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.

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.

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.