Offshore Wind: Ecological risks and opportunities

Transcription

1 Offshore Wind: Ecological risks and opportunities Guido Schild Nathalie Strookman

2 Offshore wind: Ecological risks and opportunities 1. Status of offshore wind in the Netherlands 2. Ecological risks 3. Mitigation strategies 4. Knowledge gaps 5. Ecological opportunities 6. Balancing offshore wind and ecology in the future

3 Offshore wind is projected to grow Year GW GW 2030 At least 11.5 GW (Routekaart ) <5% of the Dutch North Sea surface GW (PBL) 26% of the Dutch North Sea surface

4 NGOs call for 18,5 GW target in 2030 to meet Paris obligations The aim of max. 1,5C temperature increase Total CO 2 emission: from 195 Mton to 73 Mton in 2035 Currently: ~14%% renewable electricity which needs to be ~80% in 2030

5 ECOLOGICAL RISKS

6 There is a variety of ecological impacts associated with OWF, with certain species groups being particularly vulnerable Birds Bats Marine mammals Fish

7 Birds are at risk from direct collisions and habitat loss The effect on the population is modelled using the Potential Biological Removal (PBR) PBR has not been exceeded for planned OWF until However, for OWF s some species are in the danger zone. Potential Biological Removal: Maximum allowed mortality (part of the population) by human intervention, on top of the natural mortality Species of which the modelled mortality exceeds 10% of PBR are identified as vulnerable

8 8 seabird species are particularly at risk, with modelled mortalities caused by <2023 OWFs exceeding 10% PBR Species Northern Gannet (Jan-van-Gent) Collision Giant Skua (Grote Jager) Razorbill (Alk) Common guillemot (Zeekoet) Herring gull (Zilvermeeuw) Lesser black-backed gull (kleine mantelmeeuw) Effect of OWF s in the operational phase Collision Habitat loss Habitat loss Collision Collision At least one species benefits from OWF s: great cormorant (aalscholver) Great black-backed gull (grote mantelmeeuw) Collision Black-legged kittiwake (Drieteenmeeuw) Source: o.a. Leopold (2014), Krijgsveld (2014) Collision

9 3 bat species are known to regularly migrate across the North Sea and are at risk of collision in OWFs Little is known about bats 3 species fly regularly and in great numbers across the North Sea Other species are only seen incidentally and therefore are at low risk Source: Leopold et al. (2014) Species Common noctule (Rosse Vleermuis) Nathusius s pipistrelle (Ruige dwergvleermuis) Parti-coloured bat (Tweekleurige vleermuis) Effect of OWF s in operational phase Collision

10 Marine mammals are impacted by underwater noise during construction, but could profit from reduced fishing pressure and increased food availability during operation Species Harbour porpoise (Bruinvis) Grey seal (Grijze zeehond) Common seal (Gewone zeehond) Effect of OWF s + + Habitat loss/avoidance (construction phase) Hearing damage (construction phase) Habitat- and food enrichment (operational phase) Reduced fishing(operational phase) Marine mammals Common in the Netherlands and protected: 3 Other live sightings:14 Source: o.a. Leopold et al. (2014), Schuster et al. (2014), Geelhoed & van Polanen Petel (2011)

11 Fish are potentially impacted by underwater noise and electromagnetic fields, but could profit from reduced fishing pressure and increase food availability during operation Species Effect of OWF s in the operational phase Sharks and rays Masking of acoustic and electromagnetic communiction/perception + Habitat enrichment by hard substrate Other fish + Absence of bottom towed fisheries Masking of acoustic and electromagnetic communiction/perception Possible disturbance during migration + Habitat enrichment by hard substrate + Absence of bottom towed fisheries Source: o.a. Bergstrom et al. (2014)

12 MITIGATION STRATEGIES

13 Choice of location can be an important mitigation strategy for impacts on birds. Areas with high abundance of vulnerable species are best avoided. Example: Doggersbank seems less sensitive. Possible causes: - Lower quantities - Less sensitive birds Could be problematic on species level (Northern Gannet)! Wind farm sensitivity index for all seabirds Source: Leopold et al. (2014)

14 Besides choice of location, impacts on birds and bats can be reduced by technological measures and by stopping turbines during migration peaks Risks Habitat loss Collision Difficult to mitigate Choice of location Possibly some species adjust, but could then be at higher risk of collision Choice of location Bigger MW, less turbines, further apart Stopping turbines during migration peaks Lower cut-in-windspeed for bats

15 Technological measures are at hand to mitigate negative impacts on marine mammals and fish species Noise Sound limits Acoustic detterent device before starting construction Risks Elektromagnetic radiation Cable depth and casing

16 KNOWLEDGE GAPS

17 Many knowledge gaps remain regarding the likelihood, scale and severity of various impacts Which bird, bat, and other species end up in the danger zone due to the further upscaling of offshore wind? What is the actual spatial and temporal distribution of these vulnerable species? What is the expected impact of offshore wind on these vulnerable species, considering the different prognoses for further upscaling? Which impacts and limiting factors put pressure on these species? Which effective measures can be taken nationally and internationally to better protect vulnerable species or boost their populations? What are the impacts of offshore windfarms on physical features such as water flow, sediment transports, salinity, stratification etc.?

18 ECOLOGICAL OPPORTUNITIES

19 In OWFs, bottom towed fisheries are excluded and hard substrate is introduced, benefiting various species Species groups that benefit: Benthic species Marine mammals Fish

20 Placement of artificial reef structures or adjusting scour protection designs can increase habitat function of OWFs Currently, tests are being done on nature enhancing scour protection within JIP HASPRO by Deltares.

21 OWFs are highly suitable locations for kickstarting the restoration of native flat oysters Flat oysters: - Filter water - Absorb CO2 - Increase local biodiversity - Increase fish abundance Smaal et al. 2015: Flat oysters require hard substrate in the form of shell material, other hard substrate or existing flat oyster beds. Potential sites can be found in areas where no bottom trawling occurs. At present this is mainly limited near to offshore platforms and in wind farms.

22 BALANCING OFFSHORE WIND AND ECOLOGY IN THE FUTURE

23 Scaling up OWFs makes it increasingly challenging to maintain a balance between offshore wind and ecology. In order to have a high ambition of renewable energy and a healthy North Sea, NGOs recommend: 1. Maximise enhancement of nature underwater via tenders and regulation 2. Stimulate technical innovations to minimise negative impacts 3. Develop a fund to help transitions on the North Sea 4. Avoid building wind farms in areas of high ecological value 5. Facilitate joint fact finding and improve governance Short term action needed: Ecological research into the most vulnerable species and their distribution. An international action plan to protect these species.

24 Thank you!