Adds details throughout
The US is facing its second day of widespread electricity outages, as record-breaking cold across the midcontinent keeps many power plants off line and unable to serve high demand.
Texas has been bearing the brunt of disruptions, with a peak of 4.5mn customers in the dark after a night where temperatures dipped to 13°F (-11°C) in Houston and 3°F in Dallas. The extreme cold and electricity outages have also taken 3.6mn b/d of refining capacity off line across the US Gulf Coast, according to the US Energy Department.
The Electric Reliability Council of Texas (ERCOT), which manages most of the state's electric grid, was able to restore service to some customers but said roughly 45GW of its generation is still off line. But an estimated 3.2mn customers in Texas lacked power service as of 5:10pm ET, according to utility data.
ERCOT this afternoon said it might have to curtail electric load again, if additional power generation becomes unavailable because of fuel supply problems or units tripping because of the extreme cold. Grid operators use rolling outages to avoid a supply-demand mismatch that could cause a cascading blackout.
"If we lose some generation in this process, we might have to go back and pick up the outages again," ERCOT chief executive Bill Magness said. "Because we cannot let ourselves tumble into a situation where by acting prematurely ... we end up in that blackout that could last an indeterminate period of time, maybe month."
Power outages yesterday also reached nearby states, as a dome of frigid air across the US midcontinent created extreme demand for electricity and natural gas. The Southwest Power Pool started rolling blackouts at 7:15am ET today, after low temperatures and "inadequate supplies of natural gas" curtailed generating capacity. The Midcontinent Independent System Operator said it would continue controlled electricity outages in southeast Texas through the end of today.
But power outages in those adjacent electric grids affected only about 400,000 customers in Louisiana and Oklahoma, or less than 2pc of customers, according to federal data. That is in contrast to Texas, where at peak about 27pc of the state did not have power.
'Unacceptable' situation
Texas governor Greg Abbott (R) today said situation was "unacceptable" and ordered the state's legislature to consider reforms at ERCOT, which is unique for its lack of interconnections to other electric grids that have allowed it to remain independent from federal oversight.
ERCOT started rotating power outages yesterday at 2:25am ET, when 30GW of generating capacity that went off line. Electric utilities say poor grid conditions over the past 36 hours have impeded their ability to actually rotate outages to new areas. ERCOT said today that about 29GW of its thermal capacity was off line, compared to outages of about 16GW of wind and solar, although ERCOT in winter planning expects only a fraction of wind and solar will be available.
Power generators can be vulnerable to cold weather, particularly in areas where the main concern is excess heat rather than the cold. Coal and gas-fired power plants can trip off line because of frozen sensors. Gas-fired plants are particularly vulnerable to fuel supply problems in winter because many do not pay for firm pipeline capacity.
"It appears that a lot of the generation that has gone off line today tripped, or had to come off line, primarily due to issues on the natural gas system," ERCOT senior director of systems operations Dan Woodfin said.
The Texas Railroad Commission, which regulates oil and gas, before the arctic blast issued an emergency order prioritizing gas deliveries to residential customers and emergency facilities. The Texas Public Utilities Commission yesterday also ordered ERCOT to take extraordinary steps to keep wholesale power prices at a cap of $9,000/MW as long as there are outages, to avoid administrative rules that would slash power prices. The commission made the move after it found that energy prices across the system were clearing at as low as $1,200/MW, well below that cap and unlikely to generate an optimal response to the challenge.
The power outages have already triggered debates in Texas and in Washington, DC, over the cause of outages and efforts by President Joe Biden's administration to accelerate a transition toward electricity. Republican critics of that idea say that would make the US too reliant on a single power source.
The US Federal Energy Regulatory Commission said today it would begin a joint investigation of outages across the US with its grid reliability counterpart, the North American Electric Reliability Corporation. The agency said its priority was restoring power to customers and securing the bulk power system.
