Skip to main content

Home/ qmstech2/ Group items matching "free" in title, tags, annotations or url

Group items matching
in title, tags, annotations or url

Sort By: Relevance | Date Filter: All | Bookmarks | Topics Simple Middle
dpurdy

How do Photovoltaics Work? - NASA Science - 1 views

  • 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.
  •  
    " 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"
  •  
    "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."
olearydev99

Sustainability - Wikipedia, the free encyclopedia - 0 views

  •  
    "Sustainability is the capacity to endure"
manzellaann99

Discover Solar Energy ADVANTAGES DISADVANTAGES | PROS and CONS of Solar Energy - 4 views

  • Solar Energy systems are virtually maintenance free and will last for decades.
lemairenat98

Tidal power - Wikipedia, the free encyclopedia - 0 views

  • Tidal stream generators (or TSGs) make use of the kinetic energy of moving water to power turbines, in a similar way to wind turbines that use wind to power turbines. Some tidal generators can be built into the structures of existing bridges, involving virtually no aesthetic problems. [edit] Tidal barrage
  •  
    "Tidal stream generator Main article: Tidal stream generator Tidal stream generators (or TSGs) make use of the kinetic energy of moving water to power turbines, in a similar way to wind turbines that use wind to power turbines. Some tidal generators can be built into the structures of existing bridges, involving virtually no aesthetic problems."
warneraus98

Tidal power - Wikipedia, the free encyclopedia - 0 views

  • idal power is taken from the Earth's oceanic tides; tidal forces are periodic variations in gravitational attraction exerted by celestial bodies. These forces create corresponding motions or currents in the world's oceans
  • Because the Earth's tides are ultimately due to gravitational interaction with the Moon and Sun and the Earth's rotation, tidal power is practically inexhaustible and classified as a renewable energy resource
  • Because the Earth's tides are ultimately due to gravitational interaction with the Moon and Sun and the Earth's rotation, tidal power is practically inexhaustible and classified as a renewable energy resource
  •  
    ware tide energy comes from     
mcgarrdan98

Geothermal energy - Wikipedia, the free encyclopedia - 0 views

  • Drilling and exploration for deep resources is very expensive. Forecasts for the future of geothermal power depend on assumptions about technology, energy prices, subsidies, and interest rates. Pilot programs like EWEB's customer opt in Green Power Program [6] show that customers would be willing to pay a little more for a renewable energy source like geothermal. But as a result of government assisted research and industry experience, the cost of generating geothermal power has decreased by 25% over the past two decades.[7] In 2001, geothermal energy cost between two and ten cents per kwh.[8]
  •  
    "Hot springs have been used for bathing at least since paleolithic times[9] The oldest known spa is a stone pool on China's Lisan mountain built in the Qin dynasty in the 3rd century BC, at the same site where the Huaqing Chi palace was later built. In the first century AD, Romans conquered Aquae Sulis, now Bath, Somerset, England, and used the hot springs there to feed public baths and underfloor heating. The admission fees for these baths probably represent the first commercial use of geothermal power. The world's oldest geothermal district heating system in Chaudes-Aigues, France, has been operating since the 14th century.[10] The earliest industrial exploitation began in 1827 with the use of geyser steam to extract boric acid from volcanic mud in Larderello, Italy."
bishophan00

Wind Power Information, Wind Power Facts - National Geographic - 1 views

  • Wind is a clean source of renewable energy that produces no air or water pollution.
  • Wind is the movement of air from an area of high pressure to an area of low pressure. In fact, wind exists because the sun unevenly heats the surface of the Earth. As hot air rises, cooler air moves in to fill the void. As long as the sun shines, the wind will blow. And as long as the wind blows, people will harness it to power their lives.
  • The wind spins the blades, which turn a shaft connected to a generator that produces electricity. Other turbines work the same way, but the turbine is on a vertical axis and the blades look like a giant egg beater.
  • ...5 more annotations...
  • At the end of last year, global capacity was more than 70,000 megawatts.
  • And since the wind is free, operational costs are nearly zero once a turbine is erected.
  • Globally, generation more than quadrupled between 2000 and 2006.
  • n the energy-hungry United States, a single megawatt is enough electricity to power about 250 homes.
  • ndustry experts predict that if this pace of growth continues, by 2050 the answer to one third of the world's electricity needs will be found blowing in the wind.
  •  
    where wind energy come from
  •  
    ". At the end of last year, global capacity was more than 70,000 megawatts. In the energy-hungry United States, a single megawatt is enough electricity to power about 250 homes. "
rioshan00

History of wind power - Wikipedia, the free encyclopedia - 0 views

  • 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,
kenyonlau99

How much power is generated in the United States by solar power? - 2 views

  • just over 843,000 kilowatt-hours of electricity were provided by solar power. The vast majority of that, more than 666,500 kWh, were produced in California. Roughly 14 percent of the total renewable energy generated in the U.S. in 2008 was solar energy. And remember that these numbers continue to grow each year. The solar industry has been growing on an average of 30-40 percent each year, and as the industry grows, so will the amount of clean, renewable power it puts out. Interested in Home Solar Energy? Fill in your details below and certified solar contractors will give you FREE estimates. What type of Solar Energy services are you interested in? * Please Select Solar Electrical Solar Thermal First Name * Last Name * Zipcode *
    • kenyonlau99
       
      GOOD INFO!
  • The EIA states that just over 843,000 kilowatt-hours of electricity were provided by solar power. The vast majority of that, more than 666,500 kWh, were produced in California. Roughly 14 percent of the total renewable energy generated in the U.S. in 2008 was solar energy. And remember that these numbers continue to grow each year. The solar industry has been growing on an average of 30-40 percent each year, and as the industry grows, so will the amount of clean, renewable power it puts out.
  •  
    how much solar energy is being converted in the USA?
  •  
    "How much power is generated in the United States by solar power? ted-vollgraff According to the Energy Information Administration (EIA), renewable energy accounted for 7 percent of U.S. energy consumption in 2008. Solar power accounted for only one percent. But, considering how much energy is consumed each year in the United States, that is still a decent bit of power. The EIA states that just over 843,000 kilowatt-hours of electricity were provided by solar power. The vast majority of that, more than 666,500 kWh, were produced in California. Roughly 14 percent of the total renewable energy generated in the U.S. in 2008 was solar energy. And remember that these numbers continue to grow each year. The solar industry has been growing on an average of 30-40 percent each year, and as the industry grows, so will the amount of clean, renewable power it puts out. "
lemairenat98

Tidal stream power - Simple English Wikipedia, the free encyclopedia - 0 views

  • Tidal stream systems need to be located in areas with fast currents where natural flows are concentrated between obstructions, for example at the entrances to bays and rivers, around rocky points, headlands, or between islands or other land masses.
  •  
    "Tidal stream systems need to be located in areas with fast currents where natural flows are concentrated between obstructions, for example at the entrances to bays and rivers, around rocky points, headlands, or between islands or other land masses."
dpurdy

Wind turbine - Wikipedia, the free encyclopedia - 1 views

  • A wind turbine
  • converts kinetic energy from the wind
  • into mechanical energy
  • ...1 more annotation...
  • The first electricity-generating wind turbine was a battery charging machine installed in July 1887 by Scottish academic James Blyth to light his holiday home in Marykirk, Scotland.
whalenkil98

Photovoltaic Cells create electricity from sunlight - PV cells provide free energy | dasolar.com - 0 views

  • 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
dpurdy

Wind turbine - Wikipedia, the free encyclopedia - 0 views

  • The first electricity-generating wind turbine was a battery charging machine installed in July 1887 by Scottish academic James Blyth to light his holiday home in Marykirk, Scotland.[7
dpurdy

Tidal power - Wikipedia, the free encyclopedia - 0 views

  • Tidal stream generators (or TSGs) make use of the kinetic energy of moving water to power turbines, in a similar way to wind turbines that use wind to power turbines. Some tidal generators can be built into the structures of existing bridges, involving virtually no aesthetic problems. Likewise, “tidal bridging” is a relatively new advancement that is gaining recognition as a more practical and beneficial way to generate tidal power.
    • dpurdy
       
      Good pic of tidal stream generator working
  •  
    "Tidal stream generators (or TSGs) make use of the kinetic energy of moving water to power turbines, in a similar way to wind turbines that use wind to power turbines. Some tidal generators can be built into the structures of existing bridges, involving virtually no aesthetic problems. Likewise, "tidal bridging" is a relatively new advancement that is gaining recognition as a more practical and beneficial way to generate tidal power."
sokolkyl00

Solar Power Energy Information, Solar Power Energy Facts - National Geographic - 0 views

  • Every hour the sun beams onto Earth more than enough energy to satisfy global energy needs for an entire year. Solar energy is the technology used to harness the sun's energy and make it useable. Today, the technology produces less than one tenth of one percent of global energy demand.
  • In one technique, long troughs of U-shaped mirrors focus sunlight on a pipe of oil that runs through the middle. The hot oil then boils water for electricity generation. Another technique uses moveable mirrors to focus the sun's rays on a collector tower, where a receiver sits. Molten salt flowing through the receiver is heated to run a generator.
  • Despite the drawbacks, solar energy use has surged at about 20 percent a year over the past 15 years, thanks to rapidly falling prices and gains in efficiency. Japan, Germany, and the United States are major markets for solar cells. With tax incentives, solar electricity can often pay for itself in five to ten years.
  • ...1 more annotation...
  • Solar energy is lauded as an inexhaustible fuel source that is pollution and often noise free. The technology is also versatile.
  •  
    " Today, the technology produces less than one tenth of one percent of global energy demand."
  •  
    Intriguing facts about the suns energy on how they use it on oil and the drawback 
  •  
    Every hour the sun beams onto Earth more than enough energy to satisfy global energy needs for an entire year. Solar energy is the technology used to harness the sun's energy and make it useable. Today, the technology produces less than one tenth of one percent of global energy demand.
smithree98

Fuel cell - Wikipedia, the free encyclopedia - 1 views

  • There were 140,000 fuel cell stacks shipped globally in 2010
  • although, as of 2010, no public company in the industry had yet become profitable
  •  
    actually a pretty decent site to find info on hydrogen
« First ‹ Previous 41 - 60 of 112 Next › Last »
Showing 20 items per page