DAVID MACKAY: How 125 light bulbs can end the energy crisis

The public debate about our energy crisis will be a waste of time – unless we start using numbers we all understand.

To survive, we need to know how much energy we use, decide how much energy we would like to use in the future and learn how much energy each future source could supply. Then we can have a constructive conversation about our realistic options.

But we have to have a universal way of measuring these things – and that’s where the humble light bulb comes to our rescue.

One 40-watt light bulb, left on 24 hours a day, uses energy at a rate of about one kilowatt-hour per day and would cost about 10p. So how many ‘light bulbs’ of energy do you need?

Daily Mail