As happened in February during an unexpected freezing spell, the stresses on the system appear to result from outages of conventional power plants during a peak demand period. Some 3,000 MW of generating capacity (enough to serve the equivalent of 600,000 homes during high demand periods, or around 2.5 million homes during normal use), apparently conventional power plants, were out of service yesterday.
According to a blog article by Elizabeth Souder of the Dallas Morning News, "The high temperatures also caused about 20 power plants to stop working, including at least one coal-fired plant and natural gas plants." Souder noted that a spokesman for the Electricity Reliability Council of Texas (ERCOT), the company that manages system operations, "said such outages aren’t unusual in the hot summer, and Texas is getting some juice from surrounding states and from Mexico."
Meanwhile, some 1,800 MW of wind farm generation were available yesterday, more than double the 800 MW that ERCOT counts on during periods of peak summer demand for its long-term planning purposes. 1,800 MW of wind power is enough to power about 360,000 homes under the very high electricity demand seen yesterday.
American Wind Energy Association Manager of Transmission Policy Michael Goggin commented, "Like the Texas blackouts in February in which cold weather caused around 80 mostly fossil-fired power plants to shut down unexpectedly, this episode illustrates how common forced outages are at conventional plants, and drives home the point that no power plant is available 100% of the time. And, unlike wind energy, which ramps down gradually over a sustained period of time and is predictable, conventional power plants fail instantaneously. Wind energy is a valuable tool to diversify our portfolio of energy resources and make it more reliable. Wind plants are keeping the lights on and the air conditioners running for hundreds of thousands of homes in Texas."
By Tom Gray, www.awea.org/blog/