Since 2007 Albatern, one of Scotland’s most radical wave energy companies, has been working on a new approach to wave energy harvesting. Their new WaveNET system uses an array of floating generators called Squids to harvest energy from the rise and fall of the ocean. Albatern has set a goal of creating a 1.25-kilometer-long energy farm floating at sea that could produce over 100 megawatts by 2024.
Squid units are designed to link up in groups, creating large floating grids that can take any form and be fitted anywhere in the sea. The same idea exists in the wind power market, where floating turbines can provide an alternative to heavier fixed bed systems. The great thing about Squids is that the bigger a grid gets, the more efficient the system will be, as it can exploit different wave movements to harvest more energy through increased motion. The squid units are relatively simple in operation. Each has a ballast pole at its center that is connected to buoyant floats. Each pivoting arm is connected to a fully articulating pump unit at either end. Any movement of the arms creates hydraulic energy in the pumps, which generates electric power.
According to Albatern, “Dramatic non-linear yield movements” are created from having large arrays spread across the water like nets. Any movement in the water body creates tension, flux and compression at unpredictable points, so stabilizing the array is of utmost importance. The upside of this instability is that power is extracted from a variety of different sea movements – roll, heave, surge and sway – making it extremely efficient. The power generated en-masse is collected at these flotation points and the electricity converted is drawn into a “power take-off” module where it is eventually transmitted to shore and ultimately to the grid. The system’s visual impact is minimal from the shoreline, since the Squids operate at water level. The cost of the energy is estimated at £100-150 (US$160 – $235) per MWh, which is more expensive than other renewables – but economies of scale should bring this down in time if these arrays are constructed in larger quantities. Albatern hopes to be operating grid-scale WaveNET systems within the next 10 years.