Endless Curiosity

April 12, 2009

The problems of renewable energy

Filed under: Climate Change — Alec @ 5:14 pm

A while back I went to a private screening of an incredible DVD called What A Way To Go, which is described as “A middle class white guy comes to grips with Peak Oil, Climate Change, Mass Extinction, Population Overshoot and the demise of the American Lifestyle“. After watching the documentary there was a discussion about what we could do to help the situation. Since no one else wanted to talk, I offered the perspective that there wasn’t much we could do other than vote for the correct Presidential candidate in the next election.

The others pretty much ignored my suggestion and the rest of the discussion (at least until I left) revolved around ideas such as using fluorescent light bulbs and going to the Farmers’ Market – admirable ideas perhaps, but not ones that were going to solve the problem.

I was interested to read a piece in the Economist called Meltdown, which reviews three books about climate change. In particular the book Sustainable Energy: Without the Hot Air by David MacKay got a good writeup.

Mr MacKay favours no particular technology. He is concerned only that proposals to decarbonise the economy should add up. But his refreshingly hard-headed approach (confined to Britain, but easily adapted to other countries) comes to some sobering conclusions. Meeting Britain’s energy needs from onshore wind power would require covering literally the entire country in turbines, even assuming that the wind was guaranteed to blow. If only 10% of Britain were covered then wind could provide roughly a tenth of total demand. Switching every piece of agricultural land to biofuel production would provide just 12% of the requisite juice.

You can read a 10-page PDF synopsis of the book, and you can download the whole book as a .pdf file. Certainly the synopsis is worth reading, and if you like what you read, try the book.

Two quotes from the synopsis. The bold emphasis is mine, italic emphasis MacKay’s.

While working out the numbers for the left-hand red consumption stack, we debunk several myths. For example, “leaving mobile phone chargers plugged in” is often held up as an example of a behavioural ecocrime, with people who switch their chargers off being praised for “doing their bit.” The truth is that a typical mobile phone charger consumes just 0.01 kWh per day. The amount of energy saved by switching off the phone charger, 0.01 kWh, is exactly the same as the energy used by driving an average car for one second. I’m not saying that you shouldn’t switch phone chargers off. But don’t be duped by the mantra “every little helps.” Obsessively switching off the phone-charger is like bailing the Titanic with a teaspoon. Do switch it off, but please be aware how tiny a gesture it is. All the energy saved in switching off your charger for one day is used up in one second of car-driving. The energy saved in switching off the charger for one year is equal to the energy in a single hot bath. Your charger is only a tiny tiny fraction of your total energy consumption. If everyone does a little, we’ll achieve only a little.


The first half gives two clear conclusions. First, for any renewable facility to make an appreciable contribution – a contribution at all comparable to our current consumption – it has to be country-sized. To provide one 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 500 km of Atlantic coastline to be completely filled with wave farms. Someone who wants to live on renewable energy, but expects the infrastructure associated with that renewable not to be large or intrusive, is deluding himself.

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