What has been the environmental impact of the region’s transition to natural gas?

Natural gas has been the single biggest contributor to the long-term decline in regional emissions, according to a 2015 ISO-New England Electric Generator Air Emissions Report. As a measure of how impactful our transition from coal and oil to natural gas has been environmentally, consider that Massachusetts’ carbon emissions from electric generating stations has plummeted by 63 percent since 1990 even as consumption of electricity grew by 21 percent.