Friday 3 August 2007

The Grid Is the Battery

Wind turbines are a great low-carbon power source because once you build the turbine, the "fuel" - the wind - is free. But the wind doesn't always blow when demand for power is high. For wind power to catch on, you need a way to store that power.

Last year I was contacted by a pair of MBA students at London Business School seeking technical help for a project. They were evaluating the prospects for an American company that's developed an innovative power storage system for large-scale wind turbines. That system, which uses compressed air to store energy, may offer some cost and environmental advantages over traditional banks of batteries.

"But there's another option," I told the students. If you occasionally have more power than you need, why not just sell it to someone else over the electricity grid? And when you have a shortfall because the wind isn't blowing, you can buy some back."

In other words, use the electricity grid as your battery. Even if you have to pay a premium for the electricity you buy back, this is often more cost-effective than investing in an expensive onsite power storage system.

On a household level this is called "reverse metering" (I blogged about this a few months ago), and it has helped solar power take off in California and elsewhere.

Now The Economist magazine has caught on. Last week they published a great article calling for an interconnected electricity grid covering all of Europe. A project like this could lead to a huge surge in windpower, big enough to provide 30% of Europe's electricity and displace some of the continent's coal and nuclear power stations. As the authors rightly point out, the wind is usually blowing somewhere, so if your local wind turbines aren't spinning, someone else's will be. And with a big enough pool of electricity users, your excess wind power can be used by someone else, without the need for batteries.

Decentralised windpower with batteries or compressed air storage is a great idea for remote installations that can't be reached by power lines.

But if you want to see wind power really take off, remember: the grid is the battery.

(Carbon Clear homepage)