Simec Uskmouth Power Limited (SUP) was built and commissioned in 1962. It has a generating capacity of 363 MW. The electricity is provided by three generating sets. It is situated in an essential position for the UK national grid as there are very few power stations situated in the south of Wales. Initially it was operated by the Central Electricity and Generating Board. The station’s operations were handed over to National Power with privatization in 1990. In 1998 it was purchased by AES and the station was given a £120 million refurbishment to bring it up to date with legislative requirements. New environmental equipment was installed and it was given a refurbishment which extended the station’s life by 25 years. In 2001 the work was completed and the station was brought back online. In June 2004 the station was put back into full operation, when it was bought by Welsh Power. Welsh Power sold it to SSE in 2009. As much as £200 million has been spent on the plant over the last 15 years.
The plant occupies approximately 250 acres at the mouth of the USK river.