MEREDITH ANGWIN
Rolling blackouts are probably coming to New England sooner than expected.
When there’s not enough supply of electricity to meet demand, an electric grid operator cuts power to one section of the grid to keep the rest of the grid from failing. After a while, the operator restores the power to the blacked-out area and moves the blackout on to another section. That is a “rolling blackout.” The New England grid operator (ISO-New England) recently completed a major study of various scenarios for the near-term future (2024-2025) of the grid, including the possibilities of rolling blackouts, especially in the winter months.
In early April, Exelon said that it would close two large natural-gas-fired units at Mystic Station, Massachusetts. In its report, ISO-NE had included the loss of these two plants as one of its scenarios. The ISO-NE report concluded that Mystic’s possible closure would lead to 20 to 50 hours of load shedding (rolling blackouts) and hundreds of hours of grid operation under emergency protocols.
When Exelon made its closure announcement, ISO-NE realized that the danger of rolling blackouts was suddenly more immediate than 2024. ISO-NE now hopes to grant “out of market cost recovery” (that is, subsidies) to persuade Exelon to keep the Mystic plants operating. If ISO-NE gets permission from the Federal Energy Regulatory Commission for the subsidies, some of the threat of blackouts will retreat a few years into the future.
The foremost challenge to grid reliability is the inability of power plants to get fuel in winter. A major cause of these problems is that the New England grid is heavily dependent on natural gas. Power plants using natural gas supply about 50 percent of New England’s electricity on a year-round basis. In the winter, pipelines give priority to delivering gas for home heating over delivering gas to power plants. In deep cold snaps, many gas-fired power plants cannot get gas.
For its report on the future of the grid, ISO-NE modeled various scenarios, such as winter-long outages at key energy facilities, and difficulty or ease of delivering Liquified Natural Gas (LNG) to existing plants. Their scenarios included renewable buildouts, transmission line construction, increased delivery of LNG, plant outages and compressor outages. They also assumed no new pipelines would be built, and some older plants would close.
Ominously, 19 of the 23 of the ISO-NE’s possible scenarios led to rolling blackouts. The worst scenarios, with the longest blackouts, included a long outage at a nuclear plant or a long-lasting failure of a gas pipeline compressor.
The one “no-problem” scenario (no load shedding, no emergency procedures) is one where everything goes right. It assumed no major pipeline or power plant outages. It included a large renewable build-out plus greatly increased LNG delivery, despite difficult winter weather. This no-problem scenario also assumes a minimum number of retirements of coal, oil and nuclear plants.
This positive scenario is dependent on increased LNG deliveries from abroad. Thanks to the Jones Act, a section of the Merchant Marine Act of 1920, New England cannot obtain domestic LNG. The Jones Act prevents foreign carriers from delivering American goods to American ports. All LNG carriers are foreign flag, and therefore LNG must be imported from other countries.
To avoid blackouts, we need to diversify our energy supply beyond renewables and natural gas to have a grid that can reliably deliver power in all sorts of weather. When we close nuclear and coal plants and don’t build gas pipelines, we increase our weather-vulnerable dependency on imported LNG. We need to keep existing nuclear, hydro, coal and oil plants available to meet peak demands, even if it takes subsidies.
If we don’t diversify our electricity supply, we will have to get used to enduring rolling blackouts.
— Meredith Angwin, of Vermont, is a physical chemist whose research helped improve the reliability of renewable, fossil fuel and nuclear plants. She is the author of “Campaigning for Clean Air: Strategies for Pro-Nuclear Advocacy.”