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The Challenges of Ocean Wave Energy
With all the potential for producing energy from ocean waves, it may be surprising that there are as yet no sites in Canada that use ocean wave power. In fact worldwide, ocean wave energy usage is still in its infancy. There are several reasons why this is true.
Wave Dragon Wave Energy Collector
Photo: Wave Dragon
First, the power of ocean waves is in an oscillatory form, which is very difficult to utilize. A standard hydroelectric dam or run-of-the-river plant produces a steady flow of water through a pipe, which spins a turbine at a constant speed to generate electricity. Waves produce a very complex, up-down motion, which requires a more complex mechanism to generate electricity. The frequency, magnitude and even the propagation direction of ocean waves are usually not constant. Depending on the location, the frequency may vary over a very broad spectrum, and the magnitude may vary over more than an order of magnitude. Different wave energy converters vary in efficiency with both wave frequency and magnitude, and must be selected and optimized for a site. Site selection is critical.
Second, the ocean coastal environment is extremely harsh. Salt water is very corrosive. Electrical generating and control systems will be particularly susceptible to corrosion, and copper plays a key role in these electrical systems. More will be said later about copper’s value in ocean wave energy convertors. In addition to being corrosive, Canada’s cold, often ice blocked, and constantly pounding coastal seas are always difficult if not deadly. The high loss of life among Canada’s coastal sailors, fishers, and oilrig workers bares testimony to this brutal environment.
Third, any medium-to-large scale electricity generation from ocean waves will need to feed into the electric grid. Most of Canada’s open coast, particularly in the west and along the outer shores of Newfoundland and Labrador is not heavily populated and has no easily accessible electrical grid connection.
Ship Wreck Debris off the Newfoundland Coast
Finally, research and development of ocean wave energy is a relatively recent endeavor. Although the earliest patent for using ocean waves was granted in 1799, serious R & D only began during the energy crisis of the 1970’s primarily in the UK. That early research although vital at the time, waned as the price of oil decreased in the 1980’s. Only more recently has wave energy R&D begun again in earnest. On the other hand hydro power from rivers in the form of water wheels has been used since ancient times, and hydroelectric generation was one of Canada’s earliest sources of electricity. Wind was also used for lifting water and other loads by peoples in antiquity. Wind generation of electricity at least off grid, has been used since the early 1900’s. Grid connection of small wind generators began in 1970’s. At present about 1% to 2% of Canada’s electricity comes from wind generation and this percentage is growing. So compared to other renewable sources, ocean waved energy is an emerging technology.
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