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labrumbra99

A Basic Overview of Fuel Cell Technology - 0 views

americanhistory.si.edu/...basics.htm

fuel cell convert

shared by labrumbra99 on 15 Mar 12 - Cached
  • they generate electricity with very little pollution—much of the hydrogen and oxygen used in generating electricity ultimately combine to form a harmless byproduct, namely water.
  • Scientists and inventors have designed many different types and sizes of fuel cells in the search for greater efficiency, and the technical details of each kind vary
  • in general terms, hydrogen atoms enter a fuel cell at the anode where a chemical reaction strips them of their electrons. The hydrogen atoms are now “ionized,” and carry a positive electrical charge. The negatively charged electrons provide the current through wires to do work. If alternating current (AC) is needed, the DC output of the fuel cell must be routed through a conversion device called an inverter.
  • ...6 more annotations...
  • But in general terms, hydrogen atoms enter a fuel cell at the anode where a chemical reaction strips them of their electrons. The hydrogen atoms are now �ionized,� and carry a positive electrical charge. The negatively charged electrons provide the current through wires to do work. If alternating current (AC) is needed, the DC output of the fuel cell must be routed through a conversion device called an inverter.
  • Every fuel cell also has an electrolyte, which carries electrically charged particles from one electrode to the other, and a catalyst, which speeds the reactions at the electrodes. Hydrogen is the basic fuel, but fuel cells also require oxygen. One great appeal of fuel cells is that they generate electricity with very little pollution–much of the hydrogen and oxygen used in generating electricity ultimately combine to form a harmless byproduct, namely water.
  • A fuel cell is a device that generates electricity by a chemical reaction. Every fuel cell has two electrodes, one positive and one negative, called, respectively, the anode and cathode. The reactions that produce electricity take place at the electrodes.
  • fuel cell is a device that generates electricity by a chemical reaction. Every fuel cell has two electrodes, one positive and one negative, called, respectively, the anode and cathode.
  • One detail of terminology:
  • Oxygen enters the fuel cell at the cathode and, in some cell types (like the one illustrated above), it there combines with electrons returning from the electrical circuit and hydrogen ions that have traveled through the electrolyte from the anode. In other cell types the oxygen picks up electrons and then travels through the electrolyte to the anode, where it combines with hydrogen ions. The electrolyte plays a key role. It must permit only the appropriate ions to pass between the anode and cathode. If free electrons or other substances could travel through the electrolyte, they would disrupt the chemical reaction. Whether they combine at anode or cathode, together hydrogen and oxygen form water, which drains from the cell. As long as a fuel cell is supplied with hydrogen and oxygen, it will generate electricity. Even better, since fuel cells create electricity chemically, rather than by combustion, they are not subject to the thermodynamic laws that limit a conventional power plant (see "Carnot Limit" in the glossary). Therefore, fuel cells are more efficient in extracting energy from a fuel. Waste heat from some cells can also be harnessed, boosting system efficiency still further
  • labrumbra99 on 08 Mar 13
     
    "A fuel cell is a device that generates electricity by a chemical reaction. Every fuel cell has two electrodes, one positive and one negative, called, respectively, the anode and cathode. The reactions that produce electricity take place at the electrodes."
  • ricciardellinick on 11 Mar 13
     
    "A fuel cell is a device that generates electricity by a chemical reaction. Every fuel cell has two electrodes, one positive and one negative, called, respectively, the anode and cathode."
kenyonlau99

solar-power.jpg (430×354) - 0 views

solar picture

shared by kenyonlau99 on 13 Mar 13 - No Cached
bonnjos98

How long have people been using geothermal energy? - Curiosity - 1 views

curiosity.discovery.com/...-long-people-geothermal-energy

geothermal history

shared by bonnjos98 on 12 Mar 13 - No Cached
  • knightoli99 on 12 Mar 13
     
    "It may surprise you to know that the ancient Romans had central heating. They used geothermal energy - in the form of hot springs - to heat their homes. Geothermal heating wasn't used in an organized fashion since until the late 19th century when Boise, Idaho, piped in water from local hot springs to warm buildings. Now, geothermal energy is used globally. Reykjavik, Iceland, leads the world in use of geothermal energy, heating 95 percent of its buildings with heat from below the Earth's surface."
  • bonnjos98 on 13 Mar 13
     
    "It may surprise you to know that the ancient Romans had central heating. They used geothermal energy - in the form of hot springs - to heat their homes. Geothermal heating wasn't used in an organized fashion since until the late 19th century when Boise, Idaho, piped in water from local hot springs to warm buildings. Now, geothermal energy is used globally. Reykjavik, Iceland, leads the world in use of geothermal energy, heating 95 percent of its buildings with heat from below the Earth's surface."
coreyemi99

How is solar energy converted into electrical energy - 0 views

wiki.answers.com/...nverted_into_electrical_energy

convert

shared by coreyemi99 on 13 Mar 13 - No Cached
kenyonlau99 liked it
  • Solar energy is very easyto change to electric energy. All you have to do is to take a solar cell. Put it in sunlight or other such source of light. It will use this light energy and will convert it into electric energy.
  • coreyemi99 on 13 Mar 13
     
    how solar energy is converted into electricity
brownale99

How much more expensive is solar energy than fossil fuels - 0 views

wiki.answers.com/...solar_energy_than_fossil_fuels

geothermal cost

shared by brownale99 on 13 Mar 13 - No Cached
  • brownale99 on 13 Mar 13
     
    "Fossil fuel power stations typically cost about $2.1 dollars per watt to build solar stations around $7 at present. The efficiency is increasing and costs are falling. This of course does not represent the cost to the consumer. In addition it does not take into account all the various other costs and the advantages and disadvantages of each. Fuel (fossil stations), poor sunlight (solar stations). Maintenance costs are similar for single plants but solar stations do not have the capacity of fossil fuel stations."
careyeth99

Fuel Cells & Hydrogen | Fuel Cells 2000 - 0 views

www.fuelcells.org/fuel-cells-and-hydrogen

fuel cells hydrogen fuel cell

shared by careyeth99 on 13 Mar 13 - No Cached
  • careyeth99 on 13 Mar 13
     
    A fuel cell is an electrochemical device that combines hydrogen and oxygen to produce electricity, with water and heat as its by-product.
dittrichcai99

How long has geothermal energy been around - 0 views

wiki.answers.com/..._geothermal_energy_been_around

geothermal

shared by dittrichcai99 on 13 Mar 13 - No Cached
  • dittrichcai99 on 13 Mar 13
     
    "In some countries geothermal energy has been around for thousands of years and has been used for cooking and heating."
kennedyeri98

Climate Change: Evidence - 0 views

climate.nasa.gov/evidence

Climate climate change solar

shared by kennedyeri98 on 13 Mar 13 - No Cached
  • evidence that atmospheric CO2 has increased since the Industrial Revolution.
  • been seven cycles of glacial advance and retreat, with the abrupt end of the last ice age about 7,000 years ago
  • proceeding at a rate that is unprecedented in the past 1,300 years.1
dpurdy

Directory:Cents Per Kilowatt-Hour - PESWiki - 9 views

peswiki.com/...ectory:Cents_Per_Kilowatt-Hour

solar tide tidal wind geothermal cost fossil fuels

shared by dpurdy on 08 Nov 11 - Cached
  • Method Cents/kW-h Limitations and Externalities WindCurrently supplies approximately 1.4% of the global electricity demand. Wind is considered to be about 30% reliable. 4.0 - 6.0 Cents/kW-h Wind is currently the only cost-effective alternative energy method, but has a number of problems. Wind farms are highly subject to lightning strikes, have high mechanical fatigue failure, are limited in size by hub stress, do not function well, if at all, under conditions of heavy rain, icing conditions or very cold climates, and are noisy and cannot be insulated for sound reduction due to their size and subsequent loss of wind velocity and power. GeothermalCurrently supplies approximately 0.23% of the global electricity demand. Geothermal is considered 90-95% reliable. 4.5 - 30 Cents/kW-h New low temperature conversion of heat to electricity is likely to make geothermal substantially more plausible (more shallow drilling possible) and less expensive. Generally, the bigger the plant, the less the cost and cost also depends upon the depth to be drilled and the temperature at the depth. The higher the temperature, the lower the cost per kwh. Cost may also be affect by where the drilling is to take place as concerns distance from the grid and another factor may be the permeability of the rock. HydroCurrently supplies around 19.9% of the global electricity demand. Hydro is considered to be 60% reliable. 5.1 - 11.3 Cents/kW-h Hydro is currently the only source of renewable energy making substantive contributions to global energy demand. Hydro plants, however, can (obviously) only be built in a limited number of places, and can significantly damage aquatic ecosystems. SolarCurrently supplies approximately 0.8% of the global electricity demand. 15 - 30 Cents/kW-h Solar power has been expensive, but soon is expected to drop to as low as 3.5 cents/kW-h. Once the silicon shortage is remedied through alternative materials, a solar energy revolution is expected.
  • Tide 2 - 5 Cents/kW-h Blue Energy's tidal fence, engineered and ready for implementation, would provide a land bridge (road) while also generating electricity. Environmental impact is low. Tides are highly predictable.
  • Method Cents/kW-h Limitations and Externalities 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.
carpenteraut98

Fuel Cells Save Money, Fuel and Mother Earth | ReTechnology Power and Water Engineering - 0 views

retechengineering.com/ve-money-fuel-and-mother-earth

fuel cell pollution

shared by carpenteraut98 on 12 Mar 13 - No Cached
  • Although fuel cells are more expensive than fossil fuels, it is predicted that in the near future, fuel cell power will be less expensive and more efficient. The cost is an enticing advantage for the future.
  • The only emission is water vapor, a lot environment-friendly than the toxic elements released into the air by burning fossil fuels and gasoline burning cars.
  • The only waste product is water vapor.
  • carpenteraut98 on 12 Mar 13
     
    "Although fuel cells are more expensive than fossil fuels, it is predicted that in the near future, fuel cell power will be less expensive and more efficient. The cost is an enticing advantage for the future."
pondalb98

Wind Energy Basics - 5 views

windeis.anl.gov/...index.cfm

wind convert

shared by pondalb98 on 13 Mar 12 - Cached
  • Wind is a form of solar energy. Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth's surface, and rotation of the earth. Wind flow patterns are modified by the earth's terrain, bodies of water, and vegetative cover. This wind flow, or motion energy, when "harvested" by modern wind turbines, can be used to generate electricity.
  • The terms "wind energy" or "wind power" describe the process by which the wind is used to generate mechanical power or electricity
  • The terms "wind energy" or "wind power" describe the process by which the wind is used to generate mechanical power or electricity. Wind turbines convert the kinetic energy in the wind into mechanical power
  • ...19 more annotations...
  • Wind turbines, like aircraft propeller blades, turn in the moving air and power an electric generator that supplies an electric current
  • Modern wind turbines fall into two basic groups; the horizontal-axis variety, like the traditional farm windmills used for pumping water, and the vertical-axis design, like the eggbeater-style Darrieus model
  • wind farm, and generate bulk electrical power
  • Utility-scale turbines range in size from 50 to 750 kilowatts. Single small turbines, below 50 kilowatts
  • Wind energy is very abundant in many parts of the United States. Wind resources are characterized by wind-power density classes, ranging from class 1 (the lowest) to class 7 (the highest). Good wind resources (e.g., class 3 and above, which have an average annual wind speed of at least 13 miles per hour) are found in many locations (see United States Wind Energy Resource Map)
  • free, renewable resource, so no matter how much is used today, there will still be the same supply in the future
  • clean, non-polluting, electricity. Unlike conventional power plants, wind plants emit no air pollutants or greenhouse gases
  • higher initial investment than fossil-fueled generators. Roughly 80% of the cost is the machinery, with the balance being site preparation and installation.
  • 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
  • alternative uses may be more highly valued than electricity generation. However, wind turbines can be located on land that is also used for grazing or even farming
  • Wind is a form of solar energy. Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth's surface, and rotation of the earth. Wind flow patterns are modified by the earth's terrain, bodies of water, and vegetative cover. This wind flow, or motion energy, when "harvested" by modern wind turbines, can be used to generate electricity.
  • The terms "wind energy" or "wind power" describe the process by which the wind is used to generate mechanical power or electricity. Wind turbines convert the kinetic energy in the wind into mechanical power. This mechanical power can be used for specific tasks (such as grinding grain or pumping water) or a generator can convert this mechanical power into electricity to power homes, businesses, schools, and the like.
  • Wind turbines, like aircraft propeller blades, turn in the moving air and power an electric generator that supplies an electric current. Simply stated, a wind turbine is the opposite of a fan. Instead of using electricity to make wind, like a fan, wind turbines use wind to make electricity. The wind turns the blades, which spin a shaft, which connects to a generator and makes electricity.
  • Modern wind turbines fall into two basic groups; the horizontal-axis variety, like the traditional farm windmills used for pumping water, and the vertical-axis design, like the eggbeater-style Darrieus model, named after its French inventor. Most large modern wind turbines are horizontal-axis turbines.
  • Wind is a form of solar energy
  • The terms "wind energy" or "wind power
  • describe the process by which the wind is used to generate mechanical power or electricity.
  • Wind turbines, like aircraft propeller blades, turn in the moving air and power an electric generator that supplies an electric current. Simply stated, a wind turbine is the opposite of a fan. Instead of using electricity to make wind, like a fan, wind turbines use wind to make electricity. The wind turns the blades, which spin a shaft, which connects to a generator and makes electricity.
  • freeberntay99 on 08 Mar 13
     
    "Wind is a form of solar energy. Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth's surface, and rotation of the earth. Wind flow patterns are modified by the earth's terrain, bodies of water, and vegetative cover. This wind flow, or motion energy, when "harvested" by modern wind turbines, can be used to generate electricity."
  • pondalb98 on 12 Mar 13
     
    "Modern wind turbines fall into two basic groups; the horizontal-axis variety, like the traditional farm windmills used for pumping water, and the vertical-axis design, like the eggbeater-style Darrieus model, named after its French inventor. Most large modern wind turbines are horizontal-axis turbines."
olearydev99

Hydrogen Fuel - 0 views

www.fueleconomy.gov/...hydrogen.shtml

fuel cell cost

shared by olearydev99 on 19 Mar 12 - No Cached
  • Fuel Cost & Availability. Hydrogen is currently expensive to produce and is only available at a handful of locations, mostly in California. Vehicle Cost & Availability. Fuel cell vehicles are currently far too expensive for most consumers to afford, and they are only available to a few demonstration fleets.
  • olearydev99 on 13 Mar 13
     
    "It is an environmentally friendly fuel that has the potential to dramatically reduce our dependence on imported oil, but several significant challenges must be overcome before it can be widely used."
warneraus98

graph.png (447×324) - 0 views

tide picture

shared by warneraus98 on 13 Mar 13 - No Cached
warneraus98

My Library - 2 views

www.diigo.com/warneraus98

tide sustainable

shared by warneraus98 on 13 Mar 13 - No Cached
  • 90800Tidal energy
  • warneraus98 on 13 Mar 13
     
    power
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