Review of “Sustainable Energy – without the hot air”

I have a confession to make. “Sustainable Energy – without the hot air” had mostly gathered dust on my bookshelf for almost two years before I finally took the time to finish reading it. So why did I take it up again and finalise it this time (and, more importantly, bother to write this review and try and convince you to read it yourself)?

Well, in the last few months, several reports have been published, outlining how it would be possible to run an economy without fossil fuels in the foreseeable future – I suppose that this sudden outburst is not completely unrelated to the preparation of the European Commission’s roadmap for a low-carbon future.

While the headlines of these reports caught my attention, in most cases, I rather quickly abandoned reading them.  The main motivation for doing so was not that I fundamentally disagreed with the authors’ conclusions, but rather that the published material was not sufficiently concrete to help me make up my mind on the validity of these conclusions. Indeed, any report looking 40 years or more into the future is inevitably speculative. There is nothing wrong with that: taking into account the stock nature of greenhouse gasses, we have no choice but to think about the very-long-term consequences of today’s choices. However, with such a time horizon, it is clear that any conclusion you draw can depend critically on some assumptions that may appear to be minor but that have dramatic cumulative impacts in 40 years from now. Therefore, complete transparency with respect to the assumptions used (and how they translate into conclusions) is essential for any publication on this subject. It was precisely because this transparency was lacking in most publications on the subject that I felt that a further reading would not really enlighten my own thoughts.

It was then that I recalled that complete transparency was the key selling point of “Sustainable Energy” (one should not take “selling” too literally, as the book can be downloaded freely). To his own admission, the main motivation of the book’s author, David MacKay, a professor of Physics in Cambridge, is his concern about cutting the emissions of “twaddle about sustainable energy”. He starts from the observation that many of the things that allegedly make a difference in terms of energy consumption simply do not add up. However, he rightly points out that the debate about sustainable energy is one about numbers, and that in a climate where people don’t understand numbers, anyone can get away with murder (or energy plans that do not add up).

The book is essentially a case study of whether it is possible to draw up an energy plan for a country (in this case, the United Kingdom, but the methodology can be readily applied to any country) that would cover its entire energy needs without the use of fossil fuels.

MacKay proceeds as follows.

In the first half of the book, he compares the country’s energy consumption with “sustainable” energy production. His approach is bottom-up pushed to the extremes. On the consumption side, he takes any possible activity that uses energy (transport, heating and cooling, light, “gadgets”, food, etc) and estimates the corresponding energy use of a “typical” household. On the production side, he considers all possible sources of sustainable energy (on-shore wind, solar, hydropower, offshore wind, wave, tide and geothermal). The only constraint MacKay considers are physical constraints. His main motivation for deliberately ignoring economic or environmental constraints is that doing so helps focusing on the question whether conceivable sustainable energy production would be enough to cover total consumption.

After having verified the results of his bottom-up estimates with actual energy consumption (according to official statistics), Mac Kay goes on to the second half of the book, where he verifies whether an appropriate mix of demand (better transport, more efficient heating etc) and supply (importing renewables from abroad, nuclear, even coal with carbon capture and storage) measures would result in a renewable energy mix that actually adds up. 

In case you cannot wait to read the book, the answer to the feasibility question is: yes, it is physically possible to fulfil a country’s energy needs with renewable energy but (even if one ignores economics) it will be far from obvious and it will require some drastic changes in current consumption and production patterns. Actually, the author even hints that some climate engineering may be needed in case the sums for mitigation do not add up (see my discussion of Superfreakonomics for more on this). Whether you like this conclusion or not, I would strongly recommend to find out the details of the argument for yourself, and to verify whether you can agree with them.

What is really wonderful about this book, is that you can indeed verify every single step in the argumentation. Moreover, you can put all the assumptions in a spreadsheet, and verify how the results changes according to geography (you may well live in a country with a very short shoreline but lots of spare place and sun) or time (some of the technical assumptions may change quickly and unexpectedly when time unfolds – for instance, The Economist of 12 March hints that the potential for increased energy efficiency in aviation is much higher than Mac Kay’s estimates).

To put it simply, this is probably the most transparent book I have ever read, and it sets a very high standard for any future work in this field.

Through its emphasis on verifiable facts and figures, rather than on perceptions, the book is also very good at demystifying a lot of misconceptions (no, you will not save the planet by unplugging your mobile-phone charger when it’s not in use; yes, there are limits to energy efficiency that are not imposed by economics, but simply by the laws of physics etc), which can only lead to a better informed debate (in case, of course, that’s what you’re interested in).

Of course, the level of detail and the emphasis on hard facts may also put a lot of people off (despite the tongue-in-cheek humour, it is hardly compelling bed-time reading, which may explain why it lingered on my own “to read” list for so long).  I suppose that’s the eternal dilemma of books that are meant to be intellectually rigorous but that aim at a general audience at the same time: there’s an unavoidable trade-off between rigour and accessibility. This is typically the kind of book that boffins will enthusiastically recommend as being very “accessible”, just to find out that no one except their own kind shares this enthusiasm.

This being said, are there any other issues with the book?

Actually, it covers so much ground, that I do not feel qualified to comment on most of the details (when I wrote that you can verify every detail in the book, what I really meant is that it is possible to set up a team of experts to verify everything ).

Let me therefore limit my discussion to the few subjects where I think I know a thing or two more than Professor MacKay.

First, transport. MacKay makes a compelling case for the (physical) limits to energy efficiency in private transport. However, I am afraid he is way too optimistic concerning the potential of public transport. I do not dispute that public transport is, on average, much more energy efficient than private transport. However, current averages are a very poor predictors of actual energy efficiency if a massive shift from private to public transport were to take place. Indeed, public transport can only be more energy efficient than private transport if it used to move huge (more or less predictable) quantities of people from one (predictable) origin to a (predictable) destination. In other words: it is mainly efficient in peak time in urban areas. The problem is that a significant amount of people who are currently using their car for moving around do not fall into this category (they live spread around in large suburban areas, their work places are dispersed in other large suburban areas, etc). If these people would switch to public transport, energy efficiency of public transport is likely to decrease, not increase. Of course, my reasoning depends also on specific assumptions with respect to spatial structure: one may retort that the promotion of public transport should go hand in hand with measures against urban sprawl. Now, that’s a point I fully agree with, but the reality is that spatial structure is like housing: poor choices that were made in the past are likely to stay with us for a very, very long time. So, to summarize, in some countries where public transport has been underfunded or poorly organised, there is probably some potential to improve the energy efficiency of the transport system by promoting a modal shift. Also, this may be an interesting policy option for the hundreds of cities that will be built in India and China in the decades to come, and where spatial structure remains to be defined. But do not think you can stretch the potential of public transport much further in many European urban areas.

Second, economics. Of course, as an economist, I would have liked to see a more thorough discussion of the economics of sustainable energy (the solutions with the highest technical potential are not necessarily the ones with the highest cost-effectiveness). However, I understand Mackay’s point that you should evaluate the physical feasibility of an economy entirely based on renewable before  you even consider economics. Actually, I would have preferred if MacKay would have stuck to this approach throughout the book, because most of what he has to say on economics does not come close to the analysis of other issues. For instance, MacKay finds it odd that people have faith in market, “given how regularly markets give us things like booms and busts, credit crunches, and collapses of banks”. Very well. Using a similar line of argument, I find it odd that people have faith in governments, given that that they gave us things like decades of economic stagnation and mass famine (Soviet Union and China under Mao), and mass massacres (Birkenau, the Gulag and the Cambodian killing fields were organised by government bureaucracies, were they not?). If you think this argument is a caricature, I agree – it is. But not much more than the diatribe against markets that you can find in Chapter 29 of the book.

My point here is: finding out what is technically achievable is an essential first step in a move to an economy that is based upon renewable energy. However, it is only a first step. Once you go further than that, you have to define priorities  and you must design institutions that will induce the desired changes  in a cost-effective manner. While the design of these institutions should indeed involve legislation, regulation and taxes (as argued by MacKay), there is nothing dogmatic about affirming that you also need to harness the power of market forces to induce these most cost-effective reductions.

By the way, I also have a substantial comment or two to make on the economics. Electrical vehicles may have a lot of technical potential, but, for the foreseeable future, most economists reckon that their cost per tonne of CO2 saved is up to an order of magnitude larger than the cost per tonne of CO2 saved in other sectors of the economy (such as housing). I also doubt that the costs of all sources of renewable energy can be expected to drop in the future: whilst technological progress may induce lower prices, higher demand will also put upward pressure on prices. I do not think we can predict which effect will dominate. However, discussing these issues in depth should be the subject of a separate post on this site.

Third, MacKay barely touches upon the energy and non-energy resource cost of creating the infrastructure  that will provide all this renewable energy. This is not a trivial matter. Actually, some have argued recently that the main constraint on moving to a low carbon economy is that it will not be possible within the coming decades to mine all the minerals that are needed in the creation of this infrastructure. This is maybe an issue that should be considered in a new edition of the book. 

Of course, within the larger picture, these are minor comments. On the whole, this book is an impressive intellectual achievement. As it is freely available on-line, you do not have the excuse of the cost for not downloading it right away and making up your mind yourself (and, more importantly, for not forwarding it to all policy makers you know).

And, oh please, don’t forget to repeat its core one-liner to everyone you know: if everyone does a little, we’ll achieve only a little.