Last month’s Polar Vortex pushed electricity demand to historic levels. A new report, “Operation of the U.S. Power Grid During the January 2025 Polar Vortex,” analyzes the performance of different electricity resources during the extreme weather event across the six most heavily impacted regions of the country (PJM, MISO, SPP, ERCOT, the Southeast, and the Northeast). Here are a few takeaways from the report:
- Dispatchable resources were an essential source of electricity. Natural gas, coal, nuclear, and oil (dispatchable resources) generated 85% of the electricity that was needed across the six regions on the peak day of the weather event. Two-thirds of this electricity was generated by fossil fuels. Wind and solar generated 9% and 2%, respectively, of the total. Compared to the previous month (December 2024), electricity demand increased by an additional (incremental) 149,000 MW on the peak day in January. Fossil fuels generated more than 90% of the additional 149,000 MW of electricity that were needed on the peak day, with coal generating one-third of the incremental electricity. Wind and solar generated 3% and 0.2%, respectively.
- The coal fleet performed well. Coal-fired generators increased their output significantly during the weather event. Across the six regions, the average capacity factor for coal exceeded 80% on the peak day in January, compared to an average of 49% the month before. Coal’s ability to increase electricity output helped offset fluctuations in output from renewables.
- Natural gas also performed well. Natural gas generation also increased to meet electricity demand. The average capacity factor for gas-fired generators increased from 38% in December to 56% on the peak day in January. Unsurprisingly, the price of natural gas was volatile because of increased demand for natural gas for both heating and generating electricity.
- Wind and solar did not perform well on the peak day. On the other hand, wind and solar were challenged due to unfavorable weather conditions. On the peak day, wind and solar were able to generate 3% and 0.2%, respectively, of the incremental electricity that was needed to meet demand. Wind generation during the peak day was 7,000 MW lower than during the January 2024 storm, despite the addition of nearly 3,500 MW of wind capacity in 2024.
- Coal helped to limit price volatility. In the PJM region, for example, the dispatch of coal-fired generation limited the volatility of power prices due to volatile natural gas prices. The average coal price was $2.50/MMBtu, whereas natural gas prices increased from less than $2/MMBtu in November to almost $30/MMBtu when the weather event peaked.
- Consumers saved money because of coal. PJM’s average day-ahead power prices peaked at $225/MWh. Without coal-fired generation, power prices could have exceeded $400/MWh to $650/MWh, potentially totaling $500 million to $1.4 billion in extra costs for consumers.