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Sustainable EnergySustainable EnergyChapter 20Chapter 20
Emily DamonPeriod 4/5 APESDr. Unfried
Conservation Much of the energy Americans use is
wasted; used for trivial or extravagant purposes
Many conservation techniques are simple and cost effective Compact fluorescent bulbs produce 4x as much
light and last 10x longer, one can save $30-50 in a lifetime
Light-emitting diodes (LEDs) consume 90% less energy than regular bulbs
In 1980s, U.S. businesses saved $160 billion per year through conservation
Household Energy Conservation Today’s homes use 50% less fuel than a
home built in 1974, but can still be reduced Better insulation, double or triple glazed windows,
thermal efficient curtains or window coverings, sealing cracks and loose joints, reducing air infiltration
National standards passed in 2001 required all new washing machines to use 35% less water in 2007 Reduce water use in the U.S. by 40 trillion liters
per year
U.S. Energy Consumption
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Simple Solutions Turn off appliances; standby mode still
uses a lot of power Standby appliances represent 25% of a
monthly electric bill Home office equipment biggest consumer
Putting computer on sleep mode saves 90% of energy, but best to turn it off
Foreign Programs R-2000 program in Canada
Special double-glazed windows have internal reflective coatings and are filled with an inert gas (argon or xenon)
Have an insulation factor of R11, 10x as efficient as a single-pane window
Superinsulated homes in Sweden require 90% less energy for heating and cooling than an American home
Natural Solutions Designing homes with living spaces near sun
for the winter and shaded by tress or overhang in the summer
Earth-sheltered homes built in south-facing side of slopes or protected on three sides by an earth berm are efficient energy savers Maintain constant subsurface temperatures
Sod roofs provide good insulation, prevent rain runoff, last longer than asphalt shingles
Straw-bale construction offers high insulation qualities and a renewable, inexpensive, easy to construct building material
Carbon Zero Home
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Energy Efficiency Measurement of the energy produced
compared to energy consumed Thermal-conversion machines (steam
turbines in coal-fired or nuclear power plants) can only use 40% of energy in primary fuel into electricity or power because of waste heat Some waste heat is recaptured and used for space
heating Fuel cells convert chemical chemical energy
directly to electricity without a combustion cycle
Transportation Automobiles and trucks account for 40% of U.S. oil
consumption and produce 1/5 of carbon dioxide emissions
EPA states raising average fuel efficiency of a passenger fleet by 3 mpg, American consumers would save$25 billion a year, reduce carbon dioxide emissions by 140 million metric tons per year, and save more oil than the minimum expected production from Alaska’s Arctic National Wildlife Refuge
Bureau of Transportation reports more vehicles than drivers in U.S.
Cars used for 1 billion trips per day Census Bureau reports 3/4 of workers commute alone
in private vehicles < 5% use public transportation or carpool, 0.38% walk or ride a bike
Automobiles Gas mile averages are dependant on fuel costs In 2004, EPA stated SUVs averaged 17.9 mpg
and cars averaged 24.6 mpg Nearly half of all passenger vehicle sales in U.S.
are SUVs and light trucks Conservationists state efficiency standards should
be raised to 44 mpg for cars and 33 mpg for SUVs and light trucks
SUVs and pickup trucks more dangerous than midsize automobiles and no safer than compact or subcompact cars Daimlerchrysler ‘smart car’ from Europe gets
60mpg and easy to maneuver
Diesel-Power Some European models get 78 mpg Clean-diesel technology much cleaner
and quieter than years before Diesel fuel in U.S. is 10x higher in sulfur
(causes acid rain) than in Europe Diesel soot linked to asthma and lung
cancer
Net Energy Yield Measure of energy efficiency Based on total useful energy produced during the
lifetime of an entire energy system without the energy required to make useful energy available
Often expressed as a ratio between output of useful energy and energy costs for construction, fuel extraction, energy conversion, transmission, waste disposal, etc.
Yield/cost ratio and conversion-cycle efficiency also helpful considerations
Moneysaving Programs Utility companies pay less to finance conservation
projects than build new power plants Pacific Gas and Electric in California, Potomac
Power and Light in Washington, D.C., both instituted conservation programs Found conservation costs $350 per kilowatt saved New nuclear power plant costs $3,000 and $8,000
per kW Conservation programs also do not consume fuel
or produce pollutants South Korea began conversation program with
energy standards and economic incentives for eco-friendly practices
Cogeneration Simultaneous production of electricity and
steam or hot water at the same plant Net energy yield increased from 30-35% to
80-90% Cogeneration is not a significant part of power
supply Combined-cycle coal-gasification plants highly
efficient and cleanly operated Small power-generating units burn methane,
natural gas, diesel fuel, or coal Inexpensive, produce relatively large amounts of energy,
reliable
Cogeneration Plant
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Solar Energy All biomass results from converting light energy
into chemical bond energy Simplest use of solar energy is passive heat
absorption Using natural materials or absorptive structure with no
moving parts to gather and hold heat Modern adaptation greenhouse, glass walls with energy-
storing materials (bricks, stone, etc.) Interior, heat-absorbing wall called Trombe wall is good
heat collector Active solar systems reduce water heating energy
Accounts for 15% of U.S.’s domestic energy budget Solar energy stored in a large, insulated bin
containing stone, water, or clay
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High-Temperature Solar Energy Parabolic mirrors are curved reflecting
surfaces that collect light and focus it to a concentrated point. Two ways to collect solar energy with mirrors
Mirrors focused on a central tube containing heat-absorbing liquid; fluid reaches higher temperature than a basic flat panel collector
Thousands of small mirrors in rings around a tall central tower; track the sun and focus light on heat absorber at power tower
Used in solar cookers
Energy Policies Encourage conservation and alternative
energy sources Iowa’s Revolving Loan Fund provides low-
interest loans for renewable energy and conservation
Colorado among first to promote green pricing (profits from conservation programs) Customers agreed to pay higher electric rates to
fund wind farm 1997 British Petroleum PLC put $20 million
into solar cell manufacturing facility
Photovoltaic Cells Captures solar energy and converts
directly to electrical currents First observed by Alexandre-Edmond
Becquerel in 1839 Used in U.S. space exploration, since
then prices have dropped Part of the invention of amorphous
silicon collectors Lightweight, require less material than
conventional photovoltaic cells
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Fuel Cells Use ongoing chemical reactions to produce electrical current NASA developed modern fuel cell to provide water and
electricity for shuttles Small size, high efficiency, low emissions, net water
production, no moving parts Positive electrode (cathode) and negative electrode (anode)
separated by electrolyte (allows passage of charges atoms, but impermeable to electrons)
Proton exchange membrane (PEM) used in automobiles, lightweight, operates at low temperature, fuel efficiency less than 40%
Stationary electrical generation uses phosphoric acid immobilized in a porous ceramic matrix
Higher efficiency, 40-50%, heavier and larger, less sensitive to carbon dioxide contamination
PEM and Phosphoric Acid Fuel Cell
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Biomass Wood provides <1% of U.S. energy
Still prominent(95%) in poor countries of world Northern countries burn wood to avoid rising oil, coal
and gas prices Produces smoke, soot, carbon monoxide and hydrocarbons
EPA ranks wood burners on list of heath risks, recommend switching to low-emission models
Catalytic combustors placed inside stovetops, burn carbon monoxide and hydrocarbons, recapture heat
40% world population depends on firewood and charcoal 3/4 do not have enough
Other Options Dry and burn animal manure
Intensifies food shortages, reduces crop productions
Burned in open fires, 90% potential heat and most nutrients lost More efficient to produce methane gas with
methane digesterProduced by anaerobic decomposition of
organic material when organic wastes are placed in a container with warmth and water
Remaining sludge excellent fertilizer
Hydropower Many countries produce their electricity from water
Norway depends on water for 99% of power 2.3 of economically feasible potential remains undeveloped Recent development in large-scale dams
Bring unwanted social and environmental effects Can cause catastrophic floods and thousands of deaths Sedimentation, rotting vegetation, human displacement, wildlife losses,
pesticide pollution Low-head hydropower technology, small scale dams cause
less damage High-efficiency turbines submerged into streams, do not
require dam, minimal environmental damage Micro-hydro generators provide enough energy for one home Public Utility Regulatory Policies Act of 1978 included
economic incentives for small-scale energy projects
Wind Energy High oil prices in 1970s created new interst in wind power Can generate 5 MW of electricity, 5,000 American homes Cheapest source of new power generation Shorter planning and construction times than fossil fuel or
nuclear power plants No fuel costs or air emissions
Intermittent source,not useable in every location Germany get 1/3 of electricity from wind power
Construction cheap and simple Farmers could cultivate 90% of fields white earning $2,000 or more
in rent High bird mortality, some object to physical appearance,
not located near cities, difficult to store energy
Geothermal Energy Areas around continental plates have energy in
forms of hot springs, geysers and fumaroles Yellowstone National Park in U.S., ad Iceland, Japan
and New Zealand all high concentrations of geothermal springs and vents
Electric power production, industrial processing, space heating, agriculture, aquaculture
Long life span, no mining or transportation of fuels, little waste disposal Geothermal system with reduce home heating and
cooling by 50% and pay for itself in 5 years Potential of noxious gases in steam, noise
problems from steam-pressure relief valves
Tidal and Wave Energy Tidal station similar to hydropower dam,
turbines spin as tide flows through Fears of saltwater flooding freshwater
aquifers, flooding and discursion of shoals, salt flats, breeding grounds of aquatic species, vital food source for shorebirds
Heavy siltation, scouring of seafloor as a result of water shooting through dam
Still not well researched, wave power could contribute to 16% of world electrical output
Ocean Thermal Electric Conversion
Differences in temperature between upper and lower layers of ocean water potential source of renewable energy
Ocean thermal electric conversion system heat from warmed upper lawyers evaporates a working fluid like ammonia or Freon Gas pressure high enough to spin turbines to
generate electricity, cold water pumped to cool gas Best for locations on top of volcanic
seamounts Hawaii, west coast of Africa, south coast of Java,
and South Pacific islands all usable
Works CitedCunningham, William P., Mary Ann Cunningham, and Barbara
Woodworth Saigo. Environmental Science: A Global Concern. Boston: McGraw-Hill, 2007. Print.
"Fuel Cell." Udomi. N.p., 2009. Web. 8 Feb. 2010. <http://www.udomi.de/ fuelcell/fuelcell-basics.html>.
"How Fuel Cells Work." PBS. N.p., July 2005. Web. 8 Feb. 2010. <http://www.pbs.org/wgbh/nova/sciencenow/3210/01-fcw.html>.
"Renewable Hydropower." U.S. Energy Information Administration. N.p., n.d. Web. 8 Feb. 2010. <http://tonto.eia.doe.gov/kids/ energy.cfm?page=hydropower_home-basics>.
"Sustainable Energy." World Nuclear Association. N.p., Aug. 2009. Web. 8 Feb. 2010. <http://www.world-nuclear.org/info/inf09.html>.