West and Midwest U.S. face summer electricity shortfalls due to heat, drought, and fire
Energize Weekly, May 25, 2022
The West and Midwest U.S. risk severe electricity shortfalls this summer due to high temperatures, drought, severe storms and wildfire – all driven by a changing climate, according to the North American Electric Reliability Corp.’s (NERC) summer assessment.
The situation could be exacerbated by a loss of coal-fired generating capacity as utilities shift from fossil fuels to clean energy generation, such as wind and photovoltaic (PV) solar.
“Weather officials are expecting above normal temperatures for much of North America this summer,” the NERC assessment said. “In addition, drought exists or threatens wide areas of North America, resulting in unique challenges to area electricity supplies and potential impacts on demand.”
Extreme weather is becoming more frequent and widespread. “‘Extreme’ doesn’t mean ‘rare,’” John Moura, NERC director of reliability assessment and performance analysis, said at a media briefing. “We know these conditions are not rare.”
“It’s a very sobering report. It’s clear the risks are spreading,” Moura said.
Drought is one of the biggest and most widespread problems. “Drought conditions create heightened reliability risk for the summer,” the assessment said.
Hydropower output in the West is being hurt by widespread drought and below-normal snowpack. “Dry hydrological conditions threaten the availability of hydroelectricity for transfers throughout the Western Interconnection,” the report said.
In Texas, drought across much of the state can produce weather conditions that favor prolonged, wide-area heat events and peak electricity demand.
With the increase of solar, and some wind generation in recent years, generating reserve margins in the Electric Reliability Council of Texas (ERCOT) system have increased. “However, extreme heat increases peak demand and can be accompanied by weather patterns that lead to increased forced outages or reduced energy output from resources of all types,” the assessment warned.
A combination of extreme peak demand, low wind and high outage rates from thermal generators could force ERCOT to use emergency procedures, up to and including temporary service reductions.
Continuing drought over the Missouri River Basin may impact output from thermal generators in the Southwest Power Pool, which manages the grid in the central U.S.
“Low water levels in the river can impact generators with once-through cooling and lead to reduced output capacity,” the assessment said. “Energy output from hydro generators on the river can also be affected by drought conservation measures implemented in the reservoir system.”
The Midcontinent Independent System Operator (MISO), which operates a grid covering all or parts of 15 Midwest states and two Canadian provinces, is facing a capacity shortfall in its north and central areas “resulting in high risk of emergencies during peak summer conditions,” the report said.
At the start of the summer, a key transmission line connecting the northern and southern MISO areas will also be out of service as a result of damage by a tornado during severe storms on Dec. 10, 2021.
An active wildfire season is being forecast for the Western U.S. and Canada, as well as South Central states, beginning in June. If drought persists, the fire season for the eastern U.S. will be extended.
“The interconnected transmission system can be impacted in areas where wildfires are active as well as areas where there is heightened risk of wildfire ignition due to dry weather and ground conditions,” the report said. “Smoke from wildfires can cause diminished output from solar PV resources, and electricity supply will be affected.”
The transition from fossil fuel-fired generation capacity, particularly coal – one of the largest sources of climate-altering greenhouse gases – may lead to stress on the system as coal-fired capacity is retired.
The U.S. Energy Information Administration (EIA) is projecting the largest increase in generation this summer will come from new renewable energy sources with utility-scale solar generation growing by 10 million megawatt-hours (MWh) between June and August 2022 and wind generation increasing by 8 million MWh.
Coal and natural gas generation will be down by a total 26 million MWh this summer, the EIA said.
The situation is compounded by the fact that coal-fired plants are having difficulty obtaining fuel and other supplies due to supply chain problems, including mine closures and rail shipping limitations. Stockpiles at power plants are relatively low compared to historic levels.
“These coal supply constraints, along with continued retirement of generating capacity, contribute to our forecast that U.S. coal-fired generation will decline by 20 million MWh (7 percent) this summer,” the EIA said.