Monday morning, as a jet stream brought frigid air south to the central United States, Texas residents found themselves facing rolling blackouts as the statewide grid struggled to meet demand amid a large shortfall in generating capacity. As the day wore on, many saw these blackouts extend for ever longer periods of the day, and grid authorities are expecting problems to extend into at least Tuesday. As of noon local time on Monday, the Southwest Power Pool, which serves areas to the north of Texas, also announced that demand was exceeding generating capacity.
The shortfalls appear to be widespread, affecting everything from wind turbines to nuclear plants. One source of trouble may be an increased competition for natural gas, which is commonly used for heating in the United States.
Texas is unusual in that almost the entire state is part of a single grid that lacks extensive integration with those of the surrounding states. That grid is run by an organization called ERCOT, the Electric Reliability Council of Texas, a nonprofit controlled by the state legislature.
According to a statement released today by ERCOT, the grid entered a state of emergency shortly after 1am on Monday, meaning it could no longer guarantee enough power generation to meet customer demands. This is because roughly 30 gigawatts of generation capacity has been forced offline.
While some early reports indicated that frozen wind turbines were causing significant shortfalls, 30GW is roughly equal to the entire state’s wind capacity if every turbine is producing all the power it’s rated for. Since wind in Texas generally tends to produce less during winter, there’s no way that the grid operators would have planned for getting 30GW from wind generation; in fact, a chart at ERCOT indicates that wind is producing significantly more than forecast
So while having Texas’ full wind-generating capacity online would help, the problems with meeting demand appear to lie elsewhere. An ERCOT director told Bloomberg that problems were widespread across generating sources, including coal, natural gas, and even nuclear plants. In the past, severe cold has caused US supplies of natural gas to be constrained, as use in residential heating competes with its use in generating electricity. But that doesn’t explain the shortfalls in coal and nuclear, and the ERCOT executive wasn’t willing to speculate.