Recent advancements in the technology indicate that with a relatively small investment from the government, wave energy could soon compete with other renewable sources.
Wave energy systems place objects on the water’s surface that generate energy by rising and falling with the waves. The wave energy in turn moves a buoy or cylinder up and down, which turns a generator that sends the electricity through an undersea cable to a power station on the shore.
Pelamis Wave Power, Finavera Renewables (TSX-V: FVR), and Ocean Power Technology (OPTT) — have developed prototype wave energy conversion systems that the companies say are ready to be deployed along United States coastlines. Other companies have joined in with alternative designs [see the report on Offshore Wave Energy Conversion Devices by the Electric Power Research Institute (EPRI)].”>
Rendition of a wave farm made up of permanent magnet linear generator buoys.
At least three companies — Pelamis Wave Power, Finavera Renewables (TSX-V: FVR), and Ocean Power Technology (OPTT) — have developed prototype wave energy conversion systems that the companies say are ready to be deployed along United States coastlines. Other companies have joined in with alternative designs [see the report on Offshore Wave Energy Conversion Devices by the Electric Power Research Institute (EPRI)].
The potential energy to be captured from ocean waves could surpass other forms of renewable energy such as solar, wind, or hydropower, according to a recent study by EPRI, a research group funded by hundreds of utilities.
According to a report released in January 2005, the total wave power along the coastlines of the U.S. is approximately 2,100 terrawatt hours per year, nearly as much as all of the electricity produced by coal and roughly 10 times the total energy produced by all of the country’s hydroelectric plants. Wave energy systems can capture the same amount of energy using smaller and less expensive equipment than wind or solar systems, according to Roger Bedard of EPRI, who authored the study.
Wave energy “is among the most environmentally benign technologies,” and is less visible than off shore wind farms, according to Bedard. He says wave energy conversion devices have a smaller footprint than offshore wind farms and interfere less with marine life movements.
Bedard says that wave energy systems requires smaller investments than offshore wind energy systems because the equipment is much lighter, but the private sector has been wary to invest because the expense for setting up demonstrations is high, and obtaining federal permits can take many years (?)
Instead, Bedard says the federal government should step in with funding to help the technology succeed. “Very simply, new energy sources have always been funded by the federal government,” Bedard says.
However, “the U.S. Department of Energy does not have an ocean energy program”. The Department of Energy had a program for ocean energy, but it was discontinued, according to spokesman Tom Welch. Several wave energy systems are currently being tested in the United Kingdom, a country which according to Bedard “wants to be the world leader.”
Some facts about wave energy:
- Sea wave energy has the highest concentration of renewable energy.
- Sea waves are the result of the concentration of energy from various natural sources like sun, wind, tides, ocean currents, moon, and earth rotation.
- Waves originate from wind and storms far out to sea and can travel long distances without significant energy loss making power production steadier and more predictable. This in turn reduces project risk.
- Waves near land tend to be parallel to the coast.
- Wave energy contains roughly 1000 times the kinetic energy of wind, hence it allows smaller and less conspicuous devices to produce power.
- Wave energy varies as the square of wave height, whereas wind power varies with the cube of air speed. Water being 850 times as dense as air results in much higher power produced from wave averaged over time.
- Theoretically one could extract 40 MW (megawatts) of power per Km of coastline where there are gentle waves (say 1 meter in height) and 1000 MW per Km of coastline where the wave height is 5 meters or more.
- Unlike wind and solar, power from sea waves continues to be produced around the clock, whereas wind velocity tends to die out in the morning and at night and solar power is dependent on sun and cloud cover.
- One problem with sea waves is that they have very high force at low speeds, whereas for electricity generation higher speeds are required. The design of wave device to do this conversion is most crucial to the economics of any model.
- Another problem with wave energy is its ROI. Current devices are extremely complex with high installation costs when compared to the useful energy produced.