from Amazon.  A
book review by Leo Laverdure available below.  

For more information about the event, please contact Yuval Gonen
email at energy@grotonlocal.org

You can sign up for this event at the end of this page

Sustainable Energy – without the hot air

David J.C. MacKay

Current and former covers:

http://www.withouthotair.com/ (includes downloads for the book and a 10-page synopsis)

Endorsements for the book:

Review by Leo Laverdure,             Sustainability Commissioner for Groton, MA,

               President, Groton Local

One of my main occupations of the last 5 years has been to better understand the truth about the sustainability of our energy options, and this book is perhaps the resource that has most helped me improve my understanding.

The author, David MacKay, is a professor of physics at the University of Cambridge in the UK, and brings a physicist’s perspective to understanding our energy systems – renewable and otherwise. He does have an agenda, but it is not political. Rather, he defines the goal as having energy systems that are sustainable, wisely taking a 1,000-year view. He starts with the assertion that our current, fossil fuel-based systems are not sustainable. And, he insists that whatever anyone is advocating as the way to go, at the end of the day the numbers must add up; this is what he means by “without the hot air.” If you are advocating without a clear sense of the scale of the problem – and numbers to support your proposed solutions that are well-researched and easy to compare – you’re adding heat to the debate, but no light.

The book, published in February 2009, is 384 pages and is divided into four parts:
Part I – Numbers, not adjectives; Part II – Energy plans that add up; Part III – Technical chapters; and Part IV – Useful data.

Part I lays out the unsustainable nature of our current energy systems and levels of consumption, and investigates in 18 short chapters possibilities for energy efficiency and renewable energy sources. Three of these chapters merit further comment:

• Chapter 1, “Motivations,” lays out why the book is needed, that is, why we need national energy policies that are sustainable, and why it is critical for people to have a quantitative understanding of energy systems before they advocate policy.
• Chapter 2, “The balance sheet,” establishes the primary analytical approach: side-by-side columns totaling energy Consumption (the red stack) and Production (the green stack). This graphical treatment is maintained throughout the book, making perfectly clear the overall impact of various options in getting the stacks to balance. One of MacKay’s small but critical contributions is to put all calculations in the same terms: kilowatt-hours per day per person. This is an essential first step for understanding the overall situation and comparing alternatives.
• Chapter 18 ends Part I with the question: Can we live on renewables? His answer is a qualified yes: only if you are prepared to accept country-sized renewable energy facilities. For wind farms to make a big contribution, they would require surface area of about ¼ of the UK. Ditto for solar farms. Bio-energy crops would require ¾ of the whole country. He concludes with: “’Nuclear or wind?’ is the wrong question. We need everything we can get our hands on – all the wind, and all the nuclear – and even then, we’re still in trouble.”

Part II “explores six strategies for eliminating the gap between consumption and renewable production from the first part, then sketches several energy plans for Britain, each of which adds up.” The first three reduce demand, the others increase supply. He also looks at five different electrical energy source mixes, each of which is likely to appeal to different political/activist groups, including a “green” plan with no coal and no nuclear power. His stated goal is “not to pick winners, but to present honest quantitative facts about all the options.” But he does identify some options that don’t work well (hydrogen-powered vehicles, in particular) and a few that do (heat pumps, either ground- or air-sourced; the new generation works much better than combined heat and power). He offers a sixth plan that is a middle course of the other five.

While much of the analysis is focused on the UK (the technologies, of course are universal), Chapter 30, “Energy plans for Europe, America, and the World,” extends the analysis. For North America, the suggested starting point of the analysis is to halve our consumption to match the average energy used in Europe and Japan (125 KWH/day/person). Wind seems to be able to get us about 1/3 of this number, but that requires over a 200-fold increase in wind-turbine generating hardware. Concentrating Solar Power has an even larger potential – an area the size of New Jersey in one of the Southwest deserts would meet all our energy needs. Mackay’s bottom line for us: with a massive expansion of wind and solar, North America has enough renewables. Nuclear also has potential.

Chapter 31, “The last thing we should talk about,” analyzes the energy requirements of removing CO₂ from the atmosphere. Again, the scale is not for the faint of heart. Planting trees is woefully inadequate, for example.

Part III is strictly optional. It’s for people who are comfortable with physics and are interested in the technical details of MacKay’s calculations. Having a physics and math background, I found this section interesting and valuable. For example, I found a very understandable explanation of why the power output of a wind turbine goes up with the cube of the wind’s velocity. You can also see what MacKay has included and can adjust the calculations if you think he has missed something.

Part IV provides some useful baseline data and conversion tables, and a history of energy in the UK.

Visually the book is attractive, with clear and effective charts, tables, photos, and cartoons, including:

A final note: I commend MacKay for making his entire book freely available on the web, both as a set of pdf downloads (whole, parts, synopsis) and html pages (and many pointers to online reviews and discussions). You can also buy a printed version for around $33 on Amazon (5 stars out of 5, 26 reviewers). If you have no time to read the entire book, do read the 10-page synopsis; then you can read selected chapters in any order with very good understanding.

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