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Energy, Society, and the Environment Unit 9 TRANSPORTATION and ENERGY

Energy, Society, and the Environment Unit 9 TRANSPORTATION and ENERGY. Outline. Vehicle-Fuel link is strong The Demands for Transportation are strong and increasing Petroleum use has many problems: Dictatorships, sovereignty, pollution, greenhouse gases

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Energy, Society, and the Environment Unit 9 TRANSPORTATION and ENERGY

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  1. Energy, Society, and the EnvironmentUnit 9TRANSPORTATION and ENERGY

  2. Outline • Vehicle-Fuel link is strong • The Demands for Transportation are strong and increasing • Petroleum use has many problems: Dictatorships, sovereignty, pollution, greenhouse gases • But the fossil fuel supplies are large for the time being • Policy and technology needed

  3. World Oil Use Source: World Oil Worksheet (WOW) Model, USDOE/OTT

  4. Liquid Fuels

  5. Transportation Sector Key to Energy Use • Transportation accounts for ~1/3 of energy use • When electricity generation factored out, transportation dominates • Demand projected to increase • 97% of transportation energy from petroleum • Relatively small number of technologies employed • Transportation sector energy use can impact national security and environmental impacts

  6. Performance actually declining Source: EPA (2006)

  7. CAFE: corporate average fuel economy

  8. Source: Brandt and Farrell (2006)

  9. Getting the oil out … to the last drop

  10. Fischer-Tropsch Production • Fischer-Tropsch. In addition to traditional refinery technologies, there is one other technology that is used to produce liquid fuels: Fischer-Tropsch synthesis. • The Fischer-Tropsch process can convert any high-carbon stream ultimately to liquid fuels at significant environmental costs. • It is the process used today in several countries to convert coal and natural gas to liquid fuels.

  11. Vehicle Ownership and GDP/Capita

  12. World Vehicle Projections • By 2050, 3.0 - 4.0 BILLION vehicles in the world (depending on population growth, economic growth, consumer habits)

  13. Where does a car’s gasoline go? • 6% accelerates the car, <1% moves the driver • Three-fourths of the fuel use is weight-related • Because of efficiency, each unit of energy saved at the wheels saves ~7–8 units of gasoline in the tank (or ~3–4 with a hybrid) • So, first make the car dramatically lighter!

  14. But Small cars are unsafe, right??

  15. But Small cars are unsafe, right??

  16. Addressing Transportation • Efficiency is Job #1 • Bring U.S. vehicle efficiency standards to world standards

  17. Addressing Transportation • Efficiency is Job #1 • Bring U.S. vehicle efficiency standards to world standards • Promote the use of goal-appropriate vehicle use

  18. Efficiency is not the entire answer • Efficiency is not a source of energy, “fuels” will still be needed.

  19. Available Options and Criteria • Fossil Fuel ICEs, Hybrid electric cars, Plug-in Hybrid Electric Cars, Electric Cars, Biofuels, Hydrogen • Criteria: Vehicle Technology, Supply Infrastructure, Resource Base, Environment

  20. Hybrid Electric Vehicle (HEV)Combustion engine plus one or more electric motors. Uses only hydrocarbon fuel Battery Electric Vehicle (BEV)Use on on-board electricityRecharged from electrical grid No engine Plug-in Hybrid Electric Vehicle (PHEV)Combustion engine and stored electric energy both usedAdaptation of existing hybrids Range-Extended Electric Vehicle (REEV)Drive power is primarily electric Engine is used only when stored electrical energy is exhausted Slide Credit: Dr. Mark Duvall Electric Power Research Institute

  21. EV and PHEV • Environment • Infrastructure • Resource base • Vehicle Technology

  22. Power Plant-Specific PHEV Emissions in 2010PHEV 20 – 12,000 Annual Miles Slide Credit: Dr. Mark Duvall Electric Power Research Institute

  23. EV and PHEV • Environment:  • Infrastructure:  • Resource base:  (but keep in mind problems with overall energy demand) • Vehicle Technology: ?

  24. Batteries An electrochemical energy storage device chemical energy --> electrical energy (and back during recharging)

  25. EV and PHEV • Environment:  • Infrastructure:  • Resource base:  (but keep in mind problems with overall energy demand) • Vehicle Technology: ? Getting there.

  26. Hydrogen Fuel Cells from the Arizona Daily Wildcat

  27. DaimlerChrysler “F-Cell” Vehicle

  28. Hydrogen • The lightest element • Abundant on Earth but not found in free form • Most commonly found as H2O (water molecule) and CH4 (methane) and a variety of other hydrocarbons. • Hydrogen must, therefore, be produced from these molecules by expending energy. It can then be stored as H gas.

  29. Producing Hydrogen • Steam reforming: from methane with very high temperature steam CH4 + H2O → CO + 3 H2 • Electrolysis: passing electric current through water to separate it into O2 and H2.

  30. Hydrogen stores energy • Steam reforming and electrolysis use energy: so why do it? • Hydrogen can be stored and then recombined with oxygen and release energy. • Hydrogen is not a primary energy source; it stores energy similar to the way a battery does. • Question: Why are hydrocarbons (e.g., methane, petroleum…) primary energy sources but not hydrogen?

  31. Losses in production, storage, recombination Energy density Efficiency • Is hydrogen an efficient energy storage mechanism?

  32. Energy Density • need to compress hydrogen (by A LOT!) or liquefy it to make it transportable

  33. Storage • Optimal hydrogen storage system would have high energy density (by weight and volume), low cost, quick refueling, and good safety • Major candidates are: - compressed gas (~ 700 bar) - cold liquid (cryogenic storage) Compressed gas requires steel tanks that can withstand pressure (very heavy) or expensive materials such as carbon nanotubes, polymers Liquid hydrogen requires cryogenic tanks In either case, hydrogen storage density is ~1% by weight No realistic chemical storage is currently available

  34. How do you use hydrogen? • Fuel Cell: reverse electrolysis Recombine it with oxygen to produce energy and water

  35. Efficiency • Efficiencies multiply • For example, if half the energy lost in step 1 and half of the remaining is lost in step 2, overall efficiency is  = 1/2 x 1/2 = 1/4 (25 %) For hydrogen fuel cells: Overall “well-to-wheel” efficiency = electrolysis efficiency x compression efficiency x recombining efficiency in fuel cell  = 70% x 80 % x 60% = 34 % (optimistic)

  36. Comparison to EVs

  37. Hydrogen Fueling Infrastructure Hydrogen Energy Station in Las Vegas, Nevada

  38. Many challenges remain for hydrogen fuel cell vehicles

  39. Term Paper II • You will need to use turnitin.com to submit it. • Class ID: 2698159 • Class Password: energy • You need to create a user profile asap. Go to turnitin.com and click New User. Then, under New Students, click on Create a User Profile. • Bring printed copy to class on Friday. • This information is also available on D2L.

  40. Announcements 4/20 • Assignment #8 is posted on D2L. It is due Monday April 27.

  41. BIOFUELS Plants high in sugar: Sugarcane, sugar beet, starch Fermentation Bioalcohols Plants high in oil: Oil palm, soybean, algae Heat, purify Burn in diesel engine Cellulosic ethanol from Non-edible plants Convert to sugar with Enzymes, ferment Bioalcohols Many pathways exist for liquid, gas, solid fuels

  42. Limiting Factors • Energetic favorability • Land use • Economical factors • Technology

  43. Algae Biofuels “PetroSun has announced it will begin operation of its commercial algae-to-biofuels facility on April 1st, 2008. The facility, located in Rio Hondo Texas, will produce an estimated 4.4 million gallons of algal oil and 110 million lbs. of biomass per year off a series of saltwater ponds spanning 1,100 acres. Twenty of those acres will be reserved for the experimental production of a renewable JP8 jet-fuel.” (gas2.org) NPR’s Science Friday this past week had a discussion on algae biofuels: http://www.sciencefriday.com/program/archives/200904171

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