Swansea Bay Tidal Lagoon

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Rising tides in energy

What type of energy production can you think of that is reliable, predictable, uncomplicated, emission free, visually unobtrusive and also contributes to community recreation? We couldn’t think of any either – until now. The Tidal Lagoon, Swansea Bay project is set to commence later this year and is the first of six planned in the UK that could end up producing 8% of the UK’s total energy supply and kick start a whole new renewables industry…

The Tidal Lagoon, Swansea Bay project is being developed by special purpose vehicle (SPV) company, Tidal Lagoon Power plc and will be the first of six planned giant lagoon structures that will generate electricity and could end up making up 8% of total UK power production. This method of generating power in tidal lagoons is a world first and has the potential to kick start a whole new renewables industry sector globally.

The UK has one of the highest tidal ranges in the world, beaten only by Canada, and subsequently has a huge, previously unexploited, source of renewable energy that could help change how we produce energy in the country.

The tidal range in Swansea Bay, first of the six proposed projects, is a huge seven to nine meters. The plans for this first pilot are for a 9.5km causeway that will create an 11.5km² lagoon, capable of generating power for an estimated 155,000 homes.

The £1 billion project will create jobs in the region, as well a facility that will become a multifunctional part of the community – the company’s vision is for the lagoon to be used as a sporting and recreation facility, marine culture farm and educational centre.

In order to construct the lagoon, sand and gravel will be hovered up from the local seabed and pumped in to high strength textile geo-tubes. The tubes will then be layered up, with the area between filled with sand. Different grades of rock will be applied to act as a barrier against the sea and the causeway will run across the top of the entire length of the wall, will sit 2.8 meters above high tide level and be available to the public.

Installed in to the causeway will be the concrete turbine housing – 550 meters long and housing 26 turbines. Each one will be six meters in diameter, 18 meters long, able to generate up to 16MW per hour and expected to be active for an average 14 hours per day.

The lagoon will operate similarly to a lock gate, with the water level on either side altering dependant on the operation of the wicket gates in the turbines. When the tide rises, the wicket gates are closed and the water level in the sea will rise above the level inside the lagoon. When the tide reaches maximum height outside the lagoon, the gates are opened and water flows in to fill the lagoon, turning the 700 tonne turbines to generate power. The procedure is then reversed as the tide falls and the water flows back in the opposite direction.

One of the pivotal themes for this project and a part of the company’s ethos is the importance of using UK suppliers and expertise, thereby boosting local infrastructure. The £300 million contract for the supply of 16 bidirectional turbines to the lagoon was recently awarded to General Electric and Andritz Hydro.

Part of the reason for this award was that outlined in the company’s joint bid was a clear commitment to keeping British industrial components and expertise at the heart of the turbine production.

The turbines themselves will be based on Andritz Hydro global technology, with components being sourced in the UK. The companies have committed to the launching of a dockside Turbine Assembly Plant in Wales that will initially employ 100 skilled workers, with operations expected to be scaled up by six times by 2018.

The cost of the project will be funded by end consumers under an existing government framework to promote local, low-carbon energy. Negotiations are still ongoing, however it is estimated that electricity at the Swansea facility will cost £168 per MWh, reduced to around £90 for the next, more efficient, lagoon planned in Cardiff.

The £90 figure can be compared positively with the £92.50 price for power from the planned Hinkley nuclear power facility – evidently also having a much lower risk and with a design that will produce electricity for 120 years.

Mark Shorrock, CEO of Tidal Lagoon, Swansea Bay plc, was quoted on the BBC news, saying that, “we have a wonderful opportunity to create energy from the dance between the moon and the earth.

“It is admittedly rather expensive to begin with, but as time goes on and the capital costs are paid off it becomes incredibly cheap.”

The project has received an incredible amount of support and is backed by energy secretary, Ed Davey. Included in the National Infrastructure Plan 2014, published by HM Treasury, the project could bring up to £5 billion in investments in to Wales alone and the development of a global tidal lagoon industry could create an export industry worth £70 billion to the economy in the UK.

In this day and age we are used to the industrial and functional appearance of the power stations that are scattered across our countryside. In the case of the proposed tidal lagoon projects, there is a real opportunity to create facilities that exceed all practical expectations, while also contributing to the community in a multitude of ways not directly relating to power and remaining aesthetically pleasing at the same time.

Perhaps most importantly of all we would have a renewable, emission free, facility that can be constructed using existing technology and where the output would be completely predictable and reliable – more so than existing wind and solar technologies. A surprisingly simple solution that has the potential to birth a whole new renewables industry – in this case proving that the simple answer really is usually correct.

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