They like everything big in Texas, and wind energy is no exception. Texas has more wind generation capacity than any other state, about 9,700 megawatts. (That's nearly as much installed wind capacity as India.) Texas residential ratepayers are now paying about $4 more per month on their electric bills in order to fund some 2,300 miles of new transmission lines to carry wind-generated electricity from rural areas to the state's urban centers.
It's time for those customers to ask for a refund. The reason: When it gets hot in Texas—and it's darn hot in the Lone Star State in the summer—the state's ratepayers can't count on that wind energy. On Aug. 4, at about 5 p.m., electricity demand in Texas hit a record: 63,594 megawatts. But according to the state's grid operator, the Electric Reliability Council of Texas, the state's wind turbines provided only about 500 megawatts of power when demand was peaking and the value of electricity was at its highest.
Put another way, only about 5 percent of the state's installed wind capacity was available when Texans needed it most. Texans may brag about the size of their wind sector, but for all of that hot air, the wind business could only provide about 0.8 percent of the state's electricity needs when demand was peaking.
Why does Texas get so little juice from the wind when it really needs it? Well, one of the reasons Texas gets so hot in the summer is that the wind isn't blowing. Pressure gradients—differences in air pressure between two locations in the atmosphere—are largely responsible for the speed of the wind near the Earth's surface. The greater the differences in pressure, the harder the wind blows. During times of extreme heat these pressure gradients often are minimal. The result: wind turbines that don't turn.
Lest you think the generation numbers from Aug. 4 are an aberration, ERCOT has long discounted wind energy's capabilities. In 2007, ERCOT determined that just "8.7 percent of the installed wind capability can be counted on as dependable capacity during the peak demand period for the next year." And in 2009, the grid operator reiterated that it could depend on only 8.7 percent of Texas' wind capacity.
The incurable variability of wind is not restricted to Texas. Consider the problems with wind energy during the frigid weather that hit Britain last winter. In January, the Daily Telegraph reported that the cold weather was accompanied by "a lack of wind, which meant that only 0.2 [percent] of a possible 5 [percent] of the UK's" electricity was generated by wind over the preceding few days.
Understanding wind's unreliability is critically important now, at a time when America's basic infrastructure is crumbling and in desperate need of new investment. In June, the Government Accountability Office issued a report that said that "communities will need hundreds of billions of dollars in coming years to construct and upgrade wastewater infrastructure." Add in the need for new spending on roads, dams, bridges, pipelines, and mass transit systems, and it quickly becomes clear that politicians' infatuation with wind energy is diverting money away from projects that are more deserving and far more important to the general public.