The Severn Barrage Presentation to Severn Estuary Forum 8th June 2006 David Kerr Sir Robert McAlpine

Tidal Power from the Severn Bondi study (EP46 - 1981) was the first major study Tripartite study (EP57 - 1989) defined the present scheme Could produce power by 2017 if progressed soon

Location: Downstream of Cardiff to Weston-super-Mare 16 km length Bristol Channel/ Severn Estuary Downstream of Cardiff to Weston-super-Mare 16 km length

Tidal Power The Barrage impounds the tide, then the water is released through a turbine to generate electricity Proven Technology: La Rance in France has generated tidal power reliably for over 35 years

Barrage Operation

Barrage Layout (1989 Report) 216 Turbines, 40MW each, 8640MW total 166 Sluices 35,000m2 Ship Locks Small Locks Public Road

Facts and Figures Annual Output 17 TWh (5% of UK consumption) Installed Capacity 8640 MW Renewables Obligation: 15% by 2015 (50-55TWh) - Barrage cannot contribute 20% by 2020 would require a further 17TWh. Barrage could contribute all of this - if sanctioned soon Capital Cost £8Bn 1989 > ~£14Bn 2005 – needs re-estimate Security of supply benefit

Environmental Studies 1989 A total of 70 studies, with a budget of £2M, covering: Hydrodynamics (tides, currents, waves) Sediments, Salinity, Water Quality, Drainage Ecology, Birds, Fish

Main effects of the Barrage Tide Range reduced from 14m to 7m (springs) A smaller inter-tidal area Reduced currents, leading to:- A large reduction in suspended sediment Sunlight penetration through the water column An increase in dissolved oxygen to more normal levels A more stable seabed with more life Expected to Result in an increase in bird species and numbers

Flood protection in the Severn Estuary and Rivers Flooding in the estuary can occur when extreme high tides coincide with storm surges Flooding in the rivers can occur when these same sea conditions coincide also with high river flows The water level in the basin can be controlled - To prevent the flooding in the estuary (upstream of the barrage) To avoid obstruction to river flow caused by high tides

Use Of Barrage for Flood Protection

Environmental Balance ? Loss of the unique harsh environment Some birds may lose habitat Marine life and other birds will increase Flood protection to estuary and rivers Carbon Saving The environmental assessment needs to be updated to account for the changes in the Estuary since the 1980’s and also the changes in legislation

Transport Key Issues Ports and Shipping Forecast Shipping Movements Size of Locks to suit Portbury & Avonmouth Road and Rail Cost-benefit of a Barrage Crossing

Construction : Prefabricated Caissons

Caisson Construction Sites 1989 report identified potential UK sites shown Potential Sites in Europe Project and Employment Benefits of using many Sites

Turbine Installation

Cost – Price relationship 1 2 3 4 5 6 7 8 9 10 Cost ILEX April 2005 spot market forecast Actual Price 7 Dec 05 Tax Equity Return Transmission Opex Transmission Capex Barrage Opex Barrage Capex ROC recycle ROC buyout Wholesale electricity price p/kWh April 2005 money

The Severn Barrage should be re-examined as part of the Energy Review Conclusion The Severn Barrage should be re-examined as part of the Energy Review

Flow Patterns with Barrage

Construction Sequence (1989 Report)

Areas at Risk from Flooding

Modes of operation Ebb Generation: Preferred for most schemes Flood Generation Less usable water volume Two Way Generation No extra Energy Higher cost of Energy due to more complex turbines Energy is spread over more of the day

Outline Programme for Implementation If Government authorises a re-appraisal soon, and this demonstrates that the Project is viable having regard to the changed circumstances, first power could be available in 2015. The key to the further development of the Severn Barrage is recognition of the potential long term benefits of the Project in the forthcoming Energy White Paper. Our recent study makes it clear that Government would need to be a key part in the development and promotion of the Project. The number of parties involved across wide sectors and geography mean that only Government would be able to achieve consensus to approve the Project. The re-appraisal will examine the organisational structure, including Government’s role, and the financing of Project implementation. These aspects of the Project were withdrawn from the 1989 studies because of privatisation of the electricity industry and have never been completed. If Government decides that the Project has strategic value and agrees to support it, the preparation of the enabling legislation and its passage through parliament is expected to take 2 years - leading to Royal Assent for the Bill in the next Parliament around 2007. Completion of the detailed design and Environmental Assessment are anticipated as taking a further 2 years with construction commencing around 2007. This will enable Barrage closure and hence first power to be generated in 2015, with full commissioning by the end of 2016.