Along the craggy coast of southwestern Nova Scotia, the rocky narrows of the Digby Gut connect the Bay of Fundy with the Annapolis Basin. The treacherous tidal currents that make the Gut a risky spot for sailors also make it an ideal spot for researching ways of harnessing tidal energy.

In a three-year, $3.3 million research project, Dr. Richard Karsten of Acadia’s Department of Mathematics and Statistics is investigating the Digby Gut and two other Digby Neck channels as potential sites for underwater turbines to generate electricity. Digby Neck is a small peninsula that lies alongside mainland Nova Scotia in the Bay of Fundy.

The project will assess the sites on their greatest energy potential, but it will also consider the engineering, construction, and operational costs associated with different technologies.

Called “Reducing the cost of in-stream tidal energy generation through comprehensive hydrodynamic site assessment,” the project involves other Acadia departments and five partners, including Dalhousie University and the University of New Brunswick .

Funding of $1.6 million will come from Natural Resources Canada through its 2012 ecoEnergy Innovation Initiative competition.

In simple terms, Karsten’s part of the project is to use mathematical modelling to figure out how much power is available at the three sites, how much electricity can be generated using turbine technology, and how extracting power will change the tides. In short, it will define the opportunity to develop tidal power there.

Industry partners

The three industry partners are Fundy Tidal, Dynamic Systems Analysis, and Clean Current.

Fundy Tidal is owned by community members in the Digby Neck area. “They’re the only company in Nova Scotia that has the right to sell tidal power to Nova Scotia Power right now,” says Karsten, “and they have the right to do this in the three Digby Neck passages.”

Dynamic Systems Analysis, Halifax, engineers marine structures and cabled systems in the ocean and is able to show how a turbine will survive and react to the tidal flows. Clean Current Power Systems is a Canadian company that develops river and tidal turbines to produce electricity with minimal environmental impact and zero greenhouse gas emissions.

Each partner is critical to the project, Karsten says. “With this type of project, it had to be university and industry in partnership to do the research, but also to tackle an applied problem with the goal of generating electrical power at the end of it.”

Modelling the tides

Using computers and numerical models to predict how fast the water is moving at a given location, Karsten and his undergraduate students are modelling the tidal flow. With accurate models, they can identify the best places to site turbines. From there, they can predict how much power the turbines would generate if placed singly or as a large array, or farm.

The final task is to identify the impact turbines would have on the flow of the water and, ultimately, on the tides and local ecology.

“When the water flows through the turbine, it slows down,” Karsten says. “That’s the power you’re taking out. And if you put many, many turbines in, the slowing down of the water is going to change the tides.”

A significant slowing of the water would have two main effects. First, it would change how much electricity would be generated if more turbines were installed. Second, it would affect the plants and animals that depend on the mud flats of the intertidal zone, including marine life and migrating birds.

“We’re trying to make sure we’re always balancing the possible benefits of generating electricity from the tides with the possible impacts on the environment,” Karsten says.

Karsten’s students have done the bulk of the work developing the numerical models. One student is now looking at the potential change in area of the mud flats in the Annapolis Basin. Before any decisions are made to install turbines, the project’s environmental impact will be assessed.

Acadia’s location and people

Acadia’s location on the Bay of Fundy makes it a natural place to work on tidal projects, Karsten says, but the people here are just as important.

“For a small university, we’ve got a core of researchers here working on tidal energy,” he says. “We have formed the Acadia Tidal Energy Institute with the mission of advancing knowledge of tidal energy that respects the environment and promotes socioeconomic prosperity.”

The Institute includes Anna Redden from Biology for the environmental work; John Colton from Recreation Management and Community Development, who’s looking at how the communities around the Bay of Fundy will be affected;  and Shelley MacDougall from the School of Business, who’s looking at the economic side of the project.

The involvement of students has been vital in getting the research done, Karsten says, but also because he can teach this project in the classroom.

“We’ve tried to focus on making our research useful to the development of tidal energy, to answering the important questions about tidal energy,” he says. “And I think a large part of that is being at Acadia. We do this every day in our classrooms.”

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For more information:

NRCan news release