Nova Innovation (Nova) has received a marine renewable energy demonstration permit from the Nova Scotia Department of Energy and Mines for a 1.5 MW in-stream tidal energy project in Petit Passage, Digby Neck - the 'Nova Tidal Array.' The tidal array will be developed in three separate 500 kW phases, allowing for careful environmental monitoring at each stage.
Nova has applied for the permits required for Phase 1 of the Nova Tidal Array which would see five 100 kW in-stream tidal turbines installed in Petit Passage. The first turbine will be closely monitored before the next four turbines are installed. This will be carried out using instruments attached to the turbine and mounted on a Remote Observation Platform (ROP) that will be placed on the seabed close to the turbine.
Nova will install the ROP on the seabed in Petit Passage to gather data on marine wildlife in the area before the first turbine is installed.
What does the ROP look like and how big is it?
The ROP is a steel frame structure with ballast to hold it in place on the seabed. It will not have any surface markers or buoys and will be connected via a small cable to an onshore station at East Ferry to enable data transfer, and to provide power for the monitoring instruments it houses. The ROP cable has a diameter of 23mm and will be double armoured and secured to a 3/8” wire ground line to ensure it is well-protected and stable on the seabed. Nova Innovation has previously deployed this frame in Petit Passage and conducted many similar operations at its Shetland Tidal Array in Scotland, UK.
When installed in Petit Passage, underwater cameras and acoustic instruments will be attached to the ROP to monitor marine wildlife in Petit Passage.
When will the ROP be installed?
Installation of the ROP on the seabed in Petit Passage is planned for November but this is weather dependent. If it cannot be achieved before lobster season, the installation will be in January 2022. Notices to mariners will be issued in advance of the works. Details of the location of the ROP once installed will be provided to the Tiverton Harbour Authority, East Ferry Harbour Authority and the local community.
How is the ROP installed?
The ROP will be installed onto the seabed in Petit Passage safely and efficiently using small workboats. The ROP will be lowered onto the seabed using the vessel winch and an alignment ground chain.
Will the ROP affect fishing or navigation in the area?
Once installed in Petit Passage, the ROP will sit on the seabed at a depth of at least 30m, with no surface infrastructure such as buoys or markers. Vessels will be able to pass safely through the area and above the ROP. Use of static or mobile benthic fishing gear in the immediate area around the ROP should be avoided to prevent the risk of snagging.
Summary of safety and mitigation measures
Several measures will ensure that the installation of the ROP in Petit Passage does not create hazards to fishing and navigation, summarised below:
All maritime safety legislation will be adhered to.
Local notifications will be issued to marine users, including fisherman’s organizations, relevant authorities and other local stakeholders, to ensure that they are made fully aware of the activity at least five days before commencement of the works.
Suitable arrangements will be made to ensure the ROP remains securely in place on the seabed for the conditions expected in the area.
Questions or concerns?
Photo courtesy of Greg Trowse.