This is the scariest chart I’ve seen all week. It’s from this week’s Economist, which has a sobering piece about the prospect of brown-outs in Britain in the not-so-distant future — like 2012, depending on what Vladimir Putin’s mood is like at the time.

IN THE frigid opening days of 2009, Britain’s electricity demand peaked at 59 gigawatts (GW). Just over 45% of that came from power plants fuelled by gas from the North Sea. A further 35% or so came from coal, less than 15% from nuclear power and the rest from a hotch-potch of other sources. By 2015, assuming that modest economic growth resumes, a reasonable guess is that Britain will need around 64GW to cope with similar conditions. Where will that come from?

North Sea gas has served Britain well, but supply peaked in 1999. Since then the flow has fallen by half; by 2015 it will have dropped by two-thirds. By 2015 four of Britain’s ten nuclear stations will have shut and no new ones could be ready for years after that. As for coal, it is fiendishly dirty: Britain will be breaking just about every green promise it has ever made if it is using anything like as much as it does today. Renewable energy sources will help, but even if the wind and waves can be harnessed (and Britain has plenty of both), these on-off forces cannot easily replace more predictable gas, nuclear and coal power. There will be a shortfall—perhaps of as much as 20GW—which, if nothing radical is done, will have to be met from imported gas. A large chunk of it may come from Vladimir Putin’s deeply unreliable and corrupt Russia…

Something will have to give. My hunch is that it’ll be the UK’s carbon emission targets.