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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
Earth’s Changing EnvironmentLecture 24

Increasing Transportation Efficiency

outline
Outline
  • Car and Driver
  • Efficiency
  • Mass Transit
  • Urban Planning
  • New Technologies
cars and drivers
Cars and Drivers
  • 210 million cars and light trucks
  • 191 million licensed drivers
  • 140 billion gallons gasoline/year
  • 2.7 trillion vehicle miles
us automobile culture
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
carbon emissions
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
how do we reduce global impact of us transportation
How do we reduce global impact of US transportation?
  • Raise CAFE Standards
  • Reduce Miles Traveled
  • New Technologies
raise cafe standards
Raise CAFE Standards
  • Corporate Average Fuel Economy
  • Established in 1975 to set U.S. mileage standards.
current cafe standards
Current CAFE Standards
  • 27.5 mpg for passenger automobiles
  • 20.7 mpg for light trucks & SUVs
how can cars be more efficient
How can cars be more efficient?
  • Smaller & more streamlined (wind resistance)
  • Lighter (starting & stopping)
  • Less powerful (lower acceleration)
slide10
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.
reduce driving
Reduce Driving
  • Mass Transit
  • Urban Planning
  • Ride Sharing
mass transit
Mass Transit
  • METRORail
  • DART
  • VIA Transit
  • BART
  • Mexico City
train
Train
  • AMTRAK
urban planning
Urban Planning
  • Curitiba, Brazil
  • Portland, Oregon
ride sharing
Ride Sharing
  • HOV Lanes
  • Park & Ride
new technologies
New Technologies
  • Electric Cars
  • Hybrid Cars
  • Fuel Cells
internal combustion engine
Internal Combustion Engine
  • Engine – 20% efficient
  • Highway driving – Energy lost to air drag.
  • City driving – Energy lost during braking
electric car
Electric Car
  • Batteries are heavy and limit range to 100 miles.
  • Vehicles don’t have enough acceleration for traffic.
  • Not a practical solution.
hybrid electric vehicles
Hybrid Electric Vehicles
  • HEV Program
  • Honda Insight
  • Honda Civic
  • Toyota Prius
  • 50 mpg
why do hybrids get better mileage
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.
fuel cells and the hydrogen economy
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
barriers to hydrogen cars
Barriers to Hydrogen Cars
  • Availability of hydrogen fuel.
  • Storage of hydrogen fuel.
  • Expensive.
  • Infrastructure
fuel cells
Fuel Cells
  • In development stage.
  • Currently very expensive.
  • Are not a source of energy.
  • Hydrogen must be supplied.
hydrogen sources
Hydrogen Sources
  • Steam reforming of natural gas:

CH4 +2H2O  CO2 + 4H2

  • Electrolysis:

2H2O + energy 2H2+ O2

energy source for electrolyzer
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.
economics of hydrogen economy
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.
conclusions
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.
references links
References/Links

USDOE: EERE

Federal Highway Administration

Energy Information Agency

National Household Travel Survey

Our Nation’s Highways 2000

Hydrogen economy