Return to the green lagoon

Howard Bassford and Michael Fry from the law firm DLA Piper which advised Tidal Lagoon Power, write for Utility Week on why the government should use the opportunity in the wake of the Hendry Review to exploit tidal lagoon technology.

Charles Hendry, a former energy minister was appointed by the government to assess the strategic case for tidal lagoons in 2016. On 12 January 2017, he published his report and recommendations. Hendry’s key finding was that tidal lagoons can play a cost-effective role in meeting the UK’s energy needs: ensuring security of supply, low carbon power for many years to come and “real and substantial opportunities for the UK supply chain”. Whilst the government is not obliged to accept the Hendry Review, it would be surprising if it did not follow the findings of the independent review it set up. (Read industry reaction to the review here).

Tidal lagoon power stations use the tidal range to generate power. Turbines are installed in a seawall barrier capturing the energy from the height differential between high and low tide, generating power as sea water flows through the turbines. Areas of UK coastal waters have some of the world’s highest tidal ranges, meaning tidal lagoons are able to generate reliable power over the long periods between high and low water.

Swansea Bay

DLA Piper advised the leading tidal power company, Tidal Lagoon Power (TLP), on the pioneering Tidal Lagoon Swansea Bay (TLSB) in Wales, which is set to be the world’s first tidal lagoon power plant. We advised on consenting and real estate aspects of the proposal, putting together the case for the grant of development consent in relation to the project. This was granted in June 2015, and TLSB has been identified by Hendry as a “pathfinder lagoon”, the development of which should be seen by the Government as a “no regrets” policy.

TLSB itself comprises 16 hydro turbines, set in a 9.5km seawall, with a capacity of 320MW and generating enough annual electricity for 155,000 homes for the next 120 years. The capital spend on TLSB will be £1.3 billion, and it will create in excess of 2,000 direct construction and manufacturing jobs, with thousands of further jobs in the wider UK supply chain.

Some commentators think TLSB is expensive. However, as Hendry points out, while the initial costs are higher than offshore wind and nuclear, the life cycle of a lagoon (120 years plus) means that over a 60 year period, tidal lagoon costs are significantly lower than nuclear and less than offshore wind. Hendry estimates that the average additional cost on a household’s electricity bill from the development of TLSB will be the price of a pint of milk a year – around 30p.

As with every large-scale construction project, there are potential environmental consequences – mainly visual and in relation to the marine environment. However, securing development consent for a tidal lagoon is a rigorous process: the application for consent is examined for six months in a public forum. Local people, environmental bodies and businesses are all able to have their say, and the developer needs to respond. Environmental impact can be fully explored during this process and can be lessened through mitigation, tweaks to the design, and other protective measures. TLP’s lagoons plan to provide environmental opportunities and benefits within their lagoons, for example, the seawalls can provide the habitats allowing coral formation and shellfish to thrive.

This needs to be weighed against the many positives of TLSB: secure energy, local economic regeneration (“beyond question” according to Hendry), significant supply side opportunities, and a significant contribution to meeting the UK’s decarbonisation goals.

Tidal Lagoons – the future

Beyond the first scheme in Swansea, tidal lagoons offer the chance for the UK to be at the forefront of a 21st century technology. After Swansea, TLP is keen to progress schemes in Cardiff, Newport and Colwyn Bay in Wales. It also has schemes suitable for Bridgwater Bay in West Somerset and another Scheme in West Cumbria. Beyond that, there are many locations worldwide with hyper-tidal conditions, which offer opportunities for British concepts to be developed further.

As an idea of scale, TLSB has installed capacity of 320MW from a 9.5km seawall. TLP’s plans for further lagoons, including the next one, likely to be in Cardiff, are on a much greater scale. The capacity of the Cardiff Lagoon would be around 3GW (about the same amount as a nuclear power station) with a seawall of around 34km. TLP’s analysis shows that a network of tidal lagoons has the potential to meet up to 8 per cent of the UK’s energy needs. As more lagoons are built, there will be significant economies of scale.

With so much more to offer than just power generation, it is not surprising that lagoon projects have captured the public imagination. So often, local people are opposed to energy projects. Not so with TLSB – over 86 per cent of the thousands of people who responded to consultation have supported the project.

With so much to favour this new generating technology, and with the evidence assembled by Charles Hendry pointing out that tidal lagoons are such a good prospective investment, the government must surely look at ways to encourage Swansea and the schemes that will soon follow. There is every reason to push on with these projects.

Tidal stream vs tidal lagoons

It has been argued in Utility Week that tidal stream technology should take priority over tidal lagoons. This is not a sensible suggestion. Currently, tidal stream power is an immature technology with around 9MW of capacity deployed in the UK, to varying degrees of success. By comparison, tidal range schemes are at a large scale and employ technology that has been in use for over fifty years. Consequently, tidal stream power is considerably more expensive than power from tidal range schemes. There may well be a place for both in the energy mix but at present they are two very different propositions.