Xcel's Wind Power Experiments May Only Multiply Questions for the Industry

(MoneyWatch)  There are a lot of ideas in the air to help bring wind power mainstream. The fickleness of the wind is a major inhibitor to its broad adoption; ideas for a solution include building massive transcontinental energy grids (after all, the wind is always blowing somewhere) and various schemes to store up energy, for example by pumping pressurized air into caves.

Now Xcel Energy wants to give old-fashioned battery power a whirl, reports the Scientific American:

The energy storage in question--a series of sodium?€"sulfur batteries from Japan's NGK Insulators, Ltd.--can store roughly seven megawatt-hours of power, meaning the 20 batteries are capable of delivering roughly one megawatt of electricity almost instantaneously, enough to power 500 average American homes for seven hours. "Over 100 megawatts of this technology [is] deployed throughout the world," Novachek says. The batteries "store wind at night and they contract with their utility to put out a straight line output from that wind farm every day."

Xcel is only the latest company to look at power storage for wind. The trouble is, we've never had to store up such massive amounts of energy before. The best example to date is dams, where a hydro power plant can build up a reservoir to provide power in lean times. That's no help for wind turbines, so the folks at Xcel -- and everyone else -- are having to figure out their own best solutions.

The problem, Xcel's Novachek admitted to SciAm, is that at the moment batteries are "a little too expensive," costing $3 million per megawatt of energy. So for a gigawatt of wind power, or enough to put a smallish coal plant offline, batteries could pad the bill by a cool $3 billion. Ouch.

That's not to say that every megawatt of wind energy needs an equal amount of battery storage, or that costs won't come down at all. Unfortunately, in the world of energy production, every cent counts. In the public accounting of wind power's costs, storage has never been factored in.

That's too bad, because the hope is that wind will eventually be a major contributor. But as wind power rises to ten percent and more of any given area's energy mix, storage will become increasingly important. Without a serious breakthrough in technology, energy companies may need to emulate the home solar market, and find ways to get creative with their financing (and, perhaps, their accounting).