New York proposes NOx limits for peaking units

In an effort to cut ozone pollution, New York regulators are proposing tougher air emission requirements that are expected to force about 3,400 megawatts of older peaking units to retire.

The proposal applies to simple-cycle and regenerative combustion turbines larger than 15 MW that bid into the New York independent System Operator’s wholesale markets.

The New York State Department of Environmental Conservation is proposing to phase in lower nitrogen oxide emissions limits during the ozone season and to tighten an existing fleet averaging provision, according to the plan, released Feb. 28.

The DEC expects the proposal will lead to the shutdown of generating units installed before 1986, which total about 3,400 MW.

Units built after the mid-1980s can meet the proposed NOx emissions limits, according to the DEC.

The older peaking units make it difficult, if not impossible, for New York to meet air quality goals and Clean Air Act requirements, the DEC said.

Currently, the greater New York City area is required to meet the 2008 ozone standard by June 20, 2021, and the more stringent 2015 standard by Aug. 3, 2024.

The DEC estimates that replacing the older peaking units would cut NOx emissions by about 18 tons a day during the ozone season, representing a 10 percent reduction in NOx emissions from power plants in the New York City area and a 3.5 percent reduction from all sources.

“This represents a significant decrease in NOx emissions that would likely lead to reduced ozone formation and lower monitored ozone values downwind,” the DEC said.

On high ozone days, the old peaking units account for up to 94 percent of NOx emissions from all peaking units while producing as little as 36 percent of all the units’ electricity, according to the DEC.

The DEC said it worked with NYISO, the New York State Department of Public Service and the New York State Energy Research and Development Authority to make sure the proposal wouldn’t hurt grid reliability.

At the suggestion of stakeholders, the agency is proposing a phased-in approach to allow affected sources time to comply with the new rule.

NYISO will review any planned unit shutdown to make sure it doesn’t hurt grid reliability. If a retirement would harm the grid, the proposal allows a unit to keep running for another four years while a solution is found.

Affected units will be required to submit compliance plans by March 2, 2020, so NYISO can study their effects on the grid.

The proposal sets an emissions limit of 100 parts per million of NOx for all affected units by May 1, 2023. The limit would fall two years later to 25 ppm for units using gaseous fuels and to 42 ppm for units burning distillate oil or other liquid fuels.

Also, starting May 1, 2023, the peaking units will only be able to average emissions with other similar units at the facility or with approved energy storage or renewable energy resources during the ozone season. Under current rules, the units can average NOx emissions with other generating sources such as boilers.

While the regulation largely aims to reduce ozone pollution, state officials also contend it supports New York’s clean energy and carbon dioxide reduction goals.

“Reducing our reliance on peak-use power plants through increased energy storage deployment will accelerate us toward achieving Governor Cuomo's nation-leading vision for a 100 percent carbon-free electricity system,” said Alicia Barton, NYSERDA president and chief executive officer.

The DEC plans to hold three public hearings on the proposal in May and is taking written comments through May 20.

The proposed rule is available here.