Efforts to harvest energy from ocean have a long history with the earliest known patent being filed in 1899. To date these efforts have not resulted in any notable commercial success. A Scottish company called Pelamis Wave Power did install 2.25MW worth of grid connected wave generation off the shore of Portugal in 2008. After four month’s of operation the three wave generation units had to be towed into shore because of technical problems. In the wake of the 2008 financial crisis a decision was made to permanently close the plant, and Pelamis has since gone bankrupt.
Now an Australian company called Carnegie Clean Energy Limited (formerly Carnegie Wave Energy Limited) claims to have developed a wave energy system which they state has levelized electricity costs similar to off shore wind and which is ready for commercial deployment. This wave energy converter takes the form of a flattened cylindrical buoy which sits submerged one to two meters beneath the ocean’s surface. The buoy is moored to a concrete foundation on the oceans floor by a tether. The up and down motion of the buoy in the waves drives a hydraulic pump/generator system. The electrical current is routed through a subsea electrical cable to the shore. The latest generation of Carnegie’s wave energy harvester called Ceto 6 (The name is taken from a Greek sea goddess.) is a 20 meter diameter 1MW unit. This unit has not yet been deployed in a working installation, but three 240kW Ceto 5 units have operated for 14000 hours over four years at an island site in western Australia.
In this presentation Carnegie says they will install the first CETO 6 unit at their west Australian test site in 2017. They also have a commercial installation in the pipeline which will be installed off the coast of Cornwall in the United Kingdom. A single CETO 6 unit will be installed in 2018 and 15MW follow on build is scheduled for 2021 with an estimated capex of £60m. If convert pounds sterling to US dollars the capex works out to $5/watt which is not cheap but not outrageous for an initial build. Carnegie also claims that they have a clear technical path to lower costs in future versions of the CETO design.
Of course the real levelized costs will depend on how well the CETO converter performs in the long term in the ocean environment including their ability to withstand corrosion and to withstand storm damage. Even if CETO performs up to expectation the road to volume production will be a long one. A lot of field data on performance and reliability will be required before potential customers are going to lay out their hard earned cash.
Carenegie changed their from Carnegie Wave Energy to Carnegie Clean Energy because they have decided to enter the solar energy/energy storage markets via acquisition of the company Energy Made Clean. Pursing an alternate revenue stream in a better established market is probably a good idea. A startup company trying to to market a single new technology generally faces a long hard struggle even if they have top flight engineering.