Scientists Can Convert Ocean Waves into Energy

By Ralph Birch

When it comes to finding alternate sources of renewable energy, researchers are not shy about making waves.

While most people think of solar and wind power as the best ways to generate clean energy, these methods do have downfalls. The sun only shines during the day, and wind is inconsistent, making it difficult to capture energy with regularity.

But waves are always crashing to the shores from our planet’s oceans, making wave-based energy a nearly constant resource.

How Does It Work?

Waves are created when wind blows across the water. On the surface, it looks like the water is bobbing up and down. Although the water may appear to travel from one place to another, it doesn’t actually move very far. The water moves in a circular pattern — up to the top of the wave and back down to the other side.

This pattern of movement occurs in very deep water, where the gently bobbing waves, known as swells, are prevalent. But the action of waves changes as they get closer to the shore.

As the water gets shallower, it’s no longer able to travel in circles because the ground gets in the way. Water bumps up against the ocean floor, changing the circular motion from the deep into more of an oval. The water hits the ground, causing the top of the wave to lurch forward faster than the bottom and crash on the beach.

Underwater Energy Collection

Wave energy systems use the movement of the water to create electricity. Some devices are designed to harness the power of breaking waves, while others can generate power from swells or the pressure exerted by the waves on the ocean floor. But all of them have the same goal — to convert wave energy into clean, electrical energy.

Because of transmission limitations like the length of cables used to transmit the electrical power, wave energy works best for communities located closer to the coast. About 40 percent of the world’s population lives within 60 miles of an ocean, which means a lot of coastal communities could be powered by wave energy.

The Coasts with the Most

Not all coastal areas are ideal for generating this type of power. The land beneath the ocean affects the size and shape of the waves. Additionally, wave energy converters are costly to make, so scientists want to place them in areas with plenty of wave action, but not where the converters could be damaged by a storm.

Australian scientists are using computer modeling to zero in on the best locations to place wave energy converters. Joao Morim Nascimento and Nick Cartwright, environmental engineers at Griffith University, used the models to find hotspots with the ideal traits for converter placement on the southeast coast of Australia. Each site they found is within three miles of the shore and no more than 72 feet deep.

“There is more than enough natural energy in the ocean,” Cartwright said. “The challenge is to harness and convert enough of it into power.”

Because of the promise shown by early wave energy research, the next step is to ensure that ocean wildlife and ecosystems won’t be harmed by the process.