Revived UK Tidal Barrage Proposal Stirs Debate

A prominent Welsh politician is breathing new life into a controversial proposal to essentially dam the Severn Estuary in the western U.K. in order to draw power from its tidal flows.

The proposal, while interesting in its own right, takes on particular importance at a time when many green-minded people are struggling to balance the fight against climate change with the potential environmental impacts of clean energy projects. We’ve seen this play out with wind power, which some environmental groups endorse as a clean alternative to fossil fuels, while others say it too often harms birds and other wildlife.

severn estuary, barrage

image via Shutterstock

That very sort of debate quickly began to take shape in the U.K. in May, after Peter Hain quit Parliament and gave up his post as Welsh shadow secretary to represent a private consortium trying to revive a longstanding proposal to build a Cardin-Weston Severn barrage. In an email to the Guardian, Hain called the barrage “the single most important low carbon, renewable energy project in Europe.”

The Severn Estuary drains Great Britain’s longest river, the Severn, widening into the Bristol Channel as it divides Wales and England. Its attraction as a source of power is obvious: Massive amounts of water flow in and out of the estuary continually. A National Oceanic and Atmospheric Administration list of the 50 locations in the world with the largest tidal ranges includes several spots along the estuary.

Proposals to take advantage of this fact have come and gone, most recently in 2010, when the British government conducted a lengthy review and then announced it did not “see a strategic case for public investment in a tidal energy scheme in the Severn estuary at this time, but wishe(d) to keep the option open for future consideration.”

Several different ideas were studied by the government, but the one that was judged to be the best bet was for a $45 billion, 10-mile-wide barrage across the channel from Cardiff to Weston. Under that scheme, 216 40-megawatt (MW) turbines would have yielded 15.6 terawatt-hours of electricity annually, meeting about 5 percent of the entire U.K. energy demand.

But while such a project was seen as viable and likely to produce energy at the lowest cost, it also was determined to be the most environmentally risky. A group that fought against the proposal, Save Our Severn, said it wasn’t against trying to pull energy out of the estuary, and recommended less invasive tidal stream generation. But the government said such technology – of the sort only now beginning to be tested – was too new and uncertain to move forward with.

severn barrage

image via U.K. Government

Hain was clearly anticipating the complaints from environmentalists when he got behind the Cardin-Weston Severn barrage last month, saying the project “should be backed by all those serious about tackling climate change.” After Hain joined Consortium Corlan Hafren, the Cameron government said it would meet with the group to discuss proposal. But environmentalists were having none of it.

“A massive concrete barrage stretching across the Severn could have an enormous environmental impact, destroying vast areas of habitat of international importance,” said Gareth Clubb, director of Friends of the Earth Cymru. “Fish and bird life would be devastated and could not recover…. (T)idal energy can be captured by other means with much less damaging consequences, and could be giving us green energy far sooner than the 20 years it will take to build this barrage.”

Pete Danko is a writer and editor based in Portland, Oregon. His work has appeared in Breaking Energy, National Geographic's Energy Blog, The New York Times, San Francisco Chronicle and elsewhere.