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 sub-sea 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: