An alternate energy company Albatern, located in Scotland is trying to put a new modular spin on renewable energy generation. WaveNET is a scalable array of generator units that are like floating “Squids”, harvesting energy from the waves as their buoyant arms rise and fall with the motion of the waves. Each Squid can link up to at most three others creating a larger, more efficient grid that’s flexible in every direction and can harvest more energy from different wave movements. Albatern’s 10-year target is to have 1.25 kilometer-long farms of floating generators that will be able to pump out as much as 100 megawatts by 2024.
Each Squid unit in the WaveNET array acts as a central balancing pole, surrounded by three other buoyant floats that will connect to the central post with linking arms. The linking arms connected to the central post are attached using an articulating pump unit at each end, thus any movement of the arms causes the pumps to create hydraulic energy.
At the floatation points, the Squid units can be connected to one another. Albatern has discovered that working with a large array for this task gives you “dramatic non-linear yield improvements.” Imagine a three dimensional plane and three points X, Y and Z in the plane, floating as on the surface of the sea. Now with every wave, the points are pushed together, pulled apart and moved independently relative to one another – and for each movement these points are generating energy. This is the concept behind WaveNET.
Using a hydrostatic transmission system, the hydraulic energy generated by each one of the linking arms is gathered at a central point as the system is common and converted into electrical energy using a “power take-off” module, and from here the electricity can be transferred to the shore. Since the WaveNET system is set up as an array, the energy can be extracted from five of the six degrees of wave movements like pitch, roll, heave, surge and sway. Due to the flexibility of the array and its connection to the ocean floor at multiple points, the system resists damage from large waves.
As most of the action takes place underwater, the only visual impact of a WaveNET is a group of floating yellow buoys. The dimension of each individual Squid unit in current WaveNET testing off the Scottish coast is 6 meter (20ft) tall central ballast pole, and can generate up to 7.5 kW. Next in plan is the 12-metre version that will be able to generate up to 75 kW, followed by a giant 24-metre Squid that can generate up to 750 kW.
Albatern believes that within 10 years, it can build a 100-megawatt WaveNET generator using an array of 135 of the 24-metre Squid units, with a (1250 x 250) meter total area (4101 x 820ft). The cost of energy estimated is £100-150 (US$160 – $235) per MWh, which is higher than other renewable energy sources like solar and wind at this stage.
In offshore businesses, Albatern sees its immediate market – oil rigs, aquaculture outfits and remote communities that are far from other sources of power but close to rough seas. But the eventual goal is to operate large grid-scale operations in the coming 10 years.