“The idea of extracting tidal energy with tidal turbines is exciting, but we need to make sure we know how much power can be removed from the tides, because theoretically we know there is a maximum or optimum power for any particular coastal location.
We then need to concentrate on what fraction of this energy can be feasibly removed (allowing for aspects of hydrodynamic efficiency and cost), before we can understand the potential for the tides to make a useful contribution to energy demands.
These types of questions are very much what we like to work on.”
Scott Draper LRF Assistant Professor
Unlike oil and gas developments, the technology for renewable marine energy is in its infancy. Western Australia is one of the most promising wave and tide energy locations in the world, placing COFS at the forefront of renewable energy research.
While opportunities for technology transfer from the oil and gas sector do exist, differences in site-location, size, foundation systems and applied loads require enabling solutions before new energies can become financially viable.
Tidal energy extraction The Pentland Firth off the northwest coast of Scotland is one of the most promising tidal stream energy locations in the world. Often referred to as a possible “Saudi Arabia” of tidal energy, the site is an ideal location for many tidal energy developers to deploy rows or “fences” of underwater turbines. COFS' research Assist/Prof Scott Draper and Thomas Adcock (University of Oxford,) have modelled energy extraction at this site. They developed a numerical model of tidal currents around the Firth, and an analytical model capturing the fundamental physics of the site. This work has produced the first theoretically correct estimate of a source, and indicated that isolated deployments of tidal stream devices can interact. This means that if two or more tidal device developers operate in the Pentland Firth they must do so cooperatively.
These findings come at a critical moment in the development of the Pentland Firth. The UK Crown Estate plans to lease sites along the firth to different tidal stream developers. Draper and Adcock’s findings suggest that in order to maximise energy extraction, developers would need to work together to locate devices strategically.
Other applications to be pursued include the use of small suction installed caissons as multi-footing tri- or quadrapods. Challenges include the design of foundations for repetitive cycles uplifting into tension, installation in layered soils, optimising of foundation size and number, non-linear and three-dimensional wave, current and wind fields and accurate assessment of dynamics for these extremely flexible structures.
Another research objective will be to evaluate the feasibility of novel renewable energy solutions to the marine environment, through mapping of regional environmental and seabed soil conditions.