Killingly — The Connecticut Siting Council on Thursday will consider reopening NTE Energy's application for a proposed 650-megawatt natural gas power plant that recently secured a capacity supply obligation to New England's power grid.

Earlier this month, ISO New England's forward capacity auction, which guarantees electricity from power generators for 2022-23, included Killingly Energy Center among the 34,000-plus megawatts to meet regional electricity demands. The auction opened the door for NTE to gain a siting certificate and sparked a recent challenge from renewable energy advocates.

NTE's motion to advance the project follows two unsuccessful attempts to secure contracts in ISO New England's auctions. In 2017 the Siting Council denied NTE's initial application, finding that ISO New England had determined that the Killingly plant would not be necessary to meet the region's power needs in 2020-21.

In a statement, NTE CEO Seth Shortlidge said securing a contract in this year's auction "clearly supports the region's need" for the new natural gas plant, especially "at a time when up to 6,000 megawatts of older, less-efficient power plants across the region are nearing retirement."

Shortlidge said the plant, planned for 180 and 189 Lake Road, would help "secure the region's energy reliability."

NTE expects the $700 million plant to create about 450 construction jobs and 20 permanent full-time jobs. The Department of Energy and Environmental Protection already finalized an air permit for the plant. The Killingly Town Council last year approved a tax-stabilization agreement in which the plant would pay about $100 million over 20 years. As part of a community environmental benefit agreement approved by the Town Council, NTE will provide $5 million for scholarships and town projects, NTE said in a statement.

However, earlier this week Connecticut Fund for the Environment, Sierra Club, Wyndham Land Trust and the citizens group Not Another Power Plant urged the Siting Council to hold off on deciding on NTE's request to reopen its application for a certificate.

The groups argued the Siting Council should wait until the Federal Energy Regulatory Commission approves ISO the results of New England's auction, which at least one power generator has petitioned to be reconducted.

Connecticut Fund for the Environment and the other groups said if the Siting Council decides to reopen NTE's application, it should adopt a "robust evidentiary process" to fully evaluate environmental factors as well as state policy changes since it was originally filed.

The groups said the Siting Council must balance the environmental impacts of such a plant, as well as the state's aggressive greenhouse gas emissions reduction goals and expanded renewable portfolio standard, which calls for 40 percent of the state's electricity to come from renewable sources by 2030.

The groups noted the proposed project site is adjacent to the 32-acre Dunn Preserve, owned and maintained by the Wyndham Land Trust, and the surrounding area is located in the Quinebaug and Shetucket Valley National Heritage Corridor, also called the Last Green Valley.

"Adjacent states have similarly doubled down on their commitment to zero-carbon and non-fossil fuel resources, implicating the appropriateness of siting new fossil fuel plants across the border in Connecticut," the groups wrote to the Siting Council.

Jennifer Logue, NTE's director of communications, said the company is aware of the groups' filing and will submit "a response through the established process." She said NTE looks forward to the Siting Council's consideration to reopen the docket for the plant.

b.kail@theday.com