What is Tidal Power?
- 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.
- These two tidal energy sources are referred to as tidal stream and tidal barrage or lagoon.
- Tidal streams are currents in the ocean water column, created as the water of the ocean rises and falls with the movement of the tides.
- More recent commercialization efforts have focused on tidal stream technologies that harvest kinetic energy from the water currents.
- Tidal currents are strongest where the water passage is accelerated around headlands, over shoals or in narrows.
- Historical tidal energy developments focused more on barrage-style infrastructure where a dam-like structure is build across an area with a high tidal range.
- The Annapolis Royal tidal energy station in Nova Scotia, which still operates today, is one of only three such power stations in the world.
- The west coast of BC has been identified as having some of the best tidal energy potential in the world.
- BC has numerous areas of tidal energy potential, located in the coasts many fjords and channels.
- A 2006 tidal energy resource assessment identified 89 tidal energy project sites in BC with an estimated 4,000 MW of potential energy.
- Modern tidal turbines are also being installed in rivers, irrigation canals, wastewater flows, and estuaries.
- BC’s abundant river and estuary networks provide further renewable energy opportunities for the majority of its population.
- Due to the nature of tidal energy, it is highly predictable and forecastable.
- Tidal energy plants will be made up of arrays of individual generators in suitable high-current areas.
- Each tidal energy device is designed use the energy in tidal stream flows to drive a generator to convert it to power.
- There have been many tidal energy device designs, however three main methods are used:
- Cross-flow or vertical axis turbines
- Axial or horizontal axis turbines
- Reciprocating hydrofoils
- CROSS-FLOW OR VERTICAL AXIS TURBINES – the turbine is placed in the tidal stream flow, as the water flows past, the vertical turbine blades move to rotate a central shaft driving a generator producing power.
- AXIAL OR HORIZONTAL AXIS TURBINES – these turbines are somewhat similar to modern wind turbines; as the tidal stream flows past, the turbine blades rotate a horizontal shaft producing power through a generator.
- RECIPROCATING HYDROFOILS – working like a fish’s tail and controlled by pitch, the hydrofoils are forced up and down by the stream flow transferring power to drive a generator.
Tidal Power in BC
- In September of 2006, Clean Current Power Systems installed a tidal turbine at the Race Rocks ecological station.
- The turbine, in combination with a solar and battery system, became the first complete ocean energy power system displacing diesel on the island.
- New Energy Corp and Canoe Pass Tidal Energy have received federal SDTC funding and provincial ICE funding for a project near Campbell River.
- The Canoe Pass project is the first tidal energy project to undergo the federal environmental assessment process.
- Site investigations are underway for other potential projects.
- In 2010 BC created the potential for an emerging energy feed-in tariff program that will assist in creating a market for this sector.
Environmental & Regulatory Considerations
- There are no known environmental issues for tidal energy.
- Strategic Environmental Assessments have been completed in a number of areas, including the Bay of Fundy.
- While concerns exist for ecological impacts and disruption to local fishing, mitigation measures will be implemented.
- Research continues to be conducted on potential environmental impacts at a number of academic institutions.
- Until devices have spent significant time in the real world applications, environmental impacts can only be estimated.
- The power from ocean energy will be green electricity, using a renewable source of energy and not emitting greenhouse gases.
- This decreases the need for fossil fuels for electricity production and aids in combating the effects of climate change.
- Canadian green ocean energy will be in demand for energy exports.
- Ocean generated electricity is a method of reducing the risk associated with price fluctuations of conventional fuel sources, creating energy price security.
- Utilizing a number of different energy sources aids in energy security, decreasing the reliance on a single energy source, and increasing energy self-sufficiency.
- Ocean energy project and device development will create direct jobs as well as employment for related industries such as marine manufacturing, engineering and oceanography, and power supply and service sectors.