Petit Passage, Canada
Nova Innovation has received a Demonstration Permit to construct a 1.5 MW tidal energy array in Petit Passage: The Nova Tidal Array. The proposed location of the Nova Tidal Array is in the Petit Passage Marine Renewable Energy Area. The array would be developed in three 0.5 MW phases. Turbines will be deployed gradually within each phase, so that environmental effects can be carefully monitored.
The first 0.5 MW will be further split into two phases to enable deployment and environmental monitoring of a single turbine first (Phase 1a), before the next four turbines are added to the array (Phase 1b). Each phase of the project will be monitored to build an understanding of any environmental effects of the turbines before the next phase proceeds.
Nova has used this carefully managed, phased approach for our project in Shetland, Scotland. It has helped to demonstrate the reliability and performance of our turbines and build confidence in tidal energy.
Nova is currently discussing the best approach to phasing with the Nova Scotia and Federal Government, First Nation Communities, the fishing community and local residents. Significant work will be carried out to gather information on the marine environment in Petit Passage before Nova deploys the first turbine.
Nova Innovation has produced this Frequently Asked Questions (FAQ) document to provide information on our proposed Petit Passage tidal energy project in the Petit Passage, Digby Neck, Nova Scotia. This document is produced based on the feedback received during the public meetings in Sandy Cove, Tiverton, and Freeport in October 2019, as well as, feedback from other stakeholders throughout our engagement.
The FAQ provides a variety of information on the Petit Passage tidal energy project, including its proposed location. It also provides technical information on Nova’s tidal turbines, how they are deployed and the vessels likely to be used for installation and maintenance operations.
The Petit Passage tidal energy project is at an early stage and many of the details are not yet finalized. Nova Innovation has based this FAQ on the best and most up-to-date information available at the time.
1. Where will the tidal turbines be deployed?
The proposed location of the tidal turbines is in the Petit Passage in Digby Neck, Nova Scotia. An indicative layout of the first phase of the array can be seen in the project map presented below. The coloured circles indicate the potential location of the turbines in a potential phase 2 and phase 3.
2. How many turbines will be deployed?
Nova has received a marine-renewable energy demonstration permit from the Nova Scotia Department of Energy and Mines for the development of a 1.5 MW project. The project would use 15 Nova M100-D 100 kW turbines.
The project would be developed in three 0.5 MW phases. Each phase would consist of 5 turbines. Turbines will be deployed gradually within each phase, so that environmental effects can be carefully monitored. Each phase of the project will be monitored to build an understanding of any environmental effects of the turbines before any subsequent phase proceeds. Nova has used this carefully managed, phased approach for our project in Shetland, Scotland. It has helped to demonstrate the environmental credentials, reliability and performance of our turbines and build confidence in tidal energy.
The first 0.5 MW phase will be further split into two phases: a single turbine will be deployed first (Phase 1a) before the next four turbines are added to the array (Phase 1b).
3. When will the turbines be deployed?
The suggested timeline of the project can be seen in the figure below.
4. Why are you deploying a single turbine first?
Deploying a single turbine first has several benefits:
- It allows us to gain a better understanding of the site while minimizing all risks;
- It allows us to validate our monitoring plan and equipment and allows us to gain a better understanding of any environmental effects of the turbine;
- It helps us demonstrate the reliability and performance of our turbine, providing confidence to communities, investors, and regulators.
5. What is the regulatory process?
Before the turbines can be deployed, the project requires several permits and approvals from different government departments, both Federal and Provincial. This includes:
- A demonstration permit from the Nova Scotia Department of Energy and Mines;
- Approval from the Nova Scotia Department of Lands and Forestry;
- Approval from Fisheries and Oceans Canada;
- Approval from Transport Canada;
- Permission for the construction of the onshore substation.
Nova has received a demonstration permit from the Nova Scotia Department of Energy and Mines, and approval from the Department of Lands and Forestry. We are currently discussing the project with the other government departments and will update this FAQ when permits and approvals have been secured.
6. What turbines will the project use?
The project will use the Nova M100-D turbine. This is the updated direct drive (no gearbox and hence no oil) version of Nova’s tried and tested M100 turbines deployed at the Shetland tidal array.
Nova M100-D Key Figures:
- Nameplate capacity: 100 kW
- Design life: 20+ years
- Blade / Rotor diameter: up to 8.5 meters/ 28 feet
- Blade / Rotor speed: 15 to 25 rpm
- Mounting: gravity seabed base
- Cut-in tidal speed: 0.8 m/s
- Rated tidal speed: 2.2 m/s
Each Nova M100 tidal turbine consists of the following:
- A steel turbine nacelle unit, which contains the drivetrain and power conditioning;
- The blades, which are connected to the nacelle;
- A steel gravity base substructure with precast concrete ballast blocks to secure it to the seabed.
Each turbine has two blades, this allows for safe handling of the turbine on vessel decks during operations and enables the use of small, low-cost vessels and expanded working weather windows.
The blades are bidirectional blades. This means the turbine does not need to turn when the tide turns. It also means the turbine does not have a pitch or a yaw mechanism, something that increases reliability.
The pictures below provide an overview of the turbine layout and dimensions.
7. How many homes can one turbine power?
One turbine can power up to 40 average Canadian homes per year.
8. What is the carbon offset of a turbine?
One turbine can offset up to 395 metric tons of CO2 equivalent emissions per year. That is the same as 85 cars.
9. How are the turbines installed?
We are currently working with local experts to gain a better understanding of the conditions in Petit Passage to fully understand how installation of the turbines will be undertaken.
We recognise that local fishermen are very knowledgeable about the conditions in the passage and would welcome the opportunity to learn from this experience.
Based on our experience of installing turbines in similar sites (Shetland), the sequence of installation operations will be as follows:
- The onshore control building and electrical substation would be constructed.
- The steel substructure and concrete ballast would be towed in the water from a local harbour, to the installation location using a workboat. Once in position on site, the structure would be lowered through the water column into position on the seabed.
- The power cable would be installed using standard industry methods for cable laying, with the cable lay vessel holding position, spooling out cable and moving along the cable route as required. It may be necessary to temporarily use some cable pulling and handling equipment onshore.
- Once all the other elements of the system are in place, the turbine nacelle can be installed. This would be carried or towed from a local harbour to the installation location by a workboat and lowered onto the substructure, where it would be secured for operation.
Our previous deployments have taken less than 6 days to complete all offshore works.
Once installed, there would be a period of commissioning where the operation of the tidal turbines would be tested and any remediation work if required (including recovery and redeployment operations) could be undertaken.
10. What type of boats will be used to deploy the turbines?
The foundation structure is designed to be installed and removed using regular workboats.
Because of the small size of the turbine nacelle, relatively small vessels can be utilised to provide operation and maintenance throughout the array lifetime.
As part of the maintenance of the turbines, the turbines will need to be removed occasionally.
Based on experience in Shetland, Nova anticipates that once the array is fully up and running, each turbine will need to be removed once every two years for maintenance.
Depending on the weather, removing or redeploying a turbine can be swiftly done in a single slack water period.
12. What is the impact of the turbines on the Environment?
Making sure that our turbines do not harm the marine environment is incredibly important for us. Environmental impact considerations, including impacts on fish and other marine life, are a key part of the consenting and design process.
At our site in Scotland, we have been carrying out carefully designed environmental monitoring over the past 7 years to ensure that our turbines do not harm marine wildlife. This includes:
- regular surveys of marine mammals and seabirds where our turbines are located, as well as,
- using underwater video cameras attached to each of our turbines.
This monitoring is helping us understand how marine wildlife behaves around our turbines. We have carried out approximately 1500 hours of marine mammal and seabird surveys and gathered over 10,000 hours of underwater video footage.
No negative environmental effects or interactions between marine wildlife and our turbines have been detected from this monitoring.
A similar monitoring approach will be taken for the project in the Petit Passage. The monitoring system will be designed based on feedback from locals, regulators, and the site assessment surveys we will undertake before the installation of the first turbine.
13. Will it affect fishing areas?
Nova does not want to cause a conflict with existing fishing activity. In the same way that we engaged with the fishing community at all our sites, we want to work with fishermen to finalise the design for the Petit Passage project.
The turbines will be installed in the middle of the passage. Based on Nova’s current understanding, no fishing currently takes place in this area.
The cable will be laid from the turbines to the shore. It is our intention to come ashore on the man-made rock armour near the pier on Shore Road, next to the fish plant. We will ensure there is no impact to local fishing vessels.
14. How do you decommission the turbines?
The process of decommissioning of the Nova Tidal Array will largely be the same as the installation, but in reverse. Because of the gravity base substructure, no seabed drilling or pile driving is required for the installation of the turbines. This means all items including the subsea cable can easily be recovered from the seabed, without the need for cutting or other intrusive operations making the construction and decommissioning phases very benign compared to other tidal or offshore wind projects.
In 2017, Nova decommissioned our first grid-connected turbine, a 30-kW prototype device, which was installed in 2014. The turbine, cables, and all associated material were removed over 2 days, returning the site to its original state.
15. What happens with the turbines if you go out of business?
Nova is working with the Nova Scotia Department of Energy and Mines to set up any necessary decommissioning guarantees. For example, a bond could cover the costs of removing the turbines.
Because of the small size of the turbine nacelle, turbines can be removed by relatively small vessels. The gravity base substructure means no seabed drilling or pile driving is required for the installation of the turbines. This means all items, including the subsea cable, can easily be recovered from the seabed, without the need for cutting or other intrusive operations, returning the site to its original state.
16. What happens with the Electricity?
The electricity will be sold to Nova Scotia Power and exported to the Nova Scotia grid.
17. Will you add energy storage?
While the integration of energy storage with the Shetland Tidal Array has been successful, there are currently no plans to add energy storage to the proposed tidal array in the Petit Passage. This is something we could explore in the future based on the local requirements to provide resilience or backup power.