Tidal Lagoon Power (TLP) received backing yesterday for a pilot lagoon project in Swansea. The tides are predictable and the source of an estimated 10GW of currently untapped energy around the UK coastline. However, environmentalists fear for the fish and bird population as the effects of powerful turbines on marine life are still the subject of hot debate in the offshore wind industry. There is also some concern about the provenance of the rock to be used in building the breakwater, a warning that the steel embedded in the Portland cement may corrode after 60 years and worries about the manufacturing process which is said to be responsible for 7% of all industrial CO2 emissions.
On balance, though, the pluses are widely agreed to outweigh the minuses: the development will create 2,000 jobs, generate enough energy to power 150,000 homes and contribute to the regeneration of Swansea. It is popular with the local community, does not rely on storage to overcome intermittency problems and could see the launch of a sector in which the UK has a real chance of achieving global supremacy: the tidal resources that pound its shores account for 8% of the world’s estimated total and half of Europe’s capacity.
Tidal power is indeed in its infancy. Many have recognised its potential but its development has been tentative and concentrated in Europe where 50% of tidal energy companies are headquartered. Even so, Europe’s total operational tidal capacity was a modest 253MW in 2016  compared with 142GW for wind. 
Harnessing tidal power involves building breakwaters and using the kinetic energy of ocean tides to power hydro-electric turbines. Neither breakwaters nor turbines are new and their construction should hold little fear for the project managers. On the positive side, that means lower risk of going over-budget from technical glitches. On the negative side, it means a slimmer chance of falling costs as facilities gain critical mass. Construction is expensive and the £1.3bn price tag for the lagoon, though amortised over 120 years, is still expected to result in a generated energy cost that equals or even exceeds the £92.50/MWh that has so angered critics of the Hinkley Point C nuclear project.
TLP has already invested £35m in the Swansea lagoon with help from the Gupta family who have been strengthening their position in UK power generation recently through their companies Liberty House and SIMEC. The UK Government is being urged to subsidise the completion of the project in order to set the scene for further lagoons which could cover 8-10% of the UK’s total energy requirement. Energy Secretary Greg Clark, however, described the breakwater and turbine combination as “untried technology” and said that he would respond once he had considered the recommendations of the review, conducted by Charles Hendry, a former Energy Minister.
 Jocelyn Timperley writing in Business Green, 9.2.16