Severn Tidal Power Project Update  

The Economist has an update on plans for the Severn tidal power project in the UK, spinning it as a battle between different groups of environmentalists but also noting that it would be highly beneficial in terms of jobs created - Green on green.

FOR all its stirring rhetoric, the government’s record on renewable energy is poor. Geographically, Britain is ideally placed, enjoying (or enduring) some of the windiest weather and heaviest seas of any European country. Yet in 2005 (believe it or not, the most recent year for which comparable figures are available) Britain got less than 2% of its energy from renewable sources (mostly wind). This was considerably below the European average of 6.7% and far behind countries such as Denmark (16.2%) or Sweden (29.8%).

One single project could provide an enormous boost. The river Severn, Britain’s longest, which flows from Wales to the Bristol Channel, has a tidal range of 15 metres, the second highest in the world. Engineers have long fantasised about harnessing all that energy, and with climate change and energy security now pressing political problems, ministers are taking them seriously. On January 26th the government published a shortlist of possible projects, including three barrages (essentially gigantic dams) and two tidal lagoons (man-made tanks in the sea which fill up and empty with the tide).

It is easy to see the attraction of such schemes. Tidal energy is the best-behaved of renewable sources. Unlike wind or wave power (or even hydroelectricity, which depends on the rain), tides—governed by the immutable laws of celestial mechanics—are predictable. The sheer size of some of the plans are impressive too. When the tide is flowing fastest, the biggest option—a ten-mile, £22 billion barrage running from Weston-super-Mare to Cardiff (see map)—could generate 8.6 gigawatts, around a seventh of Britain’s peak consumption and more than every other renewable-electricity source combined. Although its average output would be far below its peak, it could still supply around 5% of Britain’s electricity every year. ...

But there are other reasons too for politicians to support the project. Like the Hoover Dam, built at the height of the Great Depression in America, a Severn barrage, the British government claims, could create tens of thousands of jobs and lots of work for firms. And as one of the world’s largest engineering projects, it would, of course, be a long-lasting monument to whichever politician approved it.

Three decades ago, engineer Peter Fraenkel created an underwater turbine to use river power to pump water in Sudan, where he worked for a charity. Civil war and a lack of funding stymied his plans. Now, his modified design generates electricity from tides off Northern Ireland.

“In the 1970s, the big snag was the market for that technology consisted of people with no money,” said Fraenkel, the 67-year-old co-founder of closely held Marine Current Turbines. “Now it’s clear governments are gagging for new renewable energy technology.”

MCT last year installed the world’s biggest grid-connected tidal power station in Strangford Lough, an Irish Sea inlet southeast of Belfast. The SeaGen project’s two turbines, which cost 2.5 million pounds ($3.6 million), can produce as much as 1.2 megawatts of electricity, enough to power 1,140 homes.

The company is one of more than 30 trying to tap tidal currents around the world, six years after the first project sent power to the grid. Investors may pump 2.5 billion pounds into similar plants in Europe by 2020 as the European Union offers incentives for projects that don’t release carbon dioxide, the gas primarily blamed for global warming. In the U.S., President Barack Obama plans to increase tax breaks for renewable energy.

“Tidal energy has an enormous future, and the U.K. has a great resource” if construction costs come down, said Hugo Chandler, renewable energy analyst at the Paris-based International Energy Agency, which advises 28 nations. “Its time may be just around the corner.” ...

Positioned between the North Sea and Atlantic Ocean, the British Isles have about 15 percent of the world’s usable tidal current resources, which could generate 5 percent of domestic electricity demand, the Carbon Trust estimates. Including wave power, the ocean may eventually meet 20 percent of the U.K.’s energy needs, the government said in June.

Grid-connected tidal power moved from theory to reality in the past decade, with the construction of smaller, test projects.

OpenHydro, a closely held Dublin company, linked a donut- shaped device with less than a quarter of the capacity of SeaGen to the grid at the European Marine Energy Centre in Orkney, Scotland, last May. Hammerfest Strom AS, whose owners include StatoilHydro ASA, in 2003 made the first tidal turbine connection with a 300-kilowatt project near Hammerfest, Norway. ...

“Fossil fuel represents burning off the Earth’s capital, and now we’re going back to the energy that’s available to the planet in the course of the day,” Wright said. “Tidal stream energy is no longer a nice-to-have. It is a must-have.