As the push to electrify the economy grows, long-range planners are wondering if power supplies will be available to meet demand spikes over the next decade.

A federal report highlights potential shortfalls throughout the United States if action isn’t taken to bring new resources online quickly and, perhaps, slow the retirements of aging fossil fuel and nuclear power plants. In the short term, performance in one of the nation’s most power-stretched regions this winter held up through two significant severe weather events, thanks to a push to weatherize existing equipment and bring new solar and storage resources online.

Every year, the North American Electric Reliability Corp. (NERC) releases a Long-Term Reliability Assessment, and the 2023 report, released in December, said pressure was mounting on the nation’s power supplies and transmission systems. Challenges have grown in just the last year.

“We are facing an absolute step change in the risk environment surrounding reliability and energy assurance,” said John Moura, NERC’s director of reliability assessment and performance analysis, in a statement accompanying the report’s release. “In recent years, we’ve witnessed a decline in reliability, and the future projection does not offer a clear path to securing the reliable electricity supply that is essential for the health, safety and prosperity of our communities.”

Demand’s growth

Multiple potential problems are piling up, with growth projections for data centers and electric vehicles contributing to higher forecasts. Plus, more homeowners are switching from fossil fuel heat sources to electric heat pumps. On the supply side, the report notes that more than 83 gigawatts of fossil-fired and nuclear generator retirements are planned through 2033, with more shutdown announcements expected. New wind, solar and storage resources will help pick up the slack, but severe weather could strain utilities’ ability to meet the increased demand.

With coal and nuclear generation on the decline, natural gas plants will face even more pressure, according to the report, especially in winter, when the fuel is used for heating and electricity generation. About 47% of U.S. households use natural gas for heat, and that figure can be much higher, regionally—climbing, for example, to 85% in some Pennsylvania communities, according to the U.S. Census Bureau’s American Community Survey. 

Nationally, about 39% of electricity generation is fueled by natural gas, but this also varies. U.S. Energy Information Administration figures from 2021 show this ranges from as low as 5.1% in Kansas (where 45% of supplies are wind generated) to as high as 73% in Florida and over 90% in Rhode Island.

The heavy dependence on natural gas poses challenges. It adds pricing pressure during winter months, when gas and electric utilities are vying for the same supplies. This can be especially true for electricity suppliers, which are more likely to buy gas on short-term markets to meet shifting daily demand. Available supplies can be strained by limited pipeline capacity. Because natural gas utilities assure their wintertime supplies through long-term contracts, their orders get priority from pipeline operators.

Heavy dependence on natural gas generating plants can raise risks if they face severe weather challenges and aren’t sufficiently weatherized.

“Subfreezing temperatures, as seen during winter storms Uri and Elliott, can disrupt the natural gas fuel supplies to generators,” said Mark Olson, NERC’s manager of reliability assessment, referring to storms during the 2021 and 2022 winters that caused outages and rolling blackouts in many U.S. regions. “When this causes an electricity supply shortfall, it can further affect natural gas infrastructure, creating more severe impacts on the energy system as a whole.”

Texas, among the states hit hardest during 2021’s Uri, also faced challenges during 2022’s Elliott. However, the state made it through this January’s winter storm Heather without major outages. 

In the wake of the previous two storms, natural gas generators have been required to undertake weatherization upgrades that kept plants running when temperatures plunged. Though residents did receive messages to dial back their thermostats due to insufficient transmission capacity, increased renewable and storage supplies helped keep Texans’ lights on.

Solar output on Jan. 16, the highest demand day during Heather, was twice that achieved during the 2021 event, topping 14,800 megawatts. In the last 3 years, utilities installed 1,000 MW of new battery capacity to support operations during critical demand periods. In close-to-the-limit situations, it seems even relatively small capacity additions can affect whether the lights stay on.

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