Seagen is a twin turbine system with a mobile cross arm on a single supporting pile 3m in diameter and 9m above the average sea level. The twin rotors have an 8m radius and will begin to generate electricity once the tide runs faster than 1m/s. At maximum speed the tips move at around 12m/s, approximately 1/3 of the average wind turbine speed.
Strangford Lough, Northern Ireland, at 24 meters water depth.
Royal Haskoning Ltd was appointed in early 2004 to provide support to the EIA process. The scoping consultation was completed in mid 2004, and the EIA commenced late 2004. The final EIA was submitted in July 2005, with the initial FEPA license being granted in December 2006. These were revised to accommodate necessary changes in installation methodology in February 2007, and again in February 2008.
Installation of the moorings for anchoring the SeaGen deployment vessel commenced in February 2008 and was completed in March 2008. The SeaGen structure was positioned on the seabed on April 2nd 2008 by the crane barge Rambiz. Drilling for the pin piles, grouting and completion of assembly was achieved using the crane barge Missing Link, which was on location from mid April to late May 2008.
Commissioning of SeaGen commenced in July 2008, culminating in full 1.2MW power generation to the grid in December 2008.
Operation is continuing within the constraints of the FEPA license with the environmental monitoring programme results contributing to an adaptive management strategy where findings are periodically reviewed and improvements to the application of the FEPA restrictions are proposed.
In January 2016 it was announced that Atlantis (the company which now owns MCT) would begin decommissioning the device in summer 2016 after much knowledge had been gained during its operation. The decommissioning process is expected to take 12 months.
The final Environmental Impact Study was submitted to the regulatory authority, the Environment and Heritage Service (EHS) in Northern Ireland in June 2005. The FEPA license for the temporary installation for the SeaGen system for a five year duration was first issued in December 2005, revised in February 2007 and again in February 2008. Pre-installation environmental monitoring commenced in May 2004. A baseline report has been completed and was submitted to EHS in August 2006. The environmental impact of SeaGen will be continuously monitored by independent science team throughout the licensed 5 year installation period. The existing FEPA license covers the initial 5-year lease granted by the Crown Estate, which will result in SeaGen being decommissioned and removed in 2013.
Strangford Lough has been identified as a site which supports internationally important examples of particular marine and coastal habitat and species features and has accordingly been given the dual status of a European Special Area of Conservation (SAC) and a European Special Protected Area (SPA). Three of the site features have been identified as potentially vulnerable to activities and impacts associated with the installation of the SeaGen turbine.
The EIA process identified various levels of uncertainty surrounding potential impacts on key marine species and features within the Strangford Lough Special Area of Conservation (SAC), they include:
- Effects of installation and operation on the integrity of the breeding harbour seal population.
- Collisions of marine mammals, fish and diving birds with the turbine rotors.
- Effects on the abundance, diversity, integrity and extent of the benthic biological communities associated with the submerged rocky reefs.
- Effects of installation and operation on the breeding bird population.