Big battery: Wind turbines charge these large-scale batteries in Luverne, Minn., while the wind blows. If the breeze calms, the batteries keep power flowing into the utility grid. (Courtesy of XCel Energy)
From The Christian Science Monitor:
Since sunlight and wind can be unreliable, renewable utilities install big backups.
One evening in late February 2008, the famously steady winds of west Texas began to wane until, at last, hundreds of giant wind turbines were becalmed – their enormous blades slowed or stilled.
In just three hours, grid operators at the Electric Reliability Council of Texas watched wind power output fall by 1,400 megawatts – power needed to supply roughly 600,000 homes. Following emergency procedures, a blackout was avoided by quickly cutting power to several industrial customers.
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