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BY ALLEN DEARMONDAND LAUREN CUMMINGS hydrogen fuel cells:the power of tomorrow
what is a fuel cell? • Generates electric power using a fuel and an oxidant • Unlike a battery, chemicals are not stored in the fuel cell; they must be replenished • Possible fuel sources: hydrogen, alcohols, hydrocarbons, gasoline • Possible oxidants: oxygen, chlorine, chlorine dioxide • Refueling of an internal combustion engine, efficient and quiet like a battery
types of hydrogen fuel cells • Polymer Electrolyte Membrane (PEM) Fuel Cells • Direct Methanol Fuel Cells • Alkaline Fuel Cells • Phosphoric Acid Fuel Cells • Molten Carbonate Fuel Cells • Solid Oxide Fuel Cells • Regenerative Fuel Cells
science of hydrogen fuel cells • Anode (-) and Cathode (+) on each side of the fuel cell, divided by an electrolyte • Hydrogen gas is channeled through anode side; oxygen passes through cathode • Platinum catalyst oxidizes hydrogen atoms into H+ and electrons • Electrons pass along external circuit; conduct electricity before entering cathode • Electrolyte allows H+ to pass into the cathode • In cathode, catalyst combines H+ , O2- and electrons, forming H2O and heat
science of hydrogen fuel cells • Anode:2H2 => 4H+ + 4e- • Cathode: O2 + 4H+ + 4e- => 2H2O • Net Reaction:2H2 + O2 => 2H2O • Exact opposite of electrolysis
optimization of fuel cells • Catalyst: increases rate of reaction without being consumed in the process • Platinum is main catalyst used in PEM fuel cells • Platinum is expensive and highly sensitive to poisoning • New platinum/ruthenium catalysts being researched for use in hydrogen fuel cells • Reaction requires lower temperatures and high humidity and pressure
present-day applications • Little-to-no pollution, doesn’t need to be recharged • 2500 fuel cell systems have been installed globally • Used to power landfills and water treatment plants • 50 fuel cell buses • Every major automotive manufacturer has designed a fuel cell-powered vehicle • Mercedes-Benz projects 40% efficiency in compact cars running on Hydrogen fuel cells • Hydrogen Fuel Initiative (2003)
present-day applications • Fuel cells require specific humidity, pressure, etc. • Catalysts are pricey and sensitive to poisoning • Difficult to produce hydrogen • Difficult to store optimum amounts of Hydrogen • If fuels other than hydrogen are used, some greenhouse gasses are emitted • Very few cars currently running on hydrogen
the future of fuel cells • Used to power personal electronic devices: cell phones, iPods, laptops • Enough energy to run for days, or weeks (instead of hours) • Potentially power all cars, airplanes, ships, etc. • 60 million tons of carbon dioxide could be eliminated from yearly greenhouse gas production • Development of cheaper and more reliable catalysts • Higher demand = cheaper
the future of fuel cells • Economic crisis has greatly slowed technological advancements • Past predictions for 2010 seem unlikely • Hydrogen cannot be the only alternative fuel source to solve the energy crisis • Many more years of research before mass production will be possible
conclusion • Hydrogen fuel cells are efficient, and clean • Also expensive, and require specific humidity, temperature, pressure • With more technological advancements, could be used in mass production for various applications • Not an instant fix for the energy crisis, but definitely a major component
works cited • Basic Elements: Fuel for the Future. Miramar High School. 3 March 2009. <http://library.thinkquest.org/04apr/00 215/energy/fuel_cells/fuel_cells.htm> • Fuel Cells. Princeton University. 3 March 2009. <http://www.princeton.edu/~ch m333/2002/spring/FuelCells/> • Fuel Cells. U.S. Department of Energy. 9 March 2009. <http://www1.eere.energy.gov/hydrogenandfuelcells/fu elcells/fc_types.html> • Hydrogen.gov United States Government. 10 March 2009. <http://www.hydrogen.gov>. • Nice, Karim and Jonathan Strickland. “How Fuel Cells Work.” 18 September 2000. How Stuff Works.com. <http://www.howstuffworks.com/fuel-cell.htm 3 March 2009>.