Question: If we're running out of resources like coal to make electricity, why don't we just stop, or use less? We want to do things like washing up really fast, so we use electricity and clean water, but then we just use the spare time to just use more electricity. Wouldn't it just be easier to use electricity for things like making medicines, so we don't have to get more electricity, and use valuable resources?

Susan Cartwright answered on 23 Jun 2015:

Making more efficient use of energy is indeed a key strategy in the energy crisis. Incidentally, we probably do have considerable unused coal, but *nobody in their right mind* really wants more coal-fired power stations: coal mining is dangerous, coal mining waste is dangerous, they are very polluting (a coal-fired power station releases lead into the atmosphere, and more radioactivity than a nuclear station does) and they create a lot of CO2.

Dishwashers are actually more energy efficient than hand washing: they use electricity, but they use a lot less water, and water has to be purified before it is supplied to your house, and then heated for use in washing up. So you shouldn’t feel too guilty about using the dishwasher!

Focusing on electricity is probably misleading. Electricity can be generated using renewable sources like solar power; as I have said before, the key technology we need is a cheap, efficient, compact battery technology, to store solar power till we need it (the problem with solar power is that you can’t turn it on and off, and it is most abundant just when you need it least!) We have to look at all forms of energy: heating, for example, and transport. As an example, oil, gas or coal-fired power stations generate a lot of heat, as well as electricity (because no generator is 100% efficient, and the inefficiency generally winds up as heat). This heat is usually almost completely wasted. It would be much better to have smaller, more local power generation, so that the waste heat could be used to heat buildings, instead of just being expelled into the atmosphere or the nearest river. This is called “combined heat and power” (CHP). CHP is much more efficient in its use of fuel than separate heating and electricity: a gas-powered CHP plant can be 85% efficient, whereas obtaining the same level of electricity and heat from separate gas-fired power stations and gas-powered central heating would only be just over 50% efficient.

Nevertheless, it would be good to save electricity. It would also be good to reduce other energy use. More demanding specifications for housing would be a good start: you can reduce heating bills to almost nothing by designing the house to conserve heat, with much higher levels of insulation than normally supplied in houses. The idea of “just using electricity for things like making medicines” is a non-starter really, especially in a country as far from the equator as the UK: you *need* lighting in the winter, since it gets dark by 4 pm! Electricity is vital for refining aluminium – aluminium smelters often have their own power stations – and much other industry: you *could* try putting cars together by hand, but not if you want the result to be something you can afford. And electricity has the great advantage that you can change the method by which you generate it without having to change any of the rest of the infrastructure: your electric light or electric oven (or tram or electric train) doesn’t care whether the electricity it uses was generated by coal, oil, gas, nuclear, wind or solar. Therefore, the key to a effective energy strategy might actually involve *increased* use of electricity, e.g. electric rather than petrol-powered cars.