This week saw a heat wave strong enough that Mark Christie, chairman of the Federal Energy Regulatory Commission, warned that “Some of our systems really came close to the edge.” He also made it clear that wind, solar, and batteries are not enough, saying, “You’ve got to have dispatchable resources. There’s no way around that.”
One of these systems “close to the edge” was the PJM Interconnection, the U.S.’ largest grid operator serving 13 states and D.C., which hit peak demand of 161 GW between 5 and 6 p.m. on Monday. This exceeded its peak demand forecast for the summer by five percent and saw the highest peak demand since 2011.
The U.S. Energy Information Administration (EIA) notes that both PJM and ISO New England hit multiyear highs on June 23 and June 24. Wholesale electricity prices hit $1,334 per megawatt-hour by 7 p.m. A week earlier, peak prices were $52 per megawatt-hour.
What sources met that demand in PJM? EIA explains:
At peak load on June 23, 44% of PJM’s generation came from natural gas, 20% from nuclear, 19% from coal, and 6% from solar. The remaining generation came from a mix of hydro, wind, petroleum, and other generation. Petroleum generation, which is generally the most expensive form and therefore only used to meet large demand loads, was three times greater compared with the same hour the day prior.
The EIA’s Hourly Electric Grid Monitor shows the peak demand within PJM.
ISO-NE saw its peak demand in the evening of June 24, which was the highest level seen since 2013. Wholesale electricity prices peaked at $1,110 per megawatt-hour, with peak prices a week earlier only being $65 per megawatt-hour. 47% of generation came from natural gas, 13% from nuclear, 12% from petroleum, and 12% from imports from Canada. Only 4% of generation came from wind, batteries, and solar.
ISO-NE only has one remaining coal-fired plant, the Merrimack facility in New Hampshire, which had to jump into action and supplied 280 MWh of generation.
What was happening in MISO, the grid serving Minnesota? MISO hit its peak demand on Monday of 119 GW, which was “about 6% below the grid operator’s all-time system peak of 127 GW set in July 2011, according to Brandon Morris, a MISO spokesman.” MISO had declared a Max Generation Warning on June 23, and PJM did too, which limited the amount of electricity that MISO and PJM could exchange to maintain both grids.
FERC Commissioner Christie said that “You never know about the next time, and there’s going to be a next time. We’ve got to have more resources. That’s the bottom line.”
Perhaps a wise place for MISO to start is by halting the retirement of reliable, dispatchable coal and natural gas-fired power plants.