David Matthewman

Sustainable energy - without the hot air, by David JC MacKay (ISBN: 978-0954452933, web site)


In short: read this book. Now.

Every so often, when considering 'green' issues, I'll find myself pondering a question like 'compared to a car engine, how much CO₂ does a person cycling give off?' or 'surely even inefficient light bulbs give off heat, which means that I have to heat the room less, so how do those savings compare?' When Top Gear broke the story about bio-fuels to the masses back in 2003, one of my first thoughts was: 'OK, that's great, but let's say we take every car currently running on diesel and power it from rapeseed oil instead, how much land are we going to need to grow the rapeseed, and will there be any space left to build roads on?'

Such questions aren't rhetorical. They're amenable to scientific analysis (I did actually make an attempt at looking up the rapeseed one from publicly available figures), and I always harboured a dream of sitting down and working out the figures. But now I don't need to, because David MacKay, a Professor of Physics at Cambridge, has done it for me. And much, much more.

His central simplification is to use a fixed unit throughout; he measures power in kWh/d, or kilowatt hours per day. If this seems odd to the physicists among us - he could just as easily have used a kW, 1kW = 24 kWh/d and doesn't have that awkward 'hours per day' bit - he justifies it by calling it a handy human-sized quantity. a 40W light bulb, for example, uses 1kWh/d when switched on, and allegedly it's also the sort of power you'd get from one human servant. Anyway, the important thing is to use consistent units throughout, which he does. This allows us to compare all the different ways that we use power with the different ways that we can generate it.

For example, someone driving 30 miles every day uses about 40kWh/d. If I fly in a fully-loaded plane to San Francisco and back once a year, I use 30kWh/d. Covering my roof with solar panels could deliver 13kWh/d of heating, or 5kWh/d of electricity (but not both). As the book goes on, he stacks up the per-person consumption of energy in a red bar alongside the per-person possible generation of energy from renewables in green.

I don't want to give away the ending, but basically unless we cover 5% of the UK with solar panels, 10% with wind farms (in the same places), enclose the North Sea in a tidal barrier and burn all our waste, we're buggered. Without reducing our energy consumption (back to the pre industrial era levels, and probably reduce our population to those levels as well), or start using non-renewable sources of energy, the sums simply don't add up.

The good news is that David MacKay has several suggestions for where to go from here. The bad news is that all of them have some aspect that most people won't like, whether it's relying on nuclear power, using 'clean coal' power stations, importing energy from other countries that can make better use of renewables or an expensive and resource-hungry programme of building wind turbines.

In a way, though, that's beside the point. If you have a better plan, this book will help you do the sums for it. This also helps to compensate for one of the other problems with the book, which is that it's very UK-centric - although this is just a narrowing of focus; he considers the global context where it's appropriate, and has a chapter where he does the same sums for the US, and for the rest of Europe.

It's also worth mentioning that this is very much a book about sustainable energy, not climate change or 'carbon footprint'. He does talk a little about both of those, but it's not the main thrust of the book, which is about securing an energy supply that's not going to run out in 100 years or so. Obviously, reducing or eliminating fossil fuels from the power-generating equation is a key component of that, so incidentally CO₂ emissions will be reduced, but even if you think that the greenhouse effect is exaggerated, or just scaremongering, you should read this book. The unsustainablity of our fossil fuel use is very real indeed.

That said, not all of the options he offers here are completely sustainable, largely because it's very, very hard to make the figures add up at all when looking purely at sustainable solutions. So he also considers solutions that 'will last us for the next 1000 years', as being close enough to sustainable as to be worth considering.

In part 1 of the book, the chapters alternate between power consumption and power generation, building up an overall picture of the balance. Part 2 considers possible solutions - these vary a lot, but some common themes are: favour electric transport, especially trains; improve the insulation of all buildings, but especially new builds; heat and cool houses through heat pumps. David MacKay likes heat pumps a lot, if I were at all suspicious that his research is being funded by an interested party, it would be a firm that makes heat pumps.

Part 3 goes into the technical details of some of the topics in part 1: the physics of deep-water waves, why aeroplanes are already about as efficient as they're ever going to be. This is a masterstroke - it allows him to stick to the calculations in part 1 without getting too bogged-down in where the figures come from, while giving details of the science behind the figures so that interested science-minded people can check his working. Similarly, there's a section at the end of each chapter where he lists references and further reading. He's separated these out very well, and there's usually enough information in the main body of the text to let you know what he's talking about without it breaking up the flow of the argument. Part 4 gives detailed figures and web links.

Actually, it's worth mentioning that this book is a great read. It's witty, the diagrams and tables are clear, and he comes up with some great analogies, like illustrating the problem with generating sustainable geothermal power by talking about drinking slushies. The whole book is available for free on the web site - if you like reading things on-line, by all means do that, but I found the book itself easier to flick backwards and forwards through.

I really, really like this book. If there's any justice, this book will become as popular a scince read as A Brief History of Time or The Blind Watchmaker, although I think it's both more accessible and more immediately relevant to day-to-day life than both of those. I'm considering buying ten copies and sending them to key politicians talking about the subject. I'm considering refusing to engage with anyone on the subject of energy policy until they've either read the book or demonstrated to my satisfaction that they're clued up enough on the figures not to need to. I like this book enough that I'm very wary of the happy death spiral with respect to it, but I think I can avoid it. At heart, the book is a set of numbers that either add up or don't, from sources that can be checked. I intend to check as many as I can.

And then to buy a heat pump.

So, this month of June, President Obama declared LGBT Pride month in the USA. How's that going for them?

Well, it appears that the Obama administration's Department of Justice marked the 40th anniversary of the Stonewall Riots by issuing this brief which argues for the U.S. Supreme Court's dismissal of the legal challenge to the 'Defense of Marriage Act' (DOMA). The best that can be said about this brief is that The Department of Justice acts independently of the President and Congress - this is in principle a good thing; New Labour's frequent attempts to short-circuit the justice system in this country is one of the most deplorable aspects of their tenure in Governemnt. However, as this blog post points out, the language used in the brief was excessively dismissive.

This entry in Box Turtle Bulletin is also worth reading; in it he points out that while those claiming that the Obama administration compares same-sex marriage to incest and pederasty are at best missing the point of that section, there is still plenty to be very, very angry about in that brief. And that Obama's much-vaunted opposition to the DOMA during his campaign worryingly vanished from the Whitehouse web site back in April.

(Do read some of the other links from those blog posts and the comments; much good debate - and some bad - is to be found therein.)

What I'd like to see from Obama - and I say this as a non-US LGBT activist so I obviously recognise that he's not my president and there's no reason on the face of it why he should listen to me - is an speedy rebuttal of many of the arguments in the brief, and a reinstated commitment to repealing the DOMA. I don't mind him recognising the independence of the DJO, in fact, I think that would be a good thing to do, and contrast well with the Bush's administration. But if he's serious about repeal of the DOMA, then he needs to argue against much of the content of the brief,
and I'd like to see him doing it. The brief makes points that need to be challenged at the highest level, and if Obama won't do it, his much-praised LGBT month looks to me, and more relevantly to LGBT people across the US, like tokenism.

This post by Ben Goldacre, brilliantly entitled 'Parmageddon', makes a lot of very good points about the coverage of swine flu, and the difficulty of reporting on a subject with a high margin of error. Without wanting to detract from that, I think it also misses a couple of important points.

The first is that the reason that the public mistrusts newspapers on stories like this (Ben Goldacre lists Sars, bird flu and MMR together, which I think is an interesting grouping, and I'll explain why later) is that the headline writers - and usually the copy writers too - instinctively go for the most extreme end of the margin of error. Faced with a study that says that sharpening pencils is probably harmless, but there's a 2% chance that it will cure cancer, and a 1% chance that it will attract meteorites, the headlines will be 'Flaming fireballs to rain destruction on school classrooms' one day, and then (for balance) 'Put lead in your pencil for a long life, say scientists' the next. Nowhere is there any coverage of the outcome that is vastly more likely, because that doesn't sell newspapers; to be fair, it doesn't sell newspapers because people find it boring to read, so it's not completely the journalists' and editors' fault.

Then along comes swine flu - a phenomenon where, as Ben Goldacre points out, it's really too early to say at this stage what the likely outcome is. We don't have enough data to make an educated guess. We can do the Bayesian thing and attempt to assign probabilities to hypothetical outcomes, but I don't think (and AFAICT Ben Goldacre agrees) that we can do it with any degree of confidence. So when the papers say '40% of the world could be infected' or '120 million people could die', it's a Bayesian 'could', and one that we don't really have a good feel for yet. We can look at past flu epidemics (although the problem here is the tendency to focus on the obvious, severe ones), but even so, we don't yet know whether this one's like any of those.

It's chaos theory. We're looking at a tiny pressure difference in the mid-Atlantic, which might fizzle out and might develop into a hurricane, but we can't measure it in enough detail (or model its complex behaviour well enough) to say yet.

Of course, the World Health Organisation and Governments need to at least try to do these calculations, and the understandable tendency is to prepare for the worst scenario that looks at all likely. But even they, at this stage, are almost certainly dealing with judgements that they simply don't have the data to make accurately at this stage. And the media reports this, as it should, although often not with the emphasis it should.

As Ben Goldacre rightly points out, that's not to say they're wrong to make such judgements, nor that they will have been shown to have been wrong if the threat doesn't materialise. When the hypothetical 'this might happen' becomes an after-the-fact 'this did happen', we're prone to looking at every 'this might happen' that didn't, and concluding that they couldn't have. (We take a frequentist approach to a Bayesian analysis, in other words, forgetting that we couldn't do a frequentist analysis before the fact anyway.) Sars and bird flu didn't become global threats (yet), but that's not to say that with slightly different starting conditions which would have been impossible for us to measure at the time, they could never have done so.

And then there's MMR, and the possible link to autism. I find it odd that Ben Goldacre groups this to Sars and bird flu at the start of his article, because he of all people should know that this really was largely a panic engineered unwittingly by the media, with no good evidence to back it up. Sars and bird flu both could have been serious threats; MMR couldn't have caused widespread autism, and this should have been apparent at the time. What's more, the fact that the story about the supposed MMR link to autism has almost certainly caused vast damage by reducing the takeup of the vaccine is a neat illustration of the fact that it's often the side effects of the story - the public's over-reaction to it - that you need to watch for. It may turn out to be that case with swine flu; if it does become a serious threat, I worry that far more people will be killed in a scrap over medical and food resources than will be killed by the flu itself. So far, though, this shows no signs of happening, which is a very good thing.

Ben Goldacre mentions the boy who cried 'wolf', and (correctly) points out that the public (incorrectly) see the headlines about swine flu to be an example of this. This is true of the story as told be Aesop; in the fable, the motivation of the boy who cried 'wolf' was to get attention for himself. However, if the boy cried 'wolf' because he thought that the thing he saw moving in the woods near the flock was indeed a wolf, even though he knew full well that it could also be a deer, that's a different story in more ways than the obvious one. Is he then wrong to cry 'wolf', even if it turns out to be a deer? Are the villagers right to ignore him the third time, after it's been a deer for the first two, knowing that there are real wolves out there? Would the village newspaper be scaremongering to print 'Wolf may lurk in wood'? Possibly, but it's a lot less clear-cut.