Sustainable Energy – Without the Hot Air by David J. C. MacKay

Written 05 June 2022

It’s become increasingly clear to me over the years that abundant, reliable and cheap energy is the cornerstone of progress we have enjoyed in the developed world for many years now. It also lies at the heart of environmental questions that are set to be at the centre of our political life for the rest of my life and so I’ve been looking to read more on Energy this year. I started with The Prize by Daniel Yergin which deals with the history of the oil industry (reviewed here), then Helen Thompson’s Disorder (which touches on similar themes) and more recently Meredith Angwin’s Shorting the Grid in which I saw this book referenced.

This is a great book, and really suits the way I tend to approach things. The author (who died at a young age in 2016) was a Professor of Engineering at Cambridge University and also the Chief Scientific Adviser to the then Department of Energy and Climate Change between 2009 and 2014. His approach is data-driven, user friendly and not principally interested in economics or political niceties. His purpose in writing the book is the obvious need for “simple numbers [that are] comprehensible, comparable, and memorable…with numbers in place, we will be better placed to answer questions”. His starting point is that climate change is real, it is caused by fossil fuel use, and it poses a threat to humanity. He wrote the book in 2009 and it is available as a free e-book through the website withouthotair.com or can simply be read there.

The first part of the book is a thorough analysis of the UK’s energy situation by looking at all aspects of our energy use and also what renewable energy sources are available to us. This is accompanied by lots of data and building up what he calls our national balance sheet. Use (on travel, “stuff”, heating and lighting, food etc) is compared to what can be reasonably obtained from renewables. These are called the red stack and the green stack. It is all very logical but also user friendly, he is interested in keeping things at a high enough level so that people can understand the issue but also not get bogged down in too much detail which is exactly what I was looking for. The graphics are good and very helpful. More technical detail is available in footnotes and appendices for those who want it.

Before I get on to the main highlights (and a couple of observations) I should say that I found this a really interesting read and I’d really recommend it to anyone interested in finding out broadly where we are starting from and what are the main policy drivers. If you don’t like e-books or reading websites then you can buy the book in paper form.

So, where are we and what are the conclusions of the book? Or rather, where were we in 2009 (for the sake of argument I doubt there’s much significant difference given that the approach in the book to themes is very much big picture).

Firstly, UK traditional renewables by themselves can’t supply the UK’s energy needs. In reaching this conclusion, MacKay does not include nuclear energy as a traditional renewable but does include waste incineration. Even on the most optimistic assumptions, maximum future renewable generation in the UK can provide a little over 90% of current use. Typical energy consumption is 195kWh per person per day, traditional renewables are assumed capable of delivering 180kWh per person per day if everything is used to the absolute maximum (and many of these uses are not compatible with each other). As the author makes clear, it is also very easy for us to increase our consumption of energy and very difficult to increase our generation. He also assumes there are no political or economic impediments to reaching the renewables figure. The 195kWh figure above includes energy in imports. Removing this and also making adjustment for NIMBYism etc he comes up with a comparison of 125kWh per person per day to 180kWh per person per day

The author examines what can be done to change these sums, and comes down firmly on a couple of options as the only way to reduce energy usage and increase generation. On the usage side we must pivot to electric cars and to heat pumps to deliver big gains in efficiency. This can bring usage down to 70kWh per person per day. There are various options to increase generation and five plans are presented. Rather than describe them the graphics are below (this also illustrates the excellent use of graphics in the book). For interest the five plans are Plan D (Domestic, little foreign supply), Plan N (the NIMBY plan, people don’t want too much new stuff), Plan L (the old Liberal Democrat plan), Plan G (the Greens, no coal or nuclear), and Plan E (for Economics with a huge pivot to nuclear). Each delivers 70kWh per person per day. And we’re there! As the author says, each plan will have plenty of detractors, and understandably so, but you are free to make up your own. But your sums do have to add up. Some will hate nuclear, many will regard “clean coal” as a step backwards while others won’t like the geopolitical implications of being highly reliant on political stability in e.g. Southern Algeria.

All in all, it’s a great book and I’m really glad I read it. It will serve as a really useful reference for the future. There are a couple of standouts for me, mainly with the benefit of hindsight given the book was written 13 years ago.

  1. Echoes of the author’s liking for wind, in particular offshore wind, as well as the move to electric transport can be seen in UK policy over recent years. So he’s had some success. It is important to understand that for the author these things must go together. Electric cars will be used to provide back up to intermittent wind generation. Not only will car owners draw down from the grid to charge their batteries, those charges will also be taken onto the grid to stabilise energy supply when wind is low. This is important, wind needs backup and millions of fully charged electric car batteries will provide some (but nothing like all) of it. This seems neat but also in practical terms looks likely to be difficult to pull off, at least at scale. Of course things might work out but I think various alternative scenarios look possible. Simply building the charging infrastructure requires monumental changes to our national infrastructure in terms of town layout (if we keep private ownership), or we move to more communal car ownership models where we have fewer cars in the country. Affordable private car ownership would become a thing of the past for most of the population. I see political difficulties as our establishment “levels with the British public” on the fact they can’t expect to aspire to owning a car.
  2. The second issue is the reliance in many of the options on solar in deserts. The book was published in 2009 (probably written earlier). Remember 2009? It was when we were living at the end of history and were moving inexorably towards a borderless world in which grubby, backwards notions like nation states and national political interests were just due for one final shove off the stage. Politics and international relations would be the province of progressive but politically unaccountable supranational bodies. The role of national governments was at best to implement, but not to decide, such things and we would all be better off for it. Roll forward to 2022, Russia has invaded Ukraine and we see how reliance on other countries’ natural resources (in this case food, oil and gas) can be weaponised. I don’t think the British public are going to be up for putting between 10% and 30% of our energy requirements in the hands of the states of the Sahara desert. It turns out that natural interests are entirely legitimate and frankly the assumptions underlying solar in deserts look hopelessly dreamy. Of course we can use desert power, it could be a part of our requirements and could be a massive boon to development of North Africa. But there would have to be redundancy. It would be as well as rather than instead of. So on the three plans with solar in deserts, the other boxes would need to be expanded by about the same amount. In reality this makes them much more difficult.
  3. The third point is perhaps the most important. The book really deals with the UK, the country that was first into the industrial revolution. It is right that we should play a central role in moving us away from fossil fuels. I doubt the idea of CO2 debts etc are going to make much headway, but the key fact is that the UK is no longer a big player in energy. Nor is Europe. The book really doesn’t have a lot to say about China and India, the big and growing players, let alone Africa. These countries have an entirely legitimate expectation of cheap, abundant and reliable energy for their billions of citizens which isn’t going to go away. The book really doesn’t deal with this subject in much depth, but to be fair it doesn’t really set out to.

I could go on for a lot longer but I’ll stop there. For myself I was a Plan E man before reading the book and I am more of one now. But it could be that it’s a bit of a Rorsacht test too! All in all I expect this to stay a top recommendation from me for someone interested in the energy debate, it’s well worth getting a copy.

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