In a surprising deal, the developer of a proposed $1 billion natural gas–fired power plant in Salem, Mass., has agreed to reduce greenhouse gas (GHG) emissions from the new facility annually over its 40-year lifespan to meet state climate change mandates—and to permanently shutter the plant by 2050. 

The settlement reached between New Jersey–based Footprint Power and environmental group Conservation Law Foundation (CLF) on Tuesday is one of the first that forces a natural gas plant to limit its GHG emissions.

Footprint Power has proposed to replace the coal- and oil-fired Salem Harbor Generating Facility after its closure in May 2014 with a combined cycle gas turbine facility that is expected to be completed in June 2016.

The New England conservation group challenged a tentative decision by the Massachusetts Energy Facilities Siting Board (EFSB) to grant seven of eight state and local approvals that Footprint Power needs to complete the plant. Last month, the Massachusetts Department of Environmental Protection (DEP) also issued decisions to grant both state and federal air permits for the proposed plant.

The group contends those decisions conflict with requirements of the Commonwealth’s 2008-enacted Global Warming Solutions Act (GWSA) to reduce GHG emissions in the state to 25% below 1990 levels by 2020, and at least 80% by 2050,.

In February 2012, CLF and HealthLink secured an enforceable commitment from Dominion Power, owner of the existing coal-fired Salem Harbor Station, , to shut down all four units at the 60-year-old plant by 2014.

Shortly after Footprint Power filed its first application for environmental review in August 2012, CLF urged the company to provide analysis on how the natural gas project could impact the Commonwealth’s ability to meet mandates outlined GWSA.

“As the first major fossil fuel power plant to be proposed in Massachusetts since the passage of the GWSA, this project is likely to establish a precedent that will guide consideration of future energy infrastructure and play a role in determining whether or not Massachusetts will meet the greenhouse gas reductions required by law,” the group argued.

The settlement will only take effect if the EFSB incorporates the entirety of the agreement into the final decision “as a condition of the approval that the Siting Board is proposing to issue for Footprint Power’s plant,” the group said.

Sonal Patel, associate editor (@POWERmagazine, @sonalcpatel)