January's polar vortex knocked several important coal-fired electricity plants in Texas offline, and the Sierra Club on Tuesday said the loss of power shows the state needs more wind turbines and energy conservation programs to avoid possible rolling blackouts.
The Electricity Reliability Council of Texas, which operates the grid that supplies electricity to 85 percent of Texans, issued a report on Friday detailing how six coal-fired plants either shut down or failed to provide the energy expected on Jan. 6, when a cold air mass brought frigid temperatures to Texas.
The temperature did not drop as low as it did in February 2011, when ERCOT resorted to rolling blackouts due to lack of power, but the sudden loss of power on Jan. 6 triggered an Energy Emergency Alert. Frozen instruments were the most-cited problem for why the plants shut down or failed to produce as expected.
Al Armendariz of the Sierra Club said wind energy and conservation efforts, known as demand response, proved their value.
"This new report from ERCOT shows that clean energy solutions, especially clean, cheap Texas wind and demand response performed as expected and under pressure, whereas numerous coal-fired and gas-fired power plants across the state couldn't handle the January cold snap," he said.
Conservative lawmakers in Austin have complained about tax breaks provided to wind companies, while generators have complained that low natural gas prices make it economically unfeasible to improve their existing plants or build new ones. Environmentalists want to shut down older coal plants, which they say create too much pollution.
The blackouts in February 2011 led to special legislative hearings, and power generators promised to weatherize their equipment to prevent future outages. ERCOT fined Luminant $750,000 for failing to supply the power it promised.
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In January, the Lower Colorado River Authority's Sandy Creek coal-powered plant was the largest to go offline, along with two plants owned by Luminant and one owned by NRG. Other plants failed to produce as much energy as expected, creating an emergency, ERCOT's report said.
"The main contributing cause was the substantial amount of resource capacity lost," it said. "ERCOT has already (re)visited generation sites who immediately indicated performance issues related to the weather, and has scheduled to visit the others."
One of the major challenges for generators is the extreme swings in Texas weather. Designing and maintaining a power plant so that it can operate in August's high temperatures, when demand is greatest, is very different from ensuring the same plant won't shut down in cold weather.
Operators have called on the Public Utility Commission to change the state's electricity market to encourage construction of new plants. Electric utilities currently only pay for the power they use, while generators want to be paid to keep reserves available in extreme weather situations such as those on Jan. 6.
Consumer groups, environmentalists and businesses oppose creating a so-called capacity market.