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hayespay99

Ancient Egyptians built places to live that allowed stored energy from the sun during t... - 0 views

www.diigo.com/...g

solar history roman ancient energy sun heat heated convert

shared by hayespay99 on 12 Mar 13 - No Cached
  • Ancient Egyptians built places to live that allowed stored energy from the sun during the day, and a heat release during the night. This kind of architecture heated homes at night while keeping the temperature low during the day. Egyptians also used the sun as part of their mummification process, using the sun to dry dead bodies. The Egyptians used a form of passive solar power. 3rd Century B.C., Greek soldiers with the help of Archimedes, focused light on a Roman fleet by using mirrors,
westkea00

Energy Basics: Wave Energy - 0 views

www.eere.energy.gov/...wave_energy.html

shared by westkea00 on 12 Mar 13 - No Cached
  • Offshore Systems Offshore systems are situated in deep water, typically of more than 131 feet (40 meters). Sophisticated mechanisms—such as the Salter Duck—use the bobbing motion of the waves to power a pump that creates electricity. Other offshore devices use hoses connected to floats that ride the waves. The rise and fall of the float stretches and relaxes the hose, which pressurizes the water, which, in turn, rotates a turbine. Specially built seagoing vessels can also capture the energy of offshore waves. These floating platforms create electricity by funneling waves through internal turbines and then back into the sea. Onshore Systems Built along shorelines, onshore wave power systems extract the energy of breaking waves. Onshore system technologies include: Oscillating Water Columns: Oscillating water columns consist of a partially submerged concrete or steel structure that has an opening to the sea below the waterline. It encloses a column of air above a column of water. As waves enter the air column, they cause the water column to rise and fall. This alternately compresses and depressurizes the air column. As the wave retreats, the air is drawn back through the turbine as a result of the reduced air pressure on the ocean side of the turbine. Tapchans: Tapchans, or tapered channel systems, consist of a tapered channel that feeds into a reservoir constructed on cliffs above sea level. The narrowing of the channel causes the waves to increase in height as they move toward the cliff face. The waves spill over the walls of the channel into the reservoir, and the stored water is then fed through a turbine. Pendulor Devices: Pendulor wave-power devices consist of a rectangular box that is open to the sea at one end. A flap is hinged over the opening, and the action of the waves causes the flap to swing back and forth. The motion powers a hydraulic pump and a generator.
  • Wave energy technologies extract energy directly from surface waves or from pressure fluctuations below the surface. Renewable energy analysts believe there is enough energy in ocean waves to provide up to 2 terawatts of electricity. (A terawatt is equal to a trillion watts.)
Connor Wiggins

fuel cell Facts, information, pictures | Encyclopedia.com articles about fuel cell - 0 views

www.encyclopedia.com/...fuel_cell.aspx

fuel cell

shared by Connor Wiggins on 12 Mar 13 - No Cached
  • Fuel cells convert chemical energy to electrical energy by combining hydrogen from fuel with oxygen from the air. Hydrogen fuel can be supplied in two ways—either directly as pure hydrogen gas or through a "fuel reformer" that converts hydrocarbon fuels such as methanol, natural gas, or gasoline into hydrogen-rich gas. A fuel cell's only emission is water.
  • Connor Wiggins on 12 Mar 13
     
    What fuel cell is and how its made 
crandallmad00

How Tidal Power is Riding the Crest of a Wave - 1 views

www.renewableenergyworld.com/...-is-riding-the-crest-of-a-wave

tide wave

shared by crandallmad00 on 12 Mar 13 - No Cached
  • The argument for tidal power is overwhelming: it’s a practically infinite supply of clean energy and has one of the smallest carbon footprints of any power source; it’s reliable, cost-efficient, has minimal effect on the marine environment and virtually zero effect on sea-gazing aesthetics. Most importantly, The World Energy Council estimates that the energy that can be harvested from world’s oceans is equal to twice the electricity that the world produces now
  • A reason many energy experts are looking at what tidal may be able to contribute, compared to other renewable sources like wind power, is that the amount of energy generated from a power-generating turbine is proportional to the density of the fluid that flows back and forth – meaning a water turbine has several hundred times the power of an air turbine.
  • Seawater is denser than air; a lot denser – 832 times to be exact, meaning an 8 knot tidal current has more energy than a 380kph wind. This means a wave farm of ‘sea snakes’ – devices built by Scotland’s Pelamis Wave Power – covering half a square mile of ocean could produce 30 MWh of power, which is estimated to be enough for 20,000 homes. A wave farm covering 472 square miles could supply 24 million households – enough for the entire UK.
  • ...1 more annotation...
  • Partly this has been due to the uncertainty of how to harness all this abundant marine energy. While it’s great that there’s the potential to harness up to 153 GW of tidal power in the UK alone,
tavarreskat99

What are the advantages and disadvantages of alternative tidal power as an energy source - 1 views

wiki.answers.com/...idal_power_as_an_energy_source

tidal energy

shared by tavarreskat99 on 12 Mar 13 - No Cached
  • Advantages: Tidal energy is an alternative energy. The energy produced is clean and non polluting. There is no carbon dioxide or any other by-products released. It produces no greenhouse gases or other waste.It is a renewable energy that will help reduce our reliance on the burning of fossil fuels. There are two tides every day and they can be relied on. The energy is there for the taking.So the electricity supply is constant and efficient.Once you've built it, the energy is free because it comes from the ocean's powerIt needs no fuel.It produces electricity reliably.Not expensive to maintain.Tides are definitely predictable. There are two tides every day and they can be relied on. So the electricity supply is constant. Offshore turbines and vertical-axis turbines are not ruinously expensive to build and do not have a large environmental impact.A plant is expected to be in production for 75 to 100 yearsUses an abundant, inexpensive fuel source (water) to generate powerMay protect coastline against damage from high storm tides and provide a ready-made road bridge
  • Holding back the tide allows silt to build up on the river bed.The dams and barrages sometimes interfere with shipping. You will need to find a way to connect the electricity to the grid.Pose same threats as large dams, altering the flow of saltwater in and out of estuaries, which changes the hydrology and salinity and possibly negatively affects the marine mammals that use the estuaries as their habitatTurbidity decreases as a result of smaller volume of water being exchanged between the basin and the sea.The average salinity inside the basin decreases, also affecting the ecosystemA barrage across an estuary is very expensive to build, and affects a very wide area - the environment is changed for many miles upstream and downstream. Many birds rely on the tide uncovering the mud flats so that they can feed.There are few suitable sites for tidal barrages.Only provides power for around 10 hours each day, when the tide is actually moving in or out.
  • It only provides about 7% of the power needed for England and Wales that means that some people get their energy close to free and some pay a lot of moneyWater is not replenished, it cannot flow away so any dirt or pollution lingers around the coast much longerNeeds a very big piece of sea to be cost effectiveCannot be used inlandBarrage systems require salt resistant parts and lots of maintenanceAffects the lives of the people who rely on fishing for a means of livingLimited because the tide never speeds up or slows down, and occurs on 6 hour cycles. It is also dependent on the fetch distance. The fetch is the distance the tide rises and falls, so some beaches have a very small fetch, and others have a big fetch but hardly any have a large enough fetch to support tidal energy
lefebvrekat99

BIOFUELS: What are they? How can they be used as an energy source (either on-...(Q&A) - 0 views

energyexperts.org/...ResourceDetail.aspx

biodiesel biofuels biofuel form

shared by lefebvrekat99 on 12 Mar 13 - No Cached
  • ofuels can be derived from almost any type of "biomass," a broad term that refers to living or recently alive biological material. Because biomass is produced on a short time scale, it is considered a renewable resource. I will describe types of biofuels—ethanol, biodiesel, syngas, bio-hydrogen, biogas, and solid biofuel—and their use. I'll also identify the crops and wastes being used to produce biofuels, and some issues surrounding biofuel production. How are biofuels being used? Biofuels are already used to supply a small fraction of our energy needs, with significant opportunities to expand their use as infrastructure is developed. In addition to ethanol and biodiesel for transportation, biofuels are currently used for power production, heating and cooling of buildings, and the thermal needs of industry. Biomass is today the largest non-hydroelectric renewable source for electricity produced in the U.S. Most of this is produced in pulp and paper mills, which often generate electricity by burning wood chips, bark, or the sludges and "liquors" that are byproducts of the paper-making process. At the same time, they recover waste heat from electricity generation to meet the thermal needs of the mill. This highly efficient combination is referred to as combined heat and power (CHP) or cogeneration. The electricity generated may be used onsite and/or supplied to the local utility for distribution to the public.
butlerlex99

Solar Energy Facts: Solar Energy, Solar Cells, Solar Panels | Resourses - 0 views

solarschoolpa.com/solar-energy-facts.html

solar solar power facts

shared by butlerlex99 on 12 Mar 13 - No Cached
  • For billions of years, the sun has poured out huge amounts of energy in several forms, including light, heat, radio waves, and even x-ray. The Earth, in orbit around the sun, intercepts a very small part of the sun’s immense output. On Earth, direct sunlight is available from sunrise until sunset, except during solar eclipses. Solar collectors and modules are designed to capture some of the sun’s energy and change it from radiation into more usable forms such as heat or electricity. In fact, sunlight is an excellent source of heat and electricity, the two most important forms of energy we consume.
  • butlerlex99 on 12 Mar 13
     
    solar energy facts
olearydev99

Benefits | Fuel Cells 2000 - 0 views

www.fuelcells.org/...benefits

fuel cell pollution sustainable picture

shared by olearydev99 on 12 Mar 13 - No Cached
  • olearydev99 on 12 Mar 13
     
    "Benefits Fuel Flexibility: Many fuel cells, like these FuelCell Energy units, can run on natural gas or biogas. Fuel cells offer a unique combination of benefits that make them a vital technology ideally suited for a number of applications.  From high efficiency to scalability, fuel cells provide a distinct advantage over incumbent energy generation technologies, which is why top companies, governments, and the military are adopting fuel cells for everyday use.  Below is a list of the major benefits that fuel cells provide."
leonardsar99

How Much Power Does a Solar Panel Generate? | eHow.com - 0 views

www.ehow.com/ower-solar-panel-generate.html

solar current

shared by leonardsar99 on 12 Mar 13 - No Cached
  • leonardsar99 on 12 Mar 13
     
    "Solar panels produce electric power according to their size, efficiency and how much sunlight they receive. For homeowners and small businesses, roof-mounted panels are a typical option. Solar panels rated at 100 to 200 watts cover about 10 square feet (1 square meter). The power you get from a 100-watt solar panel depends on how much sunlight it receives, and on a daily basis the total power is much less than the rated wattage"
cheniermab99

Wind Turbines for Electricity - 1 views

zfacts.com/244

wind co2 cost

shared by cheniermab99 on 12 Mar 13 - No Cached
  • In 2006, wind power supplied 0.6% of US electricity but reduced CO2 emission from electricity production by a full 1%.
  • What really matters is the cost to society. With current subsidy methods, it costs around 3¢/kWh
  •   One-Time Cost per kW Capacity (usage) Factor Fixed Cost per kWh Variable Cost per kWh Total Cost per kWh Gas Turbine $439 15% 5.2¢ 8.7¢ 13.9¢ Coal $1,338 90% 2.7¢ 1.9¢ 4.5¢ Nuclear $2,180 90% 4.3¢ 0.3¢ 4.6¢ Wind $1,254* 30% 7.5¢ 0.0¢ 7.5¢
  • ...1 more annotation...
  • as coal is the worst source of CO2. Thirty years from now, wind power might be cutting global GHG emissions by 10%.
dylan purner

Energy Basics: Photovoltaics - 1 views

www.eere.energy.gov/...photovoltaics.html

solar history

shared by dylan purner on 08 Mar 13 - No Cached
  • First used in about 1890, "photovoltaic" has two parts: photo, derived from the Greek word for light, and volt, relating to electricity pioneer Alessandro Volta. And this is what photovoltaic materials and devices do—they convert light energy into electrical energy, as French physicist Edmond Becquerel discovered as early as 1839.
  • kenyonlau99 on 08 Mar 13
     
    "First used in about 1890, "photovoltaic" has two parts: photo, derived from the Greek word for light, and volt, relating to electricity pioneer Alessandro Volta. And this is what photovoltaic materials and devices do-they convert light energy into electrical energy, as French physicist Edmond Becquerel discovered as early as 1839. Becquerel discovered the process of using sunlight to produce an electric current in a solid material. But it took more than another century to truly understand this process. Scientists eventually learned that the photoelectric or photovoltaic effect caused certain materials to convert light energy into electrical energy at the atomic level. PV systems are already an important part of our daily lives. Simple PV systems provide power for small consumer items such as calculators and wristwatches. More complicated systems provide power for communications satellites, water pumps, and the lights, appliances, and machines in some homes and workplaces. Many road and traffic signs also are now powered by PV. In many cases, PV power is the least expensive form of electricity for these tasks."
cottonetar98

GENERATION TO THE NATION - 0 views

www.ehow.com/es_4740597_wind-farm-work.html

wind form ehow

shared by cottonetar98 on 08 Mar 13 - No Cached
cottonetar98 liked it
  • Wind is created when the sun hits the earth. The air above water and the air above the ground heat at different rates. Since the air above the ground heats faster, the warm air from the ground hits the atmosphere first. It then is pushed out toward the sea. As the air heads toward the sea, it gets colder and sinks back down to the sea level. This creates a current pushing the sea air toward the land in the form of wind. The stronger the sun's energy on the land and water, the faster the wind will circulate.
  • As the gearbox turns, it feeds the RPM into the generator, which transfers the energy into usable electrical energy and stores it. Large cables are attached to the generator that feed the electrical currents from the generators of all the wind turbines on the farm into one electrical storage area. The energy can then be transported through power lines around the area for commercial and home usage.
  • cottonetar98 on 08 Mar 13
     
    What makes wind. 
dylan purner

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."
shinecal99

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."
dpurdy

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."
parkergar99

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."
lefebvrekat99

Answers - 0 views

wiki.answers.com/...tween_bio_fuel_and_fossil_fuel

biofuel

shared by lefebvrekat99 on 15 Mar 13 - No Cached
  • lefebvrekat99 on 15 Mar 13
     
    "Bio-fuel is produced directly from plant matter typically corn, sugar cane, sugar beets, or cellulose transforming it into alcohol. Fossil fuels are produced by either the decomposition of plant or animal matter over long periods of time under certain conditions such as high temperature and "
rascoekat00

Tidal Power - How Tidal Power Plants Work - 0 views

inventors.about.com/...tidal_power.htm

tidal energy

shared by rascoekat00 on 11 Mar 13 - Cached
  • Tidal power traditionally involves erecting a dam across the opening to a tidal basin. The dam includes a sluice that is opened to allow the tide to flow into the basin; the sluice is then closed, and as the sea level drops, traditional hydropower technologies can be used to generate electricity from the elevated water in the basin. Some researchers are also trying to extract energy directly from tidal flow streams.
  • Another form of ocean energy is called tidal energy. When tides comes into the shore, they can be trapped in reservoirs behind dams. Then when the tide drops, the water behind the dam can be let out just like in a regular hydroelectric power plant.
  • kramerjac99 on 11 Mar 13
     
    How it works
behanjos99

What are geothermal energy advantages and disadvantages? - 0 views

cognitiveanomalies.com/y-advantages-and-disadvantages

disadvantages geothermal form

shared by behanjos99 on 11 Mar 13 - No Cached
  • Advantages: Geothermal energy cost is extremely low compared to many other energy sources. It has low pollution compared to fossil fuels and nuclear energy. Geothermal energy is a renewable energy source. Almost no environmental impact when using geothermal heat from nuclear decay. Geothermal heat pump systems can reduce your energy use storing heat from the summer/sun and makes use of it in the night and winter. Low maintenance systems.
  • Disadvantages: The most important disadvantage is absolutely the geological problem.  The heat source is mostly close to volcanic activity of some sort. Chemicals are byproducts of the production electricity with hot ground water. Some geothermal plants use a lot of water and it needs to go somewhere its after use. Some of the poluting chemicals in that water and steam are sulfur, mercury, hydrogen sulfide, arsenic, ammonia. Earth is a changing creature.  A drilled hole in the ground could supply thousands of homes heat and one earthquake could change that in a second.  It can also change gradually over time. Location, location, location.  That is certainly true of geothermal energy.  It cannot be transported over vast distances.  If used to heat up houses or for hot tap water it is only the quality of the pipe that delivers the water that determines how far it can go and if it will be of any use when it arrives. If the heat is used for electrical production it helps to have plants close so the energy loss is not too great. 
  • Corrosion is a big problem.  Composition of the chemicals can vary but it is always a problem.  It is among other the reason they need to heat up clean water to use and do not use it directly in to heating of houses.  In cases it has been used directly it causes pipes to corrode. In nuclear heating rock the rock cools down over few decades and hundreds of years are needed to get initial heating back.  Power stations of that sort are therefore not considered as profitable. Geothermal Heat pump systems do have high installation cost. Some areas run out of water or run low on ground water during seasonal dry spells. Less water means less heat and less energy to produce. Some drilling sites are too hot to handle.  Yea. Drillers have actually tried and tried some holes and they just can’t get the needed equipment in because the holes shoot it out like guns.   With workers running to stay alive while steel rains down on them. 
jack wells

Wind power - sustainable power generation from wind farms across the globe - 0 views

www.bp.com/sectiongenericarticle.do

Wind sustainable

shared by jack wells on 11 Mar 13 - No Cached
  • Wind power is safe, clean and increasingly affordable – with the potential for production on a much larger scale.Government support is crucial in ensuring the expansion of wind power. We believe such support should be transitional and limited. In the US, there is continuing uncertainty over the renewal of the production tax credit, which provides incentives to invest in wind energy. We are working with other wind energy suppliers to make an effective case for wind energy generation and the renewal of the production tax credit.Wind farms can provide large volumes of electricity (sometimes at a lower cost than conventional power generation)
  • Wind power is safe, clean and increasingly affordable – with the potential for production on a much larger scale.Government support is crucial in ensuring the expansion of wind power. We believe such support should be transitional and limited. In the US, there is continuing uncertainty over the renewal of the production tax credit, which provides incentives to invest in wind energy. We are working with other wind energy suppliers to make an effective case for wind energy generation and the renewal of the production tax credit.Wind farms can provide large volumes of electricity (sometimes at a lower cost than conventional power generation) Wind energy and the environment While wind farms can be an attractive alternative energy offering, they can also stir debate. During the planning stage for each new wind farm we assess the potential social and environmental impacts.The impact on wildlife and habitat The impact of wind farms on local residentsNoise from wind turbinesShadow flicker Interference with communications signalsWe then take steps to manage any negative impacts through engineering design changes, technology and other elements.
  • Wind power is safe, clean and increasingly affordable – with the potential for production on a much larger scale.Government support is crucial in ensuring the expansion of wind power. We believe such support should be transitional and limited. In the US, there is continuing uncertainty over the renewal of the production tax credit, which provides incentives to invest in wind energy. We are working with other wind energy suppliers to make an effective case for wind energy generation and the renewal of the production tax credit.
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