Carbon emissions from New England power generation fell slightly in 2022, ISO-NE analysis finds

Electricity generation within New England produced slightly less carbon dioxide (CO₂) in 2022 than the previous year, according to estimates included in ISO New England’s latest annual analysis of power system emissions.

Higher production by oil-fired resources in 2022 led to a spike in sulfur dioxide (SO₂) emissions, the analysis found. But the increase in CO₂ emissions from these generators was offset by a 43% year-over-year decrease in coal-fired generation.

The analysis, which draws information from Environmental Protection Agency (EPA) databases and other sources, found that New England continues to see levels of power system emissions that are well below those observed in the early 2000s and 2010s.

Annual carbon dioxide (CO₂) emissions fell 18% from 2013 to 2022, and 37% from 2001 through 2022. Emission rates for all three pollutants the ISO examines—that is, the amount of CO₂, SO₂, and nitrogen oxides (NO_x) given off for every megawatt-hour (MWh) of electricity produced—also saw double-digit declines over the past decade.

The published analysis includes three components:

• The 2022 ISO New England Electric Generator Air Emissions Report is an executive summary of key findings
• A supplementary document explains the report’s background and methodology
• A technical appendix provides comprehensive system conditions and emissions data, including tables and figures

By the numbers

The table below summarizes annual average emissions and emission rates for 2022, as well as the year-over-year changes from 2021. The table includes figures for emissions from New England generation as well as data on emissions associated with New England generation plus electricity imported from other regions.

New England generation	2022 emissions (kilotons)	Change from 2021	2022 emission rate (lbs/MWh)	Change from 2021
NOx	12.3	-1.1%	0.24	-3.3%
SO2	3.38	+60.3%	0.07	+56.9%
CO2	33,382	-0.2%	643	-2.3%
New England generation and imports
CO2	34,105	-1.3%	565	-1.5%

Report takeaways

• Generation and demand: Electricity generation within New England increased by 2% in 2022. The region’s total wholesale electricity demand, known as net energy for load (NEL), was essentially flat, increasing just 0.1% year over year. Meanwhile, peak demand in summer 2022 was 5% lower than the previous year.
• Oil’s increase: More electricity came from oil-fired generators in 2022 than in the previous four years combined. At 1,845 GWh, production from these resources in 2022 was eight times higher than in 2021. Oil has a high sulfur content, so SO₂ emissions rise when these resources produce more power. Several factors contributed to the increase, including high natural gas prices driven by the Russian-Ukrainian conflict, unplanned generator outages during the summer’s warmest days, and the cold snap on December 24, 2022. New England’s energy markets select the lowest-priced resources to meet consumer demand, so oil-fired generators are dispatched more frequently when natural gas prices are high.
• Impact of imports: Hydroelectric generation accounts for a significant share of the region’s imported electricity, so the estimated CO₂ emission rate of 177 lbs/MWh for imports is lower than the rate of 643 lbs/MWh for electricity produced within New England. This results in a lower combined emission rate for regional generation plus imports. However, since the region imports more electricity than it exports, this results in an overall increase in total CO₂ emissions (kilotons) when accounting for net imports. Net imports in 2022 were 11% lower than the previous year.

Long-term trends

Annual air emissions from regional generation declined from 2013 through 2022. In addition to the 18% drop in CO₂ emissions, NO_x emissions fell by 39% and SO₂ emissions fell by 81%.

From 2001 through 2022, CO₂ emissions fell by 37%, NO_x emissions fell by 79%, and SO₂ emissions fell by 98%.

About the data

The report’s emissions estimates for generation within New England are based on data from the US Environmental Protection Agency’s Clean Air Markets Program database and the agency’s eGRID database, New England Power Pool Generator Information System monthly data, or the ISO’s calculation of emission rates based on unit type and age. CO₂ emission rates for imports are based on data from the eGRID database for the New York ISO and on Canada’s Greenhouse Gas Inventory Report.

Some data sources are not available until several months after the end of a calendar year.

In addition to the annual analysis, the ISO publishes data on estimated CO₂ emissions from New England power plants in a monthly recap of the wholesale electricity markets. Real-time estimates are available on ISO Express.