The Thornhill power station generated and supplied electricity to the town of Dewsbury and the wider regional area from 1902 to 1982, and again from 1998.

Following nationalisation of the British electricity supply industry in 1948 Thornhill power station was operated by a succession of state owned bodies.

It was also adjacent to a railway line which facilitated the delivery of coal via the power station’s sidings.

The final configuration of the steam station was achieved in 1950-54 with the addition of eight boilers and three 45 MW turbo-alternator sets.

[4] At the end of its operational life in 1982 Thornhill power station had a declared generating capacity of 135 MW.

The CEB also constructed the national grid (1927–33) to connect power stations within a region, there is a 132 kV substation at Thornhill.

Operating data for the period 1954–82 is shown in the table:[4][12][13][14][5] Thornhill steam power station was decommissioned on 1 November 1982.

Thornhill combined cycle gas turbine (CCGT) power station was commissioned in 1998.

[15] The station has a net thermal input of 106 MWth and provides an electrical output of 50 MWe in combined mode.