Does Swansea Bay signal the coming of age of the tidal lagoon?

The company building the Swansea Bay tidal lagoon insists it will be a pilot for larger projects at Cardiff and beyond. Critics call the cost of Swansea Bay ‘appalling’. Lois Vallely reports.

UK electricity demand is rapidly increasing while the generating capacity of ageing power infrastructure is in decline. The country will lose 21GW of installed capacity over the next nine years, and this, Mark Shorrock warns, has to be replaced somehow.

Shorrock is chief executive of Tidal Lagoon Swansea Bay, a company whose sole purpose is to build the UK’s first tidal lagoon generating station, with an installed capacity of 320MW and the capability of generating electricity for 14 hours every day.

At a recent conference in Berlin, Shorrock emphasised the reliability of this method of generating power. “You put this infrastructure in and it goes and goes and goes,” he said. If you want cheap renewables from the sea, he said, “you have to build bigger lagoons”.

In fact Shorrock intends Swansea to be the pilot project for an even bigger lagoon, at Cardiff Bay. It will be built by parent company Tidal Lagoon Power (also headed by Shorrock) and have an installed capacity of 1.8-2.8GW.

However, concerns have been raised about cost, specifically the estimated strike price of £168/MWh for Swansea Bay. When chancellor George Osborne announced in the March budget that the government had opened talks on the provision of financial support for the project, consumer group Citizens Advice said it was “appalling value for money” for consumers.

Unsurprisingly, Shorrock disagrees. “Because it has such a long life, we can end our subsidy period, whatever duration that is, and we can contract to give money to the government per megawatt-hour produced,” he says. “We’ve said to the government, ‘we can give you £10 on Cardiff or one of the big lagoons’, and in real numbers, we would pay back more to the consumer or the government than we would receive in subsidy.”

He says it’s all about scale. If the Cardiff lagoon produces 6,500GW over its 120-year lifetime, and receives a government subsidy over 30 years, it can spend 90 years “putting money back in the public purse”.

Recent reports in the Welsh media suggested that negotiations on Swansea Bay had hit delays, and that construction would not now start until March 2017. Undaunted, Shorrock clearly has a definite timetable. “We’re finishing the advance works phase next month,” he says. “We then do the real detailed design. We will engage with the banking community in January next year and drive towards financial close [in July].”

For its part, the Department of Energy and Climate Change insists there is “no timeframe for how long the negotiation process could take”.

The Crown Estate estimates that tidal lagoon power could contribute up to 25TWh of renewable electricity to the UK every year, meeting 8 per cent of demand. But time and tide wait for no man, and first of all the technology will have to prove it works.