Natural Power Undertakes Drop Down Video Survey at Robin Rigg OWF

International renewable energy consultancy Natural Power has recently undertaken an industry first use of Drop Down Video (DDV) surveys at Robin Rigg Offshore Wind Farm. E.ON’s Robin Rigg Wind Farm, located in the Solway Firth is the first commercial wind farm in Scottish waters.

The technology, designed and deployed by subsea camera experts Envision Mapping Ltd, has enabled Natural Power to survey turbine substation foundations, as well as sections of the export cable and inter-array cables in order to assess the level of biofouling on the structures and seabed scour around the foundations and cables.  Even in the fast flowing, silty waters of the Solway the technology and methodology proved to be very successful, representing a far less risky and more cost effective survey and inspection method compared to using divers.

The survey revealed a fascinating array of marine life living on the turbine and substation bases at Robin Rigg after only 4 years of operation. Taking place at low water, the survey showed the intertidal sections of the foundations of the turbines and substation were found to be to be colonised with typical rocky shore organisms, with an abundance of barnacles as well as occasional limpets and green seaweed, and a dense carpet of edible mussels around the low water mark. Beneath the waves the mussels continued, providing a rich feeding ground for starfish, as well as green sea urchins which feed on the anemone-like colonial animals that live on the mussel shells. On foundations in shallower waters this mussel dominated habitat extended down to the sea bed, but on those foundations located in deeper waters the lower sections were crowded by a forest of brightly coloured plumose anemones as well as pink oaten ear hydroids. Mussels and plumose anemones were even seen thriving on the export cable by the substation before it is buried beneath the sand. Throughout the surveys shore crabs and hermit crabs were seen crawling on the foundations and on the sandy seabed beneath them, and fish such as whiting swimming around the foundations.

All of the species found on the survey are native to the Solway and can be found living on rocky areas along the Cumbria and Dumfries and Galloway coast.  The foundations structures of the wind farm have provided an artificial reef for these species to colonise in the otherwise relatively barren, sandy central Solway Firth and greatly added to the productivity and biodiversity of the area.

Natural Power has provided consultancy services at Robin Rigg since it’s inception in 2000 and to date services have included:

• Stakeholder consultation;
• EIA coordination;
• Site layout;
• Bird, marine mammal, fish and benthic studies;
• Coordinantion of preconstruction, construction pahase and post construction ecological monitoring, analysis and reporting.

Commenting on the most recent studies utilising the DDV technology, Jane Lancaster, Senior Marine Ecologist at Natural Power commented: “We are so pleased to once again bring a novel methodology to the offshore renewables sector, especially at Robin Rigg where E.ON are committed to ensuring a sypathetic operational phase with respect to marine life. We hope that through this more cost effective approach to underwater studies we can help our clients to deliver their marine monitoring plans with less risk compared to conventional dive strategies.”

Tim Morgan, E.ON Operations manager  for Robin Rigg welcomed the novel approach noting: “We are keen to try innovative surveying techniques that can deliver safe, cost effective solutions to delivering our marine management plans. Natural Power continue to be a valued partner to E.ON at Robin Rigg Offshore Wind Farm providing a range of environmental consulting services to the site.”

Press Release, May 23, 2014