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How do Photovoltaics Work? - NASA Science - 1 views

science.nasa.gov/...solarcells solar history convert
shared by dpurdy on 08 Mar 13 - No Cached
  • Photovoltaics is the direct conversion of light into electricity at the atomic level. Some materials exhibit a property known as the photoelectric effect that causes them to absorb photons of light and release electrons. When these free electrons are captured, an electric current results that can be used as electricity.
  • When light energy strikes the solar cell, electrons are knocked loose from the atoms in the semiconductor material. If electrical conductors are attached to the positive and negative sides, forming an electrical circuit, the electrons can be captured in the form of an electric current -- that is, electricity. This electricity can then be used to power a load, such as a light or a tool.
  • bolendev99 on 08 Mar 13
     
    " Solar cells are made of the same kinds of semiconductor materials, such as silicon, used in the microelectronics industry. For solar cells, a thin semiconductor wafer is specially treated to form an electric field, positive on one side and negative on the other. When light energy strikes the solar cell, electrons are knocked loose from the atoms in the semiconductor material. If electrical conductors are attached to the positive and negative sides, forming an electrical circuit, the electrons can be captured in the form of an electric current -- that is, electricity. This electricity can then be used to power a load, such as a light or a too"
  • dpurdy on 12 Mar 13
     
    "The photoelectric effect was first noted by a French physicist, Edmund Bequerel, in 1839, who found that certain materials would produce small amounts of electric current when exposed to light. In 1905, Albert Einstein described the nature of light and the photoelectric effect on which photovoltaic technology is based, for which he later won a Nobel prize in physics. The first photovoltaic module was built by Bell Laboratories in 1954. It was billed as a solar battery and was mostly just a curiosity as it was too expensive to gain widespread use. In the 1960s, the space industry began to make the first serious use of the technology to provide power aboard spacecraft. Through the space programs, the technology advanced, its reliability was established, and the cost began to decline. During the energy crisis in the 1970s, photovoltaic technology gained recognition as a source of power for non-space applications."
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Energy Resources: Wave power - 3 views

www.darvill.clara.net/...wave.htm
shared by westkea00 on 08 Mar 13 - Cached
  • Waves are a powerful source of energy.
  • The problem is that it's not easy to harness this energy and convert it into electricity in large amounts.
  • wave power stations are rare
  • ...10 more annotations...
  • Once you've built a wave power station, the energy is free, needs no fuel and produces no waste or pollution
  • The energy is free - no fuel needed, no waste produced.
  • Not expensive to operate and maintain.
  • Can produce a great deal of energy.
  • Some designs are noisy. But then again, so are waves, so any noise is unlikely to be a problem.
  • Ocean waves are caused by the wind as it blows across the sea. Waves are a powerful source of energy.
  • Some designs are noisy. But then again, so are waves, so any noise is unlikely to be a problem
  • At a wave power station, the waves arriving cause the water in the chamber to rise and fall, which means that air is forced in and out of the hole in the top of the chamber. We place a turbine in this hole, which is turned by the air rushing in and out. The turbine turns a generator. A problem with this design is that the rushing air can be very noisy, unless a silencer is fitted to the turbine. The noise is not a huge problem anyway, as the waves make quite a bit of noise themselves.
  • At a wave power station, the waves arriving cause the water in the chamber to rise and fall, which means that air is forced in and out of the hole in the top of the chamber. We place a turbine in this hole, which is turned by the air rushing in and out. The turbine turns a generator. A problem with this design is that the rushing air can be very noisy, unless a silencer is fitted to the turbine. The noise is not a huge problem anyway, as the waves make quite a bit of noise themselves.
  • A company called Pelamis Wave Power are developing a method of offshore wave energy collection, using a floating tube called "Pelamis"
  • rodriguezjos99 on 08 Mar 13
     
    " Advantages   The energy is free - no fuel needed, no waste produced. Not expensive to operate and maintain. Can produce a great deal of energy. Disadvantages Depends on the waves - sometimes you'll get loads of energy, sometimes almost nothing. Needs a suitable site, where waves are consistently strong. Some designs are noisy. But then again, so are waves, so any noise is unlikely to be a problem. Must be able to withstand very rough weather."
  • gonzalezisa00 on 25 Sep 13
     
    One of them works like a swimming pool wave machine in reverse. At a swimming pool, air is blown in and out of a chamber beside the pool, which makes the water outside bob up and down, causing waves.  
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Solar electricity PV (photovoltaic) panels explained - benefits, costs, savings, earnin... - 1 views

www.energysavingtrust.org.uk/...Solar-panels-PV solar sustainable
shared by bolendev99 on 08 Mar 13 - No Cached
  • bolendev99 on 08 Mar 13
     
    "The benefits of solar electricity Cut your electricity bills: sunlight is free, so once you've paid for the initial installation your electricity costs will be reduced. Get paid for the electricity you generate: the government's Feed-In Tariffs pay you for the electricity you generate, even if you use it. Sell electricity back to the grid: if your system is producing more electricity than you need, or when you can't use it, you can sell the surplus back to the grid. Cut your carbon footprint: solar electricity is green, renewables energy and doesn't release any harmful carbon dioxide] or other pollutants. A typical home solar PV system could save over a tonne of carbon dioxide per year - that's more than 30 tonnes over its lifetime. "
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How long has wind power been used? - Curiosity - 0 views

curiosity.discovery.com/...how-long-wind-power-use history
shared by rutalil00 on 08 Mar 13 - No Cached
  • Windmills were first used to grind grain anywhere from 2000 to 4000 years ago in ancient Persia or Babylon;
  • The initial use of wind power was by Egyptians in 3000 B.C. to move their sailboats.
  • freeberntay99 on 08 Mar 13
     
    "The initial use of wind power was by Egyptians in 3000 B.C. to move their sailboats. Windmills were first used to grind grain anywhere from 2000 to 4000 years ago in ancient Persia or Babylon; crusaders brought the windmill idea back to Europe with them in the 11th century A.D. In the 1930s, windmills in rural areas of the U.S. pumped water and generated electricity."
  • justice colvin on 24 Sep 13
     
    In the 1930s, windmills in rural areas of the U.S. pumped water and generated electricity.
  • kurishkri00 on 24 Sep 13
     
    The initial use of wind power was by Egyptians in 3000 B.C. to move their sailboats. Windmills were first used to grind grain anywhere from 2000 to 4000 years ago in ancient Persia or Babylon; crusaders brought the windmill idea back to Europe with them in the 11th century A.D.
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How is Biofuel Made - 0 views

www.agrabiofuels.com/howisbiofuelmade.html biofuel convert
shared by greenhan99 on 08 Mar 13 - No Cached
  • Where does the first phase for biofuel production begin? The sun takes credit for the very first step in this process. The sun helps to grow crops and plants, which are then eventually used to produce biofuel. Biofuel is actually derived from biomass, which can come from gas, solid and liquid states.
  • These crops that are specifically grown to be used to produce biofuels are referred to as feedstocks. These feedstocks are the raw and unprocessed form that the bio fuel is derived from. Among the more common types of feedstocks and crops that are used for the production of biofuels are corn, sugar crops, and forests. In addition, even some of the byproducts of materials such as those that come from wood can be used in this process. These special byproducts are often converted to the liquid forms of biofuels, which include methanol and ethanol. With the ability to use these byproducts, production methods have gotten a lot less expensive since there is much less waste involved.
  • In addition, there are also certain natural oils that are also used to help produce this special type of fuel. For example, oil palm, soybean and algae are surprisingly capable of being burned directly in certain types of furnaces and engines and can also be blended with certain types of fuels or petroleum based fuels for a more powerful blended mixture.
  • ...2 more annotations...
  • Where does the first phase for biofuel production begin? The sun takes credit for the very first step in this process. The sun helps to grow crops and plants, which are then eventually used to produce biofuel. Biofuel is actually derived from biomass, which can come from gas, solid and liquid states.
  • Another means of producing biofuel that has proven to be especially efficient and cost effective is the conversion of vegetable oil to a burnable fuel that can be used with most types of engines.
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Solar Photovoltaics | Solar Energy - 0 views

www.premierpower.com/...how_solar_works.php solar form
shared by dylan purner on 08 Mar 13 - No Cached
  • What are photovoltaics? The word comes from “photo” (light) and “voltaic” (energy produced by a chemical reaction). Photovoltaic technology refers to the conversion of light into energy at the atomic level. Certain materials, such as silicon, cadmium, and selenium, have the ability to absorb light photons and release electrons. Solar photovoltaic technology harnesses these freed electrons and uses their electric current as DC electricity (NASA 2002). Fully powered by the sun, solar photovoltaics are a free, clean, and renewable source of energy that can be used independently of or in conjunction with conventional grid energy. Unlike solar thermal systems, solar energy panels require little maintenance, necessitate no moving parts, and last for 30-40 years.
  • kenyonlau99 on 08 Mar 13
     
    " Photovoltaics: The Science Behind Solar Energy           What are photovoltaics? The word comes from "photo" (light) and "voltaic" (energy produced by a chemical reaction). Photovoltaic technology refers to the conversion of light into energy at the atomic level. Certain materials, such as silicon, cadmium, and selenium, have the ability to absorb light photons and release electrons. Solar photovoltaic technology harnesses these freed electrons and uses their electric current as DC electricity (NASA 2002). Fully powered by the sun, solar photovoltaics are a free, clean, and renewable source of energy that can be used independently of or in conjunction with conventional grid energy."
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Advantages of Geothermal Energy - 0 views

www.energyformankind.org/...dvantages-of-geothermal-energy geothermal
shared by shinecal99 on 08 Mar 13 - No Cached
  • shinecal99 on 08 Mar 13
     
    "Pollution free production of energy. Since geothermal energy does not require fossil fuels to be burned, production of electricity using this type of energy can be considered as pollution free. Sometimes, there is the tendency that this could release some harmful gases from beneath the earth that might actually be harmful. However, these gases could be contained."
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Where does solar energy come from - 1 views

www.haqsolar.com/haqsolar15189.htm form energy solar
shared by whalenkil98 on 08 Mar 13 - No Cached
  • Solar energy originates in the depths of our sun. The sun endures a continuous stream of thermonuclear explosions as hydrogen atoms are fused into helium atoms. We encounter the resultant energy as radiation that strikes the surface of the earth.
    • kenyonlau99
      kenyonlau99 on 11 Mar 13
       
      so once the rays of the sun hit the solar panel it then is turned into energy .Fully powered by the sun.
  • hayespay99 on 08 Mar 13
     
    "Solar energy originates in the depths of our sun."
  • whalenkil98 on 11 Mar 13
     
    Where solar energy is formed and how it is formed.
  • kenyonlau99 on 11 Mar 13
     
    .Fully powered by the sun.
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Geothermal Energy - 3 views

www.renewableenergyworld.com/...geothermal-energy geothermal sustainable
shared by wooddan99 on 08 Mar 13 - Cached
  • Resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the Earth's surface, and down even deeper to the extremely high temperatures of molten rock called magma.
  • Hot water near the surface of Earth can be used directly for heat.
  • Wells can be drilled into underground reservoirs for the generation of electricity. Some geothermal power plants use the steam from a reservoir to power a turbine/generator, while others use the hot water to boil a working fluid that vaporizes and then turns a turbine.
  • ...3 more annotations...
  • Geothermal energy is the heat from the Earth. It's clean and sustainable. Resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the Earth's surface, and down even deeper to the extremely high temperatures of molten rock called magma.
  • Hot dry rock resources occur at depths of 3 to 5 miles everywhere beneath the Earth's surface and at lesser depths in certain areas.
  • of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the Earth's surface, and down even deeper to the extremely hig
  • brownale99 on 08 Mar 13
     
    "Geothermal energy is the heat from the Earth. It's clean and sustainable. Resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the Earth's surface, and down even deeper to the extremely high temperatures of molten rock called magma."
  • ...3 more comments...
  • dittrichcai99 on 08 Mar 13
     
    "Geothermal energy is the heat from the Earth. It's clean and sustainable. Resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the Earth's surface, and down even deeper to the extremely high temperatures of molten rock called magma."
  • faglejoh98 on 11 Mar 13
     
    "Geothermal energy is the heat from the Earth. It's clean and sustainable. Resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the Earth's surface, and down even deeper to the extremely high temperatures of molten rock called magma."
  • vanierfel98 on 11 Mar 13
     
    Geothermal energy can be easily found close to the surface or far down in the core.
  • parkergar99 on 11 Mar 13
     
    "Geothermal energy is the heat from the Earth. It's clean and sustainable. Resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the Earth's surface, and down even deeper to the extremely high temperatures of molten rock called magma."
  • glinbizzivic98 on 11 Mar 13
     
    "Geothermal energy is the heat from the Earth. It's clean and sustainable. Resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the Earth's surface, and down even deeper to the extremely high temperatures of molten rock called magma."
2More

Wind Energy - 0 views

www.sustainablestuff.co.uk/windpowerenergy.html wind sustainable
shared by mcgrawjac98 on 08 Mar 13 - No Cached
  • Wind Energy, like Solar Energy is fully sustainable, being generated by natural wind flows, which in the U.K. are reliable enough to guarantee a stable, near constant supply of energy. Wind Power can be easily set up, either at home (see related article) or on a larger scale, by energy suppliers keen to meet government targets to reduce carbon emissions that are produced by conventional power stations.
  • mcgrawjac98 on 08 Mar 13
     
    "Wind Energy, like Solar Energy is fully sustainable, being generated by natural wind flows, which in the U.K. are reliable enough to guarantee a stable, near constant supply of energy. Wind Power can be easily set up, either at home (see related article) or on a larger scale, by energy suppliers keen to meet government targets to reduce carbon emissions that are produced by conventional power stations."
9More

Energy Basics: Tidal Energy - 1 views

www.eere.energy.gov/...tidal_energy.html tidal current
shared by rascoekat00 on 08 Mar 13 - No Cached
  • Tidal turbines look like wind turbines. They are arrayed underwater in rows, as in some wind farms. The turbines function best where coastal currents run between 3.6 and 4.9 knots (4 and 5.5 mph). In currents of that speed, a 49.2-foot (15-meter) diameter tidal turbine can generate as much energy as a 197-foot (60-meter) diameter wind turbine. Ideal locations for tidal turbine farms are close to shore in water 65.5–98.5 feet (20–30 meters) deep
  • In currents of that speed, a 49.2-foot (15-meter) diameter tidal turbine can generate as much energy as a 197-foot (60-meter) diameter wind turbine. Ideal locations for tidal turbine farms are close to shore in water 65.5–98.5 feet (20–30 meters) deep.
  • A barrage or dam is typically used to convert tidal energy into electricity by forcing water through turbines, which activate a generato
  • ...3 more annotations...
  • Some of the oldest ocean energy technologies use tidal power. All coastal areas experience two high tides and two low tides over a period of slightly more than 24 hours. For those tidal differences to be harnessed into electricity, the difference between high and low tides must be more than 16 feet (or at least 5 meters). However, there are only about 40 sites on Earth with tidal ranges of this magnitude.
  • Tidal Turbines Tidal turbines look like wind turbines. They are arrayed underwater in rows, as in some wind farms. The turbines function best where coastal currents run between 3.6 and 4.9 knots (4 and 5.5 mph). In currents of that speed, a 49.2-foot (15-meter) diameter tidal turbine can generate as much energy as a 197-foot (60-meter) diameter wind turbine. Ideal locations for tidal turbine farms are close to shore in water 65.5–98.5 feet (20–30 meters) deep.
  • Currently, there are no tidal power plants in the United States, but conditions are good for tidal power generation in the Pacific Northwest and the Atlantic Northeast regions.
  • albrechtjen99 on 08 Mar 13
     
    "Tidal Turbines Tidal turbines look like wind turbines. They are arrayed underwater in rows, as in some wind farms. The turbines function best where coastal currents run between 3.6 and 4.9 knots (4 and 5.5 mph). In currents of that speed, a 49.2-foot (15-meter) diameter tidal turbine can generate as much energy as a 197-foot (60-meter) diameter wind turbine. Ideal locations for tidal turbine farms are close to shore in water 65.5-98.5 feet (20-30 meters) deep."
  • kramerjac99 on 11 Mar 13
     
    where its used
  • butlerlei98 on 12 Mar 13
     
    "Some of the oldest ocean energy technologies use tidal power. All coastal areas experience two high tides and two low tides over a period of slightly more than 24 hours. For those tidal differences to be harnessed into electricity, the difference between high and low tides must be more than 16 feet (or at least 5 meters). However, there are only about 40 sites on Earth with tidal ranges of this magnitude."
3More

A Quiet Breakthrough in Geothermal Energy - Businessweek - 1 views

www.businessweek.com/...akthrough-in-geothermal-energy geothermal energy cost
shared by parkergar99 on 08 Mar 13 - No Cached
  • Geothermal power has massive potential in many areas of the U.S. but it has long remained a niche technology.
  • vanierfel98 on 08 Mar 13
     
    Talks about how much potential there is
  • parkergar99 on 11 Mar 13
     
    "While traditional geothermal can be cheaper than coal power, enhanced geothermal systems are generally more expensive than traditional ones. But being able to create multiple geothermal zones from one well brings down the overall cost of enhanced geothermal by 50 percent, Petty said."
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