Harnessing tidal power in shallow waters

A new device under development in the UK could allow tidal current turbines to be used in shallow waters, dramatically increasing their potential for generating electricity.

Tidal currents offer a substantial and predictable source of renewable energy. But the potential for exploiting it is limited, as turbines currently require expensive fixed pillars to be built into the seabed. This means they must be placed in depths of around 50m, said Prof Ian Bryden, associate dean of the faculty of design and technology at Robert Gordon University, Aberdeen.

‘The difficulty with tidal power is not converting it into electricity, but in holding the turbines in place while they do this. A large proportion of the cost of tidal power generation is directly associated with the installation of the device,’ he said.

A new system, under development by the university’s tidal power team, will allow these turbines to be placed in shallow waters, cutting installation costs and significantly increasing their productivity, he said. ‘We have developed a concept that will hold the turbine rigidly in place under the water. It is capable of being installed using nothing more complex than a harbour tug.’

The team is in the process of establishing patents on the system, so Bryden could not reveal details of how it will work. But it will be installed on the seabed, be portable and easily retrievable, he said.

The system could also be used in very deep water. ‘Some of the largest and most complex sites have depths of over 50m, which pillar support systems cannot work in. There is no reason why we cannot extend the depth beyond the abilities of these pillar systems,’ said Bryden.

Tidal power could produce up to 40 per cent of the electricity needed in the UK by exploiting the currents of both shallow and very deep waters, he said. The research team also hopes to market the device overseas.

The team plans to begin designing individual components over the next few months, and hopes to have a half-sized prototype installed in a tidal channel by the early summer of 2003.

The model’s performance will be continually monitored over a full lunar cycle, and at the end of this trial the device will be retrieved and modifications made where needed. The project has been awarded £157,800 from Scottish Enterprise’s Proof of Concept fund to establish patents and produce this prototype.