Methods of Harnessing Electricity from Ocean Waves with Wave Power Generators

Imagine sitting on a sunny, warm beach in Florida watching surfers ride the waves. After pulling some tricks, a wet-suit wearing surfer with earrings and shaggy blond hair starts paddling to the shore. When he reaches the beach, he looks at you and says, “Dude, that was a 400 kilowatt wave”.

It’s a silly scenario, clearly, but it asks an interesting question: can we harness the power of moving waves to create electricity? The answer is a resounding yes.

In September of 2008, the world’s first commercial wave farm opened in northern Portugal. Located three miles offshore, the Aguçadoura Wave Park consists of three long red tubes called Pelamis Wave Energy Converters. Together, they are capable of generating 2.25 megawatts of electricity, which is enough to power over 1,500 Portuguese homes.

The Pelamis generators work by using the machine’s motion at joints to move hydraulic pumps connected to generators. For example, consider a long rope stretched across a tub of water. As the water in the tub rolls back and forth, the string bobs up and down. That bobbing motion, in the Pelamis machines, turns an electricity-producing generator.

Wave energy has some significant advantages. It is a virtually emission-free energy source; thus, no harmful chemicals are released into the environment. Also, the environmental impact is relatively low. Compared to solar and wind farms, which use many acres of wildlife habitat, wave farms barely disturb ocean ecosystems. Finally, there are vast stretches of ocean in which to place wave generators.

There are also some drawbacks, too. Wave power is very expensive and won’t be competitive with other power sources until the cost is reduced. Wave energy machines are also subject to the extreme environmental forces of oceans. A successful device would have to be resistant to both intense storms and saltwater corrosion.

Today, the Aguçadora plant is the only wave farm in the world. However, there are plans to build a farm with four Pelamis devices off the coast of Scotland and plans for a “wave hub” in Scotland. The wave hub will be like a giant extension cord with four “outlets” for wave generator arrays. Four companies, including Pelamis Wave Power, plan to plug in to this marine power station. The cord will then take the electricity generated by the arrays back to the Scottish grid.

Hopefully, there will be many new ideas and inventions for wave energy production in the near future. The current focus on wind power, solar power, and clean coal has subtracted from work on wave devices, but interest and funding has increased over the past few years. Just imagine plugging in a toaster oven and realizing that you can follow the cord four hundred miles to the bottom of the sea floor.