Wave+Energy

Julia Wai, Hayley Conacher, Emma Halupka

= Wave Energy =

Wave energy is captured from the surface waves in oceans and pressure changes beneath the surface. Interest in capturing this energy continues to fuel innovation in the renewable energy industry. Although wave energy has been in the works for many years, it has only become possible in recently as new technology makes it more effective. This renewable energy form can only be harvested in parts of the world that receive consistent waves for it to be effective, suitable areas include Scotland, Canada, the Pacific Coast of the USA, and Australia.

Patents for wave-power devices were first issued in the 1700s; however the 1973 oil crisis in the Middle East inspired the invention of modern wave energy converters, as investment in alternative energy sources was occurring in the United States and other pro-Israel countries. Stephen Salter, engineer at the University of Edinburgh, designed one of the first modern wave generator known as "Salter's Duck" in the mid-1970s, but Dr. Salter's research program was shut down in 1982 and his design was never implemented; however his work served to inspire other designs for wave energy generators. The first commercial wave farm established in October 2007 off the coast of Portugal, consisting of three "snake-like" tubes harnessing the energy from the swells of the Atlantic Ocean. Large-scale commercialization of wave energy conversion devices has yet to occur.
 * HISTORY**

Wind-generated ocean waves occur on surface of the water of oceans, lakes, rivers, and other bodies of water. An indirect and condensed form of solar energy, wave energy is induced from the transfer of energy from wind moving across bodies of water. Whereas tidal energy converters use the currents of the sea for energy generation, wave energy converters capture energy from the the rise and fall of waves on the surface or from the pressure fluctuations that occur just below the surface caused by changes in water density. As waves propagate energy can be harvested at the wave front, where a power flux can be converted into mechanical energy, which turns a turbine/generator to produce electricity.
 * METHOD OF GENERATION**

The motion of waves in bodies of water is sinusoidal (at fixed point) The power of waves, or kilowatts produced per meter of wave front, is directly proportional to the "group velocity",the velocity of wave trains, and the ocean wave energy per unit surface area (formula not given).

The amount of energy that waves produce worldwide would be enough to support our energy needs, but this energy is not so easy to capture. Certain areas of the ocean are windier than others, and waves can fluctuate greatly from day to day unlike tides, which are consistent. Because many wave technologies are new and still being tested, it is difficult to get funding because governments must believe it is media type="youtube" key="V27ZBODcv0c" height="344" width="425" align="right"flawless. Some wave generating stations close to shore may be unaesthetic, and some may make noise, although waves themselves make noise too. Some wave generating stations can interfere with shipping or other boats, and marine life either at the surface or on the ocean floor with some technologies. Strong materials must be used so the generators are able to withstand extreme weather and corrosion from salt water.
 * DISADVANTAGES**

Despite the drawbacks, it is important to remember that wave energy is completely renewable. It does not require any fuel, and does not produce any waste. A wave farm costs an average of $400 million to install, but does not require many additional costs to operate or maintain. Wave generating stations built in the right area have the potential to produce a lot of energy in a concentrated area, and could even support a base load. The price of wind turbines when they first came out were much more expensive that wave energy, but the costs have dropped by 80% as new technology is developed. Therefore if wave energy technology is supported, newer technology should also be more cost-effective.
 * ADVANTAGES**

Wave energy can be a less sporadic source of energy than other renewable energy sources, such as wind and solar energy, depending on the conditions of the water. In ideal wave conditions, wave energy converters can produce an average output of 20 - 70 kW/m. Estimates show that around 1000 - 10 000 gigawatts of global wave power could be harvested and converted into electrical energy, thereby matching the world's electrical energy consumption.

There are three types of wave technologies: nearshore, offshore and far offshore. Offshore technology systems tend to be positioned in deep water (40 meters or deeper). Wave energy technologies are typically installed at or near the surface of the water. However, they differ in the way in their energy conversion methods (usually to electricity). They also differ in their positioning relative to the waves.
 * TECHNOLOGIES**

There are many different devices that are used to convert the energy from waves into other forms. It is challenging to produce devices that are resistant to extreme weather conditions and that aren't eroded by seawater. Terminator devices are placed perpendicular to the waves and they are usually onshore or nearshore. Attenuators are floating structures that run parallel to the waves. Flexing of the device occurs because of the different wave heights. This flexing is connected to energy converters. Overtopping devices have reservoirs that are filled with water from waves. The level of water in the reservoirs is higher than the level of water in the ocean so when the water is released, it falls back down toward the ocean because of gravity. The falling water generates energy which is used to turn hydro turbines. Oscillating water columns are tubes with air and turbines that are put underwater. As water moves through an opening, the up and down motion of the waves forces air to turn the turbine. And finally point absorbers are objects on a floating structure that drive electromagnetic converters as they move with the waves.

Furthermore, a company called Wave Energy has come up with technologies to help increase the efficiency of wave energy conversion. Their Sea-wave Slot-cone Generator concept has three reservoirs stacked on top of each other. The potential energy of the incoming waves is stored in these reservoirs. The water then runs through the turbines in order to produce electricity. The use of many reservoirs together as opposed to single reservoirs, significantly increases the efficiency of the device. They have also come up with the MST (multi stage turbine). It has the ability to use many different heights of water on one turbine wheel. It only has one shaft and require one generator and grid connection system. In addition, there is the SSG Offshore, which is beneficial in supplying large amounts of electricity to surrounding oil platforms, islands or shore. There are large farms of floating SSG Offshore devices.

Aquamarine Power Ltd. and Wavegen are two companies competing to inventfeasible shoreline wave energy converters. Aquarmarine Power Ltd's Oyster consists of pumping cylinders effective for near-shore waves of a depth of 12 meters. On the other hand, Wavegen's shoreline technology is called the Limpet, which can harvest wave power at breakwaters, coastal defenses, land reclamation schemes, and harbor walls using oscillating water columns.

Sources: Grose, Thomas K. "Surfing Energy's Next Wave." //U.S. News & World Report// 147.4 (2010): 50. //MasterFILE Premier//. EBSCO. Web. 22 May 2010 [] Mark Wimbush, Neil A. Benfer, Charles S. Cox, Charles S. Cox, Allan J. Clarke, "Ocean waves", in AccessScience@McGraw-Hill, http://www.accessscience.com.ezproxy.torontopubliclibrary.ca, DOI 10.1036/1097-8542.4639 //Ocean Wave Energy.// Web. 20 May 2010.  Margolis, Jason. "Wave farms show energy potential". //BBC News//. 24 May 2010. Web. . Postelwait, Jeff. "Wave and Tidal Power Development Status". //Hydro Review Magazine.// 16 March 2010. Web. 24 May 2010. //Technology and Innovation.// Web. 20 May 2010.  "The Coming Wave" //The Economist//. 5 June 2008. Web. 18 May 2010. [] "Wave Energy". Web. 24 May 2010  "Wave Power." Web. 22 May 2010. 

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