Texas is the land of big things, so you knew when they decided to build a battery to act as a buffer for one of their giant wind farms, it was going to be huge.
The Notrees battery smooths out the delivery from the neaby Notrees Wind Farm, by storing up energy when the wind is strong but demand is weak, then dishing it out again if the wind dies down. With a storage capacity of 24 MWh, or 24 million watts for an hour, it can deliver as much as 36 million watts for shorter bursts of up to 15 minutes. That should put your D cells to shame.
Duke energy comissioned the battery's construction from a local Texas company called Xtreme Power, with the goal of making wind power just as flexible as fossil fuel burning power plants. That might seem like a strange route to take in the middle of Texas oil country, but the region is rapidly becoming a leader in renewable energy sources too.
The long term plan is to use the Notrees battery along with several similar projects, to test the viability of energy storage batteries for all kinds of green power solutions. U.S. Energy Secretary Steven Chu recently said that "without technological breakthroughs in efficient, large-scale energy storage, it will be difficult to rely on intermittent renewables for much more than 20 to 30 per cent of our electricity." I guess what surprises me is that it's a bunch of former Texas oilmen who are leading the way.
Via New Scientist