|Operating principle of the Finavera AquaBuOY. Click to enlarge.|
Pacific Gas and Electric Company (PG&E) has entered into a long-term, two megawatt (MW) commercial wave energy power purchasing agreement (PPA) with Finavera Renewables Inc., the developer of the AquaBuOY wave energy converter. (Earlier post.) This marks the first commercial wave energy power purchasing agreement in the US.
Finavera Renewables has initiated development plans for the two megawatt wave energy project to be constructed approximately 2.5 miles off the coast of Humboldt County, California for electricity delivery to PG&E's customers throughout its northern and central California service territory.
The power purchase agreement calls for 3,854 MWh of clean, renewable electricity to be delivered annually to PG&E over the term of the contract. The project is expected to offset greenhouse gas emissions by displacing an estimated 245 tons of carbon dioxide annually.
During the next two to three years of the permitting process, the overall project design and detailed specifications will be submitted to and evaluated by local, state, and federal regulators and community stakeholders including fishermen, recreational boaters and environmental groups to understand the siting, safety and environmental impacts of the wave energy plant. The licensing process will include all required environmental studies such as impacts on local fish habitat, marine mammal migration routes, and commercial and recreational fishing zones.
The Finavera AquaBuOY is a floating buoy structure that converts the kinetic energy of the vertical motion of oncoming waves into electricity. The AquaBuOY is categorized as a point absorber—having a small dimension in relation to the longer wave length in which it is operating. It utilizes a cylindrical buoy as the displacer and the reactor is a large water mass enclosed by a long vertical tube underneath the buoy.
Energy transfer takes place by converting the vertical component of wave kinetic energy into pressurized seawater by means of two-stroke hose pumps. The pressurized seawater is directed into an energy conversion system consisting of a turbine driving an electrical generator. The power is transmitted to shore by means of a secure, undersea transmission line.
Clusters of these modular devices will be moored several kilometers offshore where the wave resource is the greatest. The wave power projects are scalable from hundreds of kilowatts to hundreds of megawatts, according to Finavera.
In addition to PG&E’s agreement with Finavera Renewables, PG&E independently filed permit applications with the Federal Energy Regulatory Commission in February 2007 to develop generation projects that could convert the abundant wave energy off the coast of Mendocino and Humboldt Counties into electricity.
Named “WaveConnect,” these projects are currently undergoing initial resource, environmental, and ocean use assessments. If developed, the WaveConnect projects would use wave energy conversion (WEC) devices to transform the energy of ocean waves into clean, renewable electricity. PG&E submitted the first application in North America for a project that will allow multiple WEC device manufacturers to demonstrate their devices on a common site, which could help accelerate the development of wave energy technology. (Earlier post.)
Energy from Tidal, River, and Ocean Currents and from Ocean Waves (EPRI, Virginia Tech)