The habitat‐creation potential of offshore wind farms

Abstract

Offshore wind farms are the subject of environmental impact assessments in which potential adverse effects are identified and quantified. Those impacts will then require to be mitigated through appropriate design, construction and operation methods. Where environmental impacts cannot be mitigated, operators would be required to compensate the environment or its users for any actual or potential damage. The present study shows that the placement of offshore wind turbines gives the potential for habitat creation, which may thus be regarded as compensation for habitat lost. Using current design criteria and construction methods, the analysis here indicates that the net amount of habitat created by the most common design of offshore wind turbine, the monopile, is up to 2.5 times the amount of area lost through the placement, thus providing a net gain even though the gained habitat may be of a different character to the one that lost. Hence, the study raises important issues for marine nature conservation managers. The study also provides suggestions for further work in order to increase the empirical evidence for the value of mitigation, compensation and habitat creation.

Colonisation of fish and crabs of wave energy foundations and the effects of manufactured holes – A field experiment

“…Gill, 2005;Wahlberg and Westerberg, 2005;Petersen and Malm, 2006;Broström, 2008;Tyack, 2008). At the same time, there is an increasing interest in articulating the potentially positive aspects of creating artificial hard bottom habitats through the construction of offshore renewable energy devices (Wilhelmsson et al 2006a;Langhamer et al, 2009;Wilson and Elliot, 2009). The foundations of the energy devices will exclude trawling activities from the claimed area, and will also constitute "secondary artificial reefs" (Pickering et al, 1998) for fish and invertebrates and may also function as fish aggregating devices (FADs) (Wilhelmsson et al, 2006a;Fayram and de Risi, 2007;Wilhelmsson and Malm, 2008;Langhamer et al, 2009).…”

Coastal and Offshore Wind Energy Generation: Is It Environmentally Benign?

“…The area of habitat created depends on whether scour protection is installed, and if so, which type of material is used. Wilson and Elliott [6] showed that with synthetic fronds, which mimic seagrass, there is a potential for a direct area loss of 12.5 m 2 ; however when boulder and gravel protection are used, the habitat gain is 577 m 2 and 650 m 2 respectively, assuming a 4 m diameter turbine, and 10 m of scour protection, as above.…”

“…For example, different impacts are expected to arise from wave energy conversion devices which are floating and anchored (e.g., OPD's Pelamis system (www.pelamiswave.com) in comparison to where these are mounted on the seabed (e.g., the Oyster device of Aquamarinepower). A further, quantitative comparison tool or matrix which allows a better comparison between sectors and activities in the offshore environment has been developed [5,6], and aims to capture many of the offshore activities currently being undertaken, and a wide range of potential impacts on the marine environment, both positive and negative, which might be caused by any of these activities.…”

“…With foundations of up to 6 m diameter, there is a minimum of 12.5 m 2 lost per turbine (based on a 4 m diameter), plus a potential additional 452 m 2 lost should scour protection be installed around the foundation (assuming an area 10 m out from the base of the turbine is protected [6]. However, it should again be noted that this area is relatively minor in relation to the total area within the wind farm site boundary.…”

“…Despite the loss of area, in terms of the physical area of disturbance, it has been shown that the installation of a turbine, with the right form of scour protection where appropriate, can increase the surface area available for organisms to colonise [6]. The area of habitat created depends on whether scour protection is installed, and if so, which type of material is used.…”