The Perth Wave Energy Project has demonstrated that the CETO 5 wave energy generators, developed by Carnegie Wave Energy Limited, are capable of using the movement of the ocean to provide electricity to a naval base near Garden Island in Western Australia. The site is the first commercial ocean wave energy installation. It has channeled zero-emissions energy from three CETO 5 units into a functioning power grid for 14000 cumulative hours.
And even as Carnegie puts its CETO 5 system to the test off Garden Island, work on a next-generation system is well under way. CETO 6 is so fundamentally different, it’s enough to make you wonder why the company bothered spending A$32 million to do the quite modestly sized 720-kilowatt CETO 5 project.
CETO 5 and CETO 6 do have a point in common: They both use submerged buoys – “buoyant actuators” in the argot – that drive pumps. Being submerged protects the seascape and keeps the actuators from the most violent ocean action, but a tradeoff is less energetic water.
With CETO 5, the actuators are tethered to pumps on the seabed. As the actuators move up and down in the passing waves, the pumps send high-pressure water through a pipe to an onshore power station where generators produce electricity.
But the many drawbacks of building and maintaining onshore-generation are evident in the rationale Carnegie gives for CETO 6, which won’t send water ashore and instead will produce electricity at the buoy and deliver it shoreside via cable.
The CETO 5 system consists of three 240-kilowatt units (the energy it produces is sold at an undisclosed price to a military base on Garden Island). The system was built with A$13 million in assistance from the government’s Renewable Energy Agency (ARENA). Ottaviano says Carnegie needs to scale up its system in order to become economical, and the company has apparently concluded that wasn’t going to happen with onshore power generation.
The “buoyant actuators” that are 11 meters in diameter for CETO 5 will be 20 meters in diameter for CETO 6, increasing generating capability to 1 MW apiece, Carnegie says. The plan is to deploy the CETO 6 system offshore from Garden Island, as with CETO 5, but about 11 kilometers out at sea instead of 3 kilometers, in deeper waters said to be three times more energetic.