Government unveils designs for Severn barrages and lagoons

Long-standing plans for a tidal energy plant in the Severn Estuary moved a significant step closer to reality today with the publication of a shortlist of schemes for what would be the UK's biggest renewables project.

The shortlist of five schemes was released by the Department of Energy and Climate Change (DECC), which will now undertake a public consultation on the various proposals that are expected to attract fierce criticism from conservation groups which believe that harnessing tidal power from the Severn would disrupt local wildlife habitats.

However, the renewables industry has long argued that the Severn Estuary provides the second-highest tidal range in the world, and could generate up to five per cent of the UK's electricity.

The government is thought to be broadly in favour of the scheme, which could make a major contribution to its target of generating 15 per cent of UK energy from renewable sources by 2015 while also delivering a boost to the South West economy.

The shortlist contains variations of two technologies: a barrage that would span the estuary, or tidal lagoon schemes that trap small areas of water and release them slowly, providing much lower levels of energy but causing far less disruption to local bird habitats.

For example, a giant barrage crossing the Severn estuary from Brean Down, near Weston-super-Mare to Lavernock Point near Cardiff is estimated to provide more than 8.6GW of power, while proposals for smaller barrages further upstream or two different lagoon systems are estimated to deliver between 625MW and 1.36GW.

Energy and climate change secretary Ed Miliband today welcomed the shortlist, but insisted that other proposals still had time to make the cut. "The five schemes shortlisted today are what we believe can be feasible, but this doesn't mean we have lost sight of others," he said.

The public consultation on the five proposed schemes will now last until 23 April, after which the government will publish responses and announce its final shortlist.

A final decision on the project will then be taken at the end of the feasibility study in 2010, following a second public consultation – other technologies, if considered feasible, could be introduced to the shortlist before this stage.

But Friends of the Earth Cymru director Gordon James said today that the most appropriate technology for the site had not been shortlisted, and that the government had already decided on the barrage option.

“Friends of the Earth Cymru believes that large offshore tidal lagoons offer the most promising option for generating green electricity from the Severn Estuary. Their exclusion from the government’s short list of technologies being assessed is utterly incomprehensible," he said.

“We have long suspected that the UK Government has already decided on the Cardiff to Weston Severn barrage, and that this consultation process is little more than a cosmetic exercise. Today’s announcement appears to confirm our suspicions."

Alongside the shortlist, Miliband also announced an additional £500,000 in funding for the development of relatively low-impact tidal technologies such as tidal reefs and fences, which could improve the feasibility of lagoon options supported by Friends of the Earth.

The green group has in the past accused Parsons Brinckerhoff, the consultants which assessed the viability of all the proposals, of underestimating the power output and overestimating the cost of tidal lagoons, which it claims would cause far less damage to local wetland habitats that provide homes to tens of thousands of birds.

In related news, UK-based tidal energy specialist Marine Current Turbines (MCT) last week announced it had inked a deal with Canadian renewable energy developer Minas Basin Pulp and Power Company to install a 1.5MW tidal generator in the Bay of Fundy in Nova Scotia.

The announcement follows MCT's installation in Strangford Lough in Northern Ireland last year of what it claims is the world's first commercial-scale tidal generator to be connected to the grid.