Annex IV distributes metadata forms (questionnaires) to solicit information from developers involved in environmental monitoring around marine renewable energy project sites around the world. This page provides project descriptions, baseline assessment, post-installation monitoring, and links to available data and reports. Content is updated on an annual basis.

Strangford Lough - MCT (Seagen)

Project Site Annex IV

Title: Strangford Lough - MCT (Seagen)
Project Manager:
Start Date:
July 01, 2008
Research End Date:
June 01, 2016
Country:
Technology Type:
Info Updated:
September 08, 2016
SeaGen
Project Status: 
Device no longer in the water
Technology: 
Twin turbine system
Project Scale: 
Single device (Connected to the National Grid on December 2008)
Installed Capacity: 
1.2 MW
Description: 

Seagen is a twin turbine system with a mobile cross arm on a single supporting pile 3m in diameter and 9m above the average sea level. The twin rotors have an 8m radius and will begin to generate electricity once the tide runs faster than 1m/s. At maximum speed the tips move at around 12m/s, approximately 1/3 of the average wind turbine speed.

Location: 

Strangford Lough, Northern Ireland, at 24 meters water depth.

Process Status: 

Royal Haskoning Ltd was appointed in early 2004 to provide support to the EIA process. The scoping consultation was completed in mid 2004, and the EIA commenced late 2004. The final EIA was submitted in July 2005, with the initial FEPA license being granted in December 2006. These were revised to accommodate necessary changes in installation methodology in February 2007, and again in February 2008.

 

Installation of the moorings for anchoring the SeaGen deployment vessel commenced in February 2008 and was completed in March 2008. The SeaGen structure was positioned on the seabed on April 2nd 2008 by the crane barge Rambiz. Drilling for the pin piles, grouting and completion of assembly was achieved using the crane barge Missing Link, which was on location from mid April to late May 2008.

 

Commissioning of SeaGen commenced in July 2008, culminating in full 1.2MW power generation to the grid in December 2008.

 

Operation is continuing within the constraints of the FEPA license with the environmental monitoring programme results contributing to an adaptive management strategy where findings are periodically reviewed and improvements to the application of the FEPA restrictions are proposed.

 

In January 2016 it was announced that Atlantis (the company which now owns MCT) would begin decommissioning the device in summer 2016 after much knowledge had been gained during its operation. The decommissioning process is expected to take 12 months.

Licensing Information: 

The final Environmental Impact Study was submitted to the regulatory authority, the Environment and Heritage Service (EHS) in Northern Ireland in June 2005. The FEPA license for the temporary installation for the SeaGen system for a five year duration was first issued in December 2005, revised in February 2007 and again in February 2008. Pre-installation environmental monitoring commenced in May 2004. A baseline report has been completed and was submitted to EHS in August 2006. The environmental impact of SeaGen will be continuously monitored by independent science team throughout the licensed 5 year installation period. The existing FEPA license covers the initial 5-year lease granted by the Crown Estate, which will result in SeaGen being decommissioned and removed in 2013.

Key Environmental Issues: 

Strangford Lough has been identified as a site which supports internationally important examples of particular marine and coastal habitat and species features and has accordingly been given the dual status of a European Special Area of Conservation (SAC) and a European Special Protected Area (SPA). Three of the site features have been identified as potentially vulnerable to activities and impacts associated with the installation of the SeaGen turbine.

 

The EIA process identified various levels of uncertainty surrounding potential impacts on key marine species and features within the Strangford Lough Special Area of Conservation (SAC), they include:

  • Effects of installation and operation on the integrity of the breeding harbour seal population.
  • Collisions of marine mammals, fish and diving birds with the turbine rotors.
  • Effects on the abundance, diversity, integrity and extent of the benthic biological communities associated with the submerged rocky reefs.
  • Effects of installation and operation on the breeding bird population.

 

Environmental Webpage: http://www.marineturbines.com/Seagen-Technology/Environmental-Impact

Strangford Lough - MCT (Seagen) is located in United Kingdom.

Baseline Assessment: Strangford Lough - MCT (Seagen)

ReceptorStudy Description Design and Methods Results Status
  • Physical Environment

Alterations to Hydrodynamics

Desk based study, modelling and video footage.

The installation and operation of the SeaGen turbine will not impede or modify the flow dynamics, scour patterns or turbulence character of the Narrows in such a way that will cause a change to benthic community structure.

Completed
  • Benthic Communities

Potential impacts to Benthic Communities

Desk based study and diver surveys

The installation and operation of the SeaGen turbine will have no significant impact on the abundance, diversity and integrity of the benthic communities within the Strangford Narrows.

Completed
  • Marine Mammals

Potential impact to Cetacean populations

Desk based study and Aerial surveys

The SeaGen turbine does not displace harbour porpoises from the Strangford Narrows and the adjacent Strangford Lough SAC. The SeaGen turbine does not present a barrier effect to the free passage of harbour porpoises through the Strangford Narrows. Cetaceans not excluded from important foraging habitat or social areas within the Strangford Narrows as a result of the installation and operation of the SeaGen turbine.

Completed
  • Large Vertebrates

Potential impacts to marine mammals (General)

Desk based study and Aerial surveys

No marine mortalities occur consequence of interaction with the turbine rotors. The turbine operates in such a way as to stop when marine mammals are within 50m from the rotors. Relative abundance of marine mammals in Strangford Narrows is not significantly modified by the operation of the SeaGen turbine.

Completed
  • Marine Mammals

Potential impact to Harbour Seals

Ariel Surveys, visual surveys, desk based study

The number of harbour seal adults and pups does not decrease significantly as a result of the installation and operation of the SeaGen turbine. The SeaGen turbine does not present a barrier effect to the free passage of harbour seals through the Strangford Narrows. Harbor seals are not excluded from mportant3 foraging habitat or social areas within the Strangford Narrows as a result of the installation and operation of the Seagen turbine.

Completed
  • Marine Mammals

Potential impact of SeaGen to Grey Seal populations

Ariel surveys, visual surveys and desk based studies

The number of grey seal adults and pups does not decrease significantly as a result of the installation and operation of the SeaGen turbine. The SeaGen turbine does not cause a significant change in the use of important grey seal haul out sites within the Strangford Lough SAC. The SeaGen turbine does not present a barrier effect to the free passage of grey seals through the Strangford Narrows. Grey seals are not excluded from important foraging habitat or social areas within the Strangford Narrows as a result of the installation and operation of the SeaGen turbine.

Completed
Reports and Papers

Royal Haskoning. (2010). SeaGen Biannual EMP update. EMP update (Jan 2010).

Post-Installation Monitoring: Strangford Lough - MCT (Seagen)

General Description:

In accordance with the Environmental Monitoring Plan completed by Royal Haskoning in January 2011 the only planned mitigation measure was the establishment of active sonar systems to detect marine mammals at sufficient range from the turbine to allow for precautionary shut down. This mitigation measure is design to prevent marine mammals colliding with the rotor blades of the device.

ReceptorMonitoring Program Description Design and Methods Results Status
  • Marine Mammals

Shore based survey

Observations carried out between May 2005 and December 2010 from a fixed point on the east shore of the Narrows 10m above Mean High Water.  Observations of birds and mammals were recorded along with their location using laser range finding binoculars. During each month a total of 8x3-hour watches were carried out under different tidal states and at different times of the day.

No major impacts on marine mammals have been detected across the 3 years of post-installation monitoring.

 

Porpoise activity declined during installation; however there have been no long term changes in abundance of either seals or porpoises which can be attributed to the presence or operation of the device.

 

Seals and porpoises regularly transit past the operating turbine, clearly demonstrating a lack of any barrier effect.

 

Overall the seals transited at a relatively higher rate during periods of slack tide, indicating avoidance but also this slack water window when the turbine is not operating or is moving very slowly, ensures that there is always an opportunity for transit past the turbine.

 

Findings are described in more detail in the EMP

Completed
  • Marine Mammals

Passive acoustic monitoring (T-PODs)

The TPOD (‘Timing Porpoise Detector’) is a self-contained submersible unit that includes a hydrophone element, an amplifier, analogue electronic filters and a digital processor, as well as a battery pack and memory. worked by logging the start and end of echolocation clicks of porpoises and dolphins. The basic metric they generated was expressed at detection positive minutes (DPM) which consists of any minute in which a porpoise click train was detected. TPODS logged continuously 24 hours a day.

See above

Completed
  • Marine Mammals

Carcass post mortem

A programme of shoreline surveillance covering key areas which were predicted to be hotspots for stranding based on local advice and hydrodynamics.  It was agreed by the Science Group that these surveys were no longer required. Plans were in place for any carcasses discovered to be subjected to a post-mortem by a Vet Pathologist to determine whether the cause of death has potential to have resulted from collision with the SeaGen turbine.

See above

Completed
  • Marine Mammals

Aerial survey

Aerial surveys of seal haul out sites along the Northern Ireland coast between Carlingford Lough and Belfast Lough, including Strangford Lough were carried out annually by SMRU. Surveys were carried out from a helicopter using a thermal imaging camera.

See above

Completed
  • Marine Mammals

Harbour seal telemetry

Thirty six seals were fitted with electronic tags. These instruments were glued to the animals’ fur meaning that they detached during the annual moult. They captured location data and information on animals’ diving and haulout behaviour. The 3 deployments took place in 2006 (April-July, pre-installation), 2008 (March – July, during installation and commissioning) and in 2010 (April-July, operation). The seals were captured at sites in Strangford Narrows and the southern islands in Strangford Lough. The three groups of animals tagged contained similar mixes of ages and sexes.

See above

Completed
  • Marine Mammals

Underwater noise monitoring

Underwater noise measurements were undertaken in Strangford Lough on 23th April 2008 between 09:00 and 21:00 during drilling operations. Background underwater noise measurements were also carried out during periods when no drilling was taking place in order to determine the pre-existing noise levels in the Strangford Lough region. Noise measurements of SeaGen during operation were carried out with high-precision instruments from a drifting boat.

Population estimates derived from aerial survey and set within the context of historical data.

(Number of grey seals using the Lough based on boat counts from NIEA can also supplement these data). Haul out site seal numbers from aerial and boat-based survey. Sightings frequency over space and time (from Shore-based visual operation) in pre-operational and post- operational periods).

Completed
  • Marine Mammals

Active sonar

An active Sonar monitoring and mitigation system has been in operation on SeaGen since the turbine was commissioned in 2008. This system provided real time subsurface sonar imagery of large objects within 80m of the turbine whilst it is operating. Two Tritech Super SeaKing DST sonar heads were mounted on the upstream and downstream sides of the SeaGen tidal turbine. The depth of each sonar head when the crossbeam was lowered was approximately 11.5m below MLWS. This was close to the middle of the water column. Each sonar head provided approximately 120-180o horizontal coverage x 40o vertical coverage around the turbine.

See above

Completed
  • Sea and Shorebirds

Shore based observations

Observations carried out between May 2005 and December 2010 from a fixed point on the east shore of the Narrows 10m above Mean High Water.  Observations of birds and mammals were recorded along with their location using laser range finding binoculars. During each month a total of 8x3-hour watches were carried out under different tidal states and at different times of the day.

While some fine scale displacement of birds had been recorded in the immediate vicinity of the device, the overall numbers in the Narrows remained stable.

Completed
  • Hydraulics
N/A

Vessel- or bottom mounted ADCP measurement of upstream and downstream flow character and turbulence signature. Diver video survey for scour effects.

The data showed no evidence of significant change to the ambient velocity or flow direction within the Lough, subsequent to the installation of the turbine. The findings show that it is unlikely that marine traffic between Strangford town and Portaferry has been affected. The wake which can be observed on the water surface is not propagated into the water column.

Completed
  • Benthic Communities

Benthic hard communities

Four relocatable sample stations were established by installing Ultra Short Baseline (USBL) transceivers. Three stations were placed in line with the rotational axis of the east turbine at 20m, 150m and 300m down/upstream to the south-east (approx.) of the turbine installation (Figure 3.2). A further single reference station was installed approximately 50m to the ENE of the turbine structure. Diver video was collected by Irish Diving and Marine Contractors Ltd.

The data collection and analysis are robust in determining that the changes observed appear to be gradual and in line with natural variation. Colonisation of the device since its installation has replaced the community lost at the device foundations during construction.

Completed
Reports and Papers
  • Royal Haskoning. (2010). SeaGen Biannual EMP update. EMP update (Jan 2010).
  • Keenan, G.; Sparling, C.; Williams, H.; Fortune, F. (2011). SeaGen Environmental Monitoring Programme: Final Report. Report by Royal Haskoning. pp 81.
Research N/A
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