THE PELAMIS ATTENUATOR
BY PELAMIS, EDINBURGH, SCOTLAND
THE INSPIRATION In the early 1990s, while sailing the notoriously rough waters off the coast of Scotland, mechanical engineer (and avid seaman) Richard Yemm spent a lot of time trying to solve one of wave energy’s most vexing problems: the tendency of big waves to destroy machines out in the open ocean. He engineered the Pelamis attenuator to survive such a battering. The device, which he designed in 1996 after completing a doctoral degree at the University of Edinburgh, nimbly adjusts its position in shifting seas by nose-diving straight into oncoming swells (much like a surfer does to reach the break). Thousands of pounds of sand and Styrofoam stuffed into its steel hull, paired with the same kind of mooring systems used in oil rigs, help stabilize the machine—smart engineering that greatly reduces damage to the attenuator itself.
THE MACHINE It looks like a floating missile, but this 500-foot-long tube of hollow steel is actually hinged in three places. Unlike most other wave energy devices, in which seawater comes into direct contact with turbines (which spin to create electricity), the attenuator’s mechanics are contained in a sealed joint. As waves travel the length of the machine, the attenuator bends and its hydraulic pistons compress—a movement that pumps oil into a pressurized reservoir (much in the way a bike pump pushes air into a tire). The oil is then released through a series of turbines at a constant rate.
THE OREGON CONNECTION Des McGinnes, an Oregon Wave Energy Trust board member and Pelamis’s business development manager, thinks Oregon’s seas could become the first in the United States to host a working attenuator farm. McGinnes has visited Oregon about 15 times to meet with state and federal agencies, manufacturers, utilities, and coastal communities, armed with specific (and confidential) proposals for wave projects—but Pelamis has yet to sign any formal agreement.
THE REAL WORLD Each device produces just 750 kilowatts of electricity, or enough for 500 homes. However, more than 100 attenuators can be packed into a single square mile of ocean, and the machines’ durability has investors ponying up cash: Pelamis has raised nearly $80 million, and European utility companies are placing orders. This month, Pelamis hopes to launch three devices off the coast of Portugal for a Portuguese energy company. By 2010, it plans to place four near Orkney, Scotland, for Scottish Power, and seven near Cornwall, England, for German energy company E.ON.