More than half the U.S. faces electricity supply problems in the face of a long, hot summer

More than half the U.S. faces electricity supply problems in the face of a long, hot summer

Energize Weekly, July 7, 2021

More than half the U.S. – primarily in the West, Texas, Midwest and to a lesser extent, New England – is at risk of energy emergencies this summer, according to the North American Electric Reliability Corporation (NERC).

In its 2021 Sumer Reliability Assessment, NERC identifies the combination of above-normal heat and generating capacity issues in some regions as a recipe for brownouts and blackouts.

Area-wide heat events – such as the August 2020 heat wave that covered much of the Western U.S. – could also lead to fewer resources being available to transfer electricity from one service area to another.

“The summer of 2021 is shaping up to be a challenge for electric system operators in many parts of North America,” the NERC assessment said.

Drought conditions extend over the western half of the U.S. and the middle-third of Canada with fire risk already above normal as the summer begins presaging an active fire season.

California faces the highest risk as its generating reserve margin before the summer began was below the 18.4 percent margin the Western Electricity Coordinating Council calculated was needed to maintain loss-of-load risk at an acceptable level.

An estimated 10,185 megawatt-hours (MWh) of demand this summer will not be served, according to probabilistic studies.

“Over 3 gigawatts (GW) of additional resources are expected for this summer with most coming in the form of new solar photovoltaic (PV) generation,” NERC said. “These generation plants can provide energy to support peak demand; however, solar PV output falls off rapidly in late afternoon while high demand often remains high.”

Later in the summer, California, as well as other parts of the West, could face challenges from wildfires as hotter and drier condition are expected to elevate fire risks. Bulk power system operations can be hurt in areas with active wildfires and even in areas where there is heighten risk of wildfire ignition.

Texas is facing an elevated risk this summer, but its reserve margin has improved to 15.3 percent from 12.9 percent last summer with an additional 7,858 megawatts (MW) of wind, solar and battery capacity.

Still, the risk of extreme weather affecting both generation and demand could “cause energy shortages that lead to energy emergencies in the Electric Reliability Council of Texas (ERCOT),” NERC said. ERCOT is the statewide grid operator.

Another challenge Texas faces is having enough backup generation for the wind farms, which make up about a quarter of the state’s capacity, during low-wind output periods.

Across the West – from the Pacific Northwest through the Rocky Mountains to the Southwest – there are risks of outages. “Overall capacity and demand projections for the area at similar levels to those seen in 2020 when a wide-area heat event caused energy emergencies and managed firm load loss,” NERC said. “Overall resource capacity is lower compared to 2020.”

The situation could also lead to a reduced availability of surplus capacity for transfer to stressed areas.

The Midcontinent Independent System Operator (MISO) – which serves all or parts of 15 states and the Canadian province of Manitoba – has sufficient generating capacity under normal peak demand scenarios, NERC said.

It’s “expected underserved energy” for the summer is projected at 18.6 MWh, less than 1 percent of California’s underserved energy forecast.

Still, there is a risk, particularly in July, the typical peak demand period, if there are above-normal peak demand loads. This could lead to interventions such as demand response programs, energy transfers and short-term load interruption.

MISO has contracted for 2,979 MW of firm energy transfers for the summer of 2021, the most of any region.

ISO New England, which serves the six New England states, also looks to have sufficient resources for peak periods. Peak demand for the summer is forecast at 24,810 MW the week of Aug. 8, with a projected margin of 1,910 MW (7.6 percent).

“The summer demand forecast takes into account the demand reductions associated with energy efficiency, load management, behind-the-meter photovoltaic systems, and distributed generation,” NERC said.

But just as in the case of MISO, above-normal summer peak brought on by above-normal temperatures, could lead to outage conditions that would require mitigation steps such as demand response, energy transfers and short-term load interruptions.

As for the rest of the country, NERC said. “All other areas have sufficient resources to manage normal summer peak demand and are at low risk of energy shortfalls from more extreme demand or generation outage conditions.”

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