(Bloomberg) -- Don’t point too many fingers at Texas wind turbines, because they’re not the main reason broad swaths of the state have been plunged into darkness.
While ice has forced some turbines to shut down just as a brutal cold wave drives record electricity demand, that’s been the least significant factor in the blackouts, according to Dan Woodfin, a senior director for the Electric Reliability Council of Texas, which operates the state’s power grid.
The main factors: Frozen instruments at natural gas, coal and even nuclear facilities, as well as limited supplies of natural gas, he said. “Natural gas pressure” in particular is one reason power is coming back slower than expected Tuesday, added Woodfin.
“We’ve had some issues with pretty much every kind of generating capacity in the course of this multi-day event,” he said.
The blackouts, which have spread from Texas across the Great Plains, have reignited the debate about the reliability of intermittent wind and solar power as the U.S. seeks to accelerate the shift to carbon-free renewable energy. Rolling outages in California last summer were blamed in part on the retirement of gas plants as the state pursued an aggressive clean-energy agenda.
Wind shutdowns accounted for 3.6 to 4.5 gigawatts -- or less than 13% -- of the 30 to 35 gigawatts of total outages, according to Woodfin. That’s in part because wind only comprises 25% of the state’s energy mix this time of year.
While wind can sometimes produce as much as 60% of total electricity in Texas, the resource tends to ebb in the winter, so the grid operator typically assumes that the turbines will generate only about 19% to 43% of their maximum output.
Even so, wind generation has actually exceeded the grid operator’s daily forecast through the weekend. Solar power has been slightly below forecast Monday.
“The performance of wind and solar is way down the list among the smaller factors in the disaster that we’re facing,” Daniel Cohan, associate professor of environmental engineering at Rice University, said in an interview. Blaming renewables for the blackouts “is really a red herring.”
That doesn’t mean that frozen turbines are playing no role in the energy crisis, which the grid operator has highlighted. Cody Moore, head of gas and power trading at Mercuria Energy America, noted that wind generation this week is down markedly this week from last week, possibly indicating that turbines are automatically shutting down due to ice.
“We are seeing wind generation down 60% week-over-week,” said Matt Hoza, manager of energy analysis at BTU Analytics. But wind and solar that are operating “are in a very advantageous position” as power prices have topped $1,000 a megawatt-hour.
The situation raises questions about the grid’s preparedness. “Grid demand is so much higher than we’ve really built the system for in the wintertime,” said Joshua Rhodes, a research associate at the University of Texas at Austin.