Tidal Lagoon May Be Cheaper Than Hinkley, Government Report Says

Generating power in the U.K. by harnessing the ebb and flow of tidal lagoons may be significantly cheaper than building new nuclear electricity plants or offshore wind farms, according to a government-backed review.

Tidal lagoons, such as the 1.3 billion-pound ($1.6 billion) pilot project planned in Swansea Bay off the coast of South Wales, would likely cost “well-below” all other forms of low-carbon energy over their 120-year lifespan, said Charles Hendry, the former energy minister who carried out the review published on Thursday.

The Swansea demonstration project proposed by Tidal Lagoon Plc would cost U.K. households 30 pence a year to finance, resulting in a “no-regrets policy” choice, Hendry told reporters at a briefing in London. Larger tidal projects, like the one planned in Cardiff Bay, would require subsidy payments averaging 70-pounds a megawatt hour over the 30-year contract period, Hendry said.

In contrast, the government has agreed to pay 92.50 pounds a megawatt hour for Electricite de France SA’s planned nuclear plant at Hinkley Point in Somerset. Recent contracts for offshore wind have been agreed at an average of 137 pounds per megawatt hour. Hendry said tidal power could be built alongside alternatives like nuclear.

Tidal Lagoon is in talks with the U.K. government for a long-term contract for an initial “pathfinder” project off the coast of Swansea that would harness the power of the world’s second-largest tidal range. Using a rock wall 11.5 kilometers long (7.1 miles), it would enclose an area of seabed to create huge differences in water levels that could be driven through 16 turbines to produce power. Keeping the turbines gates shut for three hours would create a height difference of 4.3 meters between water inside and outside of the lagoon, according to Tidal Lagoon.

Hendry’s report, which will influence contract discussions, urges the government to move to the final stage of talks and launch a competitive tender process, offering lagoons contracts for difference, similar to those already available for offshore wind farms and other forms of wave and tidal power.

Greg Clark, U.K. Business and Energy Secretary, welcomed the report and said a full response would be published in due course.

The Swansea plant could be the first of six planned lagoons harnessing the power of the tides. Unlike wind farms and solar projects that typically have a 25–year lifespan, the lagoons would be in place for 120 years.

The U.K. should take a risk in investing the large sums of money required, or else lose out to other countries, such as South Korea, France and China that also have large tidal ranges, Hendry said.

“If we do not decide to take the lead in developing marine renewables as we have done with offshore wind then we will leave it to other to reap those benefits,” he said.

After the first pathfinder project is built, Hendry recommended assessing environmental and economic impacts for at least year before proceeding with a full-scale lagoon.

The Swansea project could be commissioned by 2022, with the first full-scale project in place by 2028/29, said Hendry. In total, the U.K. could accommodate 18 gigawatts of tidal lagoon capacity, according to the report.

At that scale, the lagoons could help to revitalize the U.K.’s beleaguered steel manufacturing industry, Hendry said. The Swansea project alone could support 2,260 jobs across a range of sectors, while a larger plant in Cardiff could support 11,482, according to Tidal Lagoon.

“If a project goes ahead in Swansea, the government must ensure that maximum use can be made from locally manufactured steel to ensure not just ‘jobs being created’, but ‘jobs saved for the long-term,’” said Gareth Stace, director of U.K. Steel, an industry group, in an e-mailed statement.

The project could also help tackle climate change. Tidal energy could provide more than 10 percent of the U.K.’s total power generation if 25-gigawatts of capacity was commissioned by 2030, allowing the U.K. to meet its carbon reduction targets, according to Aurora Energy Research that was included in Hendry’s review.

Environmental campaign group Greenpeace urged the government to “get on with” building the project, saying tidal lagoon energy is the most reliable source of renewable energy for the U.K.

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