June 24 (Reuters) - Constellation Energy on May 31 permanently shut down the natural gas-fired Mystic Generating Station located in Charlestown, Massachusetts, the Energy Information Administration (EIA) said in a report on Monday.

The agency added Mystic's future had been uncertain when in 2018 its then-owner, Exelon, sought to retire the plant due to profitability concerns.

However, recognizing its role in ensuring fuel security and system reliability during the peak winter demand season, grid operator Independent System Operator New England (ISO-NE) mandated the plant remain operational until May 31, 2024, the report said.

The retirement of Mystic also raised concerns about the future of the adjacent Everett LNG terminal, also owned and operated by Constellation and which supplied 100% of the plant's natural gas, EIA added.

However, under new long-term supply contracts secured with regional utilities, Constellation will keep the Everett terminal operational through winter 2029-2030, according to the EIA report.

The contracts ensure a steady supply of natural gas for New England, particularly during the critical winter months when natural gas price spikes are common due to pipeline limitations, EIA said.

(Reporting by Rahul Paswan in Bengaluru; Editing by Chris Reese)