ARCHIVED – Canada’s Adoption of Renewable Power Sources – Energy Market Analysis
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Several renewable technologies currently have little or no market penetration in Canada’s power sector, but have made significant breakthroughs elsewhere and have the potential to play a larger role in the Canadian energy mix. Those technologies include tidal, offshore wind and geothermal energy.
Electricity can be generated from tidal movements in four ways: tidal streams, tidal barrages, tidal lagoons and dynamic tidal power.
Tidal stream generators use underwater turbines to capture energy from tidal currents. Tidal stream systems extract the kinetic energy (energy in motion) from moving water generated by the tides without altering the environment. This technology has been deployed around the world, mostly in demonstration projects of less than 10 MW.
A tidal barrage is similar to a reservoir hydro dam except that it is built across a tidal estuary. The gates of the barrage are opened as the tide rises into the estuary and closed during high tide to capture a reservoir of water. Water is then released through a turbine generator during low tide to produce power. The largest tidal barrage in the world, in Korea, has a capacity of 254 MW.
Table 7 – Top Five Countries for Tidal Capacity in 2015
|Country||Tidal Power Capacity (MW)|
A tidal lagoon is an enclosed ring wall that encircles an area of sea, forming an artificial lagoon. Like a tidal barrage, a tidal lagoon captures a reservoir of water at high tide, and releases water through turbines built into the wall during low tide to generate power. The 320 MW Tidal Lagoon Swansea Bay in the United Kingdom is the first proposed facility of its type and is planned to be commissioned in 2019.
Dynamic tidal power is a conceptual technology based on a long dam built out to sea from the coast, with many turbines embedded along its length. As the tide cycles, water would flow from one side of the T-like structure to the other, passing through the embedded turbines. Dynamic tidal power is still being researched and no facility has been constructed.
The only tidal power plants in North America are in Nova Scotia. The Annapolis Tidal Station was installed in Nova Scotia in 1984. The station has an installed capacity of 20 MW and generates 29 to 37 GW.h of electricity per year, depending on tides. Cape Sharp Tidal began testing the first turbine of a 4 MW project in the Bay of Fundy in late 2016. The project consists of two 2 MW in-stream tidal turbines, which, once operational, are estimated to reduce Nova Scotia’s CO2 emissions by 6,000 tonnes per year. Other projects planned for Nova Scotia are Black Rock Tidal Power (5 MW), Minas Tidal Limited Partnership (4 MW), Atlantis Operations Canada Limited (4.5 MW), Halagonia Tidal Energy Limited (4.5 MW), and Fundy Tidal Inc. (2.95 MW).
South Korea, France and the United Kingdom lead Canada in installed tidal capacity. Much of South Korea’s capacity comes from its 254 MW Sihwa Lake project, which is situated on the west coast of South Korea and is connected to a 43.8 km² artificial lake. By opening the gates twice a day when the West Sea is at high tide, the power plant is able to generate about 552.7 GW.h of electricity annually.
Efforts to improve the efficiency of wind farms led to the installation of wind turbines offshore, where wind speeds are generally faster and larger turbines with higher capacity factorsFootnote 1 can be used. Offshore turbines are essentially the same as their land based counterparts, but are modified so that they can be installed in water. Shallow water turbines have a base fixed to the seafloor, while deep water turbines are attached to a floating base that is tethered to the seafloor.
Offshore wind is a proven technology that has operated in many parts of Europe for over 25 years. In 2015, Europe had approximately 11 GW of offshore wind capacity. Wind Europe set a target of 40 GW to be installed by 2020 and 150 GW by 2030. In contrast to Canada, Europe has a higher incentive to pursue offshore renewables due to higher energy and electricity costs, higher coastal population density, and a shortage of available land.
No offshore wind farms exist in Canada, but projects totaling more than 3.6 GW have been proposed. The 400 MW NaiKun Project in Hecate Strait, B.C. is the only West Coast proposal. Five projects totaling more than 3 200 MW, are planned by Beothuk Energy for Atlantic Canada: two off the coast of Newfoundland and Labrador, and one each off the shores of Nova Scotia, Prince Edward Island, and New Brunswick.
Environmental issues related to offshore wind are similar to those for onshore wind, but with concerns about marine ecosystems replacing concerns about primarily birds and bats. Because offshore wind farms are often located beyond the sight and reach of most onshore residents, they can minimize objections related to noise, recreation, and visual disturbances.
Offshore wind farms are more costly than onshore installations. Constructing in deep water is expensive, requires different materials, takes longer, and is more dependent on weather. Due to more extreme temperature shifts and corrosion issues, materials do not last as long and facilities require more operation and maintenance. Collisions with icebergs and motorized water craft can be additional risks.
On the other hand, winds blow harder and more consistently offshore, producing up to 50% more electricity. Offshore winds also blow harder during the day, when electricity demand is highest, while onshore wind typically blows stronger at night, when demand is low. Finally, capacity factors for offshore wind are approximately 45%, as opposed to 30% for onshore.
Geothermal energy is produced from heat in the earth, whether from magma, hot rocks, hot water, or steam. Adding fluid into hot areas creates steam which can then be used to generate electricity. Although the technology to generate power from geothermal energy has existed for over 100 years, no geothermal power plants operate in Canada.
At the end of 2015, world levels of installed capacity were 13.2 GW. The countries with most geothermal power capacity in 2015 were the United States, the Philippines, Indonesia, Mexico, and New Zealand.
All of Canada has geothermal energy. However the principal areas showing the most promise are B.C., Alberta, the Yukon, the Northwest Territories, and Saskatchewan. Canada’s west coast, on the eastern periphery of the Ring of Fire around the Pacific Ocean, is suited for larger-scale commercial power production. Isolated northern communities are exploring synergies between geothermal heat and power, even at smaller scales, in order to displace comparatively high energy costs for electricity and heat.
Primary factors determining whether a site is economically viable are how hot the water or steam is, and the speed and pressure at which it reaches the surface. Additional factors include how close the resource is to the surface, and proximity to transmission lines and markets. Unlike the majority of renewables, geothermal power is suited for base load generation as, once operational, it has a 98% reliability rate. Fuel costs are extremely low, as are operational and maintenance costs.
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