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Humboldt Wave Energy

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Wave energy has the potential to be a major contributor to the supply of economic, renewable energy in California. Currently Pacific Gas and Electric Co. (PG&E) is exploring the feasibility of harnessing wave energy off the coast of California. The PG&E website states that, “Studying the potential of ocean wave energy is important to California's environmental future and the ongoing discovery of sustainable, renewable energy sources.” This page is dedicated to the PG&E's work off the coast of Humboldt County in Northern California. To read more about wave power see the Wikipedia article on wave power.

Introduction[edit]

Pacific Gas and Electric Co. began studying the feasibility of wave power off the coast of Northern California in 2007. Initially, two sites were considered; one off of the coast of Mendocino County, and one off the coast near Fairhaven. This study led to a proposal in 2009 called the Humboldt WaveConnect™ pilot project, whose purpose was to research and develop potential sources of wave energy. Project construction was set for the Summer of 2012, with operation commencing in 2013, and decommissioning of installed structures in 2018/2019. [1]

Humboldt WaveConnect™ Pilot Project[edit]

The WaveConnect™ Program was introduced by PG&E in 2009.[2] Part of the program proposed a pilot study to be conducted three miles off the coast of Humboldt County, near Fairhaven. The preliminary permit was for a region between two and four miles off the coast, stretching between Arcata and Table Bluff. This area represents 136 square miles, but would be narrowed down based upon technical, environmental, and economic constraints. This permit allowed PG&E to conduct studies only, not construction, exclusion, or any physical disturbance. Further permitting would be required before construction. [3]

In total, the pilot project would be composed of up to four separate arrays with a maximum of thirty installed wave energy conversion (WEC) structures. PG&E planned to test a variety of types of generator technologies, and the installation would have a total expected output of 5MW. A sub-sea cable would connect these arrays to an onshore power conditioning unit, and feed into the grid at the Fairhaven substation at 12kV.[4]

Technology[edit]

Several different types of technology were to be used in the pilot project. Wave energy is a new frontier for renewable energy and consequently PG&E wanted to try several different approaches to harness the energy. A maximum of four wave energy converter technologies were to be selected for the study location, each with an array of one or more devices.[5] [6] [7]

Attenuator[edit]

Attenuators are long, multi-segmented structures that float parallel to the direction of the wave. As a wave passes, it causes the structure to bend at the segments. This bending motion is converted to electricity.

Point Absorber[edit]

Point absorbers are floating structures that have that are moved by wave action. One component is moved by the wave while the other is stationary. This relative motion drives devices that convert movement into electricity.

Oscillating Water Column[edit]

Oscillating Water Column devices extend perpendicular to the direction of wave travel and capture or reflect the power of the wave. Water enters through a subsurface opening into a chamber with air trapped above it. The wave action causes the captured water column to move up and down forcing the air though an opening connected to a turbine.

Oscillating Wave Surge Converter[edit]

Oscillating Wave Surge Converter's (OWSC's) operate somewhat differently than other technologies. Unlike most, which move vertically with the waves, OWSC's oscillate horizontally (parallel to the motion of the wave). These structures are typically used closer to shore (10-20m). [8]

Challenges[edit]

  • New technology
  • Developing regulatory framework
  • Uncertainty of environmental effects [9]
  • Conflict with existing uses
  • High Costs[10]
    • PG&E estimated the cost of installing the infrastructure for power transmission, monitoring, and other equipment to be $50 million.
    • Operation and maintenance cost of the project was estimated at $5 million annually. This cost excludes the expense of carrying out environmental protection measures.

Suspended[edit]

The proposed Humboldt WaveConnect™ pilot project was suspended in Fall 2010. The main reasons for canceling the project were that the costs rose above the level of expenditure that the company could justify and a lack of available technology.[11]The cost of securing government permits, installing the prototypes, and building the infrastructure needed to bring the power to shore made the project unfeasible.[12]

Future Projects[edit]

PG&E is currently studying the feasibility of the Central Coast WaveConnect project off the coast of Santa Barbara County. PG&E filed for a FERC permit in December 2009 for this site, which could have a capacity up to 100 MW. The permit was granted in May 2010.

References[edit]