Strategic Impact Assessment of Offshore Windpower in Norway - Impacts on Seabirds


Title: Strategic Impact Assessment of Offshore Windpower in Norway - Impacts on Seabirds
Publication Date:
March 01, 2012
Document Number: NINA Report 825
Pages: 180

Document Access

Website: External Link
Attachment: Access File
(21 MB)


Lorensten, S.; Christensen-Dalsgaard, S.; Follestad, A.; Langset, M.; May, R.; Dahl, E.; Hamre, Ø. (2012). Strategic Impact Assessment of Offshore Windpower in Norway - Impacts on Seabirds. Report by Norwegian Institute for Nature Research (NINA). pp 180.

(The majority of the report is in Norwegian. However, there is an abstract in English.)


This report is part of a strategic environmental impact assessment of technical and environmental aspects related to possible establishment of offshore wind power plants in Norwegian waters. The basis of this evaluation was the parliamentary resolution (Stortingsmelding nr. 34(2006-2007)) on the Norwegian climate policy, where it was concluded that a national strategy for production of electricity from offshore wind power plants and other marine renewable resources should be developed. Following this, a new parliamentary resolution (Ot. Prp. Nr 107 (2008-2009)) concluded that possible areas for the development of offshore wind power plants should be elucidated. To do this a group of people from the Norwegian Water Resources and Energy Directorate (in lead of the group), the Directorate for Nature Management, the Directorate of Fisheries, the Norwegian Coastal Administration and the Norwegian Petroleum Directorate was established. In their report this group concluded that a number of possible sites for offshore wind power plants should be evaluated. The following report threats possible conflicts between seabirds and wind power plants at eleven suggested sites for bottom fixed structures along the Norwegian coast; Sørlige Nordsjø I and II southeast of Egersund, Frøyagrunnene and Olderveggen in Sogn and Fjordane county, Nordøyan–Ytre Vikna in Nord-Trøndelag county, Trænfjorden–Selvær, Gimsøy north and Nordmela in Nordland county, Auvær and Vannøya northeast in Troms county, and Sandskallen-Sørøya Nord in Finnmark county.


Introductorily in the current report a review of known effects of wind power plants, and wave- and tidal power plants on seabirds is given. Following this, the suggested sites for possible establishment of wind power plants are described, with their technical specifications. The seabird fauna along the Norwegian coast and their population trends and red-list status are also described.


The present report gives a description of the occurrence and abundance of breeding, moulting and wintering seabirds in the suggested sites. This description is mainly based on existing knowledge, but for some of the sites breeding and moulting seabirds were censused in 2011. Red-listed species was the main focus. In the breeding season, many seabird species can fly far (>100 km) to find food for their chicks and, thus, birds from colonies quite far from the suggested sites can find their food within these sites. The possible occurrences of birds from colonies outside the suggested sites are evaluated. Possible consequences for seabird species, and ecological groups of seabird species are given for the different phases of establishing a wind power plant (establishment, operation and dismantling).


In connection with the strategic environmental impact assessment, studies of habitat choice of breeding European shag (Phalacrocorax aristotelis), and common guillemot (Uria aalge) at Sklinna, close to the Nordøyan–Ytre Vikna, and black-legged kittiwake (Rissa tridactyla) at Sør-Gjæslingan, close to Nordøyan–Ytre Vikna, and Anda, close to Nordmela, were conducted using GPS-loggers. In order to evaluate possible conflicts between seabirds and offshore wind power plants it is essential to know how seabirds use the areas around their colonies for food searching. Such knowledge also might advise on the most optimal placing of power plants in order to reduce possible conflicts with seabirds. The results from this study showed that the probability for conflict between European shags breeding at Sklinna will be small. Black-legged kittiwakes from both study colonies used the closest sites suggested for offshore wind power plants, and it is suggested that the possible conflicts, on a scale from low to high, will be intermediate. The results from the study on common guillemots were too limited to base a conclusion on. Due to expected annual variation in foraging areas, this study should be repeated before decisions on possible establishment on wind power plants are being made.


In connection with the strategic environmental impact assessment a study using radar to track bird migration at the proposed sites Frøy agrunnene and Olderveggen was performed. The radar surveillance, combined with ground truthing, gave a very good view of when and where birds could be expected to migrate through the area. This knowledge, combined with a general knowledge of bird migration along the Norwegian coast, expected consequences were given for all sites proposed for offshore wind power. In addition, based on general and theoretic models, estimated consequences from the proposed sites' size and shape, their orientation along the coast, and their distance from the coast, are given.


At the end of the report summed consequences for all sites are given based on the seasonal occurrence and abundance of seabirds in the proposed sites, their red-list status, the occurrence of birds from nearby colonies, the area-use of selected species, and the migration of birds along the coast and the expected barrier effects of the sites. The consequences for seabirds by the establishment of offshore wind power plants within the sites are expected to be low for four of the sites (Sørlig Nordsjø I og II, Frøyagrunnene, and Sand skallen-Sørøya Nord), and medium for the remaining sites (Olderveggen, Nordøyan–Ytre Vikna, Trænfjorden–Selvær, Gimsøy nord, Nordmela, Auvær og Vann øya nordøst). However for four of the sites the consequences are expected to be high for some of the themes evaluated. For Olderveggen the consequences are expected to be high if an oil-spill from ships occurred during construction and removal. For Nordøyan – Ytre Vikna the expected consequences are expected to be high for resident birds in the area and from possible oil spills from ships during construction and removal. For Trænfjorden – Selvær the consequences for migrating birds are expected to be high, and for Gimsøy north the consequences are expected to be high for resident birds.


Norwegian Title: Fagrapport til strategisk konsekvensutredning av fornybar energiproduksjon til havs - sjøfugl

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