Severn Barrage Feasibility Study

Yesterday the government announced a new feasibility study will investigate the Severn Barrage, a tidal power plan that could provide about 5% of UK electricity, 17 TWh of power per year, equivalent to about 18 million tons of coal or 3 nuclear reactors. Expected output at 8640 MW during flow, or 2000 MW average power. The cost of the project which includes a 16km (10 miles) barrage from Lavernock Point to Brean Down with 200 turbines is set to exceed £14 billion and could be generating electricity by 2018.

The Severn Barrage is not a new concept to locals in the region with the concept dating back over 150 years, the last time the project was touted was in the early eighties. The building of the Severn Barrage would be an engineering feat, comparable with some of the world's biggest construction projects. The huge size and cost of most of the ideas over the years are what have kept plans firmly on the drawing board. The study will examine the social, economic and environmental aspects of the barrage. As well as the long term environmental benefits through reduced CO2 emissions, negative impacts from the project will also be addressed. Social benefits will be through the creation of up to 35 000 jobs in the construction industry and up to a further 40 000 permanent positions.

Due to the fact the UK is an island, the country has great potential for generating electricity from tidal power. To date, wave and tidal power have received very little money for development and consequently have not yet been exploited on a significant commercial basis due to doubts over their economic viability in the UK (due to the low cost of oil in 1975). Yesterday's news follows on from an announcement in February for the UK's first wave farm by the Scottish Executive in February 2007. It will be the world's largest, with a capacity of 3 MW generated by four Pelamis machines and a cost of over 4 million pounds.

"I grew up in south Wales and I remember the barrage being discussed. The idea has been around for a long time. It has got great potential for creating clean energy. It is now extremely pressing and I think we should leave no stone unturned. The price of doing nothing about changing our energy mix, how we generate our energy and not reducing our carbon footprint means several years down the track the habitat of the Severn could be affected anyway. We've got to do something. The last time this was looked at in detail was 1989. We want a serious study into its potential and to say whether this could be best realised by a barrage or lagoon."

Stephen Williams, Bristol West, Member of Parliament

"It's probably more likely than it's been for perhaps 20 years - with the threat of climate change on us, we need to look at new ways of tackling that and generating our energy. This is now being looked at but if it did go ahead, it would still be nearly 2020 probably before any power was generated - and what we're doing at the RDA is pioneering some projects in the region to try to bring other renewable technologies to fruition which can also help tackle climate change."

Jonny Boston, South West Rural Development Agency

I fully support renewable energy projects that will have an overall positive effect on the environment and can be accepted by the majority. This project is a serious way that the UK can increase the proportion of renewable energy and reduce CO2 emissions by in excess of 9m tonnes annually (about 1.5% of UK CO2 emissions). The project also has other supplementary benefits;

• Predictable source of "green" energy during lifetime of barrage
• Home-grown facility, independent of foreign uncertainties
• Flood protection for the vulnerable Severn estuary, including against global warming sea level rises
• Transport links for road and/or rail
• Better shipping and boating conditions behind the barrier
• Boost to local economy - construction industry in the short term, tourism and infrastructure in the long term
  
• Reduced turbidity (cloudiness) of water will improve the density and spread of invertebrate colonies in the estuary. This should lead to better carrying capacity for migratory fish and birds.

Whilst there are positives to such projects from one aspect we must also listen to voices from all parties who will be affected by the project. Some of the negative impacts of the project are;

• Existing ecosystems would be heavily altered, with new species moving in and perhaps dominating old species
• Some of the low-tide mud-flats would be lost, displacing some of the wading birds that make the estuary a protected area
• Lack of industry skill in the UK for a project of this size.
• Likely to stimulate silting in some areas and coastal erosion in others
• Enhance flood risk on the seawardside because only a proportion of the water that presently flows up stream will pass through the barrage leaving the remainder to rise up outside possibly raising levels by as much as a metre.
• Shipping would have to navigate locks
• Costs associated with navigating the locks would impact trade and commerce
• Severn bore weakened
• All industry discharges into the Severn (eg Avonmouth) will have to be reassessed.

Some of the voices speaking out against the project are from environmental organisations Friends of the Earth and Royal Society for the Protection of Birds.

"The Severn barrage was a bad idea in 2003 and is an even worse proposal now, not least because there are better, less damaging alternatives. Clean energy technology is developing apace and there will soon be less intrusive ways of harnessing the tides with little environmental cost. Tidal stream systems are being tested in the Bristol Channel, Scotland and Northern Ireland and could generate far more energy and cause little environmental harm. The RSPB strongly supports the development of renewables but today's white paper lacks the drive to develop the best green energy projects quickly enough."

Dr Mark Avery, Conservation director, RSPB

"We are opposed to the large Severn barrage because it would have a major negative environmental impact. Any proposal to build a barrage could face strong legal challenges on environmental grounds. It would take a long time to build, there would be high costs and it would generate a lot of carbon dioxide as it was being built. There are better alternatives available such as a tidal lagoons."

Gordon James, Campaigner, Friends of the Earth Cymru

Whatever the outcome of the feasibility study, it will continute to be a talking point for the future to come.

Image: Second Severn Bridge by David Moreau