The primary objective of Green Volt Floating Offshore Windfarm is to help decarbonise oil and gas platforms by powering them with renewable energy. Green Volt will allow the full retirement of existing offshore power generators and use a grid-connected wind farm to deliver reliable, renewable electricity, significantly reducing the carbon emissions of the platform’s power demand – by more than 80%. This supports a move away from the dependency upon gas-fired or diesel power generation systems which are fuel-hungry and carbon-intensive. Surplus renewable electricity will be exported back to the National Grid.
Green Volt has been allocated New Deer as the onshore grid connection point for the project by National Grid and this has been a determining factor in the identification of potential landfall options for the export cable.
The offshore export cable route has sought to avoid environmentally sensitive areas, other marine infrastructure, marine disposal areas, whilst minimising the route length. Seabed conditions and suitability for cable burial have also been considered and avoiding crossing steep underwater ridge features. The onshore cable route has sought to avoid nature conservation sites, historic designations, residential properties, flood zones, contaminated land, other infrastructures (such as roads and buried cables) and limit the number of water crossings.
Two potential landfall options are considered in the EIA:
- St Fergus South Landfall Option: Located north of Peterhead
- NorthConnect Parallel Landfall Option: located south of Peterhead
There are various possible locations for an onshore / offshore jointing pit and onward cable route to New Deer. Horizontal Directional Drilling (HDD) will be used to take the cable from the jointing pit to a location approximately 750 m offshore at either location.
The offshore export cable will be installed using specialist cable installation vessels. Due to the length of the export cable route, multiple burial tools are envisaged to tackle the different seabed conditions along the route, which will be confirmed by pre-installation route surveys. The Project will implement all cabling industry standards for cable burial.
In line with industry safety standards, safety zones will be applied for, and appropriate communications will inform other marine users of the cable installation works and potential temporary restrictions for safety purposes.
Green Volt’s intention, when possible, is to keep impacts to local harbours and fishermen to an absolute minimum. However, we understand it’s challenging for both activities to operate in a specific area at the same time. During any pre-construction/installation survey works, early dialogue with the local fishermen is key to insuring everyone is aware of planned activities, also when and where these are taking place. Should gear relocation be required to access a busy fishing area, this will be done through the correct channels and in line with The Fishing Liaison with Offshore Wind and Wet Renewables Group Best Practice Guidance.
Commercial fisheries are scoped into the Environmental Impact Assessment (EIA) for the Project and potential impacts will be fully considered and suitable mitigation measures developed, as appropriate.
Green Volt have a Fisheries Liaison Officer (FLO) who has been engaging with inshore and offshore fishing organisations since the end of 2021. Notices to Mariners will continue to be issued for all marine activities. Green Volt plan to avoid any interactions with fishing equipment, such as creels, during all marine works. However, compensation packages to offset any losses may be available in relevant and appropriate situations. Such packages were offered during the inshore environmental survey works in April 2022 but were not required. For any future compensation claims, evidence is required to show activity levels and value of landings, also vessel certification (UK FVC, fishing licence and MCA inspection report)
What steps have been taken to protect the marine life in the area, especially in regard to the welfare of migrating salmon and sea trout?
Green Volt site selection has been undertaken to avoid key commercial fisheries and protected fish species and habitats, including sites designated for nature conservation, as far as possible. Site-specific surveys have been completed and previous survey data has been reviewed to support site selection. The anchors for the floating wind turbines do not require pile driving and are quick to install with limited underwater noise. We have modelled the potential impacts from underwater noise and electromagnetic fields to develop appropriate mitigation to minimise impacts to fish and marine mammals. To further minimise effects on fish species (including migratory fish), the following mitigation has been embedded into the project design:
- Cables, wherever possible, will be buried to a target depth of 0.6-1.5m to reduce the potential for impacts relating to electromagnetic fields (EMF);
- Cables will be specified to reduce EMF emissions as per industry standards and best practice;
- To minimise the extent of any unnecessary habitat disturbance, material displaced as a result of cable burial activities will be back filled, where necessary, in order to promote recovery;
- An approved piling strategy will be in place outlining any mitigation and management measures that will be implemented during the offshore sub-station pile installation; and
- Piling soft starts will be used, with lower hammer energies used at the beginning of the piling sequence before increasing energies to the higher levels, to reduce the risk of injury to fish or marine mammal species in the immediate vicinity of piling operations.
A Construction Environmental Management Plan (CEMP) will be developed to ensure construction activities are undertaken in adherence to all relevant guidance and best practice construction techniques, including protective measures and management of pollution events from accidental spills.
The onshore export cable route is likely to traverse several water courses which range in size from ditch systems to small rivers and tributaries of rivers. The route and design of onshore works are still under development. New watercourse crossings will be designed in accordance with best practice and enable the free passage of fish and other wildlife. The onshore Scoping Opinion, detailing the approach that will be taken to assess onshore works, is available from Aberdeenshire Council Planning Service and they can be contacted on 01467 534333 and by email at email@example.com
All materials for marine works will be transported to the Project site by sea, so there will be no increased traffic on the trunk road network during the marine works.
Potential impacts upon traffic and transport from onshore works will be fully considered within the onshore Environmental Impact Assessment (EIA). Consultation will be undertaken during the development of the onshore EIA to ensure any potential impacts are understood, assessed and minimised to within acceptable levels. The onshore Scoping Opinion, detailing the approach that will be taken to assess onshore works, is available from Aberdeenshire Council Planning Service and they can be contacted on 01467 534333 and by email at firstname.lastname@example.org
Will there be any impact on North Sea swell as it passes through the wind farm site and on to the surfable coastline?
Green Volt have considered the potential effect of the Project on the baseline wave climate in Chapter 5 (The Physical Environment) of the Scoping Report. We have collated and reviewed wave data from available sources, including undertaking an ‘extremes analysis’ and conclude that the limited number of floating wind turbines (up to 35) is likely to have, at worst, only a very small impact on the wave climate and only limited to a localised area (<1 km). The floating wind turbines will be anchored in position so there will only be very small and very localised direct impact on the incoming wave climate from the installed infrastructure. Long-period swell waves will not be affected by such local interruptions. Due to the long-period nature of swell waves, we do not envisage that these will be affected adversely by the wind farm which is situated some 80 km from shore.
The landfall of the cables will involve horizontal directional drilling (HDD). This installation method is intended to minimise the impact on the coast, both visually, ecologically and in terms of coastal processes (waves, tides, sediment transport). Drilling at the ‘entry point’ is planned to start inland of the coast and the ‘exit point’ will surface between 1 km and 1.3km offshore. This is well away from any surf waves and so it will not cause disruption to the surfing beaches in the vicinity.
Potential impacts associated with onshore construction works will be fully considered within the onshore Environmental Impact Assessment (EIA). Consultation with stakeholders will continue during the development of the onshore EIA to ensure any potential impacts are understood, assessed and minimised to within acceptable levels. The onshore Scoping Opinion, detailing the approach that will be taken to assess onshore works, is available from Aberdeenshire Council Planning Service and they can be contacted on 01467 534333 and by email at email@example.com
A draft Construction Environmental Management Plan (CEMP) will accompany the planning application. The CEMP sets out the general approach of environmental management and mitigation of impacts associated with the construction works. The appointed Construction Contractor will update and finalise the CEMP and will be responsible for ensuring that any adverse effects from the construction phase are minimised.
Third party verification (TPV) of the mooring systems will be undertaken by an independent and competent body to ensure they meet the required standards.
All the wind turbines will be continuously monitored via Global Positioning System (GPS), with the capability of being tracked via Automatic Identification Systems (AIS) in the event of loss of station. Each wind turbine will also have an alarm system in place, whereby an alert will be provided to the Marine Coordination Centre if any floating substructure leaves a pre-defined ringfenced alarm zone. This means in the unlikely event that a floating substructure suffers total loss of station and drifts outside of its alarm zone tracking can take place and the necessary emergency arrangements made.
The Offshore EIA Report (EIAR) is required to support the consents application to Marine Scotland for the offshore infrastructure associated with the project located seaward of the MLWS.
A separate onshore EIAR is being prepared to accompany the planning application that will be submitted to Aberdeenshire Council for the Project’s onshore infrastructure landward of the MLWS.
Where a technical topic is required to be assessed for both offshore and onshore, such as socioeconomics, a separate chapter is provided in each EIA Report.