The US Energy Information Administration has reported analysis by the North American Electric Reliability Corporation (NERC) that suggests that if temperatures spike this summer, parts of the United States could face electricity supply shortages as demand for cooling increases. The latest NERC summer reliability report warns that two-thirds of North America is at risk of energy shortfalls during periods of extremely high electricity demand.
In summer, electricity demand increases as temperatures rise and homes and businesses turn up the air conditioning to cope. Above-normal summer temperatures further push up demand and can reduce electricity supply if power plant outages or reduced output stem from heat-related issues. In addition, widespread heat waves can limit electricity transfers because the electricity is needed to meet local demand. The combination of higher electricity demand and reduced supply is what causes the energy shortfalls. NERC releases a comprehensive summer reliability report ahead of the summer months each year.
All 20 NERC assessment areas have adequate power resources to meet normal peak summer demand this year, according to NERC. However, certain assessment areas are at elevated risk of electricity supply shortages if confronted with more extreme summer conditions. These areas include the U.S. Western Interconnection, SPP, MISO, ERCOT, SERC-Central, and New England.
In the US Western Interconnection zone widespread heat waves could put the area at elevated risk of energy supply shortfall because it relies on regional electricity transfers to meet peak demand as well as in the evening hours when solar power drops off. Parts of the Western Interconnection, especially California, host a large and growing share of generation from solar power.
SPP and MISO, which cover most of the central United States, are home to a significant amount of wind power and intermittency would play a part as wind output during periods of high electricity demand is a key factor in determining whether the system has sufficient electricity supply to maintain reliability in these areas.
ERCOT covers most of Texas. There is a risk that dispatchable generation, such as generation from natural gas- or coal-fired power plants, may not be sufficient to meet electricity demand during an extreme heat wave with unusually low winds. In June ERCOT asked residents to voluntarily curb electricity use as a heatwave reached Texas. As in SPP and MISO, wind plays a significant role in ERCOT’s generation mix.
For the SERC-Central zone (Tennessee and parts of Georgia, Alabama, Missouri, and Kentucky,) the NERC assessment expects there to be sufficient supply for normal peak summer demand. Utilities may deploy demand side management in cases of above-normal peak summer demand or high outage conditions.
In the NPCC-New England zone, although New England has less available capacity this summer than it had last summer, NERC projects that it still has sufficient capacity to meet normal peak summer demand, but during more extreme demand or low resource conditions, operating procedures for obtaining emergency resources and electricity supplies from neighbouring areas are likely to be needed.
• ERCOT issues weather watch
On 23 June ERCOT issued a Weather Watch from 25 - 30 June due to forecast higher temperatures and higher electrical demand. Grid conditions are expected to be normal during the period. ERCOT says it is monitoring conditions closely and will deploy all available tools to manage the grid and will continue its reliability-first approach to operations.
ERCOT set a new June peak demand record of 79 304 MW on 19 June. ERCOT’s 6 day Supply and Demand dashboard is showing the possibility of a new all-time peak demand record.
Data source: North American Electric Reliability Corporation (NERC), 2023 Summer Reliability Assessment