Tidal Energy: A Wave of Opportunity for Atlantic Canada
- Aug 26, 2021 4:26 pm GMT
This summer, off the coast of Scotland, the world’s most powerful tidal turbine began generating electricity to the public energy grid. The 680-tonne turbine is now anchored in the Fall of Warness where a subsea cable connects the 2MW offshore unit to the local onshore electricity network. The powering on of this turbine made headlines around the world as a significant development for renewable energy. These developments have important implications for Atlantic Canada. With the most powerful tides on the planet, we have a significant potential to produce a large amount of reliable renewable energy from tidal sources.
Tidal energy is the term used to describe the energy generated from power found in ocean tidal currents and the use of tidal height differences. There are currently three different ways to get tidal energy: tidal streams, barrages, and tidal lagoons. For most tidal energy generators, turbines are placed in tidal streams. A tidal stream is a fast-flowing body of water created by tides. A turbine is a machine that takes energy from a flow of fluid. That fluid can be air (wind) or liquid (water). Because water is much denser than air, tidal energy is more powerful than wind energy.
Another type of tidal energy generator uses a large dam called a barrage. With a barrage, water can spill over the top or through turbines in the dam because the dam is low. Barrages can be constructed across tidal rivers, bays, and estuaries.
Turbines inside the barrage harness the power of tides the same way a river dam harnesses the power of a river. The barrage gates are open as the tide rises. At high tide, the barrage gates close, creating a pool, or tidal lagoon. The water is then released through the barrage's turbines, creating energy at a rate that can be controlled by engineers.
The final type of tidal energy generator involves the construction of tidal lagoons. A tidal lagoon is a body of ocean water that is partly enclosed by a natural or manmade barrier. Tidal lagoons might also be estuaries and have freshwater emptying into them.
A tidal energy generator using tidal lagoons would function much like a barrage. Unlike barrages, however, tidal lagoons can be constructed along the natural coastline. A tidal lagoon power plant could also generate continuous power. The turbines work as the lagoon is filling and emptying. (https://www.nationalgeographic.org/encyclopedia/tidal-energy/)
Tidal energy developments have been happening for some time now and have made international headlines. In August of 2021, it was announced that two Japanese firms had begun supporting the development of tidal energy projects in the Bay of Fundy. Such projects have garnered support of groups based around the world, from Nova Scotia itself to Ireland and indeed Japan. This particular project, developed by Irish firm DP Energy, and supported by Japanese firms Chubu Electric Power and Kawasaki Kisen Kaisha has been funded Natural Resources Canada as well. When the three 1.5MW turbines currently being developed come online, with another phase of the project aimed to produce 9MW in the future, it will be governed by a 15-year power purchase agreement with Nova Scotia Power Incorporated, which comes in at $530 Canadian dollars (around $422 USD) per megawatt hour. Note that this is one of the most expensive prices for energy from the sources available to our utilities.
To fully understand the balance of cost and reward, however, lets look at the economic impact of tidal energy development in Nova Scotia. By 2040, the tidal energy industry could contribute up to $1.7 billion to Nova Scotia’s gross domestic product (GDP), create up to 22,000 full-time jobs, and generate as much as $815 million in labour income, according to a study commissioned by the Offshore Energy Research Association of Nova Scotia (OERA). Several local companies that are developing tidal energy solutions have received tens of millions of dollars worth in funding from various levels of government. Along with these economic impacts, one must consider the reliability aspect of tidal energy. One of the main criticisms leveled at renewable energy sources such as wind and solar is an issue of reliability; stipulating the rhetorical misleading axiom of 'when the wind doesn’t blow or the sun doesn’t shine, solar and wind are useless'.
Tidal throws this inaccurate argument out the window. One of the most reliable aspects of human life for thousands of years has been the coming and going of the tides. The Bay of Fundy has the highest tidal range in the world and flows 160 billion tonnes of water in and out of its passage twice a day. That amount of force is more than the combined flow of all the rivers in the world. At Canada's leading test site for tidal energy, the Fundy Ocean Research Center for Energy ('FORCE'), the tide flows as fast as five meters per second! Therefore, the Bay of Fundy presents us with an immense opportunity to produce undeniably reliable renewable energy, with economic benefits and impacts on our communities.
New Brunswick, and some local companies based here, are investing in developing tidal energy. Despite the immense expense of tidal energy, it may be a significant renewable energy source to aid us in accessing clean, reliable power for the future. The tides in the Bay of Fundy have long been held in the wonder of New Brunswickers and tourists who come here. Tidal energy may be a way in which the wonders of the highest tides on the planet could help save us from climate change which in turn is raising those very sea levels. Stay tuned to see how tidal energy develops in Atlantic Canada in the coming years.
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