1. Energy
Chapter 13
Sections 5-8

2. Question of the Day Name three of the six types of Renewable Energy.
Or all six for two monkey faces.

3. Answer of the Day The six types of Renewable Energy are. Solar
Flowing water
Wind
Biomass
Hydrogen
Geothermal

5. Renewable Energy
Sustainability (Fig. 6-18, p. 126) mostly depends on solar energy
Why renewable energy is not more widely used
Passive and active solar heating
Cooling homes with less energy

6. Passive and Active Solar Heating
Summer sun
Heavy
insulation
Superwindow
Winter sun
Superwindow
Stone floor and wall for heat storage
Fig a, p. 313
PASSIVE

7. Passive and Active Solar Heating
Heat to house
(radiators or
forced air duct)
Heavy insulation
Pump
Hot water tank
Superwindow
Heat
exchanger
Fig b, p. 313
ACTIVE

8. Question of the Day
What is the difference between primary and secondary/tertiary oil recovery?

9. Answer of the Day
Primary recovery - natural pressure of the reservoir, combined with pumping equipment, brings oil to the surface. (10% of oil recovered)
Secondary - water or gas is injected to displace oil. (20-40% of original oil)
Tertiary - other gases, CO2, and chemicals, along with heat.

10. Passive Solar Designs Direct Gain Ceiling and north wall
heavily insulated
Summer
sun
Hot air
Warm
air
Super
insulated
windows
Winter
sun
Cool air
Earth tubes
Fig a, p. 314

11. Passive Solar Designs Greenhouse, Sunspace, or Attached Solarium
Summer cooling vent
Warm air
Insulated
windows
Cool air
Fig b, p. 314

12. Passive Solar Designs Earth Sheltered Reinforced concrete,
carefully waterproofed
walls and roof
Triple-paned or
superwindows
Earth
Flagstone floor
for heat storage
Fig c, p. 314

13. Tradeoffs of Passive and Active Solar Heating
Passive or Active Solar Heating
Advantages
Disadvantages
Energy is free
Net energy is moderate (active) to high (passive)
Quick installation
No CO2 emissions
Very low air and water pollution
Very low land disturbance
(built into roof or window)
Moderate cost (passive)
Need access to sun
60% of time
Blockage of sun access by
other structures
Need heat storage system
High cost (active)
Active system needs maintenance and repair
Active collectors unattractive
Fig , p. 314

14. Solar Energy for High-Temperature Heat and Electricity
Solar thermal systems
Central receiver system (power tower)
Heliostats
Solar thermal plant
Solar cookers
Photovoltaic (solar) cells

15. Tradeoffs of Solar Energy for High-Temperature Heat and Electric
Heat and Electricity
Advantages
Disadvantages
Moderate net energy
Moderate environmental
Impact
No CO2 emissions
Fast construction (1-2 years)
Costs reduced with natural gas
turbine backup
Low efficiency
High costs
Needs backup or storage system
Need access to sun
most of the time
High land use
May disturb desert areas
Fig , p. 315

16. Tradeoffs of Solar Energy for High-Temperature Heat and Electric
Fig , p. 315

17. Tradeoffs of Solar Energy for High-Temperature Heat and Electric
Single Solar Cell
Boron-enriched silicon
Junction
Phosphorus-
enriched silicon
Fig a, p. 315

18. Solar Cells Provide Electricity for a Village
Fig , p. 316

19. Tradeoffs of Solar Cells
Advantages
Disadvantages
Fairly high net energy
Work on cloudy days
Quick installation
Easily expanded or moved
No CO2 emissions
Low environmental impact
Last years
Low land use (if on roof or built into walls or windows)
Reduce dependence on
fossil fuels
Need access to sun
Low efficiency
Need electricity storage system or backup
High land use (solar cell power plants) could disrupt desert areas
High costs (but should be
competitive in 5-15 years)
DC current must be converted to AC
Fig , p. 316

20. Producing Electricity from Flowing Water
Dams and reservoirs
Greenhouse emissions
Large- and small-scale hydropower
Tidal and wave energy

21. Tradeoffs of Large-Scale Hydropower
Advantages
Disadvantages
Moderate to high net energy
High efficiency (80%)
Large untapped potential
Low-cost electricity
Long life span
No CO2 emissions during operation
May provide flood control below dam
Provides water for year-round
irrigation of crop land
Reservoir is useful for fishing and recreation
High construction costs
High environmental impact from flooding land to form a reservoir
High CO2 emissions from
biomass decay in shallow tropical reservoirs
Floods natural areas behind dam
Converts land habitat to lake
habitat
Danger of collapse
Uproots people
Decreases fish harvest below dam
Decreases flow of natural fertilizer (silt) to land below dam
Fig , p. 317

22. Producing Electricity from Wind
Becoming more popular, especially in Europe
Indirect form of solar energy
Great potential in the Great Plains states

23. Wind Turbines
Fig , p. 318

24. Wind Turbines Gearbox Electrical generator Power cable Wind Turbine
Fig a, p. 318

25. Wind Turbines
Wind Farm
Fig b, p. 318

26. Tradeoffs of Wind Power
Advantages
Disadvantages
Moderate to high
net energy
High efficiency
Moderate capital cost
Low electricity cost
(and falling)
Very low environmental
impact
No CO2 emissions
Quick construction
Easily expanded
Land below turbines
can be used to grow
crops or graze livestock
Steady winds needed
Backup systems when
needed winds are low
High land use for wind farm
Visual pollution
Noise when located
near populated areas
May interfere in flights of migratory birds and kill
birds of prey
Fig , p. 318

27. Biomass Fuel Stepped Art Fig. 13-38, p. 318 Solid Biomass Fuels
Wood logs and pellets
Charcoal
Agricultural waste
(stalks and other plant debris)
Timbering wastes
(branches, treetops, and wood chips)
Animal wastes (dung)
Aquatic plants (kelp and water hyacinths)
Urban wastes (paper, cardboard),
And other combustible materials
Biomass Fuel
Direct burning
Conversion to gaseous
and liquid biofuels
Gaseous Biofuels
Synthetic natural gas
(biogas)
Wood gas
Liquid Biofuels
Ethanol
Methanol
Gasonol
Stepped Art
Fig , p. 318

28. Producing Electricity from Biomass
Wood, crop residues, and animal wastes
Liquid and gas biofuels
Biomass plantations
No net carbon dioxide emissions
Biogas
Ethanol, gasohol, and methanol fuels
Methanol economy?

29. Fuel from Animal Manure
Fig , p. 319

30. Tradeoffs of Solid Biomass Fuels
Advantages
Disadvantages
Large potential supply in some areas
Moderate costs
No net CO2 increase if
harvested and burned
sustainably
Plantation can be located on
semiarid land not needed for
crops
Plantation can help restore
degraded lands
Can make use of agricultural,
timber, and urban wastes
Nonrenewable if harvested
unsustainably
Moderate to high environmental
impact
CO2 emissions if harvested
and burned unsustainably
Low photosynthetic efficiency
Soil erosion, water pollution, and loss of wildlife habitat
Plantations could compete with
cropland
Often burned in inefficient
and polluting open fires
and stoves
Fig , p. 320

31. Tradeoffs of Ethanol Fuel
Advantages
Disadvantages
High octane
Some reduction in CO2 emission
Reduced CO emissions
Can be sold as gasohol
Potentially renewable
Large fuel tank needed
Lower driving range
Net energy loss
Much higher cost
Corn supply limited
May compete with growing
food on cropland
Higher NO emission
Corrosive
Hard to start in
colder weather
Fig , p. 320

32. Tradeoffs of Methanol Fuel
Advantages
Disadvantages
High octane
Some reduction in CO2 emissions
Lower total air
Pollution (30-40%)
Can be made from natural gas, agricultural
wastes, sewage sludge, and garbage
Can be used to produce
H2 for fuel cells
Large fuel tank needed
Half the driving range
Corrodes metal, rubber, plastic
High CO2 emissions if made
from coal
Expensive to produce
Hard to start in cold weather
Fig , p. 321

33. Geothermal Energy Earth’s internal heat Geothermal heat pumps
Geothermal exchange (geoexchange)
Dry and wet steam
Hot water
Molten rock (magma)
Hot dry-rock zones
Warm-rock reservoir deposits
“The Geysers”

34. Tradeoffs of Geothermal Power
Geothermal Fuel
Advantages
Disadvantages
Very high efficiency
Moderate net energy at accessible sites
Lower CO2 emissions than fossil fuels
Low cost at favorable sites
Low land use
Low land disturbance
Moderate environmental impact
Scarcity of suitable sites
Depleted if used too rapidly
CO2 emissions
Moderate to high local air pollution
Noise and odor (H2S)
Cost too high except at the most concentrated and accessible source
Fig , p. 322

35. Hydrogen Power Realistic alternative to petroleum?
Hydrogen is environmentally friendly
Hydrogen takes energy to produce
Fuel cells are expensive
Science Spotlight, p. 323: Producing Hydrogen from Green Algae Found in Pond Scum
Iceland
Storing hydrogen

37. Tradeoffs of Hydrogen Power
Advantages
Disadvantages
Can be produced from plentiful water
Low environmental impact
Renewable if produced
From renewable energy
resources
No CO2 emissions if produced from water
Good substitute for oil
Competitive price if environmental and social costs are included in
cost comparisons
Easier to store than electricity
Safer than gasoline and natural gas
Nontoxic
High efficiency (65-95%) in
fuel cells
Not found in nature
Energy is needed to produce fuel
Negative net energy
CO2 emissions if produced from
carbon-containing compounds
Nonrenewable if generated by
fossil fuels or nuclear power
High costs (but expected to come down)
Will take 25 to 50 years to phase in
Short driving range for current fuel cell cars
No distribution system in place
Excessive H2 leaks may deplete ozone
Fig , p. 322

38. A Sustainable Energy Strategy
Improve energy efficiency
Rely more on renewable sources
Shift to decentralized micropower systems
Natural gas and possibly nuclear fusion
Reduce harmful environmental effects of fossil fuel use
Role of government in developing sustainable energy
Political and economic issues

39. Decentralized Power System
Bioenergy
Power
plants
© 2006 Brooks/Cole - Thomson
Wind farm
Small solar cell
power plants
Fuel cells
Rooftop solar
cell arrays
Solar cell
rooftop systems
Transmission
and distribution
system
Commercial
Small
wind
turbine
Residential
Industrial
Microturbines
Fig , p. 324

40. More Sustainable Energy Future
More Renewable Energy
Improve Energy Efficiency
Increase renewable energy to
20% by 2020 and 50% by 2050
Increase fuel-efficiency
standards for vehicles,
buildings, and appliances
Provide large subsidies and tax
credits for renewable energy
Use full-cost accounting and
life cycle cost for comparing all energy alternatives
Mandate government
purchases of efficient
vehicles and other devices
Encourage government
purchase of renewable energy
devices
Provide large tax credits for
buying efficient cars,
houses, and appliances
Greatly increase renewable
energy research and
development
Offer large tax credits for
investments in efficiency
Reduce Pollution and
Health Risk
Reward utilities for
reducing demand
Cut coal use 50% by 2020
Encourage independent
power producers
Phase out coal subsidies
Levy taxes on coal and oil use
Greatly increase efficiency
research and development
Phase out nuclear power or put
it on hold until 2020
Phase out nuclear power
subsidies
Fig , p. 325

41. What Can We Do?
Drive a car that gets at least 15 kilometers per liter (35 miles per gallon) and join a carpool.
Use mass transit, walking, and bicycling.
Superinsulate your house and plug all air leaks.
Turn off lights, TV sets, computers, and other electronic equipment when they are not in use.
Wash laundry in warm or cold water.
Use passive solar heating.
For cooling, open windows and use ceiling fans or whole-house attic or window fans.
Turn thermostats down in winter and up in summer.
Buy the most energy-efficient homes, lights, cars, and appliances available.
Turn down the thermostat on water heaters to 43-49ºC ( ºF) and insulate hot water heaters and pipes.
What Can You Do?
Energy Use ad Waste
Fig , p. 326
© 2006 Brooks/Cole - Thomson