Via theCLog. More from the guardian.co.uk:

For decades, “grid parity” has been the Holy Grail for alternative energy. The rap from critics was that technologies like wind and solar could not compete, dollar-for-dollar, with conventional electricity sources, such as coal and nuclear, without large government tax breaks or direct subsidies. But suddenly, with rapid technological advances and growing economies of manufacturing scale, wind power is now nearly at grid parity — meaning it costs roughly the same to generate electricity from wind as it does from coal. And the days when solar power attains grid parity may be only a half-decade away.

So with grid parity now looming, finding ways to store millions of watts of excess electricity for times when the wind doesn’t blow and the sun doesn’t shine is the new Holy Grail. And there are signs that this goal — the day when large-scale energy storage becomes practical and cost-effective — might be within reach, as well. Some technologies that can store sizeable amounts of intermittent power are already deployed. Others, including at least a few with great promise, lie somewhere over the technological horizon.

New storage approaches include improvements to existing lithium ionbatteries and schemes to store energy as huge volumes of compressed air in vast geologic vaults. Another idea is to create a network of small, energy-dense batteries in tens of millions of homes. Under such a “distributed storage” scheme, utility computers could coordinate electricity flows over a “smart grid” that continually communicates with — and adjusts the flow of power to and from — local batteries. This would even include batteries in future plug-in hybrid or all-electric vehicles.

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