Renewable energy comes in many forms, with sunlight, wind, and flowing water being the most common. There is also an enormous amount of untapped energy in ocean waves. The US Energy Information Administration says the theoretical annual energy potential of waves off both coasts of the United States is 64 trillion kilowatt-hours — equal to more than 60% of the total amount of electricity generated in America in 2018.
Ocean Energy has spent the past 10 years designing systems to capture the energy contained in ocean waves and converting it into electricity. Its latest creation, called OE35, is the culmination of everything the company has learned in that time. Weighing 826 tons, it is essentially a sealed chamber that floats on the surface of the ocean. As waves pass beneath it, they force air upward in the chamber. That moving column of air spins a turbine that generates electricity. The beauty of the Ocean Energy technology is that it also harnesses the energy of the air column as it flows back into the chamber as a wave passes on. Think of it as a compound steam engine that makes power as its piston moves in both directions.
The concept is little different in principle than the one proposed by ShipEco Marine which proposes to cut large holes in the bottom of old oil tankers to take advantage of the same wave-activated compressed air column. Whether its idea is realistic or practical remains to be seen. The ocean has unimaginable power, with wave heights in storms often reaching 60 feet or more. Whether or not an old oil tanker with holes cut into it bottom could survive the rigors of such storms is open to conjecture.
That’s what sets the Ocean Energy OE 35 apart from other concept systems. It has been engineered specifically to withstand the constant assault of wind, waves, and salt that will batter it every hour of every day. The first prototype has left the west coast and it being towed across the Pacific to the US Navy Wave Energy Test Site in Kanehoe Bay, Hawaii where it will be evaluated for 12 months. If it passes its sea trials, the company plans to build five more units and deploy them in the Oregon Wave Energy Test Site near Newport, Oregon.
“The OE Buoy is designed around the science of an oscillating water column,” Ocean Energy tells Digital Trends. “The buoy is shaped like an ‘L’ with a long open chamber that sits below the water line, and a turbine above the water. As water enters the open chamber it forces air upward, which turns the turbine, generating electricity. When the water recedes, it creates a vacuum and air rushes in to fill it, keeping the turbine spinning, and the cycle repeats.” The Wells turbine that makes all this possible is the only moving part of the OE 35. “The beauty of the OE design is its simplicity. Having only a single moving part substantially increases its reliability in the often hostile ocean environment,” the company says.
Is there a future for ocean wave power generation? Ocean Energy certainly thinks so. Each OE 35 unit will be capable of generating enough electricity to power a small town. Unlike offshore wind turbines, it is extremely simple and robust, making it able to survive years at sea with little to no maintenance. And unlike wind and sunlight, waves hardly ever stop. Wave generators may never be as popular as offshore wind but they could be an important additional source of renewable energy in areas of the world where wind turbines and solar power are not feasible. Going forward, the world will need all the renewable energy it can get.