Constructed as a 498 MWe combined-cycle gas plant, it is now used to provide inertial response and reactive power services to the grid.

Deeside power station is sited on land of a former British Steel Corporation steelworks, and was commissioned in November 1994, costing £200 million.

[3] In March 2018, the plant was again mothballed, and in January 2020 it was awarded a contract to supply the National Grid with inertial response and reactive power services.

It is believed to be the first conversion of a gas power station to provide standalone grid stability services.

[4] In 2022, part of the building, which housed the Heat Recovery Steam Generator, needed to be deconstructed[5] as part of the power station's transition from a Combined Cycle Gas Turbine (CCGT) configuration to an Open Cycle Gas Turbine (OCGT) configuration.