Solar and wind power are the two main sources of renewable energy generation in Canada. One that could soon be joining the ranks is tidal energy. This sustainable energy solution is currently used in France, China, and South Korea. Canada has great potential to use the technology. However, tidal energy is a fairly new concept, and many people are unfamiliar with how it works. In this article, we’ll cover how tidal energy works, its pros and cons, and how Canada can utilize tidal energy in the future.
What is tidal energy?
As its name suggests, tidal energy is power produced from the rise and fall of ocean tides. Specially built generators are placed in areas with significant tidal range (i.e., an area with a great difference between high and low tide). The captured energy is converted into electricity. There are three different ways to obtain tidal energy:
- Tidal streams: These are turbines using the kinetic energy of moving water to generate electricity. One way to think of tidal stream generators is a wind turbine placed underwater.
- Barrages: This type of tidal generator is essentially a large dam. Water either flows over the side of the structure or through the turbines.
- Tidal lagoon: A body of water is partly enclosed by a natural or man-made barrier. It operates similar to a barrage; however, a tidal lagoon can be placed along a coastline.
Tidal energy in Canada
As we mentioned above, Canada is one of the best places in the world for tidal energy generation. According to Marine Renewables Canada, Canada has an estimated 37,000 megawatts (MW) of tidal energy potential. The Bay of Fundy, located between Nova Scotia and New Brunswick, has been identified by the Electric Power Research Institute (EPRI) as one of the best sites in North America for tidal power generation. The predicted energy potential is between 2,500-7,000 megawatts, enough to power two million homes or the entirety of Atlantic Canada.
While Canada is poised to be a leader in tidal energy, there have been some roadblocks in adopting the technology. In April 2023, Sustainable Marine Energy Canada removed its tidal energy project from off the coast of Nova Scotia. The company cited “bureaucratic barriers” raised by the federal Department of Fisheries and Oceans. The main concern highlighted by the DFO was the potential harm the turbines can cause to marine species. However, there are more tidal energy projects under development.
The benefits of tidal energy
There are many positives of tidal energy generation. To start, it is much more predictable than wind or solar energy. Tidal currents are relatively consistent and can be forecasted days in advance. Therefore, it is easier to determine availability and the expected output from tidal energy. Wind and solar availability fluctuate frequently due to weather. Due to water’s density, tidal energy is an abundant power source. A tidal turbine can generate significantly more power than a wind turbine or solar panel.
Tidal generators take up less space than wind or solar farms. The largest tidal power station in the world, Sihwa Lake Tidal Power Plant in South Korea, spans 12.7 kilometres. In comparison, the largest wind farm in Alberta takes up 50,000 acres (202 square kilometres) of land. Installing tidal energy generators is relatively easy. For example, tidal streams are scalable, which means they can be installed one at a time and not all at once.
The downsides of tidal energy
Tidal energy has enormous potential, but it does have some disadvantages. The main hurdle is the cost of developing, installing, and connecting tidal energy generators. In Canada, the estimated cost of tidal energy is $0.66 per kWh. In comparison, wind energy costs between $0.20-$0.30 per kWh. Despite Canada having one of the best locations in the world for tidal energy, other suitable locations are limited. Among these locations, some are far from the grid, requiring expensive undersea cables for transmitting generated electricity. While tidal energy produces zero greenhouse gas emissions, there are concerns about environmental effects. Tidal energy structures can change the sea level and quality of the water. The turbine blades can also harm marine wildlife and disrupt marine animal navigation and communication due to the underwater noise. However, scientists and engineers are working to improve tidal energy technology to reduce its environmental impact.
How efficient is tidal energy
According to PMI Industries, tidal energy converts approximately 80% of kinetic energy into electricity. Wind turbines are 20%-40% efficient in converting wind into electricity, while solar panels are about 40%-50% efficient.
How much energy does a tidal turbine produce?
The answer to this question depends on various factors, including tidal generation type and the location of the tidal energy plant. A single tidal turbine has a capacity of 25-50 MW. Therefore, many generators are needed to produce a substantial amount of power. Plus, the average output of tidal energy is less than 40% of the installed generating capacity.
How many tidal energy plants are there in Canada?
Currently, there are no operational tidal energy plants in Canada. However, there are several projects under development, primarily in Nova Scotia. In a 2022 report by Marine Renewables Canada, six tidal energy projects were in development, while the Sustainable Marine project was up and running. Previously, the only operation tidal power plant in Canada was the Annapolis Royal Generating Station. The plant was decommissioned in 2019 after 34 years of operation. The tidal project by Sustainable Marine Energy Canada had a promising start. However, the company pulled the plug on their station in April 2023.
Why is tidal energy not widely used in Canada?
There are varying reasons why tidal energy is not used in Canada. Many projects face regulatory challenges from governing bodies. For example, the closure of the Annapolis Royal tidal station in 2019 was partly due to the Department of Fisheries Oceans determining the facility caused harm to fish. The high cost of tidal energy projects is the second factor in the technology’s slow advancement in Canada. Some companies may run out of funds before their projects can get up and running.
On the bright side, scientists and engineers are continuously developing tidal technology to reduce the economic and environmental costs. Once these two issues are resolved, more tidal energy projects should pop up in Canada.
Are there other ways to generate hydropower?
Besides tidal energy, there are several ways to generate electricity from water. The most common and proven method is with a dam. There are over 15,000 dams in Canada producing 385 TWh/ year, which is 60% of Canada’s total electricity generation.
River current energy is similar to tidal energy in that the electricity produced comes from the “volume of water and the speed of the current”. The difference is a river current device is placed in a river, where the current continuously flows in a single direction. Some strengths of river current technology include:
- Low cost and durability
- Smaller environmental footprint than other forms of hydropower
- High energy capacity
- Provides a continuous, reliable source of energy
Wave energy harnesses electricity from the motion of ocean waves. There are different ways to generate wave energy, but in each case, it involves placing electricity generators on the ocean surface. The kinetic movement of the waves turns the turbines, which in turn creates energy converted into electricity. Some wave energy generators use the up and down motion waves to power pistons or turn generators. While wave energy has the same advantages as other forms of hydropower, it does have disadvantages. The amount of energy produced is dependent on the size of the waves at a given time. There are also several unpredictable factors for wave energy, such as wave height, wave speed, wavelength, and wave density.
