First tidal lagoon project moves closer; wave power may be too expensive

Construction of the first in a series of tidal lagoon energy projects took a step closer to reality with the publication of a positive, government-commissioned ‘independent review’ of tidal lagoons carried out ex-energy minister Charles Hendry.

Hendry said: ‘I believe that the evidence is clear that tidal lagoons can play a cost-effective role in the UK’s energy mix and there is considerable value in a small (less than 500 MW) pathfinder project. I conclude that tidal lagoons would help deliver security of supply; they would assist in delivering our decarbonisation commitments; and they would bring real and substantial opportunities for the UK supply chain. Most importantly, it is clear that tidal lagoons at scale could deliver low carbon power in a way that is very competitive with other low carbon sources.’

The report makes more than 30 recommendations for delivering maximum benefit to the UK, including:

allocation by a competitive tender process for large scale tidal lagoons;

informing the consenting process with a National Policy Statement for tidal lagoons similar to nuclear new-build, where specific sites are designated by the government as being suitable for development; and

the establishment of a new Tidal Power Authority at arm’s-length from government with the goal to maximise UK advantage from a tidal lagoon programme.

Hendry continued: ‘The aim now is that we should move to secure the pathfinder project as swiftly as possible, so the learning opportunities it offers can be maximised. I have, however, also concluded that the smaller pathfinder project needs to be operational before we move to larger-scale projects.’ He added: ‘Tidal lagoons can be an important and exciting new industry for the UK. We are blessed with some of the best resources in the world, which puts us in a unique position to be world leaders.’

Developer Tidal Lagoon Power has already secured permission to build the world’s first tidal lagoon power plant in Swansea Bay, Wales, and is in the early stages of developing a fleet of six tidal lagoons, potentially to meet up to 8% of UK electricity demand. But there has been much discussion on levels of financial support from the government needed to make schemes viable.

Meanwhile, reflecting on its 10 years of work in the various parts of the marine energy sector, the Energy Technologies Institute (ETI) has concluded that the focus should clearly be on exploiting tidal stream technology commercially, as this has the potential to compete with other low carbon energy sources over the coming decades. Other marine renewable sources are at a less developed stage and therefore carry with them higher costs. 

Wave energy can work technically and has been proven through a small number of installations, but it is presently up to 10 times more expensive than other low carbon alternatives and there needs to be a radical rethink if it is to become cost competitive, says the ETI. Tidal lagoons currently lie in between the development stages of tidal stream and wave energy, and require large levels of investment to demonstrate and then deploy at scale. 

The main value of tidal stream energy from an energy systems view is that it is reliable and predictable, says the ETI. The challenge comes from the distribution of the energy generated. Because many of the most powerful tidal sites are at remote locations the source is often a long way from the end consumer, the ETI foresees that it will work best serving inhabited coastal locations as a prime source of energy consumption.