Two years from now, New York City may run short on power, potentially leading to blackouts during normal summer temperatures. Heat waves would exacerbate the problem, and power outages would mean no air conditioning, overheated “cooling” centers and an increase in deaths, especially among the poor and elderly.

The shortfall in electricity supply is the most important finding in the latest Short-Term Assessment of Reliability report from the New York Independent System Operator (NYISO) which covers a five-year study period, from April 2023 to April 2028.

The increasing risk of power outages is driven by expected increases in peak demand for electricity and the mandated closure of “peaker” plants that make it possible to meet that demand.

Peakers are power generation facilities that operate only when demand peaks. Some are turned on for a few hours each day to meet daily peak demand while others are fired up only a few times a year, such as during the hottest days of summer.

But the state’s 2019 “Peaker Rule,” is forcing the shutdown of many of these emergency backup power generators. The rule puts strict limits on emissions of ozone-forming nitrous oxide (NOx), during the summer ozone season. The limits went into effect in May and become stricter in 2025. Older peakers have a hard time meeting the stricter requirements because they are generally the least efficient facilities, supplanted for daily use by newer, more efficient, power plants and kept around only for use during periods of critical need.

The NYISO reports that 1,027 megawatts of peaker plants have been deactivated or operationally limited as of May 1 of this year. Two years from now, another 590 megawatts will be unavailable. Added to the 2,000 emissions-free megawatts lost with the shutdown of the Indian Point nuclear plant, that adds up to roughly 3,600 megawatts of power denied to the city compared to just a few years ago. With peak summer demand reaching just under 12,000 megawatts, that means 30 percent of the electricity supply needed to meet that demand will have been taken offline.

The potential 2025 shortfall will be as much as 446 megawatts. That’s equivalent to having 400,000 homes too many for the available electrical supply. And that will be the case just in normal summer weather. The shortfall will become even worse if there is a heat wave that increases demand.

The city and Con Edison will have no choice but to make heroic efforts at reducing demand during heat waves, encouraging people to keep the lights off, delay cooking and clothes drying until late in the evening, avoid charging electric cars, and sleep in unhealthily warm temperatures. But if the shortfall is large enough, or if the heatwave is beyond NYISO’s planning expectations, those desperate measures may not be enough. Then rolling blackouts may be necessary to keep the whole city from plunging into darkness. Last year, these efforts just barely kept Gotham’s lights on, but in July 2019, Con Edison had to turn off power to 50,000 people in Brooklyn to prevent damage to its equipment when temperatures in the low 90s sent demand skyrocketing.

The situation will temporarily become less dire in 2026 with the addition of Quebec hydropower via the Champlain-Hudson Power Express (CHPE), assuming it is completed on time. But the CHPE was originally planned more than a decade ago as extra power on top of what New York had available then. Its 1,250 megawatts were not intended as a replacement for the then-unanticipated loss of 3,600 megawatts of power.

So even after the CHPE is completed, New York City will continue to have a smaller reserve margin than is considered safe by energy experts. And that margin will continue to shrink as the increasing electrification of the city causes demand to continue growing in the coming years.

Optimists pin their hopes on the development of both offshore and onshore windpower (with the latter coming to the City through the CleanPath project), which will add to the downstate area’s total electrical supply. But offshore wind will lack a critical feature that makes peaker plants invaluable: dispatchability. The peakers can be turned on, and their power guaranteed to be available, when critical need arises. Offshore wind may produce enough to meet the City’s needs during a heat wave, but there’s no guarantee that it will. A massive high-pressure system that creates a multi-day heat wave could also cause a lull in wind, simultaneously increasing the demand for electricity while reducing its supply.

The Peaker Rule does allow for a power plant to be designated a “reliability source” and temporarily kept on-line even if it cannot comply with the NOx limitations. But this reprieve is only for two years, so by 2027 all non-complying plants will presumably have to shut down.

It’s possible that the Federal Energy Regulatory Commission will step in and exercise its emergency authority to require that enough peaker plants remain online to ensure continued reliability. If not, it may take a blackout for the state to finally take seriously the negative consequences of the Peaker Rule.

Reducing atmospheric NOx is in itself a good goal, as the gas can exacerbate lung ailments and breathing problems, leading to increased hospitalizations and potentially increased mortality. But the worst offenders among power plants only produce those pollutants a few days per year, and their power production saves lives by reducing heat stress. There’s a substantial risk that the Peaker Rule could take more lives than it saves.

The mistake New York has made is not its goal to eventually reduce NOx emissions but its rush to shut down the peakers — and Indian Point — before developing reliable replacement sources of power. Notably, the Department of Environmental Conservation rejected proposals by NRG Energy to update nearly 1,000 megawatts of electricity production in the city to newer, cleaner-burning, and NOx-standard compliant combined-cycle power plants, claiming that NRG “failed to demonstrate the need or justification for the proposed project.”

This “shutdown first, replace later” model was a major cause of rolling blackouts on the West Coast, but New York authorities didn’t bother to learn from California’s experience. Simple common sense would indicate that the wise approach would be to find assured sources of reliable and dispatchable electricity production before taking critical power plants offline. Sadly, common sense was the first victim of New York energy policy. Even more sadly, it won’t be the last.