The document discusses proposals for a tidal barrage across the Severn Estuary between Cardiff and Weston-super-Mare that could generate renewable energy from tidal power. It would utilize proven tidal power technology, impounding the tide with the barrage and releasing the water through turbines. The barrage could produce up to 17 terawatt-hours of electricity annually, helping the UK meet its renewable energy targets. However, the project would require an estimated capital cost of £14 billion and further environmental review given changes in the estuary since prior studies in the 1980s. The document reviews the potential construction, operation, costs, benefits, and impacts of the proposed tidal barrage.