Water Works

If you've ever beewo the beach, then you've felt the force of the ocean. Waves knock you over and toss you around. The tide drags at your feet. If only we could only put some of that energy to work...

People have used the power of moving water in rivers and waterfalls for thousands of years. And now, scientists are dipping into the ocean to provide electricity to people around the world.

Waves and tides keep the ocean in constant motion. Why not tap into some of that energy?

Rocking, Rolling Waves

Wave power is the new wave in water power research. As wind blows across open ocean, it causes swells that rhythmically rise and fall. The height of each wave, its length, and how fast it travels determine how much power it carries. Strong and abundant waves, such as those off the coast of Oregon, work best to provide the most power.

For some time now, engineers have been inventing and designing devices called wave power generators that transform the energy of ocean waves into electricity. The generators bob offshore, where the wave motion is active, but close enough to send the electricity back to land.

Wave power generators create electricity, and power cables transfer the electricity along the ocean's floor, under the beach, and then to what's called a transmission grid. From the grid, the power can reach nearby homes or businesses.

One wave power generator, called the Pelamis, will soon snake over the ocean's surface off the coast of Portugal. This is the first wave power site in the world to actually sell electricity from waves to people nearby. Eventually, the Portuguese government plans to install enough Pelamis models to cover about half a mile of ocean and create electricity for 20,000 homes.

Turning, Churning Tides

The gravitational pull of the moon tugs bulges of water back and forth, every day, around the world. We call this movement tidal flow. The tide rushes in and out, day after day, in a regular, predictable pattern, which makes it an ideal source of renewable energy.

Oceans and rivers meet at the river's mouth. The funnel shape of many river mouths increases the rush of the tides. This makes river mouths ideal sites for tidal power generators.

Small tidal power generators were installed last year in the mouth of New York City's East River. They're powering a nearby supermarket and parking garage. If everything works as expected, the company will install 300 generators-enough to power 8,000 homes. The city of San Francisco also plans to place tidal generators in the rushing waters of San Francisco Bay.

Waves of the Future

Of course, working in an ocean comes with challenges. Power generators need to float where waves swell with the most force and tides pull the strongest, without blocking shipping routes and fishing areas or harming the local environment. Plus, the technology is so new that the electricity produced is still expensive. Storms can be damaging, and some waves, called rogue waves, are freakishly high and strong. So wave power generators have to be built tough. Plus, salt water eats away at metal and can destroy all this expensive equipment. Wave power companies have learned from the builders of offshore oil rigs about special coatings to protect metals from salt water.

Researchers are testing these new technologies around the world. Ocean power projects exist in the United States, Portugal, England, and Australia. How well do the designs survive in the ocean? How efficiently do they create electricity? Can they be built without costing too much money? Are there any challenges in transporting the energy to shore? Do the blades on tidal generators kill sea life?

Energy engineers are hopeful about the future. Waves and tides contain a tremendous amount of energy, enough to supply about 10 percent of the world's energy needs.

Copyright Carus Publishing Company Apr 2007
Provided by ProQuest Information and Learning Company. All rights Reserved