Distributed Energy

Going with the Flow

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In recent years, tidal power has emerged as a source of renewable energy. Tidal energy is more expensive than traditional resources such as wind energy. However, tidal energy is clean, pollution-free, reliable, and predictable. The major downside is the potential for environmental change, such as damage to marine or shoreline ecosystems—and especially to their fish populations.

Tidal dams or barrages were the typical models of tidal power facilities up until a few years ago. Due to concerns about the environmental impacts of barrage-style dam construction, both current and future efforts will focus more on in-stream tidal energy.

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According to Renewable Northwest, “[Several] models for tidal facilities have emerged in recent years, including tidal lagoons, tidal fences, and underwater tidal turbines. […] Perhaps the most promising is the underwater tidal turbine. Several tidal power companies have developed tidal turbines, which are similar in many ways to wind turbines. These turbines would be placed offshore or in estuaries in strong tidal currents where the tidal flow spins the turbines, which then generate electricity.” These modern systems are thought to have less of an impact on the land, and they also allow for alternate routes for fish and mammals to move around the propellers.

The technology still has a long way to go in terms of resilience. In 2009, tidal currents destroyed the propeller blades of a turbine—the first ever installed in the Bay of Fundy, near Maine and the Canadian province of Nova Scotia. It had been placed on the sea floor in the Minas Basin, a narrow inlet with some of the highest tides on earth. Taking advantage of the extreme power of these tides also comes with the risk that those tides will be too extreme. According to an article from The Walrus, the Bay of Fundy is one of the greatest potential sources of untapped tidal energy on the planet. The article goes on to say, “Nova Scotia, a province still largely dependent on burning coal for electricity, currently has a government that is determined to see these tidal forces converted into electricity.” Experts believe that the tidal energy could one day provide enough power for all of Nova Scotia without doing any serious environmental damage.

In-stream tidal energy can cost anywhere from two to three times as much per kilowatt-hour than offshore wind energy. Although it is expensive, Nova Scotia has agreed to buy tidal electricity from five approved developers. One of these, Cape Sharp Tidal, installed a turbine in 2016. This was the first in-stream turbine to provide Nova Scotia’s energy grid with power. This year, another turbine was deployed in Minas Basin and connected to the grid in July. However, due to issues with funding, the project was put on hold.

“Every project is like a new challenge,” says Voytek Klaptocz, managing director of Mavi Innovations, a renewable energy company in Vancouver focused on developing tidal and river current turbines. Most of British Columbia is already supported by cheap and clean hydro energy. Therefore, Klaptocz explains, “Remote communities are our target because they’re already paying the highest prices, and we will be offsetting diesel.”

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Last week, a federal agency (Natural Resources Canada) announced almost $30 million (CAD) of funding for a 9-MW tidal energy project off the coast of Nova Scotia. This will be one of the largest tidal array projects ever built, and indicates a big win for tidal energy and also that there is confidence in the technology.

As the technology continues to improve, costs of tidal energy may lower, just as costs of solar and wind power technologies have and continue to decrease. (Partly due to supply chains becoming more competitive, as well as increasing economies of scale, it’s estimated that the cost of electricity from solar and wind power could fall by as much as 59% between 2015 and 2025.)

What are your thoughts? Will tidal energy follow suit and become a more affordable form of power, along with wind and solar? Is it likely that tidal energy will also find a place in the US market, despite its higher cost?

“Low tide on the Bay of Fundy shores at Alma, New Brunswick, where the Halagonia tidal energy project will be constructed.” (Axios.com)
Photo credit: Education Images/UIG via Getty Images


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