Although the turbine could be used in river and even ocean currents, the most immediate
potential use is in tidal streams. The British Isles are surrounded by millions of tons of
moving water twice per day, with concentrations in the Pentland Firth, the Channel Islands,
and many localised sites.
There is no market yet, but the need for tidal power is well recognised - it is probably the
cleanest and certainly the most reliable form of renewable energy.
Once our turbine is established, there is a potential worldwide market of many billions of
pounds.
Other stream turbines are marginally economic, at best, only in absolutely optimal sites, but
even then they have to be considered wasteful because it is simply not possible for any of
them to maximise the resource (e.g: 8% max possible extraction vs 20% 'allowable' by
environmental standards).
It is easiest to provide an example from a specific case study that we have carried out for the
Corran Narrows in Loch Linnhe, NW Scotland. Here the tide is 'only' some 1.3 metres/sec
root mean cube velocity (rmcv) and is considered uneconomic by MCT, the longestestablished
tidalstream developer.
However, Corran is a very sheltered site that borders the A82 and a major power line is
already in place, so, without affecting the leisure boat traffic, an initial investment of only
£5m would produce annual profits of some £11.5m. It represents a Net Present Value of
£110m at a discount rate of 7%. All figures derived from a DTI study by Edinburgh
University and the Government ROC (Renewables Obligation Certificates) scheme.
All of this with minimal harm to the underwater environment or the visual amenity - only a
few pontoons would be showing.
So, the opportunity is undoubtedly there once we can prove the concept and produce
meaningful amounts of electricity from a prototype.
There will obviously be technical problems to be overcome but the main difficulties have
usually been environmental (see Severn Barrage). Our turbine is very acceptable
environmentally, and socially with the promise of local jobs and a devolved power supply.