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Catch the Wave

WavePacific Gas & Electric’s (PG&E) pilot program for harnessing the power of the Pacific.

Last week the Federal Energy Regulatory Commission ( FERC) issued a preliminary permit for PG&E’s Central Coast WaveConnect pilot program off the coast of Santa Barbara, California.  This is the second location selected in California for participation in a study of the offshore environment and to determine the feasibility of a wave energy facility.

This preliminary permit will allow a baseline study of the offshore environment with an area of approximately 16 miles long and 3 miles wide.  This permit allows no construction or disturbance of research site and surrounding area, and is only used to determine if the site is suitable for construction. This new site has high quality wave energy resources with swells from the north and south is conveniently located to existing energy transmission infrastructure, located at Vandenberg Air Force Base, and avoids protected, sensitive marine habitats.

This non-invasive study will examine the topography of the ocean floor, and both the onshore and offshore ecosystems to help determine the environmental impact this new technology might have on the environment.  If the pilot program is successful, construction of the equipment for the offshore wave project will begin in 2015 with the implementation set for 2020.

Generating electricity from the the motion of the ocean, by capturing the energy directly from surface waves or from pressure fluctuations below the surface, isn’t a new idea, but the engineering necessary to bring the concept to functionality is lagging far behind the vision.  With California’s state mandate that 33% of it’s energy be produced by alternative sources, by 2020, wave energy production on the central coast, might not make the deadline, but will become part of an energy strategy that  is clean, sustainable  and renewable.

Waves are caused by the wind blowing over the surface of the ocean. In many areas of the world, the wind blows with enough consistency and force to provide continuous waves. There is tremendous energy in the ocean waves and while attempts have been made, harnessing wave energy isn’t widely employed.  Wave power devices extract energy directly from the surface motion of ocean waves or from pressure fluctuations below the surface. Wave power varies considerably, but this golden state location offers a potentially consistent source of energy production, given the turbulent waters in this area.

Currently six types of wave technology methods exist, but only 3 basic methods are currently implemented at this time.  Each is designed to be installed onshore, offshore or deep offshore (approximately 131 feet offshore).  Each of these technologies differ depending on their position to the waves, their interaction with them and how they collect, convert energy to electricity and how transmission to the grid takes place.  The following wave technologies are the latest in researched wave technology.

There are three basic methods used for converting wave energy to electricity:

  • Point absorbers are a float or buoy system that use the up and down motion of ocean swells to drive hydraulic pumps. These objects can be tethered to a floating buoy or anchored to the ocean floor. A series of anchored buoys rise and fall with the waves. The movement "strokes" an electrical generator and makes electricity that is then shipped ashore by underwater power cable and can then be added to the electrical utility grid.
  • Oscillating water column devices are a form of point absorbers, in which the in-and-out motion of waves at the shore enter an opening and force air to turn a turbine. The column fills with water as the wave rises and empties as it descends. In the process, air inside the column is compressed and heats up, creating energy the way a piston does. That energy is then harnessed and sent to shore by electrical cable.
  • An attenuator is a long, segmented, floating, device that works parallel to the wave direction and basicaly ride the waves. Movements along its length causes flexing where the segments connect.  This flexing is connected to hydraulic pumps or other converters.  It has a lower area parallel to the waves in comparison to a terminator, so the device experiences lower wave forces, therefore producing less energy.

The world's first commercial wave farm is based in Portugal, at the Aguçadoura Wave Park, which consists of three, 750 kilowatt Pelamis devices, which according to the company, “The Pelamis Wave Energy Converter is the result of many years of engineering development by PWP. It was the world’s first commercial scale machine to generate electricity to the grid from offshore wave energy and the first to be used commercially.”

This project has been generating and exporting energy to the local grid off the Atlantic coastline of Portugal since September, 2008.  The The Pelamis wave machine was developed by the Scottish company Pelamis Wave Power, using the attenuator system to deliver enough power to meet the average electricity demand of more than 1,500 Portuguese homes.

With proven projects in place, only time will tell if this location off the coast of Santa Barbara will be a viable location for offshore energy production. While environmentalists and PG&E support alternative energy development, wave energy is a difficult if not costly process, due to the severe pressure of the ocean and salt on the equipment needed to harness and process energy.  The life span of the systems and devices are short and increase the costs of energy production.

According to Megan Birney, Community Environmental Council’s renewable energy specialist, “We look forward to working with PG&E and the community to better understand any potential benefits and risks associated with Central Coast WaveConnect, and to see if this project could be a part of the solution.”

With increased research this emerging technology will become just one of many sources of clean and renewable energy here in Santa Barbara and around the globe.

©Spark Interactive Inc.

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