od energy group read

David adopts an avowedly arbitrary definition of a sustainable burn rate: can a burn-rate be sustained for 1000 years? If yes, it is sustainable. That definition allow shim to relate the UK's coal reserves with a daily per person sustainable consumption rate --- there would be less than 1 kWh of electricity per person available from clean coal. But we consume 180 kWh/day/person, so clean coal is a stop gap --- it will not see our way of life go on for that long. This relies pretty crucially on the definition of sustainability, which I think is wrong for the purpose. David adopts what one might call the Ise Shrine notion of sustainability. The Ise Shrine was first built in 4BC and has been rebuilt, identically, ever since then every 20 years. It was last rebuilt in 1993. This is "sustainability" as in keeping on and on doing the same thing. David is ISe-esque in choosing our ability to do the same thing - burn British coal - for a very long time to come.

The nuclear decommissioning authority has an annual budget of £2 billion. In fact, this clean-up budget seems to rise and rise. The latest figure for the total cost of decommissioning is £73 billion. news.bbc.co.uk/1/hi/uk/7215688.stm

It’s been estimated that making each unit of petrol requires an input of 1.4 units of oil and other primary fuels (Treloar et al., 2004).

The total amount of car travel in the UK is 686 billion passenger-km per year, which corresponds to an “average distance travelled by car per British person” of 30 km per day.

I want to estimate the energy consumed by someone who chooses to drive

The lion's share of the money is thus cleaning up military mess, not civilian-power mess.

a little adds up to a lot,” if all those “littles” are somehow focused into a single “lot” – for example, if one million people donate £10 to one accident- victim, then the victim receives £10 million. That’s a lot. But power is a very different thing. We all use power. So to achieve a “big difference” in total power consumption, you need almost everyone to make a “big” difference to their own power consumption.

by reducing our population

Many gadgets consume a surprising amount of power on standby. David cut his electricity consumption by half by making sure his "vampire appliances" were kept off. There are real savings available here. David and friends set up "ReadYourMeter.org" to try to encourage others to make this sort of saving. According to the International Energy Agency, standby power consumes a surprising8% of residential electricity.

Sustainable Energy - without the hot air

Least woolly of all is David MacKay’s book (which can be bought or downloaded free from www.withouthotair.com). Irritated by the waffle that often surrounds discussions of energy and climate change, Mr MacKay, a physicist at Cambridge University, has chosen to illustrate the challenge of breaking our fossil-fuel addiction armed only with the laws of physics, reams of publicly available information and the back of an envelope.

For forest-dwellers, there’s wood. For everyone else, there’s heat pumps.

143The average internal temperature in British houses in 1970 was 13 °C! Source: Dept. of Trade and Industry (2002a, para 3.11)

In Japan, thanks to strong legislation favouring effi- ciency improvements, heat pumps are now available with a coefficient of performance of 4.9.

What’s a reason- able thermostat setting to aim for? Nowadays many people seem to think that 17 °C is unbearably cold. However, the average winter-time tempera- ture in British houses in 1970 was 13 °C!

How much energy does Britain use - and how much could we generate without burning fossil fuels? Physics professor David MacKay has been doing the sums.

The average winter-time temperature in English homes in 1970 was 13C. Today, 50% more than that is usually thought of as just about tolerable. There are three strategies for reducing the carbon footprint of keeping warm: reduce the temperature difference between the inside and outside; reduce heat losses from inside to outside and increase the efficiency with which energy is transformed into heat. The first two seem obvious and cheap solutions. We hear a lot about "nudging" as a policy, and this seems an ideal area for clever devices to make people aware that they could be heating less and leaking less heat. David does not mention my own favourite long term solution here---a widespread move to small exoskeletons as a substitute to housing: we should be able to walk around with our temperature control close to our bodies and our living spaces open to the elements. David makes a powerful argument for heat pumps rather than Combined-Heat-and-Power plants, and slips in a big fault-line in eco-politics versus eco-engineering: energy transformation efficiency tends to rise as scale rises, whereas green politics loves to decentralise and make solutions small and local. This chapter is full of low-ish tech, labor-intensive investments that make energy-efficiency sense today. This is just what government policy should be stimulating our economies with today.

A final impediment to rational discussion of combined heat and power is a myth that has grown up recently, that decentralizing a technology somehow makes it greener. So whereas big centralized fossil fuel power stations are “bad,” flocks of local micro-power stations are imbued with goodness. But if decentralization is actually a good idea then “small is beautiful” should be evident in the numbers. Decentralization should be able to stand on its own two feet. And what the numbers actually show is that centralized electricity generation has many benefits in both economic and energy terms. Only in large buildings is there any benefit to local generation, and usually that benefit is only about 10% or 20%.

Electrify transport. There's not much to beat trains+bicycles, and any government looking for a Keynesian stimulus should find lots of infrastructure opportunities here. David MacKay comes down softly on the car---which shows great realism---and finds that electrification is the only real solution there. He debunks hydrogen as a good energy carrier. Flying is a really tough case---there is not much that can be done to reduce its energy intensity. (I was sitting in an easyjet plane the other day that tried to convince me of its greenery by saying: "Flying contributes less CO2 than driving to the atmosphere" ...). Batteries are the way to go---though just wait for the peak lithium scares. David has an interesting aside on nuclear ships. If we could make the (political) world safe for small-scale nuclear power, maybe there's more than ships that could benefit.

The congestion charge would be proportional to the number of bleeps received; this charge could be paid at refuelling stations whenever the vehicle is refuelled. The radio transmitter/receiver would replace the current UK road tax disc.

there is no prospect of significant improvements in plane efficiency.

the amount of lithium may be a concern, especially when we take into account the competing ambitions of the nuclear fusion posse (Chapter 24) to guzzle lithium in their reactors.

So I conclude that switching to electric cars is already a good idea, even before we green our electricity supply.