Bit by bit, without really planning ahead or indeed any planning at all, I seem to be becoming a strident critic of microgeneration, i.e home-baked renewable power. I criticise the government, always an easy target, for their barmy zero carbon homes scheme and their mean stamp duty tax break for zero carbon homes. Then I turn my guns on Bill Dunster, a far less comfortable target for me as I am otherwise well-disposed towards him. I spend a couple of days worrying about whether I am just being spiteful for the sake of it. Maybe I am developing blogger syndrome where everything exists merely to be shot down in flames by cynics.
So I turn to Wikipedia and to trusty Excel and I start crunching some numbers. How do all the green and not-so-green methods of generating electricity stack up?
Turns out the UK is currently consuming 350 terawatt hours of electricity per annum. That’s 350,000,000,000 kWh. If you divide it by the 65 million people in the UK, it works out at a more manageable 5,300 kWh/annum each, round about average for Europe. In comparison, the USA consumes 12,000 kWh per annum each, India just 480 kWh per annum each.
Now, just suppose you were to try to make this amount of electricity using zero or low carbon sources. How would you go about it? Ignore for the moment all the arguments about practicalities and intermittent supply and everything like that.
350 terawatt hours per annum would require either
• 14,000 giant 10MW off shore wind turbines, operating at around 30% efficiency or
• 260 million 1kW micro wind turbines, operating at 15% efficiency, (that’s roughly ten mounted on every building in the land) or
• 4,000 sq km of PV cells. That’s pretty much the size of a county like Suffolk or Hampshire. Or enough to cover the south facing roofs of around 100 million homes — there are just 25 million in the UK or
• how about 25 European Pressurised Nuclear reactors (EPRs), as being built today in Finland? Each one is designed to have an output of 1600MW.
And what about comparitive costs?
Nuclear power plants cost around £1 billion each, so 25 No. would require £25 billion to supply UK’s 350TWh/a electricity needs. What is harder to factor in is the running costs and the clean-up costs at the end of the lifespan: nuclear power is notoriously difficult to cost because of this.
Giant off shore wind turbines. Around £5 million a piece, so 14,000 would cost £70 billion in total.
Micro-wind turbines. Around £1,500 each from B&Q, so 260 million would cost £525 billion in total.
PV arrays, around £1,000 per m2. A county-full would cost around £3,500 billion.
I think my case rests. Microgeneration is ridiculously expensive, just as I thought.