Winter Storm Fern brought heavy snow, sleet, and freezing rain to more than 170 million Americans last month. It also tested the U.S. electric grid and found it vulnerable. As the United States is poised for rapid growth in electricity demand in the coming years, the grid will have to expand with reliable, affordable sources of power to meet it.
Across the U.S., coal-fired generation rose 31% over the prior week to meet demand during Winter Storm Fern. Natural gas generation rose 14% over the prior week. The Energy Information Administration notes that “generation from solar, wind, and hydropower declined,” from the prior week. Natural gas, coal, and nuclear together provided 77% of total U.S. electricity generation during the week of Fern—and a larger share during overnight hours and periods of low wind speeds, when solar and wind output fell sharply.
Although operators avoided catastrophe, parts of the country came uncomfortably close to the edge. In the Northeast, grid operators turned to oil-fired generation to maintain reliability. Although petroleum contributes less than 1% of total utility scale generation in the U.S., the Northeast maintains oil-fired units to use during peak winter demand. Petroleum was the predominant energy source in the Northeast between midday on January 24 and the morning of January 26.
Hydroelectric didn’t ride to the rescue for the Northeast, despite being an oft-cited clean and reliable backstop for the region. A long-anticipated transmission line, the New England Clean Energy Connect (NECEC), between Quebec, Canada, and the U.S. Northeast opened in January. It is intended to help the Northeast import more hydroelectric power. Unfortunately, when it’s cold in the Northeast, it’s cold in Canada, too—so from January 24 to January 26, during the height of Fern, Canada shut down its imports and the Northeast was left to fend for itself.
These challenges come as the grid faces mounting pressure. The North American Electric Reliability Corporation (NERC) released its long-term assessment of the electric grid last week, finding that half of the U.S. is at a high risk of summer and winter blackouts. NERC’s forecasts take into account announced generator retirements, including coal-fired plants, which utilities should consider keeping open until the end of their useful lives.
Utilities and regulators should take Fern’s lessons seriously. The grid narrowly avoided widespread outages, not because the system was well-prepared for it, but because aging, fuel-secure generators were still available. Retiring dispatchable generation without replacing it with equally reliable alternatives increases the risk that the next Fern will push the system past its limits.