Tag Archives: UK

Lagoons to provide tidal waves of power

We’ve all heard of the story regarding fossil fuels: they’re running out, they’re damaging the environment and they’re causing climate change. The energy sector must diversify into new forms of production if we’re to secure the future of our planet.

Fossil fuel plant (Courtesy - Gerry Machen)

Fossil fuel plant (Courtesy – Gerry Machen)

Moves have been made across the world towards nuclear energy. France generates 75% of its requirements in this manner, with low costs of production and high economic gains of over €3 billion per year to the economy. However, this will fall to 50% by 2025 due to concerns over safety given the 2011 Fukushima, Japan nuclear disaster following a tsunami. Over 19,000 people died, whilst a further 120,000 remain uprooted with 67.5% stating they have relatives who are showing signs of physical or psychological distress.

Artist’s impression of the Swansea lagoon (Courtesy Tidal Lagoon Power)

Renewable energies offer an alternative, from wind turbines to solar farms, but what of the ocean? The UK-based firm Tidal Lagoon Power has unveiled plans for six lagoons in Wales and England to provide 8% of the UK’s electricity. These tidal energy lagoons would be a world-first and have been supported by the UK government; the Energy Secretary Ed Davey has set-aside £30 billion from the existing renewable energies budget. The first installment would construct a five mile wide breakwater more than two miles out to sea in Swansea. This scheme could produce energy for 14 hours per day, powering 155,000 homes. If successful, a much larger Cardiff lagoon of 90 turbines over 22 km could follow and be in operation by 2022, powering more than 1.5 million homes. Tidal systems provide predictable energy sources, unlike wind and solar, but just how would this be captured?

Video courtesy – NMANewsDirect

The lagoons would operate a gated mechanism. As the tide comes in, water builds up outside the wall before gates are opened and water enters. Turbines capture this motion and generate electricity. As the tide goes out once more, the water is released from the lagoon with energy captured by turbines once again.

Concerns have been raised regarding the initial costs of the project along with the price of the energy when returned to the grid. At £168 per MWh, the cost is more than twice that of onshore wind. However, as technology develops and efficiency increases, costs will fall to £90-95 per MWh; this is comparable to nuclear energy priced at £92.50 per MWh.

Environmental groups are widely positive upon the prospects of the lagoons. Minimal impact is forecast regarding the tide flow of estuaries; the vital habitat of wading birds. However, anglers are concerned that migrating fish may stray into turbines. Although, Tidal Lagoon Power states that this effect will be offset by the sea walls creating reef habitat to actually increase numbers.

Wading bird of the estuarine habitat (Courtesy Clematis Wilt)

Wading bird of the estuarine habitat (Courtesy Clematis Wilt)

Overall, the construction of tidal lagoons to harness natural ocean movements appears a positive. After the initial costs fall, the system will provide a substantial portion of electricity at low environmental costs in a renewable manner. The UK could act as a platform for such systems on a global scale.

Toby Buttress