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Energy Resources: Tidal power - 0 views

www.darvill.clara.net/...tidal.htm tide wave
shared by crandallmad00 on 11 Mar 13 - Cached
  • A huge dam (called a "barrage") is built across a river estuary. When the tide goes in and out, the water flows through tunnels in the dam. The ebb and flow of the tides can be used to turn a turbine, or it can be used to push air through a pipe, which then turns a turbine. Large lock gates, like the ones used on canals, allow ships to pass. If one was built across the Severn Estuary, the tides at Weston-super-Mare would not go out nearly as far - there'd be water to play in for most of the time. But the Severn Estuary carries sewage and other wastes from many places (e.g. Bristol & Gloucester) out to sea. A tidal barrage would mean that this stuff would hang around Weston-super-Mare an awful lot longer! Also, if you're one of the 80,000+ birds that feeds on the exposed mud flats when the tide goes out, then you have a problem, because the tide won't be going out properly any more.
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History of wind power - Wikipedia, the free encyclopedia - 0 views

en.wikipedia.org/...History_of_wind_power
shared by rioshan00 on 11 Mar 13 - No Cached
  • The first windmills in Europe appear in sources dating to the twelfth century. These early European windmills were sunk post mills. The earliest certain reference to a windmill dates from 1185, in Weedley, Yorkshire, although a number of earlier but less certainly dated twelfth century European sources referring to windmills have also been adduced.
  • The first windmill used for the production of electricity was built in Scotland in July 1887 by Prof James Blyth of Anderson's College,
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tidal energy - National Geographic Education - 0 views

education.nationalgeographic.com/...tidal-energy current tide
shared by butlerlei98 on 11 Mar 13 - No Cached
  • Tidal energy is produced by the surge of ocean waters during the rise and fall of tides.
  • During the 20th century, engineers developed ways to use tidal movement to generate electricity in areas where there is a significant tidal range—the difference in area between high tide and low tide. All methods use special generators to convert tidal energy into electricity.
  • For most tidal energy generators, turbines are placed in tidal streams. A tidal stream is a fast-flowing body of water created by tides. A turbine is a machine that takes energy from a flow of fluid.
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  • The world's first tidal power station was constructed in 2007 at Strangford Lough in Northern Ireland. The turbines are placed in a narrow strait between the Strangford Lough inlet and the Irish Sea. The tide can move at 4 meters (13 feet) per second across the strait.
  • butlerlei98 on 11 Mar 13
     
    ". The United States has no tidal plants and only a few sites where tidal energy could be produced at a reasonable price."
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Directory:Cents Per Kilowatt-Hour - PESWiki - 0 views

peswiki.com/...ectory:Cents_Per_Kilowatt-Hour fossil fuels cost
shared by mchughkon99 on 22 Mar 13 - No Cached
  • GasCurrently supplies around 15% of the global electricity demand. 3.9 - 4.4 Cents/kW-h Gas-fired plants and generally quicker and less expensive to build than coal or nuclear, but a relatively high percentage of the cost/KWh is derived from the cost of the fuel. Due to the current (and projected future) upwards trend in gas prices, there is uncertainty around the cost / KWh over the lifetime of plants. Gas burns more cleanly than coal, but the gas itself (largely methane) is a potent greenhouse gas. Some energy conversions to calculate your cost of natural gas per kwh. 100 cubic feet (CCF)~ 1 Therm = 100,000 btu ~ 29.3 kwh. CoalCurrently supplies around 38% of the global electricity demand. 4.8 - 5.5 Cents/kW-h Increasingly difficult to build new coal plants in the developed world, due to environmental requirements governing the plants. Growing concern about coal fired plants in the developing world (China, for instance, imposes less environmental overhead, and has large supplies of high sulphur content coal). The supply of coal is plentiful, but the coal generation method is perceived to make a larger contribution to air pollution than the rest of the methods combined. NuclearCurrently supplies around 24% of the global electricity demand. 11.1 - 14.5 Cents/kW-h Political difficulties in using nuclear in some nations. Risk of widespread (and potentially lethal) contamination upon containment failure. Fuel is plentiful, but problematic. Waste disposal remains a significant problem, and de-commissioning is costly (averaging approximately US $320MM per plant in the US).
  • mchughkon99 on 22 Mar 13
     
    cost for fossil fuels
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How Is Fossil Fuel Converted Into Electricity? | eHow.com - 0 views

www.ehow.com/el-converted-electricity_.html fossil convert current
shared by dpurdy on 22 Mar 13 - No Cached
  • The fossil fuels are then burned to heat water.
  • The steam from the water then increases in pressure, forcing a turbine to spin. The turbine is used to rotate a magnet encased in a generator a high speeds. As the magnet spins, electrons are produced, and they power the electricity grid.
  • As of 2009, fossil fuels supplied about 85 percent of the world's energy demands.
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Unearthing the True Cost of Fossil Fuels : TreeHugger - 0 views

www.treehugger.com/...true-cost-fossil-fuels.html fossil fuels cost
shared by dpurdy on 21 Mar 13 - No Cached
  • “true” cost of coal: Depending on how you factor in the costs of climate change, it could be between a few additional cents per kWh to a whopping ¢26.89 extra per kilowatt hour—the high-end estimate from the Harvard study. By way of comparison, the average American paid ¢11.54 per kWh on their residential electric bills last year.
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How Does CO2 Cause Global Warming? | eHow.com - 0 views

www.ehow.com/1_co-cause-global-warming.html global warming co2 fossil fuels pollution
shared by dpurdy on 23 Mar 13 - No Cached
  • Carbon dioxide contributes to global warming by absorbing heat energy from the earth, trapping it and preventing its release into space.
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Photovoltaic Cells create electricity from sunlight - PV cells provide free energy | da... - 0 views

www.dasolar.com/...photovoltaic-cells photovoltaic cells electricity sunlight energy sustainable form
shared by whalenkil98 on 18 Mar 13 - No Cached
  • When sunlight strikes a solar cell, electrons are knocked loose. They move toward the treated front surface. An electron imbalance is created between the front and the back. When a connector, like a wire, joins the two surfaces a current of electricity occurs between the negative and positive sides
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How Do PV Solar Panels Work - Solar - 0 views

www.reuk.co.uk/ow-Do-PV-Solar-Panels-Work.htm convert
shared by coreyemi99 on 20 Mar 13 - No Cached
  • When a visible light photon strikes a solar cell it can do one of three things: pass straight through, be reflected, or be absorbed. If the photon is absorbed, its energy is absorbed by an electron in an atom of the solar cell enabling it to escape from its normal position (photon excitation), cross the junction and fill a hole. Since electrons are physically moving across the PN junction, the positive charge carrying holes are effectively moving in the opposite direction around the load circuit (a rechargeable battery or light bulb etc). This completes the circuit providing more holes for the electrons to combine with and providing usable electricity.
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Tidal stream generators - Brightside - 0 views

www.brightknowledge.org/...tidal-stream-generators tidal how
shared by dpurdy on 03 Nov 12 - No Cached
  • Tidal stream generators look and work like underwater wind turbines. As opposed to using the rising and falling movement of the tides, tidal stream generators take advantage of the fast moving sea currents (tidal streams), which flow when tides are moving in and out. These tidal streams cause the turbines to rotate, turning the generators which generate electricity. Tidal stream generators have the advantage of being much cheaper to build, and do not have as much of an environmental impact as a tidal barrage. The turbines turn relatively slowly, hence do not affect sea life. This is different to tidal barrages which can disrupt fish migrating up rivers from the sea.
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Wave Power - 1 views

www.thinkglobalgreen.org/WAVEPOWER.html
shared by westkea00 on 30 Oct 12 - No Cached
  • 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.
  • Wave energy is generally considered to be the most concentrated and least variable form of renewable energy. It is the high power density of wave energy that suggests it has the capacity to become the lowest cost renewable energy source.
  • Wave energy is a renewable, zero emission source of power
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Wave Hub wave energy hydropower infrastructure project on track for summer 2011 deploym... - 0 views

www.hydroworld.com/...wave-hub-wave-energy.html infrastructure wave
shared by dpurdy on 31 Oct 12 - No Cached
  • Hartlepool-based JDR Cable Systems is constructing the armored 25- kilometer subsea cable that will connect Wave Hub to the grid and the hub structure that will sit on the seabed. Work also is progressing on the hub assembly, which will provide a connection between the main cable from the shore and the tails leading to the wave energy devices.
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Wave Energy - 2 views

ocsenergy.anl.gov/...index.cfm wave location
shared by logansar99 on 22 Oct 12 - Cached
  • northwestern coasts of the United States.
  • Positive or negative impacts on marine habitat (depending on the nature of additional submerged surfaces, above-water platforms, and changes in the seafloor);
  • Toxic releases from leaks or accidental spills of liquids used in those systems with working hydraulic fluids;
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  • Conflict with other sea space users, such as commercial shipping and recreational boating;
  • Visual and noise impacts (device-specific, with considerable variability in visible freeboard height and noise generation above and below the water surface)
  • Wave power varies considerably in different parts of the world, and wave energy can't be harnessed effectively everywhere
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How much energy can a wind farm produce? - Curiosity - 0 views

curiosity.discovery.com/...energy-can-wind-farm-produce
shared by egglestonjoc98 on 22 Oct 12 - No Cached
  • At 1.8 megawatts, that turbine produces 5.2 million kilowatt-hours of electricity, enough power for 600 households. As more turbines are grouped together, they collect more energy from the available wind.
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Group items tagged pollution - qmstech2 | Diigo Groups - 0 views

groups.diigo.com/...pollution location mrpurdy
shared by filionmar99 on 22 Oct 12 - No Cached
    • filionmar99
      filionmar99 on 22 Oct 12
       
      read this
  • The major challenge to using wind as a source of power is that it is intermittent and does not always blow when electricity is needed. Wind cannot be stored (although wind-generated electricity can be stored, if batteries are used), and not all winds can be harnessed to meet the timing of electricity demands. Further, good wind sites are often located in remote locations far from areas of electric power demand (such as cities).
  • Although wind power plants have relatively little impact on the environment compared to fossil fuel power plants, there is some concern over the noise produced by the rotor blades, aesthetic (visual) impacts, and birds and bats having been killed (avian/bat mortality) by flying into the rotors. Most of these problems have been resolved or greatly reduced through technological development or by properly siting wind plants.
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  • A Renewable Non-Polluting Resource Wind energy is a free, renewable resource, so no matter how much is used today, there will still be the same supply in the future. Wind energy is also a source of clean, non-polluting, electricity. Unlike conventional power plants, wind plants emit no air pollutants or greenhouse gases. According to the U.S. Department of Energy, in 1990, California's wind power plants offset the emission of more than 2.5 billion pounds of carbon dioxide, and 15 million pounds of other pollutants that would have otherwise been produced. It would take a forest of 90 million to 175 million trees to provide the same air quality.
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Green Rock Energy - Geothermal Energy - Sustainability - 0 views

www.greenrock.com.au/geothermalSustainability.php geothermal sustainable
shared by brownale99 on 22 Oct 12 - No Cached
  • The Benefits "Geothermal energy has the potential to generate and deliver sustainable supplies of clean, renewable base load power. Depending on the nature of the resource and the reservoir, individual production wells have the potential to generate consistent supplies of base load power for decades."
  • Geothermal energy has the potential to generate and deliver sustainable supplies of clean, renewable base load power.
  • individual production wells have the potential to generate consistent supplies of base load power for decades.
  • ...2 more annotations...
  • Base load electricity generated from geothermal energy is clean, renewable and has minimal impact on the environment.
  • Unlike burning fossil fuels, the process emits no greenhouse gases, pollution or hazardous wastes.
  • messinaaar98 on 22 Oct 12
     
    "The Benefits "Geothermal energy has the potential to generate and deliver sustainable supplies of clean, renewable base load power. Depending on the nature of the resource and the reservoir, individual production wells have the potential to generate consistent supplies of base load power for decades.""
  • gazdiknic99 on 11 Mar 13
     
    main idea, supporting facts, and conclusion
  • brownale99 on 11 Mar 13
     
    ""Geothermal energy has the potential to generate and deliver sustainable supplies of clean, renewable base load power. Depending on the nature of the resource and the reservoir, individual production wells have the potential to generate consistent supplies of base load power for decades.""
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