Energy Efficiency and Renewable Energy

1
Energy Efficiency and Renewable Energy
Chapter 16 G. Tyler Millers Living in the
Environment 13th Edition
2
Doing more with less

• Energy efficiency
• is the percentage of total energy input into an
  energy conversion device or system that
• does useful work and
• is not converted to low-quality heat.

3
The Importance of Improving Energy Efficiency

• 84 of all commercial energy produced in the U.S.
  is wasted!

Fig. 16-2 p. 381
4
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/ wasted
• used (First Law of Thermodynamics)
• automatically wasted (Second Law of
  Thermodynamics)
• unnecessarily wasted (this is what needs to be
  conserved)

• Least Efficient
• Incandescent light bulb (5)
• Internal combustion engine (10-15)
• Nuclear power plants (8-14)

5
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.

6
Efficiencies (fig. 16-4 p. 382)
7
Energy Efficiency
8
Could we save energy by recycling energy?

• No
• Second Law of Thermodynamics

9
Ways to Improve Energy Efficiency

• In Our Homes
• Insulation
• Eliminate air leaks
• Clean 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

10
Energy Savings TIPS

• Open Save Energy link from Wikispace!
• http//www.fypower.org/res/tools/energy_tips.html
• http//www.fypower.org/res/ads/

11
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
12
How do we get power?

• CURRENT MEANS via centralized power system and
  existing grid. (Fig 16-39)
•  

13
How do we get power?

• FUTURE MEANS via decentralized power systems and
  grid revision. (Fig 16-40)
• need govt aid in upstarting alternative energy
  sources
• Advantages include low emissions, use locally
  available renewable resources, reliable

14
Shifting to Alternatives

• Advantages
• decreases reliance upon foreign oil
• increases autonomy
• but relies upon economic and politic shift
• STRATEGIES TO ASSIST IN SHIFTING (Fig
  16-44) p. 412
• 1. Competition in free market w/out govt.
  interference
• - Is this feasible?
• - w/out subsidies/taxes/regulation
•  
• 2. Keeping prices artificially LOW to encourage
  use of selected energy resources
• - using subsidies/taxes/regulation
•  
• 3. Keeping prices artificially HIGH to discourage
  use of selected energy resources

15
Shifting Strategies

• (Fig 16-44) p. 412
• Competition in free market w/out govt.
  interference
• Is this feasible?
• w/out subsidies/taxes/regulation
• 2. Keeping prices artificially LOW to encourage
  use of selected energy resources
• - using subsidies/taxes/regulation
• 3. Keeping prices artificially HIGH to discourage
  use of selected energy resources

16
Solar Energy

• DIRECT SOLAR - using radiation from sun, used to
  heat buildings/water through active passive
  systems

17
Using Solar Energy to Provide Heat and
Electricity

• Passive solar heating

• Active solar heating

18
Passive Solar
Absorbs stores heat from sun directly within
structure   Fig. 16-17 p. 394 Fig. 16-18 p.
395     Ex. Energy efficient windows, attached
greenhouses, walls/floors of various materials
19
Active Solar
Collectors absorb solar energy and fan/pumps
supply heat   - several collectors places on
roof, heat stored in tanks filled with
water/rocks/sand for release as needed
20
Using Solar Energy to Provide High-Temperature
Heat and Electricity

• Solar Thermal Systems

21
Here are Rachels Panels
22
Using Solar Energy to Provide High-Temperature
Heat and Electricity

• Photovoltaic (PV) cells

23
PV Cells
PHOTOVOLTAIC (PV) CELLS - convert solar energy
directly to electrical energy by energizing
electrons within cell (semiconducting wafer thin
material) and creating electrical current also
called Solar Cells   EX. Roofing material, glass
walls/windows, cars
24
Using Solar Energy to Provide High-Temperature
Heat and Electricity
25
The Solar-Hydrogen Revolution

• Extracting hydrogen efficiently

• Storing hydrogen

• Fuel cells

26
Hydrogen Cells Fuel Cells
Hydrogen Cells - uses hydrogen gas as fuel when
oil is gone , decreases air pollution, CO2
emissions 2 H2 O2 ? 2 H2O -
produced by the splitting of water by
electrolysis or thermolysis   IS IT TOO GOOD TO
BE TRUE? takes energy to produce fuel
scientists working on renewable methods to
produce hydrogen (p. 407)   Fuel Cell (p.
387 409) H2 O2 combine to produce
electrical currents but the problem is mainly
COST!
27
Hybrid Car (Electric Internal Combustion
Engine)
Fuel
Electricity
28
Fuel Cell Cars
Fuel
Electricity
29
H2
Cell splits H2 into protons and electrons.
Protons flow across catalyst membrane.
Hydrogen gas
3
1
O2
React with oxygen (O2).
2
Produce electrical energy (flow of electrons) to
power car.
4
H2O
Emits water (H2O) vapor.
30
Fuel Cells

• Advantages
• Energy efficiencies of 65-90
• No moving parts
• Quiet
• Emit only water and heat
• More reliable
• Disadvantage
• Cost

31
Geothermal Energy

• Geothermal reservoirs

• Dry steam

• Wet steam

• Hot water

• Molten rock

• Hot dry-rock zones

32
Geothermal Reservoirs
33
Geothermal Energy
GEOTHERMAL ENERGY - uses earthen heat energy
in rocks/fluids as dry steam, wet steam, and hot
water - reservoirs can be depleted if extracted
and used faster than they can naturally be
replenished below ground - nonrenewable resource
on a human scale but due to vast potential
availability, thought to be renewable
34
Producing Electricity from Moving Water

• Large-scale hydropower
• Small-scale hydropower
• Pumped-storage hydropower

35
Producing Electricity from Moving Water

• Tidal power plant
• Wave power

36
Producing Electricity from Heat Stored in Water

• Ocean thermal energy conversion (OTEC)

• Saline Freshwater solar ponds

37
(No Transcript)
38
Producing Electricity from Wind
Fig. 16-28 p. 402
Fig. 16-29 p. 402
39
(No Transcript)
40
Producing Energy from Biomass

• Biofuels
• Biomass plantations
• Crop residues
• Animal manure
• Biogas
• Ethanol
• Methanol

41
Entering the Age of Decentralized Micropower

• Current Centralized power systems

• Future Decentralized power systems

• Micropower systems

42
SolutionsA Sustainable Energy Strategy
43
WAYS TO IMPROVE AUTOENERGY 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 since 1985.

Figure 17-5
44
Increased Fuel Economy

• Rechargeable battery systems

• Hybrid electric-internal combustion engine

• Fuel cells