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Over the last ten days, I’ve been reading “Sustainable energy – without the hot air“.

It’s no surprise that the reviews for it on Amazon.com are, at time of writing, 95% 5-star, and only 5% 4-star.  In many way, this an exemplary book:

1. The book is made up of easily digestible chunks;
2. Each chunk contains numbers.  Anyone who disagrees with the conclusions of the book is therefore invited to identify the numbers that they disagree with;
3. In each case, the author explains where the various numbers come from;
4. The author makes the numbers seem plausible, but also provides copious references for people to investigate by themselves;
5. Mathematical formulae are provided too – but separated into appendices at the end of the book, to avoid detracting from the main flow of the argument;
6. The author punctures a lot of what might be called “hot air” – which he also calls “twaddle”: wishful thinking about how sustainable energy might be achieved;
7. There are many “mythconceptions” sections where various widespread notions are gently but firmly dismantled;
8. The text is accompanied by a set of very clear diagrams;
9. The author sets out a range of possible solutions, rather than identifying a single way forwards;
10. The author makes it clear that none of the solutions are going to be easy, and each will require substantial (“country-sized”) changes.

Since publishing the book, the author – David JC MacKay, physics professor at Cambridge University – has been appointed Chief Scientific Advisor at the UK’s Department of Energy and Climate Change – an appointment that took effect on 1st October 2009.

The author says he seeks to avoid being labelled as “pro-wind” or “pro-nuclear”, declaring instead that he wishes to be known as “pro-arithmetic”.  Whatever solutions are contemplated, he says, must meet the test of adding up.  He disagrees with those who say that “if everyone does a little, it will add up to a lot”.  Instead, he says, if everyone does a little, it will add up to a little.  That’s because of the scale of the total amount of energy used by an entire country.  Actions need to be effective:

Here are two simple individual actions. One is useless, one is very effective.

Turning phone chargers off when they are not in use is a feeble gesture, like bailing the Titanic with a teaspoon.

The widespread inclusion of “switching off phone chargers” in lists of “10 things you can do” is a bad thing, because it distracts attention from more effective actions that people could be taking.

In contrast, turning the thermostat down (or the air-conditioning in hot climates) is the single most effective energy-saving technology available to a typical person.

Every degree you turn it down will reduce your heating costs by 10%; and, speaking of Britain at least, heating is likely to be the biggest form of energy consumption in most buildings.

The entire book is available free online.  The online summaries (eg page 238–239) reiterate the following point:

We have a clear conclusion: the non-solar renewables may be “huge,” but they are not huge enough. To complete a plan that adds up, we must rely on one or more forms of solar power. Or use nuclear power. Or both.

Any viable solar power solutions need to consider collecting energy from sunnier climates, and then transporting huge amounts of that energy to sun-deprived countries like the UK.  From page 178:

…focusing on Europe, “what area is required in the North Sahara to supply everyone in Europe and North Africa with an average European’s power consumption? Taking the population of Europe and North Africa to be 1 billion, the area required drops to 340 000 km², which corresponds to a square 600 km by 600 km. This area is equal to one Germany, to 1.4 United Kingdoms, or to 16 Waleses.

The UK’s share of this 16-Wales area would be one Wales: a 145 km by 145 km square in the Sahara would provide all the UK’s current primary energy consumption.

Backing up this idea, David MacKay speaks favourably about the Desertec concept.  From the Desertec website:

In the upcoming decades, several global developments will create new challenges for mankind. We will be confronted with problems and obstacles such as climate change, population growth beyond earth’s capacity, and an increase in demand for energy and water caused by a strive for prosperity and expansion.

The DESERTEC Concept provides a way to solve these challenges…

The DESERTEC Concept describes the perspective of a sustainable supply of electricity for Europe (EU), the Middle East (ME) and North Africa (NA) up to the year 2050. It shows that a transition to competitive, secure and compatible supply is possible using renewable energy sources and efficiency gains, and fossil fuels as backup for balancing power.

A close cooperation between EU and MENA for market introduction of renewable energy and interconnection of electricity grids by high-voltage direct-current transmission are keys for economic and physical survival of the whole region. However, the necessary measures will take at least two decades to become effective. Therefore, adequate policy and economic frameworks for their realization must be introduced immediately. The role of sustainable energy to secure freshwater supplies based on seawater desalination is also addressed.

David MacKay’s chapter on nuclear energy is also an eye-opener.  It ably addresses the objections that have been made against nuclear energy.  Among the positive messages in this chapter:

…the nuclear energy available per atom is roughly one million times bigger than the chemical energy per atom of typical fuels. This means that the amounts of fuel and waste that must be dealt with at a nuclear reactor can be up to one million times smaller than the amounts of fuel and waste at an equivalent fossil-fuel power station.

…I conclude that ocean extraction of uranium would turn today’s once-through reactors into a “sustainable” option

…Japanese researchers have found a technique for extracting uranium from seawater at a cost of $100–300 per kilogram of uranium, in comparison with a current cost of about $20/kg for uranium from ore. Because uranium contains so much more energy per ton than traditional fuels, this 5-fold or 15-fold increase in the cost of uranium would have little effect on the cost of nuclear power: nuclear power’s price is dominated by the cost of power-station construction and decommissioning, not by the cost of the fuel. Even a price of $300/kg would increase the cost of nuclear energy by only about 0.3 p per kWh. The expense of uranium extraction could be reduced by combining it with another use of seawater – for example, power-station cooling.

…we must not let ourselves be swept off our feet in horror at the danger of nuclear power. Nuclear power is not infinitely dangerous. It’s just dangerous, much as coal mines, petrol repositories, fossil-fuel burning and wind turbines are dangerous. Even if we have no guarantee against nuclear accidents in the future, I think the right way to assess nuclear is to compare it objectively with other sources of power. Coal power stations, for example, expose the public to nuclear radiation, because coal ash typically contains uranium. Indeed, according to a paper published in the journal Science, people in America living near coal-fired power stations are exposed to higher radiation doses than those living near nuclear power plants.

…Spurred on by worries about nuclear accidents, engineers have devised many new reactors with improved safety features. The GT-MHR power plant, for example, is claimed to be inherently safe; and, moreover it has a higher efficiency of conversion of heat to electricity than conventional nuclear plants

…the volumes are so small, I feel nuclear waste is only a minor worry, compared with all the other forms of waste we are inflicting on future generations. At 25 ml per year, a lifetime’s worth of high-level nuclear waste would amount to less than 2 litres. Even when we multiply by 60 million people, the lifetime volume of nuclear waste doesn’t sound unmanageable: 105 000 cubic metres. That’s the same volume as 35 olympic swimming pools. If this waste were put in a layer one metre deep, it would occupy just one tenth of a square kilometre.

There are already plenty of places that are off-limits to humans. I may not trespass in your garden. Nor should you in mine. We are neither of us welcome in Balmoral. “Keep out” signs are everywhere. Downing Street, Heathrow airport, military facilities, disused mines – they’re all off limits. Is it impossible to imagine making another one-square-kilometre spot – perhaps deep underground – off limits for 1000 years?

…the assertion that “civil nuclear construction on this scale is a pipe dream, and completely unfeasible” is poppycock. Yes, it’s a big construction rate, but it’s in the same ballpark as historical construction rates.

So far, I haven’t found any significant criticism of the points made in this book.  It’s highly recommended.  You may also enjoy David MacKay’s blog.

Footnote: for further reading on nuclear energy, take a look at “10 reasons to support nuclear power“; and for more about Desertec, see their FAQ.