Transcript Fig. 16-2 p. 381 The Importance of Improving

Energy Efficiency and Renewable
Energy
Chapter 16
G. Tyler Miller’s
Living in the Environment
13th Edition
Key Concepts
•
•
•
•
•
•
•
•
Improving energy efficiency
Solar energy
Hydropower (flowing water)
Wind
Biomass
Hydrogen fuel
Geothermal
Decentralized power systems
Doing more with less
• Energy efficiency
– is the percentage of total energy
input into an energy conversion
device or system that
1) does useful work and
2) is not converted to low-quality heat.
The Importance of Improving Energy
Efficiency
• 84% of all
commercial
energy produced
in the U.S. is
wasted!
Fig. 16-2 p. 381
The Importance of Improving Energy
Efficiency
• Lower life cycle cost
– Initial cost plus lifetime operating cost
• Net energy efficiency
– Total amount of useful energy available minus the
amount of energy
• used (First Law of Thermodynamics)
• automatically wasted (Second Law of Thermodynamics)
• unnecessarily wasted.
Least Efficient
• Incandescent light bulb (5%)
• Internal combustion engine (10-15%)
• Nuclear power plants (8-14%)
REDUCING ENERGY WASTE AND
IMPROVING ENERGY EFFICIENCY
• Four widely used devices waste large amounts
of energy:
– Incandescent light bulb: 95% is lost as heat.
– Internal combustion engine: 94% of the energy in
its fuel is wasted.
– Nuclear power plant: 92% of energy is wasted
through nuclear fuel and energy needed for waste
management.
– Coal-burning power plant: 66% of the energy
released by burning coal is lost.
Efficiencies (fig. 16-4 p. 382)
Uranium
mining
(95%)
Uranium
100%
Uranium processing
and transportation
(57%)
95%
Waste
heat
Power Transmission
plant of electricity
(31%)
(85%)
Waste
heat
14%
17%
54%
Waste
heat
Resistance
heating
(100%)
Waste
heat
Electricity from Nuclear Power Plant
Sunlight
100%
90%
Energy
Efficiency
Passive Solar
Waste
heat
14%
Could we save energy by
recycling energy?
• No
• Second Law of Thermodynamics
Ways to Improve Energy Efficiency
In Our Homes
 Insulation
 Eliminate air leaks
 Air-to-air heat exchangers
Industry
 Cogeneration
– Two useful sources of energy are produced from the same fuel
source
 Efficient electric motors
 High efficiency lighting
 Increased fuel economy
Saving Energy in Existing Buildings
• About one-third of the heated air in typical
U.S. homes and buildings escapes through
closed windows and holes and cracks.
Figure 17-11
WAYS TO IMPROVE ENERGY
EFFICIENCY
• Average fuel
economy of new
vehicles sold in
the U.S. between
1975-2006.
• The government
Corporate
Average Fuel
Economy (CAFE)
has not increased
after 1985.
Figure 17-5
Increased Fuel Economy
 Rechargeable battery systems
 Hybrid electric-internal combustion engine
 Fuel cells
Hybrid Car
(Electric – Internal
Combustion Engine)
A Combustion engine
B Fuel tank
C Electric motor
D Battery bank
B
E Regulator
D
F Transmission
E
F
C
Fuel
Electricity
A
Fuel Cell Cars
A Fuel cell stack
B Fuel tank
C Turbo compressor
B
D Traction inverter
D
C
E
A
Fuel
Electricity
E Electric motor /
transaxle
1 Cell splits H2 into protons
Hydrogen gas
and electrons. Protons flow
across catalyst membrane.
1
2 React with oxygen (O2).
3 Produce electrical
energy (flow of
electrons) to power car.
4
(H2O) vapor.
H2O
3
O2
2
4 Emits water
H2
The Solar-Hydrogen Revolution
Extracting hydrogen efficiently
Storing hydrogen
Fuel cells
Fuel Cells
Advantages
• Energy efficiencies of 65-90%
• No moving parts
• Quiet
• Emit only water and heat
• More reliable
Disadvantage
• Cost
Using Solar Energy to Provide Heat
and Electricity
Passive solar
heating
Active solar
heating
Using Solar Energy to Provide HighTemperature Heat and Electricity
Solar thermal systems
Using Solar Energy to Provide HighTemperature Heat and Electricity
Photovoltaic (PV) cells
Using Solar Energy to Provide HighTemperature Heat and Electricity
Producing Electricity from Moving Water
 Large-scale
hydropower
 Small-scale
hydropower
 Pumped-storage
hydropower
Producing Electricity from Moving Water
 Tidal power
plant
 Wave power
Producing Electricity from Heat
Stored in Water
 Ocean thermal energy conversion (OTEC)
 Saline solar ponds
 Freshwater solar ponds
Producing Electricity from Wind
Fig. 16-28 p. 402
Fig. 16-29 p. 402
Producing Energy from Biomass
Biofuels
Biomass plantations
Crop residues
Animal manure
Biogas
Ethanol
Methanol
Geothermal Energy
Geothermal reservoirs
Dry steam
Wet steam
Hot water
Fig. 16-36
p. 409
Molten rock
Hot dry-rock zones
Geothermal Reservoirs
Fig. 16-37 p. 410
Entering the Age of Decentralized
Micropower
 Current Centralized power systems
 Future Decentralized power systems
 Micropower systems
Fig. 16-39
p. 411
Fig. 16-40 p. 411
Solutions:
A Sustainable Energy Strategy