Go with the flow

In January a review by former UK energy minister Charles Hendry broadly supported the idea electricity generation using a tidal lagoon in Swansea, a scheme we covered in Eureka! last February.

It will cost in the region of £1.3bn and generate 320MW, which compares to the cost of building Hinkley Point C of £18bn with its generation capacity of 3200MW. Or to put it another way, 10% of the capacity for 7% of the costs. Unless we decide to get use overseas financing options, we would also not be tied into sky high unit costs for the electricity generated. Nor would we have to factor in the decommissioning costs – Sellafield looks like it will end up costing an astonishing £70bn!

Don’t get me wrong, I am not against Hinkley, but if it makes sense from environmental, financial and energy security perspectives then surely the Swansea scheme must be worth committing to.

As with any renewable energy source, the environmental aspect should not be dismissed, and the scheme is bound to change the ecosystem. But given natures inherent adaptability, will it actually cause any damage? The 1967 scheme at Rance in northern France saw some fish species disappear (sand eels and plaice) while others returned (sea bass and cuttlefish) – so environmental credentials may vary depending on perspective.

The only other tidal power station of any size is at Sihwa Lake in South Korea. Only coming on stream in 2012 it is too early to assess its environmental impact, but it was designed to in tandem with schemes for land reclamation and to reduce agricultural pollution.

This French facility did take 20 years to pay back costs, but is now producing electricity at under the cost of nuclear stations.

The most compelling argument in favour of the Cardiff scheme is that if it was the trailblazer for a series of other tidal energy schemes it could provide a useful baseload for the National Grid. Admittedly the nature of tides means that there are only certain times of day when the turbines can run, but the proposed other sites range from South Wales to the North West of England, and the difference in tidal cycles is around five hours, so taken as a whole there could be a consistent and predictable amount of electricity being fed to the grid, possibly providing up to 10% of requirements.

Beyond the Swansea scheme we have reported on a number of other tidal energy projects in Eureka! and it feels that this is the time when British engineers could take a lead in harnessing a global resource.