Multi-directional wave-testing centre gets funding boost

The world’s first multi-directional wave- and current-testing centre for marine energy is set for construction in Scotland after receiving £6m in public funding.

Edinburgh University plans to build the 30m-diameter indoor tank on its King’s Buildings campus, following a grant award by the EPSRC.

The tank, which will hold more than 1.4 million litres of water, will provide a controlled environment for initial trials of wave- and tidal-powered turbines without the large costs and risks associated with testing them at sea.

Most existing tanks, such as Edinburgh’s existing facility, are smaller and only simulate either waves or tides. Those that can fulfil both functions, such as the one in Nantes, France, were built to test ships.

Prof David Ingram, one of the project’s co-investigators, told The Engineer: ‘Testing in a tank gives you two advantages. The first is you’re testing in a controlled environment. So if you want to know the survivability of a machine, you can dial up a once-in-200-years storm every few minutes.

‘The other is it’s much, much cheaper than testing at sea. Testing in a small facility costs a few thousand pounds, a larger facility tens of thousands. Even with the smallest-scale model at sea it’s tens of thousands of pounds just for the boat. If you go to more than quarter scale it could cost, in total, tens of millions.

‘If you put a test model into our facility and break it, you can haul it out, it goes to the workshop at the other end of the lab, spend a day fixing it and put it back in the water. If you put your model in the sea and it sinks you have to get divers out.’

The proposed tank will be 2m deep and simulate currents of 0.8m/s and 700mm-high waves for models that are between one 20th and 40th the size of the final equipment design. Smaller facilities are typically designed for one-100th scale models.

‘The waves and currents can be generated from any direction and that’s unique,’ said Ingram. ‘There’s no other facility that will do that in the world.’

These specifications are designed for deep and intermediate water equipment, and are suitable for most existing technologies, but the tank could be adapted for shallow-water turbines such as Aquamarine’s Oyster device.

The university is working with wave-generator firm Edinburgh Designs and designers led by Mace Group to draw up the building specification and civil engineering plans and hopes to start a 12-month construction programme in October 2011.

The £6m EPSRC grant will cover the cost of the scientific equipment and the tank but the university is underwriting the cost of the external building and is pursuing opportunities for industrial investment.

While the civil construction of the facility is expected to be relatively straightforward, a second EPSRC project at the university is investigating the design of the wave and current generators.