Greenhouse gas pollution from electricity generation slid 4% in 2023, according to a new analysis from regional electric grid operator ISO-New England.
Last year's drop in climate-warming carbon dioxide emissions is linked to mild winter and summer temperatures that limited periods of high electricity demand, according to the grid operator.
Oil and coal power plants have historically fired up to boost electricity generation when the grid experiences tight system conditions, ISO-New England said. That can happen during a heat wave, when electricity demand spikes to run air conditioners, or during a winter cold snap, when natural gas pipeline capacity is constrained, the organization added.
Thanks to a warmer winter and cooler summer last year, those resources weren't used as much, resulting in lower emissions, according to the analysis.
Falling natural gas prices in 2023 also made that fuel more economical than coal or oil for electricity generation, the grid operator added.
But the growth of solar and wind power played a role in curbing greenhouse gas pollution too, according to ISO-New England's analysis of emissions data from the U.S. Environmental Protection Agency and other sources.
Wind and solar generation has soared in the last decade and now account for 6% of the electricity made on the six-state grid. Coal and oil, which contributed about 4.6% of generation in 2014, have been almost entirely replaced by wind and solar, according to the analysis.
ISO-New England spokesperson Mary Cate Colapietro said that while there will be annual variations in emissions, greenhouse gas pollution is waning.
Renewables are being added as five New England states, including Maine, move to meet emissions reduction goals.
"Looking at the long-term trajectory here, this is a real decrease and is kind of symbolic of the ongoing clean energy transition in the region," Colapietro said.
The growth of rooftop solar has also lowered the overall demand for electricity from generators on the New England grid. Power produced from panels on homes and businesses — called "behind the meter" solar, is used by those structures which lowers the need for power from other generators.
Last year's emissions dip aligns with a long-term decline of air pollution from power plants in New England.
Carbon dioxide emissions have fallen 40% since 2001, according to ISO-New England. In the same time period, nitrogen dioxide, a major contributor to smog, has decreased more than 80% and sulfur dioxide, another air pollutant, is down 99%, according to the grid operator.
New England still relied on natural gas plants to fuel about half its power generation last year. But spokesperson Randy Burlingame said the grid operator expects a shift away from gas as more renewables come online in the near future.
"Just over the past 10 years, wind and solar have already doubled in the region here, and we're anticipating moving more and more away from natural gas and more towards those renewable energy resources over the next decade," Burlingame said.
