Oil

1
Renewable energy sources

• Consumption rate Renewal rate
• Existing developing sources
• solar
• hydropower
• wind
• biomass
• H2 gas
• geothermal

2
Firstlets get more efficient

• 84 of U.S. energy is wasted
• Low-efficiency vehicles
• Low-efficiency furnaces
• Poorly insulated buildings
• Inefficient items
• Incandescent light bulbs (95 lost)
• Internal combustion engines (86-90 lost)
• Nuclear power plants (86-92 lost)
• Coal power plants (66 lost)
• Increased efficiency decreased reliance on
  foreign oil (or any oil)

3
How do we get more efficient?

• Solar energy
• Cogeneration plants (electricity heat)
• Replace electric motors
• Increase fuel efficiency of vehicles
• Hybrid cars
• Hydrogen fuel-cell cars

• Energy-saving windows
• Use instant water heaters
• Replace incandescent bulbs with fluorescent ones
• Insulate houses, pipes

4
Solar energy

• passive solar heating
• orient structures with the sun
• energy-efficient windows
• walls floors absorb solar heat, release heat
  slowly
• cover windows at night to keep in heat

• active solar heating
• solar collectors (photovoltaic cells)
• heat stored in tanks, rocks, water, chemicals
• heat hot water

5
Solar energy

• solar power plants
• huge arrays track sun, focus sunlight on central
  tower
• or arrays focus sun on oil-filled pipes
• heat creates steam, drives turbines
• Availability related to
• latitude
• season
• day / night cycle
• cloud cover
• New Jersey incentives
• http//www.njcep.com/html/2_incent.html

6
Hydropower

• Dam a river, creates reservoir
• Power from falling water drives turbines
• 10 U.S. / 20 world energy from hydropower
• Environmental costs
• destroys habitat
• changes natural river flow
• increases evaporation
• displaces people, homes
• reservoir traps nutrients
• diseases, parasites
• (e.g. schistosomiasis)

Schistosoma trematode fluke
7
Wind

• 2002 4 / kwh ( cost of coal electricity)
• Need good, consistent wind
• Low environmental impacts ()
• No CO2 emissions
• Could be used to make H2 fuel
• Looks bad, kills some birds, uses up land (-)

8
Biomass

• Energy from burning organic matter
• Wood
• Manure
• Charcoal
• Can produce CO2, depending on fuel source
• Biogas in gas form, used like natural gas
• e.g. methanol, ethanol, methane
• Ethanol mix with gasoline, burns cleaner

9
Hydrogen as the next fuel?

• Positives
• Only emission H2O
• No CO2 emitted
• H2O is everywhere

• Negatives
• May need to use fossil fuels to get H2 from H2O
• Currently expensive to make

10
Geothermal heat

• Energy from steam hot water trapped in rock
• Steam used to heat homes buildings
• CO2 emissions at many plants

Figure 20-32 Page 532
11
Discuss with your group

• What 3 things would you be most interested in
  doing to reduce your energy consumption?
• Which of these renewable energy sources do you
  think is most likely to succeed? ( why)