The present status of the Severn Barrage project studies

The Severn Estuary has one of the world´s highest tide ranges. In 1981, the Severn Barrage Committee suggested a 7200 MW ebb generation barrage linking Lavernock Point near Cardiff to Brean Down near Weston-super-Mare. During 1983-85, the Severn Tidal Power Group (STPG) Interim Study compared that site with an alternative at English Stones and again recommended the Cardiff-Weston alignment. The £4.2 M Severn Barrage Development project was then undertaken by STPG and the results were published by HMSO and the Energy Technology Support Unit (ETSU). The authors describe the `reference project´ defined by those studies which comprised a 16 km long barrage of reinforced concrete powerhouse, sluice and plain caissons, together with sand and rock fill embankments. The installed capacity was 8640 MW which would provide 17 TWh of electricity per annum. Ship locks would be included and a public road provided along the barrage. Power would be transmitted by 400 kV cables from the barrage to the national grid on both sides of the estuary. The capital cost in 1988 prices was some £9000 M and annual running costs were estimated at £70 M. Unit electricity cost was 3.4 p/k Wh at 5% discount rate