NERC report outlines how pandemic mitigation could affect electric reliability this summer
Despite heightened uncertainty—stemming from efforts to slow the progression of the novel coronavirus disease (COVID-19)—in demand projections, the North American Electric Reliability Corporation's (NERC) recent 2020 Summer Reliability Assessment finds that enough resources are available to meet this summer's projected peak electricity demand in most areas of the country. The Electric Reliability Council of Texas (ERCOT) has the smallest anticipated reserve margin, but each of the remaining regions exceeds, or substantially exceeds, a 20% anticipated reserve margin.
NERC is a nonprofit corporation that oversees regional electric reliability entities in the Lower 48 United States, Canada, and parts of Mexico. At the beginning of each summer, NERC publishes a reliability assessment that tabulates anticipated electricity demand and supply changes and highlights any regional challenges or expected conditions that may affect the bulk power system. This year, NERC also released a special report in April that assessed certain issues for the reliability of the bulk power system during the pandemic.
Among the most relevant measures of expected reliability in NERC’s assessment are the anticipated reserve margin and planning reference margins for each region.
- The anticipated reserve margin considers the amount of resources (capacity to generate) anticipated to be available to meet net internal electricity demand. A reserve margin of 15% means that 15% of a region’s electric generating capacity would be available as a buffer to supply unexpected changes in the summer’s peak hourly load.
- Planning reference margins are reserve margin targets based on each area's load, generating capacity, and transmission characteristics. Reliability entities in each region aim to have their anticipated reserve margins surpass their planning reference margins. Some states, provinces, independent system operators, or other regulatory bodies require an anticipated reserve margin at least as big as the planning reference margin.
ERCOT typically has one of the smallest anticipated reserve margins in the country, meaning it may have relatively little unused electric generating capacity during times of peak electric load. Earlier this year, ERCOT planners were expecting relatively tight operating conditions similar to those faced in the summer of 2019.
As a result of adding more than 1.9 gigawatts (GW) of on-peak resource capacity, ERCOT’s anticipated reserve margin has risen from 8.5% last summer to 12.9% for the upcoming summer. ERCOT’s summer assessment also assumes the ability to import up to 817 megawatts (MW) from the neighboring Southwest Power Pool (SPP) during its forecast summer peak load hours. ERCOT’s assessment assumes no COVID-19-related delays occurred for projects that were expected to come online before this summer.
Many areas of the country have experienced reduced electricity demand and have changed electricity consumption patterns because of stay-at-home orders and other pandemic mitigation efforts. Some owners and operators of power plants and other electric system infrastructure have deferred or canceled maintenance that would have been typically done before the summer.
Last July, the Florida Reliability Coordinating Council (FRCC) integrated with the Southeast Reliability Corporation (SERC). SERC covers approximately 350,000 square miles and now serves a population estimated at 69 million, or about 20% of the total United States. NERC estimates that SERC’s total internal electricity demand this summer will be 181 GW, making it the largest assessment area in terms of electricity demand.
NERC’s 2020 report also described potential issues for the California Independent System Operator (CAISO), which covers much of the state. Below-normal hydro conditions in California and the Pacific Northwest, which often exports electricity to CAISO, could reduce energy available from hydro resources throughout the summer.
Principal contributor: O. Nilay Manzagol