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Earth’s Changing Environment Lecture 24

Earth’s Changing Environment Lecture 24 Increasing Transportation Efficiency Outline Car and Driver Efficiency Mass Transit Urban Planning New Technologies Cars and Drivers 210 million cars and light trucks 191 million licensed drivers 140 billion gallons gasoline/year

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Earth’s Changing Environment Lecture 24

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  1. Earth’s Changing EnvironmentLecture 24 Increasing Transportation Efficiency

  2. Outline • Car and Driver • Efficiency • Mass Transit • Urban Planning • New Technologies

  3. Cars and Drivers • 210 million cars and light trucks • 191 million licensed drivers • 140 billion gallons gasoline/year • 2.7 trillion vehicle miles

  4. US Automobile Culture • Transportation consumes18% of Household Expenses • 91% travel by private vehicles vs. 2% by mass transit • 76% rides to work are solo • 2.7 trillion vehicle miles per year

  5. Carbon Emissions • US Automobiles add 1.3 billion metric tons of CO2 to atmosphere annually. (23% of US total emission) • Efficiency of cars is 20 miles/gallon • Drivers travel 14,000 miles annually

  6. How do we reduce global impact of US transportation? • Raise CAFE Standards • Reduce Miles Traveled • New Technologies

  7. Raise CAFE Standards • Corporate Average Fuel Economy • Established in 1975 to set U.S. mileage standards.

  8. Current CAFE Standards • 27.5 mpg for passenger automobiles • 20.7 mpg for light trucks & SUVs

  9. How can cars be more efficient? • Smaller & more streamlined (wind resistance) • Lighter (starting & stopping) • Less powerful (lower acceleration)

  10. SUVs • Mileage varies, but as low as 10 mpg as compared with 20 – 30 mpg for many cars and 50 mpg for hybrid electrics. • Possible to achieve a more than 40% improvement with payback within ownership period.

  11. Reduce Driving • Mass Transit • Urban Planning • Ride Sharing

  12. Mass Transit • METRORail • DART • VIA Transit • BART • Mexico City

  13. Train • AMTRAK

  14. Urban Planning • Curitiba, Brazil • Portland, Oregon

  15. Ride Sharing • HOV Lanes • Park & Ride

  16. Bicycle Lanes

  17. Pedestrian Access

  18. We prefer to ride.

  19. New Technologies • Electric Cars • Hybrid Cars • Fuel Cells

  20. Internal Combustion Engine • Engine – 20% efficient • Highway driving – Energy lost to air drag. • City driving – Energy lost during braking

  21. Electric Car • Batteries are heavy and limit range to 100 miles. • Vehicles don’t have enough acceleration for traffic. • Not a practical solution.

  22. Hybrid Electric Vehicles • HEV Program • Honda Insight • Honda Civic • Toyota Prius • 50 mpg

  23. Why do hybrids get better mileage? • Smaller engine. Electric motor boosts gas engine for acceleration. • Regenerative braking. • Electric motor runs at low speed where gas engine is very inefficient. • Electric motor shuts off when stopped.

  24. Fuel Cells and the Hydrogen Economy • Fuels Cells use hydrogen to produce electrical energy • 2H2 +O2 2H2O + energy • Fuel cells could be used to power cars with hydrogen as the fuel. • Clean fuel

  25. Barriers to Hydrogen Cars • Availability of hydrogen fuel. • Storage of hydrogen fuel. • Expensive. • Infrastructure

  26. Fuel Cells • In development stage. • Currently very expensive. • Are not a source of energy. • Hydrogen must be supplied.

  27. Hydrogen Sources • Steam reforming of natural gas: CH4 +2H2O  CO2 + 4H2 • Electrolysis: 2H2O + energy 2H2+ O2

  28. Energy Source for Electrolyzer • Electrolysis requires energy. • Energy could come from Solar, Nuclear, or Wind. • In the short term, it would probably come from coal.

  29. Economics of Hydrogen Economy • Burning gasoline produces a therm for $1.50. • Coal can produce a therm for $0.08. • Coal burned at a power plant to produce electricity to run an electrolyzer could produce power cheaper than gasoline.

  30. Vehicle Carbon Emission(grams per mile)

  31. Conclusions • Hybrid vehicles offer major short-term advantages • Fuel cells are expensive and have infrastructure issues. • Fuel cells based on electricity from coal plants could increase emissions • Mass Transit & other non-automotive options must be considered.

  32. References/Links USDOE: EERE Federal Highway Administration Energy Information Agency National Household Travel Survey Our Nation’s Highways 2000 Hydrogen economy

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