Sustainable Design Update

Wind Turbines in Minnesota

The intermittent nature of wind presents a challenge we must face as we transition to greater usage of renewable energy.  Xcel Energy has 1.1 gigawatts of wind turbines installed in Minnesota. They hope to triple that amount by 2020.  Xcel, in an effort to increase the efficiency of their wind power systems, and combat the intermittent nature of wind has installed a bank of sodium-sulfur batteries capable of storing 7 megawatt-hours of electricity.  From the article in SciAm:

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.”

That removes one of the big hurdles to even broader adoption of wind power: so-called intermittency. In other words, the wind doesn’t always blow when you want it to, a problem Texas faced earlier this year when a drop in wind generation forced cuts in electricity delivery. But with battery backup, the 11-megawatt wind farm outside Luverne, Minn., can deliver a set amount of electricity at all times, making it more reliable or, in industry terms, base-load generation. Plus, the battery effectively doubles the wind farm’s output at any given moment—both the megawatt being produced by the wind farm itself (that would otherwise have gone to charging the battery) and the megawatt delivered by the battery.

From what I have been able to glean from the interwebs, sodium-sulfur batteries are excellent batteries for storing grid energy.  They are made from inexpensive, abundant materials, have a high energy density and have high efficiency charge/discharge cycles.

-Ben Connor Barrie

Picture via: -Chad Johnson

This entry was posted on Monday, December 29th, 2008 at 7:37 pm and is filed under Sustainability. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.