The ISO New England Electric Generator Air Emissions Reports available below provide a comprehensive analysis of New England electric power generator air emissions (nitrogen oxides [NOX], sulfur dioxide [SO2], and carbon dioxide [CO2]) and a review of relevant system conditions.
Refer to the Air Emissions related link for more key statistics on the region’s emission trends.
For estimated real-time emissions by fuel type, see the Estimated CO2 Emissions graph in ISO Express.
For estimated monthly and year-to-date emissions by fuel type for the current year compared to the previous year, see ISO Newswire’s monthly recap of the wholesale electricity markets. The ISO uses data from the latest ISO New England Electric Generator Air Emissions Report to develop emissions factors for each fuel for both the monthly and real-time estimates.
The Regional Greenhouse Gas Initiative (RGGI) is a cap-and-trade program that covers generators in the New England states, Delaware, Maryland, New Jersey, New York, and Pennsylvania. Quarterly auction results are available on the RGGI website; RGGI allowance prices can be tracked on S&P Global (requires subscription).
Estimated monthly CO2 emissions from Massachusetts generators that are subject to the Massachusetts Electricity Generator Emissions Limits (EGEL) program under the Global Warming Solutions Act (GWSA) are shown below. This is a cap-and-trade program for CO2 emissions from electricity generation in the state, with annually declining emission limits.
Note: Low and high estimates of the year-to-date CO2 emissions are based on an analysis of the generator’s emission rates. These estimates are compared to the 3-year historical and current year emissions that generators report to the EPA’s Clean Air Markets Database (CAMPD) on a quarterly basis.
The 2024 emission cap is set at 7.61 million metric tons (MMT). As of 12/31/24, the December estimated GWSA CO2 emissions range between 494,547 and 602,037 metric tons. Year-to-date 2024 estimated emissions range between 75% and 93% of the 2024 cap of 7.61 MMT. According to the CAMPD, the 1st, 2nd, and 3rd Quarter (January-September) 2024 GWSA CO2 emissions were 4.7 MMT, or 62% of the 2024 cap of 7.61 million metric tons.