A novel-design turbine currently undergoing tests may become the first grid-connected tidal flow energy device in the UK. RPS Consulting Engineers client, OpenHydro, has successfully installed a 250kW tidal turbine demonstrator at the European Marine Energy Centre, (EMEC) in Orkney.

This news article contains more information on this exciting renewable energy project.

This is the first tidal device i.e. driven by tidal flow rather than wave motion, to be installed at the EMEC test site and is likely to be the first grid-connected tidal energy device in the UK. RPS was involved in the design of the turbine, the associated temporary structures and the final piled support structure - and also undertook the contract administration and procurement.

RPS has been working with Openhydro for around two years, beginning when Mike Shaw accompanied the OpenHydro's founder, Brendan Gilmore, to Florida to meet the turbine's inventor, Herbert Williams. Mike prepared a preliminary due diligence report on the device and, shortly after, OpenHydro was born. It is a major achievement by OpenHydro and RPS that a working turbine demonstrator has been designed, constructed and installed in such a short time.

James Ives, OpenHydro's Chief Executive Officer, says that the next stage - to be completed during 2007 with engineering assistance from RPS - is to develop a seabed-located device. If this device proves successful, the plan is to develop, in conjunction with Nova Scotia Power, a large-scale farm in the Bay of Fundy on the northeast part of the Gulf of Maine.

Dr Nick Wells, technical director for renewable energy, has been acting for OpenHydro for nearly two years on the hydrodynamic design of the multi-bladed open-centre turbine. He has provided advice and developed numerical models of the turbine that have been used to predict performances and productivity at various tidal sites around the world.

The marine engineering department of RPS Consulting Engineers, including Mike Shaw and Adam Holland, has been responsible for the procurement of a contractor to undertake the installation of the device at EMEC. The contract was the NEC 3 Option F: Management Contract which was augmented to suit OpenHydro's specific requirements. This type of contract was chosen due to the challenging nature of the work and the unknown site conditions - which required the risk to be shared between both client and contractor. Such a potentially difficult project required an excellent team work ethic, transparency of price and close monitoring of costs.

Adam Holland and Nick Wells, assisted by other members of the marine engineering team, undertook the detailed design of the piled platform structure. The installation of this structure presented a number of challenges - the piles needed to be socketed into the rock seabed and positioned within fine tolerances to allow the turbine to be moved in and out of the sea. However, the greatest challenge was to formulate a successful construction methodology which would enable the structure to be installed in fast-flowing tidal conditions in an exposed offshore location. The methodology was planned in conjunction with OpenHydro, the contractor and other specialists dealing with the electrical and mechanical elements of the structure. As with many projects of this type, minor problems were encountered during construction - but these were resolved through good teamwork and a flexible "can-do" approach by all those involved.

As well as the design of the piles, which had to cope with the hydrodynamic loading and turbulence associated with the tidal location, RPS was also responsible for the design of the major temporary structures necessary to build the structure in the challenging conditions.

The platform was designed in one piece for ease of installation. It acts as an inspection and maintenance platform for the turbine, a housing for the electrical plant and a base for the winches which lift the turbine out of the sea for test and maintenance purposes. A key challenge of the platform design was fitting the electrical and mechanical equipment into the small space available.

The structure was installed by McLaughlin and Harvey Limited using two jack-up barges, a 100 ton crane and an 80 tonne drilling rig.

For more information contact:
RPS Belfast Elmwood House - Planning & Development
T: 028 9066 7914