Energy and Waste Chapters 15, 16, and 22 Living in the Environment, 11th Edition, Miller

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Renewable Energy Chapters18 Living in the
Environment, 14th Edition, Miller
Advanced Placement Environmental Science A.C.
Mosley High School Mrs. Dow
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Energy Efficiency Solar Energy Hydropower Wind
Power Biomass Geothermal Hydrogen Sustainability
www.bio.miami.edu/beck/esc101/Chapter1415.ppt
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Energy Efficiency
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Efficiency of Some Common Devices

• Device Efficiency ()
• Dry-cell flashlight battery 90
• Home gas furnace 85
• Storage battery 70
• Home oil furnace 65
• Small electric motor 62
• Steam power plant 38
• Diesel engine 38
• High-intensity lamp 32
• Automobile engine 25
• Fluorescent lamp 22
• Incandescent lamp 4

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Energy Efficiency
percentage of energy input that does useful work
in an energy conversion system
www.bio.miami.edu/beck/esc101/Chapter1415.ppt
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Ways to Improve Energy Efficiency

• Between 1985 and 2001, the average fuel
  efficiency for new motor vehicles sold in the
  United States leveled off or declined
• Fuel-efficient models account for only a tiny
  fraction of car sales
• Hybrid-electric cars are now available and sales
  are expected to increase
• Fuel-cell cars that burn hydrogen fuel will be
  available within a few years
• Electric scooters and electric bicycles are
  short-range transportation alternatives

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Energy use of various types of transportation
www.bio.miami.edu/beck/esc101/Chapter1415.ppt
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Ways to Improve Energy Efficiency

• Superinsulated house is more expensive than a
  conventional house, but energy savings pay back
  the extra cost
• Strawbale houses have the additional advantage of
  using an annually renewable agricultural residue,
  thus slowing deforestation

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Ways to Improve Energy Efficiency

• Existing homes can be made more energy efficient
• adding insulation
• plugging leaks
• installing energy-saving windows
• wrapping water heaters
• installing tankless models
• buying energy-efficient appliances and lights

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Natural Gas or Electricity

• Water heater
• Electricity is produced at power plant via gas or
  coal and transferred via wire to your home
• Some energy is lost over the wire,

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Water Heater

• Tank
• Water is heated 365/24/7
• Because heat is lost through the flue and the
  walls of the storage tank (this is called standby
  heat loss), energy is consumed even when no hot
  water is being used.

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Water Heater

• Tankless
• The energy consumption of these units is
  generally lower since standby losses from the
  storage tank are eliminated.
• Demand water heaters with enough capacity to meet
  household needs are gas- or propane-fired.
• http//www.aceee.org/consumerguide/topwater.htm

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Energy Efficiency Solar Energy Hydropower Wind
Power Biomass Geothermal Hydrogen Sustainability
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Solar Energy

• Buildings can be heated
• passive solar heating system
• active solar heating system
• Solar thermal systems are new technologies that
  collect and transform solar energy into heat that
  can be used directly or converted to electricity
• Photovoltaic cells convert solar energy directly
  into electricity

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Suitability of Solar Usage
best when more than 60 of daylight hours sunny
www.bio.miami.edu/beck/esc101/Chapter1415.ppt
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Solar Heating
Passive system Absorbs stores heat from the
sun directly within a structure
Active system Collectors absorb solar energy, a
pump supplies part of a buildings heating or
water heating needs.
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Trade-offs
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
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Solar Domestic Hot Water (SDHW)

• An open circuit hot water system heats the
  domestic water directly on the roof of the
  building
• The water flows from the heat collector into the
  hot water tank to be used in the house
• Integration of solar energy conservation in homes
  can reduce energy consumption by 75-90.
• www.iea-shc.org

www.earlham.edu/parkero/Seminar/
SOLAR20AMERICA5B15D.ppt
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Photovoltaic (Solar) Cells
Provides electricity for buildings
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Inside the PV cell

• PV cells are made from silicon alloys
• PV module
• 1cm by 10cm cells
• 36 cells connected

www.earlham.edu/parkero/Seminar/
SOLAR20AMERICA5B15D.ppt
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Trade-Offs
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 20-40 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
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Solar Thermal Techniques
Solar Two
www.earlham.edu/parkero/Seminar/
SOLAR20AMERICA5B15D.ppt
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Heliostats

• Heliostats provide concentrated sunlight to the
  power tower
• The reflecting mirrors follow the sun along its
  daily trajectory

www.earlham.edu/parkero/Seminar/
SOLAR20AMERICA5B15D.ppt
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Power Tower

• Sunlight from mirrors are reflected to fixed
  receiver in power tower
• Fluid transfers the absorbed solar heat into the
  power block
• Used to heat a steam generator

Solar One
www.earlham.edu/parkero/Seminar/
SOLAR20AMERICA5B15D.ppt
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Trade-Offs
Solar Energy for High-Temperature 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
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Solar-Hydrogen Revolution

• Splitting water can produce H2 gas
• If scientists and engineers can learn how to use
  forms of solar energy to decompose water cheaply,
  they will set in motion a solar-hydrogen
  revolution
• Hydrogen-powered fuel cells could power vehicles
  and appliances

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Energy Efficiency Solar Energy Hydropower Wind
Power Biomass Geothermal Hydrogen Sustainability
www.bio.miami.edu/beck/esc101/Chapter1415.ppt
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History of Hydroelectric

• B.C. - Used by the Greeks to turn water wheels
  for grinding wheat into flour, more than 2,000
  years ago
• 1775 - U.S. Army Corps of Engineers founded, with
  establishment of Chief Engineer for the
  Continental Army
• 1880 - Michigan's Grand Rapids Electric Light and
  Power Company, generating electricity by dynamo,
  belted to a water turbine at the Wolverine Chair
  Factory, lit up 16 brush-arc lamps.

www.usd.edu/phys/courses/scst601/
hydroelectric/hydro.ppt
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History of Hydroelectric

• By 1940 - 40 of electrical generation was
  hydropower
• Between 1921 and 1940 - conventional capacity in
  the U.S. tripled almost tripled again between
  1940 and 1980
• Currently - about 10 of U.S. electricity comes
  from hydropower.

www.usd.edu/phys/courses/scst601/
hydroelectric/hydro.ppt
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www.usd.edu/phys/courses/scst601/
hydroelectric/hydro.ppt
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Turbine Technologies

• Reaction
• fully immersed in fluid
• shape of blades produces rotation

www.usd.edu/phys/courses/scst601/
hydroelectric/hydro.ppt
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Trade-Offs
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 irrigatio
n 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
Figure 18-22Page 396
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Tidal Power Plant
www.bio.miami.edu/beck/esc101/Chapter1415.ppt
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Energy Efficiency Solar Energy Hydropower Wind
Power Biomass Geothermal Hydrogen Sustainability
www.bio.miami.edu/beck/esc101/Chapter1415.ppt
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Rotary Windmill
www.usd.edu/phys/courses/scst601/wind_energy.ppt
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Vertical Blades
www.usd.edu/phys/courses/scst601/wind_energy.ppt
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www.bio.miami.edu/beck/esc101/Chapter1415.ppt
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Energy from Wind

• Production of electricity and hydrogen gas by
  wind farms is expected to increase
• Western Europe currently leads in the development
  of wind power
• Land used for wind farms also can be used for
  ranching or crops and most profits stay in local
  communities
• North Dakota

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Optimization

• Low Torque Rapid Speed
• good for electrical generation
• High Torque Slow Speed
• good for pumping water
• Small generator
• low wind speeds
• captures small amount of energy
• Large generator
• high wind speeds
• may not turn at low speeds

www.usd.edu/phys/courses/scst601/wind_energy.ppt
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www.bio.miami.edu/beck/esc101/Chapter1415.ppt
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Source American Wind Energy Association
www.usd.edu/phys/courses/scst601/wind_energy.ppt
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Trade-Offs
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
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Energy Efficiency Solar Energy Hydropower Wind
Power Biomass Geothermal Hydrogen Sustainability
www.bio.miami.edu/beck/esc101/Chapter1415.ppt
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Energy from Biomass

• In the developing world, most people heat homes
  and cook by burning wood or charcoal
• Plant materials and animal wastes also can be
  converted into biofuels,
• Biogas
• Liquid ethanol
• Liquid methanol
• Urban wastes can be burned in incinerators to
  produce electricity and heat

www.bio.miami.edu/beck/esc101/Chapter1415.ppt
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Types of Biomass Fuel
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Biorefinery

• Fuels
• Ethanol
• Renewable Diesel
• Methanol
• Hydrogen
• Electricity
• Heat
• Products
• Plastics
• Foams
• Solvents
• Coatings
• Chemical Intermediates
• Phenolics
• Adhesives
• Fatty acids
• Acetic Acid
• Carbon black
• Paints

Conversion Processes

• Biomass
• Feedstock
• Trees
• Forest Residues
• Grasses
• Agricultural Crops
• Agricultural Residues
• Animal Wastes
• Municipal Solid Waste

• Acid Hydrolysis/Fermentation
• Enzymatic Fermentation
• - Gas/liquid Fermentation
• - Thermochemical Processes
• - Gasification/Pyrolysis
• - Combustion
• - Co-firing

www.sc.doe.gov/bes/besac/BESACGarman08-02-01.ppt
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Trade-Offs
Solid Biomass
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
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Energy Efficiency Solar Energy Hydropower Wind
Power Biomass Geothermal Hydrogen Sustainability
www.bio.miami.edu/beck/esc101/Chapter1415.ppt
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Geothermal Energy

• Geothermal energy can be used to heat buildings
  and to produce electricity
• Geothermal reservoirs can be depleted if heat is
  removed faster than natural processes renew it,
  but the potential supply is vast

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Technology

• Geothermal Heat Pumps
• shallow ground energy
• Direct-Use
• hot water can be piped to facilities
• Power Plants
• steam and hot water drive turbines
• dry steam plants
• flash steam plants
• binary cycle plants

www.usd.edu/phys/courses/scst601/
geothermal/GeothermalEnergy.ppt
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Dry Steam Power Plants

• Hydrothermal fluids are primarily steam
• Steam goes directly to turbine
• No fossil fuels

www.usd.edu/phys/courses/scst601/
geothermal/GeothermalEnergy.ppt
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Flash Steam Power Plant

• Fluids above 200 degrees Celsius
• Fluid is sprayed into tank at lower pressure
• Fluid rapidly vaporizes
• Steam drives turbine

www.usd.edu/phys/courses/scst601/
geothermal/GeothermalEnergy.ppt
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Binary Cycle Power Plant

• Cooler water (below 200 degrees Celsius)
• Hot thermal fluid and a second fluid pass through
  heat exchanger

www.usd.edu/phys/courses/scst601/
geothermal/GeothermalEnergy.ppt
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Heat Mining

• Last week the Massachusetts Institute of
  Technology released a study concluding that heat
  mining could generate enough energy by 2050 to
  replace the coal-fired and nuclear power plants
  that are likely to be retired over the next
  several decades.
• Boston Globe Gareth Cook, Globe Staff    January
  29, 2007 _at_ http//www.boston.com/news/globe/health
  _science/articles/2007/01/29/the_power_of_rocks/

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• At present the DHM project and drilling
  activities are financed by the Swiss Federal
  Office of Energy (SFOE), the canton of the city
  of Basel, the water and energy public utilities
  of Basel (IWB), a power company (Elektra Basel
  Land), and a private foundation (G.H. Endress)
  http//www.geothermie.de/iganews/no45/the_swiss_de
  ep_heat.htm

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Benefits

• Clean Energy
• one sixth of carbon dioxide vs. natural gas
• very little if any nitrous oxide or sulfur
  compounds
• Availability
• 24 hours a day, 365 days a year
• Homegrown
• Renewable

www.usd.edu/phys/courses/scst601/
geothermal/GeothermalEnergy.ppt
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Environmental Effects

• Only emission is steam
• Salts and dissolved minerals reinjected
• Some sludge produced
• Mineral extraction
• Little Visual Impact
• Small acreage, no fuel storage facilities

www.usd.edu/phys/courses/scst601/
geothermal/GeothermalEnergy.ppt
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Location

• Hot geothermal fluid
• Low mineral and gas content
• Shallow aquifers
• Producing and reinjecting the fluid
• Private land
• Simplifies permit process
• Proximity to transmission lines

www.usd.edu/phys/courses/scst601/
geothermal/GeothermalEnergy.ppt
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www.eren.doe.gov/power/consumer/
rebasics_geothermal.html
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Trade-Offs
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
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Future

• Only tiny fraction is currently used
• Dry hot rock heated by molten magma
• Drill into rock and circulate water

www.usd.edu/phys/courses/scst601/
geothermal/GeothermalEnergy.ppt
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Energy Efficiency Solar Energy Hydropower Wind
Power Biomass Geothermal Hydrogen Sustainability
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Hydrogen 18.8

• Produced from water organic molecules
• Nonpolluting water vapor when burned
• Ready by 2020-2030
• Possible to use bacteria to process

• Problems
• Chemically locked up in water organic compounds
• Takes lots of energy (it is not a source of
  energy, simply fuel)
• Fuel cells are expensive
• Hard to store
• How will hydrogen affect atmosphere

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Trade-Offs
Hydrogen
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
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Energy Efficiency Solar Energy Hydropower Wind
Power Biomass Geothermal Hydrogen Sustainability
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A sustainable energy strategy

• Govt subsidies
• Tax breaks
• Avoid wasted energy
• Tax fossil fuels
• Use the sun
• Cut pollution
• U.S. is a first world nation with a third world
  grid system

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73 billion
Nuclear energy (fission and fusion)
32 billion
Fossil fuels
19 billion
Renewable energy
Energy efficiency (conservation)
15 billion
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Suggestions to make the transition to a
more sustainable energy future.
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What Can You Do?
Energy Use ad Waste

• 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 (110-120ºF) and insulate hot water
  heaters and pipes.