- a barrage could produce around 5% of the current annual electricity needs of the UK;
- it would be a reliable source of power - the tides are pretty predictable! - and using a proven technology that has worked in France for 40 years;
- it would be a very 'green' source of power;
- it could act as a partial flood defence for the Severn Estuary;
- at a time of uncertainty of international energy supplies, it would be 'home-made' power.
- although it could cost £15 billion, if the costs of the appraisal and planning process were taken out of the equation, the utility companies might be willing to operate it on a commercial basis, just as they build power stations on that basis at present.
The big downside, apart from the cost, is the worry about the environmental impact on the estuary. But even here there are some potential benefits. Apparently, the lower tidal reach above the barrage would mean less sediment disturbed, cleaner water, more sunlight getting through, more marine life and therefore more bird life! There might be a downside in terms of the impact on the mudflats further up the estuary, and this clearly needs to be looked at. But I came away from the meeting convinced that an appraisal of this idea - which hasn't been updated since the 1980s - is long overdue.