What is Tidal Power?
Tidal power is power generated from harnessing the kinetic energy of tidal currents (“tidal stream”) and tidal height differences (“tidal barrage/lagoon”).
Tidal currents are strongest where the water passage is accelerated around headlands, over shoals, or in narrows. Historical tidal energy is focused on barrage-style infrastructure where a dam-like structure is built across an area with a high tidal range. Theoretically, tidal energy plants would be constituted by arrays of generators in suitable high-current areas.
There have been many tidal energy device designs, however, three main methods are used:
- Cross-flow or vertical axis turbines – Vertical turbine blades move to rotate a central shaft driving a generator and producing power.
- Axial or horizontal axis turbines – 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.
The west coast of British Columbia has some of the best tidal energy potential in the world which is in the coast’s many fjords and channels.
BC’s vast river and estuary networks provide further applications for tidal energy technology with modern tidal turbines being installed in rivers, irrigation canals, wastewater flows, and estuaries. Due to the nature of tidal energy, it is also highly predictable and forecastable.
Environmental & Regulatory Considerations
There are no known environmental issues for tidal energy.
While concerns exist for ecological impacts and disruption to local fishing, mitigation measures will be implemented, and research continues to be conducted on potential environmental impacts at several academic institutions. Until devices spend significant time in operation, environmental impacts can only be estimated.