Yes, we can solve the energy crisis

The Sunday Times
May 10, 2009
The physicist's new book tries to make us face the facts on the energy that we use to keep our daily lives running smoothly

David MacKay

We have an addiction to fossil fuels, and it’s not sustainable. The developed world gets 80% of its energy from fossil fuels – Britain gets 90%. This is unsustainable for three reasons.
First, easily accessible fossil fuels will run out, so we will eventually have to get our energy from elsewhere.
Second, burning fossil fuels is having a measurable, and very probably dangerous, effect on the climate.
Third, even if we don’t care about climate change, a sharp reduction in Britain’s fossil-fuel consumption would seem a wise move if we care about security of supply. Continued rapid use of the North Sea oil and gas reserves will otherwise soon force Britain to depend on imports from untrustworthy foreigners. (I hope you can hear my tongue in my cheek.)
How can we get off our addiction to fossil fuels?
There is no shortage of advice on how to “make a difference”, but the public is confused, uncertain whether the schemes proposed are fixes or fig leaves. People are rightly suspicious when companies tell us that buying their “green” product means we have done our bit. They are equally uneasy about the national energy strategy. Are wind farms merely a gesture to prove our leaders’ environmental credentials? Is nuclear power essential?
We need a plan that adds up. The good news is that such plans can be made. The bad news is that implementing them will not be easy.
Can Britain, famously well endowed with wind, wave, and tidal resources, live on its own renewables?
We often hear that Britain’s renewables are “huge”. But it’s not sufficient to know that a source of energy is “huge”. We need to know how it compares with another “huge” – namely our huge consumption. To make such comparisons, we need numbers, not adjectives.
Where numbers are used, their meaning is often obfuscated by enormousness. Numbers are chosen to impress, to score points in arguments, rather than to inform. In contrast, my aim is to present honest, factual numbers in such a way that the numbers are comprehensible, comparable and memorable.
I express energies as quantities per person in kilowatt-hours (kWh), the same units that appear on household energy bills; and power is expressed in kilowatt-hours per day (kWh/d) per person. The charts (above right) illustrate a few quantities compared in these units. For example, driving an average car 50km a day uses 40kWh/d. In the graphic above on the right, some renewable resources are represented: covering 10% of the country with wind farms would yield 20kWh/d per person on average.
One reason for liking these personal units is that it makes it much easier to move from talking about Britain to talking about other countries or regions. For example, imagine we are discussing waste incineration and we learn that British waste delivers power of 7TWh (terawatt-hours) a year and that Denmark’s delivers 10TWh a year (1TWh is a billion kWh). Does this help us say whether Denmark incinerates more waste than Britain? While the total power produced from waste in each country may be interesting, I think that what we usually want to know is the waste incineration per person. For the record, that is: Denmark 5kWh/d per person; Britain 0.3kWh/d per person. So Danes incinerate about 13 times as much waste as Britons.
With simple, honest numbers in place, we are able to answer questions such as – can Britain conceivably live on its own renewable-energy sources? Will a switch to advanced technologies allow us to eliminate carbon-dioxide pollution without changing our lifestyle?
So how much energy do we use, and how much might we hope to generate from the potential renewable resources available in Britain?
In working out the consumption, we debunk several myths. For example, leaving mobile-phone chargers plugged in is often held up as an example of eco-crime, with people who switch their chargers off being praised for “doing their bit”.
The truth is that a typical mobile-phone charger consumes only 0.01kWh a day. The amount of energy saved by switching off the phone charger, 0.01kWh, is the same as the energy used by driving an average car for one second.
I am not saying that you shouldn’t switch off phone chargers. But don’t be duped by the mantra “every little helps”. Obsessively switching off the phone-charger is like bailing out the Titanic with a teaspoon. Do switch it off, but be aware how tiny a gesture it is. The energy saved in switching off the charger for one year is equal to the energy in a hot bath. If everyone does a little, we will achieve only a little.
Another memorable number is the contribution of long-distance flying to a person’s energy footprint. If you fly to Cape Town and back once a year, the energy you use in that trip is nearly as much as the energy used driving an average car 50km a day, every day, all year.
There are two clear conclusions from this. First, for any renewable facility to make an appreciable contribution – a contribution at all comparable with our current consumption – it has to be on a national scale. To provide a quarter of our current energy consumption by growing energy crops, for example, would require 75% of Britain to be covered with biomass plantations.
To provide 4% of our current energy consumption from wave power would require 500km of Atlantic coast line to be filled with wave farms. Someone who wants to live on renewable energy, but expects the infrastructure associated with that not to be large or intrusive, is deluding himself.
Second, if economic constraints and public objections are set aside, it would be possible for the average European energy consumption of 125kWh/d per person to be provided from these renewable sources.
The two big contributors would be photo-voltaic panels, which, covering 5% or 10% of the country, would provide 50kWh/d per person; and offshore wind farms, which, filling a sea area twice the size of Wales, would provide another 50kWh/d per person on average.
Such an immense panelling of the countryside and filling of British seas with wind farms (having a capacity five times greater than all the wind turbines in the world today) may be possible according to the laws of physics, but would the public accept and pay for such arrangements?
If we answer no, we are forced to conclude that current consumption will never be met by British renewables. We require a radical reduction in consumption, or significant additional sources of energy – or both.

Sustainable Energy – Without the Hot Air, by David MacKay, is published by UIT Cambridge, priced £19.99. Copies can be ordered for £17.99 with free postage and packing from The Sunday Times Books First on 0845 271 2135
PHYSICIST WHO TIRED OF THE NONSENSE BEING TALKED ABOUT ENERGY
DAVID MACKAY’s book Sustainable Energy – Without the Hot Air has become an unlikely hit among economists, politicians and anyone else with an interest in energy policy and climate change, writes Dominic O’Connell.
MacKay a Cambridge physicist whose specialities are computational neuroscience, information theory and machine learning, started writing it four years ago when he became irritated by the nonsense he heard being talked about energy, and in particular renewable energy.
“I was just driven crazy by the level of the debate – it was so polarised, so extreme.” He had written only a textbook before (“well-received”, he says), but he didn’t let this relative lack of experience stop him.
He published a draft on the internet four years ago, and amended it after receiving feedback from readers. All the equations, for example, were taken out of the main text and packed into appendixes. The book is still available online free at www.withouthotair.com.
It was published in December but didn’t take off until earlier this year when rave reviews from www.boingboing.net and The Economist (“a tour de force”) lead to the first print run of 5,000 selling out. Another, three times the size, should hit the shops in the next fortnight.
The book is not, as MacKay points out, about climate change. It is about energy – how much we use and how much might be available from renewable resources or other alternatives to fossil fuels. Its strength lies in its down-to-earth, nonpartisan approach, and from the use of snappy, easy-to-understand examples.
MacKay debunks, for example, the idea that switching off electrical appliances when not in use will make a big difference. Turning off your mobile-phone charger between charges for a year, he said, saves the same amount of energy required for one hot bath. As well as setting out the problem, he comes up with some possible solutions – it is not a pessimistic book.
He said if politicians want to enlist his services in formulating policy, he won’t say no. “I would be happy to get on a train and go to London. I am keen to help.”