Blackouts during extreme weather still a risk this winter: NERC

Large swaths of the US could be at risk of blackouts this winter if there is extreme weather and a high level of generator outages, the North American Electric Reliability Corporation said Nov. 18.

Energy emergencies can be expected in Electric Reliability Council of Texas, Southwest Power Pool and Midcontinent Independent System Operator if there is another event like the February cold snap, NERC said in its Winter Reliability Assessment. And in the Northwest and Rocky Mountain region, low hydro and predicted colder weather could cause problems, it said.

"Increased demand caused by frigid temperatures and higher than anticipated generator forced outages and derates in susceptible areas could create conditions that lead system operators to take emergency operating actions, up to and including firm load shedding, as a result of energy emergencies," NERC said.

The situation is most dire in ERCOT, where reserves could be 37% below demand during extreme conditions and high outages, the commission said.

Texas risks

During the February cold weather event, outages in Texas were long lasting because the shortfalls were so large the state could not really rotate the outages, John Moura, director of reliability assessment and performance analysis at NERC, said on a Nov. 18 press call.

While NERC has made winter readiness recommendations that aim to reduce the number of generator outages and consequent blackouts, the sheer size of the potential reserve shortfall in Texas still a "significant concern," Moura said.

One key improvement in Texas going into this winter is that many more gas facilities like compressors have been identified as critical gas facilities that will not be cut off during load shedding, Mark Olson, manager of reliability assessment at NERC, said on the call. This change should provide better resilience for generators' fuel supply, he said.

NERC also noted that Texas regulators are requiring entities to complete certain winter weather emergency preparations by the end of 2021. ERCOT is performing inspections of generators as required by state regulators, Olson said. This is a strong measure and no other area has a similar requirement, he said.

Still, NERC was disheartened to see that some generators had not completed weatherization plans or not taken all the steps recommended in NERC's August alert on winter readiness, Olson said. As a result, grid operators should be prepared to manage potential supply shortfalls in extreme weather, he said.

MISO and SPP also face shortfall risks, NERC said. In MISO, reserves could dip 1.2% below demand during extreme weather, and SPP's reserves would be reduced 0.8% during cold conditions, it said.

In the Northwest Power Pool & Rocky Mountain Reserve Sharing Group region, reserves could be 1.5% below demand, NERC said. With the National Oceanic and Atmospheric Administration predicting colder temperatures across the Pacific Northwest, along with the low hydro linked to continued drought, there are some scenarios that need to be monitored in the Northwest Power Pool, the commission said.

Low hydro conditions in the West can also reduce the transfers needed to mitigate a wide-area cold weather event, NERC said.

Fuel supplies

NERC also warned that generators may have a hard time getting fuels this winter because many supply chains are stressed. Coal stockpiles have declined rapidly in the last few months and natural gas in storage is below average levels for the upcoming winter, NERC said.

"No specific [bulk power system] reliability impacts are currently foreseen; however, owners and operators of fossil-fired generators will need to monitor their coal and fuel oil stores and natural gas contracts as late-stage acquisitions are less assured this winter," it said.

Natural gas supply disruptions in infrastructure-limited areas could also impact winter reliability, NERC said. California has limited gas storage and a gas line that ruptured in August has reduced the amount of gas flowing into California, NERC said.

New England's gas infrastructure can become constrained in cold weather and the region competes for natural gas supply on the world market, NERC noted. Unprecedented high LNG demand is anticipated for the upcoming winter, it said.