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Group items matching "hydrogen potential" in title, tags, annotations or url - qmstech2... - 0 views

groups.diigo.com/...search fuel cells potential
shared by carrowluk99 on 24 Oct 12 - No Cached
  • carrowluk99 on 24 Oct 12
     
    if we fix our problems with price and how we make it hydrogen, we have the potential to generate all of our electrical need using fuel cells 
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Group items matching "change future" in title, tags, annotations or url - qmstech2 | Di... - 0 views

groups.diigo.com/...search biofuel future change
shared by filionmar99 on 24 Oct 12 - No Cached
  • We are working to produce biofuels that are low cost, low carbon, sustainable and able to fulfil the world’s transportation fuel needs on a large scale without compromising food production
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Group items matching "fuel cells potential" in title, tags, annotations or url - qmstec... - 0 views

groups.diigo.com/...search fuel cells location
shared by carrowluk99 on 23 Oct 12 - No Cached
  • carrowluk99 on 23 Oct 12
     
    because there is no source, hydrogen is not limited by its location
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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."
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Environmental, economic, and energetic costs and benefits of biodiesel and ethanol biof... - 0 views

www.pnas.org/...11206.short biofuels costs benefits biodiesel ethanol environmental
shared by tillmanash98 on 15 Mar 12 - No Cached
  • Negative environmental consequences of fossil fuels and concerns about petroleum supplies have spurred the search for renewable transportation biofuels.
  • To be a viable alternative, a biofuel should provide a net energy gain, have environmental benefits, be economically competitive, and be producible in large quantities without reducing food supplies.
  • Ethanol yields 25% more energy than the energy invested in its production, whereas biodiesel yields 93% more. Compared with ethanol, biodiesel releases just 1.0%, 8.3%, and 13% of the agricultural nitrogen, phosphorus, and pesticide pollutants, respectively, per net energy gain. Relative to the fossil fuels they displace, greenhouse gas emissions are reduced 12% by the production and combustion of ethanol and 41% by biodiesel. Biodiesel also releases less air pollutants per net energy gain than ethanol.
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  • Even dedicating all U.S. corn and soybean production to biofuels would meet only 12% of gasoline demand and 6% of diesel demand. Until recent increases in petroleum prices, high production costs made biofuels unprofitable without subsidies. Biodiesel provides sufficient environmental advantages to merit subsidy. Transportation biofuels such as synfuel hydrocarbons or cellulosic ethanol, if produced from low-input biomass grown on agriculturally marginal land or from waste biomass, could provide much greater supplies and environmental benefits than food-based biofuels.
  • We use these criteria to evaluate, through life-cycle accounting, ethanol from corn grain and biodiesel from soybeans.
  • These advantages of biodiesel over ethanol come from lower agricultural inputs and more efficient conversion of feedstocks to fuel. Neither biofuel can replace much petroleum without impacting food supplies.
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