Wave Energy

As reported in Discover magazine, researchers around the world have developed all sorts of wave power devices.

Pelamis wave energy conversion field image: Ocean Power Delivery

For example, there are moored buoy systems, such as the AquaBuOY, which heave up and down in the waves, converting the vertical energy of the wave into power that is transmitted to shore by means of an undersea power line.

Another device known as the "Wave Dragon" is what they call a terminator. "Terminator devices basically intercept the wave and they don't let any wave energy go behind them, or very little energy go behind them," he explains. The Wave Dragon has a ramp for waves to surge up and, "spill water into the container. They create a higher level of water in the container than in the surrounding ocean, so that it can drain back through a hydroelectric turbine and generate power."

The Scottish company Ocean Power Delivery developed a snake-like device called the Pelamis, which absorbs energy from its bending hinges as waves pitch it up and down. "The Pelamis looks a bit like a broken pencil floating on the sea surface," Hagerman says. "It would orient itself — it would weathervane — so, as the waves flow along the device, energy is pulled out of the waves by the relative pitching of this broken pencil." The Pelamis falls into a group of wave power devices called attenuators.

"The technology has not only as much promise, but even more promise than wind energy," says Hagerman.

However, wave energy is nothing new. "There was an initial spurt of work in wave energy systems in the U.S. in the early 70's following the energy crisis," explains ocean engineer Malcolm Spaulding, from the University of Rhode Island. "The Department of Energy started investing, other people interested in power production started investing, and that happened around the world. What happened was that the power costs per kilowatt were really high."

Hagermans says it's interesting to see a new generation of wave energy devices in the water. "These devices are now in the water, but w'ere 20 years down the road and the world has consumed 20 years more worth of oil. And the impending gap between demand and production in fossil fuels in now coming closer," he says. "By 20 years further down the road we will need to have alternative sources of energy online or else we'll be totally dependent on oil from the Middle East."

image: Fugro OCEANOR

Unlike the killer tsunami that was caused by an undersea earthquake, ocean waves are created from the sun's energy. Unequal heating of the earth's surface produces winds, and winds blowing over water produce waves. "At each step in that process the form of solar energy becomes more and more concentrated," he explains. "There's an amplification factor of about ten in terms of how the energy gets concentrated.

Places like the west coasts of Europe and the U.S. have consistently large waves, making them well suited for harnessing wave power, while the eastern seaboard of America and the countries of southeastern Asia aren't prime areas for wave power.

In the future, "fields" of wave devices could be found in coastal waters off Oregon and California.

"And as they're deployed and installed, the cost of energy will come down and will be competitive with other alternatives," Hagerman explains.

He says this is an important time for the future of wave power, but the biggest test will be whether these devices can survive the power of nature. "It's sort of a watershed time," he says. "This is kind of a little bit of make or break in terms of these wave energy devices."

The state of Oregon seems to think it's a good bet. They are currently in the process of setting up a pilot wave power project to supplement their power supply.

A particular resource can't supply all of the energy we need," Hagerman says. "We're such an energy-thirsty civilization that we need them all… we need nuclear, and we need coal, and we need fossil fuels, and we need alternative and renewable resources. There is not one resource that will get us where we want to go."