New inventions and innovative approaches are burgeoning.In the ocean energy field, new inventions and innovative approaches to generating electricity from ocean waves are burgeoning. A quick Internet search will identify dozens of devices, some which have been tested at sea and others which are still on the drawing board.
Previously, Maui Weekly printed some articles describing how oscillating water column (OWC) devices worked. OWC is the type of system used by Oceanlinx, the company which has proposed a wave power plant off Pa‘uwela Point on Maui’s North Shore. Other articles mentioned some wave demonstrations on O‘ahu and a snake-like device called Pelamis, which is being commissioned in Portugal for what would be the world’s first, multi-unit, commercial wave power plant.
There are many other approaches to tapping wave energy. Consider the “overtopping device,” which allows waves to run up a slope into a reservoir above sea level. The water is then released through a turbine, similar to a standard hydroelectric system. Overtopping devices can be built into coastlines, or they can be at-sea power plants. An example of the latter is the Wave Dragon, a Danish design that was demonstrated for 21 months at sea before a mooring was damaged in a 2005 storm.
Another method of converting energy from ocean waves uses linear generators. Are you familiar with those “forever flashlights” which you shake up and down? That’s the concept behind linear generators—as the waves make a floating device bob up and down, electricity is generated. Some of these devices are designed to be semi-submerged and work with deep ocean swells, while others bob on the surface, responding to wind waves.
There are also wave energy converters that work like giant flaps, waving back and forth (or up and down) with the motion of the sea.
There’s another, the AquaBuOY, which uses a flexible “hose pump” that contracts when stretched and broadens in diameter when shortened (the stretching and shortening are responses to the motions of a buoy), pumping water through the system.
A number of these devices have been accepted for testing and demonstration at sites around the world, as mentioned in previous articles. The AquaBuOY, for instance, has received preliminary and conditional licenses from the Federal Energy Regulatory Commission for several projects off the West Coast and has been selected by the California utility Pacific Gas & Electric to provide two megawatts of power.
As wave energy technology matures, some of these innovative designs will prove to be superior to others. Meanwhile, the creativity is inspiring!
In partnership with the state’s energy office, the Maui Weekly provides this feature to help Valley Isle homeowners reduce their utility bills and increase their environmental awareness.