Dawit Welderafael Jonathan Lester Wave Power Dawit Welderafael Jonathan Lester

Wave Power Differential warming of the earth causes pressure differences in the atmosphere, which generate winds As winds move across the surface of open bodies of water, they transfer some of their energy to the water and create waves World Energy Council, “Wave Energy,” available at http://www.worldenergy.org/wec-geis/publications/reports/ser04/fuels.asp?fuel=Wave%20Energy Tom Heath, “Realities of Wave Energy,” available at http://www.wavegen.co.uk/pdf/art.1727.pdf

Wave Power Wave power is practically in practically inexhaustible and classified as a renewable energy source. Wave energy can be extracted and converted into electricity by wave power machines. They can be deployed either on the shoreline or in deeper waters offshore.

Wave Power Wave energy fluxes in open sea or against coasts may vary from a few watts to kilowatts per meter. In favorable locations, wave energy density can average 65 megawatts per mile of coastline. The total power of waves breaking on the world's coastlines is estimated at 2 to 3 million megawatts. The cost/ kwh is 10-30 cents

How to create Electricity ?

Wave Power There are many ways to create Electricity 1.Float or Pitching Device or buoyant moored device 2.Oscillating Water Columns (OWC)

1.Float or Pitching Device or buoyant moored device The device floats on or just below the surface of the water and is moored to the sea floor. A wave power machine needs to resist the motion of the waves in order to generate power: part of the machine needs to move while another part remains still.

1.Float or Pitching Device or buoyant moored device In this type of device, the mooring is static and is arranged in such a way that the waves motion will move only one part of the machine. Electricity is generated from the bobbing or pitching action of a floating object which can be mounted to a floating raft or to a device fixed on the ocean floor. http://youtu.be/F0mzrbfzUpM

2.Oscillating Water Column As a wave enters the collector, the surface of the water column rises and compresses the volume of air above it. The compressed air is forced into an aperture at the top of the chamber, moving past a turbine. As the wave retreats, the air is drawn back through the turbine due to the reduced pressure in the chamber. Alternative Fuels, “Ocean Power: Waves,” available at http://irishfuelprices.com/alternativefuels/wave.html Research Institute for Sustainable Energy, “Wave Energy,” available at http://www.rise.org.au/info/Tech/wave/index.html BBC News, “How it Works: Wave Power,” available at http://news.bbc.co.uk/1/hi/sci/tech/1032148

Oscillating Water Column The turning of the turbine drives a generator, producing electricity! Research Institute for Sustainable Energy, “Wave Energy,” available at http://www.rise.org.au/info/Tech/wave/index.html

Advantages & Disadvantages of Wave Power

Advantages A much greater extent of power is concentrated in the motion of waves than in the movement of air. Whereas the power density at a good wind energy site may be of the order of a few square meter, the power density in a corresponding area of wave motion may be up to 100 times greater. It produces no greenhouse gases or other waste. It needs no fuel.

Advantages….. Wave energy has this advantage over wind or solar energy that the energy has been naturally concentrated by accumulation over-time and space and transported from the point at which it was originally present in the winds. Wave power devices do not use up large land masses like solar or wind. It produces electricity reliably. It is free and renewable energy source.

Advantages….. These devices are relatively pollution free, and because they remove energy from the waves, the water is left in a relatively placid(calm) state in their wakes.

Disadvantages The major disadvantage of wave energy, as compared to wind, is that the energy is available in the ocean. Therefore the extraction equipment must operate in a marine environment which will have to be taken into account during its construction and its maintenance ,lifetime and reliability should be considered since the energy may have to be transported through a great distance to the shore.

Disadvantages… There is relative scarcity of accessible sites of large wave activity. Wave energy conversion devices that have been proposed are relatively complicated . Economic factors such as the capital investment, costs of maintenance, repair and replacement as well as problems of biological growth of marine organisms which seem to be very large, are all relatively unknown.

Disadvantages… Wave energy converters must be capable of withstanding very severe peak stresses in storm.

History The first known patent to use energy from ocean waves dates back to 1799 and was filed in Paris by Girard and his son.  An early application of wave power was a device constructed around 1910 by Bochaux-Praceique to light and power his house at Royan, near Bordeaux in France. It appears that this was the first oscillating water-column type of wave-energy device. From 1855 to 1973 there were already 340 patents filed in the UK alone.

History… Modern scientific pursuit of wave energy was pioneered by  Yoshio Masuda's experiments in the 1940s. He has tested various concepts of wave-energy devices at sea, with several hundred units used to power navigation lights. Among these was the concept of extracting power from the angular motion at the joints of an articulated raft, which was proposed in the 1950s by Masuda.

Wave Power in the World The World Energy Council has estimated that approximately 2 terawatts (2 million megawatts), about double current world electricity production, could be produced from the oceans via wave power. It is estimated that 1 million gigawatt hours of wave energy hits Australian shores annually and that 25% of the UK's current power usage could be supplied by harvesting its wave resource.

Wave Power The strongest winds blow between 30˚ and 60˚ in latitude. Western coastlines at these latitudes experience the most powerful waves. Robert W. Thresher, “Wave and Tidal Energy: What’s Happening?” available at http://www.mms.gov/offshore/PDFs/WaveTidal%20Energy_1-RobertThresher.pdf World Energy Council, “Wave Energy,” available at http://www.worldenergy.org/wec-geis/publications/reports/ser04/fuels.asp?fuel=Wave%20Energy Tom Heath, “Realities of Wave Energy,” available at http://www.wavegen.co.uk/pdf/art.1727.pdf, last visited . Global Wave Energy Resource Distribution (measuring the amount of power in kW contained in each linear meter of wave front)

Rhode Island – Energetech’s GreenWave Project Energetech proposed constructing an OWC similar to that in Port Kembla off the coast of Rhode Island – called the GreenWave project Analysis has shown the area to be an ideal location due to local wave and geological structure, proximity to the power grid, and ease of installation Alternative Consumer, “Rhode Island Wave Power Plant Caught Up in Red Tape,” available at www.alternativeconsumer.com/2007/03/24/rhode-islands-wave-power-plant-caught-up-in-red-tape

Rhode Island – Energetech’s GreenWave Project The structure would have a generating capacity of 500 kW, enough to power 300 homes The project is not for profit, but to demonstrate the commercial viability of wave energy technologies Energetech intended the device to be operational in 2006, but the project is currently caught in the regulatory red tape U.S. Department of Energy, Energy Efficiency and Renewable Energy, “Rhode Island Launces Wave Energy Pilot Project,” available at http://www.eere.energy.gov/states/state_news_detail.cfm/news_id=8628/state=RI

sources http://www.eere.energy.gov/states/state_news_detail.cfm/news_id=8628/state=RI http://en.wikipedia.org/wiki/Wavepower www.alternativeconsumer.com/2007/03/24/rhode-islands-wave-power-plant-caught-up-in-red-tape http://www.mms.gov/offshore/PDFs/WaveTidal%20Energy_1-RobertThresher.pdf

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