Interest in deriving large scale electrical power from the Severn Estuary began seriously in 1925 when an official study group was commissioned. A scheme of 800MW was investigated and although considered technically possible, it was prevented on economic grounds 1.

In 1975 the authority charged with meeting and delivering electrical supply in the UK, the Central Electricity Generating Board (CEGB), published a study with evidence from Bristol and Salford universities to the Secretary of State’s Advisory Council on Research and Development for Fuel and Power. From the study, the council established that a barrage could not be commissioned unless the energy situation deteriorated significantly in order for such a project to become economically feasible 1.

Building on the 1975 report, work continued from 1979 and 1986 at various levels which were initiated by the Department of Energy. Published in 1989, the scheme included a closed barrage 15.9km long with a total installed capacity of 8,640MW from 216 turbines. This would, on average, produce 17TWh annually; replacing approximately 8 million tonnes of coal or 17.6 million tonnes of carbon dioxide