Sweet. A utility called American Electric Power is going to set up a huge bank of batteries to store wind power.

The short write-up in the NYT is both exciting, in that it’s good to see storage moving to the deployment phase, and sobering, in that it highlights the limitations of current battery technology.

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Here’s the setup:

The batteries can each deliver one megawatt of power — enough to run a medium-size shopping center — for a little more than seven hours. Replenished nightly, they give back about 80 percent of the electricity put into them. Each is the size of a double-decker bus, and installation is not permanent; they can be moved to another site as the need arises.

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The batteries will be built by NGK Insulators Ltd. of Japan. They use a sodium sulfur chemistry and operate at temperatures of more than 800 degrees Fahrenheit.

Unfortunately, at this stage, the bang-for-the-buck ratio isn’t great:

At least at this stage, saving money by storing a windmill’s production for peak-price hours will be difficult. The cost is very high, $27 million for six megawatts of capacity, or about $4,500 a kilowatt, including the price of substation improvements. Building a gas turbine of that size to meet peak needs would cost substantially less. …

And while the batteries are large by the standards of previous installations, they are small relative to wind production; one battery would hold about as much energy as a single large wind machine could produce in a day, Mr. DeMeo pointed out. And they are small relative to total energy demand.

We really, really need some big breakthroughs in storage, and soon. Coal isn’t waiting.