Song for Jasmine

“Sustainable Energy – without the hot air” is a book by David MacKay. It’s a thorough but clear analysis of how Britain could attempt to satisfy its present power-requirements without trashing the climate.

The book is available on the web for free download as a PDF and in other formats. David is more interested in having the book read than in making a profit from it. If you’d like to have a taste before reading the whole book, you can start with the 10-page summary he also provides on his site.

I think this is one of the most important books on tackling climate change that I have come across. Anyone who wishes to understand the complex question of how to reduce the carbon footprint of a nation should definitely read it. There are several reasons why I think that, here are some of them.

Though David is a every inch a scientist, the book is written in plain english, you don’t need a PhD to understand it. That said, non-native English speakers may have to look up words like ‘twaddle’ in a dictionary from time to time.

David starts by considering how much energy the British need to run their daily lives. By converting all uses of energy to a single unit he can produce a simple yet useful picture that includes electricity, transport, heating, food, and other lifestyle factors. This makes it easy to see what part of our lives is responsible for consuming energy, which makes it easy to see where we should look if we want to make changes.

He does not promote or favour a particular technology as part of the solution. He is not pro-wind, pro-solar, pro-nuclear, or pro-clean-coal. Nor is he against any of these or other climate-friendly energy-generation technologies. He considers all possible contributions to lowering Britain’s carbon footprint. Then he goes on to see if any different mix of technologies can possibly meet Britain’s energy requirements, or if it simply doesn’t add up. This makes the whole book very easy to comprehend.

He keeps things simple by looking only at what could potentially be done, if we captured all the available sources of energy. So, he looks at the total amount of wave-power energy arriving along the entire Atlantic coast. He looks at the total solar power we could get if we put panels on every south-facing rooftop. He considers the power we could get from wind if we put up turbines everywhere we feasibly could. He clearly and concisely works out what we could hope to get if we deploy these and other technologies on a nation-wide scale.

He is fully transparent about everything he does. All his assumptions are explained, he tells us where all his numbers come from, and he gives references to the material he used. So you can check his numbers yourself, there is no need to decide if you trust him or not. It’s all there for you to verify. He also uses round numbers, rather than quoting calculations to 10 decimal places like Spock in Star Trek, so we can follow the big picture more easily.

He does not rule out anything for political reasons, or for ethical reasons. He concentrates strictly on the basic facts instead. As he says:

and

These days, there is so much written about climate change and what we need to do about it, with so many people reaching different conclusions, that is can be very hard to know who to trust. Some authors have their own conclusions that they want to convince us to agree with, so they bias their writing. Some fail to take account of important factors, which makes their conclusions unreliable. Some are deliberately trying to mislead us, working to a hidden agenda, as happens in so many walks of life. Some, finally, are simply too difficult to understand, with complex arguments that non-experts have no hope of following. We live in a world where the opinion of an expert is considered suspect, and is often rejected because, being an expert, we believe that they must be biased.

The result is that we are left with a choice among different viewpoints without knowing the facts, without knowing who is right or wrong, who is honest and who is not, or who is trying to manipulate us for their own gain. That’s not a good position to be in. That’s why it’s refreshing to find a scientist who wants us to reach our own conclusions.

That, in a nutshell, is why this book is important. Rather than pushing an agenda, David wants us to understand the limits of what we can do, and must do. He looks at the possibilities to see how they adds up, and he wants us to understand how he does it.

David’s simple way of looking at how we use energy is to convert everything to kilowatt-hours (kWh). One kWh is the amount of energy used by a 1 kW appliance left running for one hour. A 100 watt lightbulb running for 10 hours also uses 1 kWh. A 40 watt bulb would take 25 hours to use one kWh, and so on. Your electricity meter measures consumption in kWh, so it’s a sensible unit, we can all relate to it because it appears on our monthly bills.

Other forms of energy can also be expressed in kWh. Driving the mythical average car 30 miles (50 km) consumes about 40 kWh of energy in the form of petrol. So if your commute to work is a 30-mile round trip, 5 days a week, that uses about the same amount of energy as running a 1 kW heater all day long, every day. The heater would use 1 kW x 168 hours per week = 168 kWh per week, the car would use 40 kWh per day x 5 days, which equals 200 kWh. That’s close enough to being the same thing, as I’m sure David would agree.

Similarly, if you take one long-distance flight per year, that also works out to be the equivalent of 30 kWh per day for that year. So just getting to your holiday destination uses the same amount of energy as if you left a 1 kW heater on all day long, every day, for the whole year.

That’s not to say that these things are exactly equal. After all, if you do leave your heater on for a year, you won’t suddenly wake up in the Bahamas on New Year’s Day (more’s the pity!). But it does allow you to start comparing things. 1 long-distance-flight = commuting 30 miles per day to work for a year = a 1 kW heater left on all year long. So, if you want to reduce your carbon footprint, you might consider car-pooling with a colleague, which will halve your energy consumption for your commute. Or, if you could cut out that long-distance flight, that’s going to be twice as effective, equivalent to taking your car off the road completely!

David does all the other sums for us too. Heating accounts for 37 kWh per person per day. Lighting accounts for 4 kWh, electrical and electronic gadgets (such as computers, phones, stereos and vacuum cleaners) consume about 5 kWh. The food we eat requires about 15 kWh to produce, when you add up everything that goes into it. Consumer goods (from cars to newspapers and other things that we buy) come with a cost of about 49 kWh. That huge number comes up when you take account of the energy needed to produce the raw materials, manufacture the object, use it, and dispose of it. Packaging alone adds 4 kWh per day to our consumption.

So do you unplug your phone-charger, as we are often told to do? Sure, go ahead, though it won’t make much difference. Change your light bulbs and turn down your thermostat? Definitely some savings to be had there. Trade in that SUV for a real car? Great idea! Don’t overlook how much you can save in other ways, like not buying stuff you don’t need, and not throwing things out when there’s still some use in them. Small economies and reducing waste are always a good idea, but we need to make bigger changes, on a national scale, if we want to save the planet.

David also tackles the question of how to look at the energy needs of the entire country. This is where many analyses come unstuck. For example, take the recently announced wave and tidal energy projects in Scotland. These are described with phrases like “major milestone”, and “Saudi Arabia of marine power”. These projects between them will yield the same amount of electricity as a large nuclear power station. That sounds impressive, but is it really? Could we simply build more of these and satisfy our energy needs that way?

David MacKay points out that Britain has about 1000 km of Atlantic coastline, and the waves crossing it have an energy of 40 kW per metre of coastline. If we build wave-machines that can collect half of that, and build enough to cover half of our coastline, we would get (drum roll please) 4 kWh per person, per day. [update: See also "Tidal power - no thanks" in New Scientist]

That’s not so much after all, just enough to keep the lights on. Is it worth covering half the coastline with wave machines for that? It certainly doesn’t sound like Saudi Arabia to me!

Using a similar approach, David calculates that if we were to cover one tenth of Britain with windmills, that would give us each 20 kWh per day, or one sixth of what we currently use. Covering every south-facing roof with solar water-heating panels would give us 13 kWh per day. Biofuels? If we converted all the farmland in Britain to producing biofuels, that would give at most 36 kWh each per day (and no more food!).

David then goes on to consider what mix of technologies might be used to balance the energy needs of the UK in some foreseeable future, and proposes a number of simple plans to illustrate the possibilities and the limits of what might be achievable. Rather than go into details about them here, I’ll let you read the book for yourself and see if any of them appeal to you.

If you have the slightest interest in sustainable energy, I urge you to read this book. It’s the best illustration I’ve seen of what it means to wean a nation off of fossil fuels. That’s something that is really difficult to grasp, it’s such an enormous undertaking, yet David presents it in a way that makes sense. If you don’t want to let yourself be fooled by people with their own bias or hidden agenda, this is the book you need.

David MacKay is a professor of natural philosophy at Cambridge University. At the beginning of October he started work for the Department of Energy and Climate Change (DECC) in the UK. He is now their Chief Scientific Advisor, and if you ask me he is clearly the right man for the job.

He’s written a book, Sustainable Energy – without the hot air, which you can download for free from the web (in several formats). Unlike many scientists, he’s an excellent communicator, able to put things in terms that are easy to understand with just a bare minimum of maths. As the book title suggests, he explains a lot about the realities of sustainable energy, in plain english, and with numbers to put it all into context and to set the scale of things.

For example, he converts everything to kilowatt-hours, the amount of energy used by leaving a 1 kW heater on for one hour. By converting everything to the same units, he makes it easier to compare things directly, like the energy you use by driving your car, flying off on holiday, or heating your bath. The kilowatt-hour is also the unit you are charged for on your electricity bill, so it’s something we can all relate to.

He doesn’t have a personal agenda to promote, either. Or rather, he does, but his agenda is to ensure that people can make informed decisions on their own, based on the facts. As he says:

and

As a scientist, he obviously accepts the concensus view that we need to stop using fossil fuels, and fast. He points out that nine-tenths of the electrical power in Britain comes from fossil fuels, so replacing it means increasing the amount of every other form of energy by a factor of 10, or some equivalent mix.

The British are famous for opposing change. Brits are opposed to having windmills, wave-machines, or nuclear power stations anywhere near them, protest groups will spring up like daisies anywhere you propose to put them. There are currently about 2400 wind turbines in Britain; if we were to attempt to power Britain from wind alone, we would need 600,000 of them. That’s 6 wind turbines per square mile (2.5 per square kilometer). Next time someone tells you that Britain could be powered by wind alone, ask them where they’re going to put all those turbines!

Nor is it easy to construct that many wind turbines. They take a lot of steel and concrete to build, and a lot of cable to connect them to the electrical grid. Barry Brook has an excellent article about the cost and effort of building such infrastructure (I’ve borrowed one of his charts, on the right).

Barry is not the only one speaking out, the Institute of Mechanical Engineers have recently criticised the UK government for setting climate-targets without providing the support needed to make them happen. They say there’s no way to build that much new infrastructure without a significant change of strategy.

I’m sure they’re right, but I’m not convinced by some of their proposals for solving the problem, which include carbon capture and storage (as yet unproven) and building ‘artificial trees’ (also unproven technology). I guess engineers would naturally choose an engineering solution! However, they also propose giving much more authority to the DECC, where David MacKay has just started work, and that sounds like a great idea to me.

David has a real knack for putting all these facts and figures into easily understandable forms. But rather than me telling you about him, why not take a look at the video and see for yourself. It’s only six minutes long. (Thanks to Charles Barton of The Nuclear Green Revolution, which is where I found it!)

If you like the video, why not read David’s book, or maybe start with his own 10-page synopsis of it if you’re pressed for time. You’ll get a clear, no-nonsense analysis of what it means to power Britain with sustainable energy, with no politics attached. Though his analysis is specific to the UK, many of the lessons apply elsewhere, of course.

I find it very encouraging that the UK government has decided to listen to David. I hope more people do too, he’s someone we can all understand.