Fugro Seacore recently won an exciting £2.5milion contract to install Oyster®, an innovative Wave Energy Converter for Aquamarine Power Ltd at the European Marine Energy Centre (EMEC) wave test site 400m west of Orkney mainland.
"This is an important time for Aquamarine Power. We are installing a full scale demonstrator of our Oyster wave device…we want it to be installed correctly and carefully and we need a world class contractor to do that - that is why we have chosen Fugro Seacore”. Martin McAdam, Chief Executive Officer, Aquamarine Power.
Between May and October 2009 Fugro Seacore completed a £3m project to install Oyster, the world’s largest working hydro-electric wave energy device on behalf of Aquamarine Power at the EMEC wave test site in Orkney. Oyster is designed to capture the energy found in nearshore waves and was installed approximately 500m from the shore in 15m of water. Being a prototype device, the installation required meticulous planning to ensure sufficient resources were available to deliver Oyster’s components to Orkney and install them on time. The solution was for Fugro Seacore - acting as Principal Contractor – to carry out the main installation works directly and draw upon the specialist expertise of various local, national and international contractors where required.
The project was divided into several stages: Installation of a Pile Connector Frame (PCF) onto the seabed, creating a secure foundation upon which Oyster would be attached. Once lowered to the seabed by Deep Diver’s new Kobelco crane, the 36t PCF was anchored in place by four 1m diameter piles grouted into sockets drilled up to 14m below the seabed. Resting on several adjustable legs, the PCF required accurate positioning & levelling to compensate for the rocky, uneven seabed and once installed, the final connection to the piles was made by mixing & pumping Densit D4 grout – another first for Seacore!
The second stage was to lower the Power Capture Unit (PCU) onto the PCF and bolt the two halves of Oyster together. With dimensions 18m x 12m x 4m and weighing 200t, the PCU was towed to Orkney onboard a flat top barge and installed during a complex operation involving GPS Marine’s Apollo shearleg. 120t of seawater was pumped into ballast tanks within the PCU to provide sufficient negative buoyancy to aid its descent before being lowered under the guidance of divers. The PCU was landed on the first attempt within three hours of the Apollo being deployed onsite.
Following bolting of the PCU to the PCF, the third stage was to connect Oyster to its onshore generating station via three subsea pipelines. This involved the installation of flexible pipelines, a 600m long data umbilical cable and a variety of instruments to monitor Oyster’s performance. To stabilise and protect the flexible spools from the site’s harsh wave conditions, they were carefully covered with concrete mattresses, each weighing 15t.
Finally, once preliminary tests of the hydraulic and electronic systems were completed, Oyster was brought to life in a deballasting operation to remove the seawater added previously.
Despite the challenges of deploying a prototype device in a harsh, remote environment and simultaneously co-ordinating teams from six different companies, the project was a resounding success and has attracted widespread attention, culminating in Oyster being officially launched on 20th November 2009 by Scotland’s First Minister Alex Salmond.
“I’m delighted to see first-hand the full-scale Oyster now installed and operating offshore. This is a key milestone for Aquamarine Power and for Scotland’s marine renewables sector.”
Alex Salmond, Scottish First Minister.
“Getting Oyster into the water and connected to the seabed was always going to be the most difficult step and its completion is a real credit to everyone who has worked hard on planning and executing this major engineering feat on schedule and without any complications”.
Martin McAdam, Chief Executive Officer, Aquamarine Power
To find out more about Oyster and Aquamarine Power, visit www.aquamarinepower.com