Imagine this: It's a beautiful, sunny day at the beach. The waves are rolling in, 2- to 4-foot sets, glassy and perfect. Just a few other surfers share the lineup, loving life. At the same time, just a few miles off shore, snake-like machines are riding those same swells, passively generating electricity.
If you think waves are just for surfing, the Pelamis Corporation would like you think again. Founded in 1998 with the aim of developing the first viable wave-energy farm, the Pelamis Wave Energy Converter can now be found in action at the Agucadoura wave farm, five kilometers off the northern coast of Portugal. Here, three of the 140-meter long, 3.5-meter wide cylindrical machines can be seen riding the passing swells. They use energy from the waves to power internal hydraulic motors, which drive generators that create electricity. The power is then fed down a cable to the ocean floor which links to the shore, feeding into the cityís power grid. Presto, wave energy powering near-by homes.
Each Pelamis Wave Energy Converter can conceivably power approximately 500 homes per year, depending on the wave action. It sounds like an ideal solution to the energy crisis, but to some critics, the biggest problem with this technology is its scale. Production of 30 megawatts of energy requires 1 square kilometer of ocean surface to house 40 machines. Considering that a city like Los Angeles uses 13 gigawatts of energy, a sufficient wave farm would have to cover the surface area of 256 square kilometers of ocean. It's hard to justify tying up such a vast swath of ocean. If, however, this technology is used in combination with other alternative energy solutions, it could prove to be a very viable piece of the renewable energy puzzle.
What does this mean for Hawai'i? For starters, we have some of the most powerful waves per square meter in the world. Then, consider that each of our islands operates on a stand-alone energy system. With these smaller pockets of energy consumption, a reasonably sized wave farm could provide a considerable portion of each island's energy needs.
There are some exciting plans in the works already for wave energy farming in Hawai'i. On Maui, the Australian company Oceanlinx Ltd. has announced a plan to farm wave energy for the island with a patented system similar to the Pelamis model. It uses rising and falling sea swells to push a turbine and create electricity. They say this system could be in place off the northeast coast of Maui by 2011, providing up to 2.7 megawatts of energy for the island. The Office of Naval Research is testing another experimental system using buoys outside of Kane'ohe Bay. The traditional buoy shape allows an internal generator to create energy using the up and down bobbing motion. HECO is currently helping with the transfer of the energy to shore.
When it comes to renewable energy, there is no one right answer. The future will likely be composed of a combination of technologies suited to a variety of climates and the renewable resources available there. Fortunately for us, Hawai'i enjoys an abundance of all things renewable: wind, sun and surf. So the next time you're in the lineup waiting to catch the perfect wave, just think of all that usable energy rolling past you. That's energy that could one day soon help to power our lives, fossil fuel free.