Dutch program offshore wind energy Cumulative effects and Mitigation measures ORELG 4 february 2016

Outline 1. Introduction to the Dutch program Offshore Wind energy 2. Framework for assessing ecological and cumulative effects a)Harbour porpoise and underwater noise 3. Mitigation measures 2

2013 Energy Agreement: 4450 MW offshore wind installed by 2023 Almost 1000 MW installed or under construction Another 3450 MW to be tendered in Government coordinates and ensures a robust legal framework (Offshore Wind Energy Act) that allows to scale up offshore wind 1. Introduction to the Dutch program Offshore Wind energy: 2013 Energy Agreement 3

New approach aims at cost reduction Main characteristics: Road Map Standardisation sites and transmission Flexibility in configuration windfarm Tenders per site, competition on price Built four years after tender ( ) Year Amount Area MWBorssele MWBorssele MWDutch Coast S MWDutch Coast S MWDutch Coast N 4

Wind farm site decisions Wind farm site decision –Offshore wind energy act Nature conservation act –Conditions in site decision –Cumulative impact assessment 5

2. Framework for assessing ecological and cumulative effects - Why a framework A Strategic Environmental Assessment was made for the construction and exploitation of the 10 planned wind farms. Recommendation from the Dutch Commission for Environmental Assessment: “Further research on (cumulative) effects of wind farms on birds and marine life is necessary for the implementation of Offshore Wind Farms at a project level.”

Goals of the framework 1.Energy agreement – understanding and evaluating cumulative effects for implementation of the Energy Agreement 2.Framework Offshore Wind Farms – methodology for determining cumulative effects of offshore wind 3.Generic framework - methodology for determining cumulative effects Assessment for sea mammals (underwater noise), birds and bats. The Framework will obtain official status in the second version of the National Water Plan, which will come into force in the beginning of 2016.

Subdivision of goals Specific to Energy Agreement Understanding cumulative effects - strategic advice Specific to the Framework Offshore Wind Farms: How to assess cumulative environmental effects (initial focus on priority species-effect combinations)? How to define maximum level of acceptable effects (in cumulation)? What are the options for mitigation?

The Framework will provide: Understanding of the cumulative effects due to implementation of offshore wind energy as stated in the Energy agreement - strategic advice Evaluation of expected effectivity of mitigation measures Advice regarding regulations/conditions for wind farm site decision (on ecology) Overview of knowledge gaps – basis for a monitoring program related to offshore wind energy Relation wind farm site decisions and the Framework

Generic Framework Ambitions for 2015 and onwards: Coordination with neighbouring countries (North Sea wide?) Take into account MSFD indicators (when sufficiently developed) Expansion with more activities (sand-extraction, fisheries,...?) including assessment of effects Incorporation of results of new scientific research

2A. Harbour porpoise and underwater noise Assessment of the effects of pile driving on harbour porpoises Development of a methodology for the propagation of underwater noise and application of that method Assessing cumulative effects of all wind farms to be developed according to Energy Agreement – different scenario’s for construction phase. Inclusion of foreign wind farms Effects of other sources of underwater noise (seismic surveys) Determination of the population size of harbour porpoises and harbour and grey seals (legal and ecological relevant populations) Determination of population consequences (using I-PCOD) Determination of maximum level of acceptable effect Effect-evaluation

Stepwise approach for impact calculations 1.Noise propagation per pile blow or seismic airgun pulse 2.Impacted area (based on disturbance threshold level harbour porpoise) 12 3.Number of disturbed animals 4.Animal disturbance days per offshore project and in cumulation (Energy-agreement) 5.Population Impacts over the years through Interim PCOD model

Area of disturbance Disturbed animals (100%) swim away until they are out of the area where noise is above the disturbance threshold The size of the area is determined by the noise level at the bottom of the sea. Size of the area is the average of the area under windy and calm conditions Disturbance thresholds: 136 dB, 140 dB and 144 dB

Calculation of the noise propagation and disturbed area 14

Disturbance days Disturbance days are determined by the area of disturbance the density of the harbour porpoise in the area the number of piling days 1 pile per 24 hours Harbour popoise disturbed for 24 hours

Calculation number of harbour porpoises 16 Number per square Density 7 juni 2016

Interim Pcod model Conversion based on expert judgment of number of disturbed porpoises to population level effects by computing " porpoise disturbances days " 17

Variations in parameters for PCoD runs Size of vulnerable population –Population in subareas as in figure –Population in smaller areas (disturbance area around a site) Duration of disturbance –8 h –1 day (the day of piling) –2 days (the day of piling plus one day after piling)

Acceptable change Significant impacts on harbour porpoises: based on ASCOBANS Restore and / or maintain populations at 80 % or more of the 'carrying capacity' of the porpoise. We have chosen for the maximum reduction of 5 % of the 'carrying capacity' as level of maximum acceptable effect for offshore wind with a 95 % chance of a smaller effect (“unfavorable conservation status”) –Carrying Capacity is denfined as the current population –Towards favourable conservation status –Impacts on population due to other activities 19

Acceptable change? Maximum acceptable effect level for porpoise population (reduction) per OWF site: 255 porpoises Without noise mitigation impact not acceptable example Borssele I: 20

Results flexibel noisetreshold 21 Maximum acceptable effect level for porpoise population (reduction) per OWF site: 255 porpoises Without noise mitigation: With noise mitigation: alternatief 1 (38 turbines)alternatief 2 (95 turbines) bvvd pop. reductie bvvd pop. reductie jan – mei jun - aug sep – dec , alternatief 1 (38 turbines)alternatief 2 (95 turbines) norm (dB re 1 µPa 2 s op 750 m) bvvd pop. reductie norm (dB re 1 µPa 2 s op 750 m) bvvd pop. reductie jan – mei n.v.t. *00 jun - aug sep – dec Smaller impact due to lower densities Smaller impact due to fewer piles (#piling days)

Flexibele noise limitation treshold Depending on: –Number of piles –Season (harbour porpoise density) Goal/side effects: –As much flexibility as possible for constructors –Stimulating the building of bigger windturbines 22

Questions? Downloads: use/Maritime_wind_energy/ecology/