FirstEnergy Solutions has put forth a timetable for its previously announced plan to permanently deactivate its three nuclear power stations.

The power-generating subsidiary of Akron-based FirstEnergy Corp. said in a news release Wednesday that it spelled out a three-year plan in a letter filed with he U.S. Nuclear Regulatory Commission.

FES cited “severe economic challenges” in explaining its decision, which calls for closing:

• Davis-Besse Nuclear Power Station by May 31, 2020.

• Beaver Valley (Pa.) Power Station Unit No. 1 by May 31, 2021

• Perry Nuclear Power Plant by May 31, 2021

• Beaver Valley Power Station Unit No. 2 by October 31, 2021

The plant closures will affect about 2,300 plant employees, FES said in the release.

Last month, FES notified PJM Interconnection, the regional transmission organization about its intention and also gave initial, informal notification to the NRC.

The plant closures are subject to review by PJM for potential impacts on reliability of the electrical grid. In the interim, the plants will continue normal operations.

But FES also indicated it is continuing to seek a path to keep the plants operating — perhaps through governmental assistance.

“We are actively seeking policy solutions at the state and federal level as an alternative to retiring these plants, which we believe still have a crucial role to play in the reliability and resilience of our regional grid,” said Don Moul, president of FES Generation Companies and chief nuclear officer.

“Absent legislative or regulatory relief, we cannot continue to operate the plants on their current uneconomic basis.”

FES, its subsidiaries and FirstEnergy Nuclear Operating Company (FENOC) filed for Chapter 11 bankruptcy protection March 31. The case is proceeding in U.S. Bankruptcy Court for the Northern District of Ohio in Akron.