Energy Efficiency and Renewable
Energy
G. Tyler Miller’s
Living in the Environment
14th Edition
Chapter 18
Key Concepts
Improving energy efficiency
Types and uses of solar energy
Types and uses of flowing water
Uses of wind energy
Types and uses of biomass
Use of geothermal energy
Use of hydrogen as a fuel
Decentralized power systems
The Importance of Improving Energy
Efficiency
 Energy efficiency useful
vs. loses to low quality heat
 Net energy efficiency
Least Efficient
 Incandescent lights
 Nuclear power plants
 Internal combustion
engine
 84% of all U.S. energy is
wasted
Fig. 18-3 p. 381
Energy Efficiencies (Fig. 18-5 p. 381)
Ways to Improve Energy Efficiency
Cogeneration
Efficient electric motors
High-efficiency lighting
Increasing fuel economy
Alternative vehicles
Insulation
Plug leaks
Overview
•Hydrogen is not a primary source of energy, unlike petroleum.
Hydrogen is used to move energy.
•The prospect of clean hydrogen fuel-cell vehicles creates a
sustainable environment without compromising extreme
personal mobility.
Overview
•Fuel cells convert hydrogen gas into
electricity cleanly, making
possible nonpolluting vehicles
powered by electric drive
motors.
• A chicken-and-egg problem exists:
large numbers of fuel-cell
vehicles require adequate fuel
availability to support them,
but the required infrastructure is
hard to build unless there are
significant numbers of fuel-cell
vehicles on the roadways.
•Despite steady improvements, today’s vehicles are only up
to 25% efficient in converting the energy content of
fuels into drive-wheel power. (expected to plateau
around 30%)
•Hydrogen fuel-cell vehicle is nearly twice as efficient, so it
will require just half the fuel energy.
•Of even more significance, fuel cells emit only water and
heat as by-products. Finally, hydrogen gas can be
extracted from various fuels and energy sources, such
as natural gas, ethanol, water (via electrolysis using
electricity) and, eventually, renewable energy systems.
Hybrid and Fuel Cell Cars
 Hybrid electric-internal combustion engine
 Fuel cells
Fig. 18-9 p. 385
Octane 100
Octane 120
6 lbs of CO2 per gallon!
This breaks bonds to make energy
2 H2
1 O2
2 H2O
0 lbs of CO2 per gallon!
This makes bonds to release energy!
Using Solar Energy to Provide Heat
Passive solar heating
Active solar heating
Fig. 18-16 p. 391
Using Solar Energy to Provide HighTemperature Heat and Electricity
Fig. 18-21 p. 395
 Solar thermal systems
 Photovoltaic (PV) cells
Fig. 18-20 p. 394
Producing Energy from Biomass
Biomass and biofuels
Biomass plantations
Crop residues
Animal manure
Biogas
Ethanol
Methanol
Fig. 18-25 p. 398
Producing Electricity from Moving Water
 Large-scale hydropower
 Small-scale hydropower
 Pumped-storage hydropower
 Tidal power plant
 Wave power plant
Reviewing the Trade-offs of
Hydropower Dams
Fig. 15-9 p. 313
Large-scale Hydroelectric Power:
Trade-offs
Fig. 18-22 p. 396
Producing Electricity from Wind
Fig. 18-23 p. 396
Fig. 18-24 p. 397
Geothermal Energy
Geothermal heat pumps
Geothermal exchange
Dry and wet steam
Hot water
Molten rock (magma)
Hot dry-rock zones
The Hydrogen Revolution
Environmentally friendly hydrogen
Extracting hydrogen efficiently
Storing hydrogen
Fuel cells
The Hydrogen Revolution
Fig. 18-31 p. 403
Entering the Age of Decentralized
Micropower
 Decentralized power systems
 Micropower systems
Fig. 18-32 p. 405
Solutions: A Sustainable Energy
Strategy
Fig. 18-35 p. 407