Aberthaw 'A' Power Station was opened in February 1966 and Aberthaw 'B' Power Station was opened in 1971. The 'A' Station operated until 1995 and was subsequently demolished; its two 425 feet (130 m) high chimneys being the last section to be demolished in 1997. Aberthaw 'B', specifically designed to burn the low-volatile coal which comes from opencast mines in Wales, was downgraded in 2017 following a European Court of Justice finding in 2016 that the plant had been emitting illegal levels of pollution. The plant closed in April 2020 and is now being decommissioned by RWE Generation UK.

Sources:

'Aberthaw power station pollution 'too high', EU court rules', BBC News, 21 September 2016
'Aberthaw Power Station set to close, risking 170 jobs', BBC News, 1 August 2019
'The last coal-fired power station in Wales has closed', Business Live, 1 April 2020

Meilyr Powel, RCAHMW, October 2020.