Alternative Energy

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Alternative Energy
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Alternative Fuels/Renewable Energy

• Fossil fuels are non-renewable.
• Uranium-235 is also non renewable. Once it
  fizzes, thats it.
• renewable energy resourcessuch as wind and
  solar energyare constantly replenished and will
  never run out. --DOE

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Advantages of Renewable Energy

• Because these energy sources never run out they
  would provide a cheap, clean alternative to
  fossil fuels.
• There would be no reliance on foreign oil.
• Renewable energy is also pollution-free. No
  greenhouse gases or acid-rain producing /
  smog-producing chemicals are released.
• Renewable energy (sunlight for example) is
  readily available and reliable

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Renewable Energy Sources US and Global Trends

• 6 of US energy is from renewable resources.
  Worldwide the value is higher, 14.
• The majority of this renewable energy (90)
  comes from just two sources
• Hydroelectric
• Biomass (burning wood)

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Alternative Energy Sources
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Renewable Energy Sources

• Many renewable energy forms are directly or
  indirectly related to the sun.
• Solar, hydroelectric, and wind
• Some renewable energy sources not related to the
  sun are
• Geothermal
• Tidal

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Renewable Intro

• For each type of energy source, think about three
  things
• The advantages e.g., unlimited source, no
  pollution, etc.
• The disadvantages environmental consequences,
  limitations to development, other drawbacks
• The practicality (or cost/benefit) how likely
  are these energy sources to provide energy to the
  masses? How can they be improved?

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Figure 14-5
Fusion
A significant portion of energy emitted by
the sun is UV, visible light, and infrared (both
near infrared and thermal infrared).
Thermal infrared (heat), longer wave lengths
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Solar Energy (Cont.)

• At the top of the atmosphere the Earth receives
  1370 watts/m2.
• Approximately 50 of this energy hits the Earths
  surface. The amount of solar energy reaching the
  surface is approximately 700 watts/m2 or 700
  megawatts per 1000 km2.
• Just 40 minutes of sunlight is equivalent to a
  years energy expenditure from fossil fuels.
• The sun delivers 10,000 times the energy used by
  humans
• The use of solar energy for heating or power does
  not change the global energy balance

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Solar Energy, Limitations

• The main problem associated with using solar
  energy is one of taking a diffuse and
  intermittent source and concentrating it into an
  amount and form, such as fuel or electricity,
  that can be used as heat and to run vehicles,
  appliances, and other machinery. In addition,
  what do you do when the Sun is not shining?
  These problems involve the collection,
  conversion, and storage of solar energy. Also,
  in the final analysis, overcoming such hurdles
  must be cost effective.

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Solar Energy Uses

• Solar energy can be used in more limited ways,
  both actively and passively.
• Active solar energy involves the direct capture
  of sunlight and converting it to electricity of
  heat using solar collectors
• Passive, uses solar energy without a collector
  (e.g. a window allows sunlight to warm the house).

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Active Solar Energy

• Active solar energy can be used to
• Power small appliances
• Generate electric power Heat water and homes
• The conversion of solar energy (kinetic) into
  electrical energy (potential) occurs through a
  photovoltaic cell.

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Photovoltaic Cells

• Each cell consists of two very thin layers of
  semiconductor material (silicon) separated by a
  junction layer.
• The kinetic energy of light photons dislodges
  electrons from their atoms, allowing them to flow
  through the semiconductor material to produce
  electricity.

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PV Cell
Photovoltaic Cell
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Photovoltaic Cell Uses

• Currently PV cells are used to power
• Watches
• Calculators
• Satellites
• Outdoor lighting
• Small appliances

http//library01.gsfc.nasa.gov/gdprojs/images/land
sat.jpg
www.eere.energy.gov/.../renewable_energy.html
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PV Cells at Home

• PV Cells can be used in the home to generate
  electricity.
• PV cells are combined to from a module
• 10 modules are mounted in a PV array
• 10 20 arrays are needed to generate enough
  power for the home
• Source DOE, NREL

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Photovoltaic Cells

• Photovoltaic (PV) cells can be manufactured into
  roofing tiles.
• From NERL Thin film technology has made it
  possible for solar cells to now double as rooftop
  shingles, roof tiles, building facades, or the
  glazing for skylights or atria.

http//www.nrel.gov/learning/re_photovoltaics.html
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Solar Energy Power Plants

• Three basic designs of solar power plants (DOE
  National Renewable Energy Lab)
• Parabolic-trough systems concentrate the sun's
  energy through long rectangular, curved
  (U-shaped) mirrors. The mirrors are tilted toward
  the sun, focusing sunlight on a pipe that runs
  down the center of the trough. This heats the oil
  flowing through the pipe. The hot oil then is
  used to boil water in a conventional steam
  generator to produce electricity.

http//www.nrel.gov/learning/re_csp.html
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Solar Energy Power Plants (continued)

• A dish/engine system uses a mirrored dish
  (similar to a very large satellite dish). The
  dish-shaped surface collects and concentrates the
  sun's heat onto a receiver, which absorbs the
  heat and transfers it to fluid within the engine.
  The heat causes the fluid to expand against a
  piston or turbine to produce mechanical power.
  The mechanical power is then used to run a
  generator or alternator to produce electricity.
• A power tower system uses a large field of
  mirrors to concentrate sunlight onto the top of a
  tower, where a receiver sits. This heats molten
  salt flowing through the receiver. Then, the
  salt's heat is used to generate electricity
  through a conventional steam generator. Molten
  salt retains heat efficiently, so it can be
  stored for days before being converted into
  electricity. That means electricity can be
  produced on cloudy days or even several hours
  after sunset.

Source http//www.nrel.gov/learning/re_csp.html
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Solar Electric Power
Power Tower System
Dish-Engine System
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Solar Water Heaters
Solar water heaters, water temperatures can be
around 170F
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Solar Energy and Home Heating

• Solar energy can also be used to heat homes.
• south-facing sides of the house
• This only works during the day, not at night.
  Also if you had a thick cloud cover it wouldnt
  be of much use.
• During the summer months you could block the
  windows.
• Some house designs take advantage of the
  different solar angles throughout the year.

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Solar Heating
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Solar Heating
Summer sun is at a higher angle
Winter sun is at a lower angle
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Benefits of Solar Power

• Currently
• Save lots of money and would reduce pollution
  emissions.
• Federal and State governments provide tax breaks
  and home improvement loans to utilize.
• Curb our dependence on foreign oil

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Wind Power Pros and Cons

• Wind energy is used to turn a turnbogenerator,
  which then creates electricity. Wind energy is
  free and produces no pollutants.
• However winds are not constant everywhere.
• Also wind turbines are known to reduce bird
  populations. The turbine blades grind up flying
  birds like a Cuisinart.
• True, your pet cat probably kills more birds in a
  given day than a single wind turbine (Lumborg,
  The Skeptical Environmentalist), but when
  turbines are spread out along a fly zone they can
  be very detrimental to our feathered friends.
• The Wind turbines are visually unappealing and
  may scar the landscape.

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Wind Turbines

• Turbines are mounted 100 feet above the surface
  to intercept stronger winds.
• A blade acts much like an airplane wing. When
  the wind blows, a pocket of low-pressure air
  forms on the downwind side of the blade. The
  low-pressure air pocket then pulls the blade
  toward it, causing the rotor to turn. This is
  called lift. The force of the lift is actually
  much stronger than the wind's force against the
  front side of the blade, which is called drag.
  The combination of lift and drag causes the rotor
  to spin like a propeller, and the turning shaft
  spins a generator to make electricity.

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Wind Turbines
http//www.nrel.gov/learning/re_wind.html
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(No Transcript)
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Wind Turbines
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US Wind Potential

• The following map (from NERL) shows the windiest
  places in the US. The color code ranges from
  white (very little wind) to red (super windy
  conditions).
• Super windy conditions the red colors. Given
  your Geosciences education to date, can you
  explain why these locations occur where they do?
  That is, what accounts for the variation in wind?
  Why is central Colorado or northwest Wyoming
  windier than the Southeast?
• Check out the wind potential maps for your own
  state
• http//www.eere.energy.gov/windandhydro/windpoweri
  ngamerica/wind_maps.asp
• Other untapped wind resources may be on the
  ocean. Just a thought, but couldnt someone
  design a floating wind turbine system?

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(No Transcript)
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Hydroelectric Power

• Hydroelectric power is the most widely used
  renewable energy.
• The potential energy of water behind a dam is
  converted into electricity. The force of the
  water flowing through the dam gates turns a
  turbine, which is used to make electricity.
• Water is domestically abundant and
  hydroelectric power doesnt generate any
  pollution.
• Hydropower is limited to regions where there are
  large volumes of flowing water (Tennessee Valley,
  the Southeast, and the Northwest).

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Downside of Hydroelectric Power

• Flooded farmland, natural scenery
• Dams displace thousands of people. Construction
  of the Three Gorges Dam in China will displace
  1.9 million people (putting that in perspective,
  thats 2/3s of the residents of the state of
  Mississippi).
• The reservoir environment can alter the
  microenvironment. Construction of the Aswan Dam
  in Egypt has been linked to the spread of
  schistoplasmosis (a parasitic worm) and has been
  associated with advanced denudation of the
  historic Giza Pyramids.
• Damming of rivers poses great ecological threats.
  

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Geothermal Energy
http//www1.eere.energy.gov/geothermal/overview.ht
mlpower_plants
Power plant produces electricity from
geothermal heat
http//www.energy.ca.gov/geothermal/images/geysers
_geothermal.jpg
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Geothermal Energy

• The principle of using geothermal heat to
  generate power is quite sound.
• Heat from the Earths interior is used to boil
  water to generate steam. Like so many other
  sources we have discussed so far, the steam is
  used to turn a turbine that produces electricity.
• This is the only renewable energy source that
  is not directly or indirectly related to the sun.
• Geothermal energy works where there is
  volcanically active landscapes.

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Geothermal Power

• The following is from the DOE website
  http//www1.eere.energy.gov/geothermal/egs_animati
  on.html

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Tidal Power

• The ebb and flow of tides can also be used to
  generate energy.
• The kinetic energy from tides is used to turn
  turbines analogous to wind turbines.
• Tidal power would work best where tides are
  concentrated, such as across bays.

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Tide Power Criticism

• The establishment of tidal barrages (dam-like
  structure across a bay, group of tidal turbines)
  is very controversial for several reasons
• tidal turbines detrimental to the marine life.
• Migration of marine organisms would be
  obstructed.
• The turbines may affect deposition of sediment
• Turbines may have unforeseen ecological
  consequences by mixing salinities
• Tidal barrages would interfere with marine
  navigation
• In addition to these ecological and
  transportation issues, tidal power plants are
• Expensive to build
• Only work for about 10 hours a day
• Could possibly be destroyed by a strong storm
  surge.

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Tidal Power
www.darvill.clara.net/.../MarineTurbines.jpg
http//rhapody2000.free.fr/images/wallpapers/Findi
ng-Nemo-4_800X600.jpg
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Alternative Vehicles

• In addition to developing renewable energy
  sources, there has been substantial development
  in the design of non gasoline-powered vehicles.
  The following slides discuss these alternative
  vehicles.

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Hybrid Cars
Photos from fueleconomy.gov
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Hybrid SUVs
Ford Escape
Mercury Mariner
Saturn Vue
Toyota Highlander
Photos from fueleconomy.gov
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Hybrid Electric Design
http//www.fueleconomy.gov/feg/hybridtech.shtml
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Fuel Economy in Hybrid Cars miles per gallon
Source fueleconomy.gov
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Fuel Economy Hybrid SUVsmiles per gallon
Source fueleconomy.gov
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Full Hybrids

• In the Full Hybrid design, the electric motor
  plays a more important role. The electric motor
  is used
• When the car is started it powers the lights,
  A/C radio, etc. If the battery needs more power,
  the gasoline engine will turn on and recharge.
• When the car is in low gear or at low speeds,
  such as in stop and go traffic.
• At mid and high speeds the gasoline and electric
  motors are used in tandem

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Federal Tax Income Incentives for Hybrid Vehicle
Purchases

• The IRS will give you a tax credit on hybrid
  vehicles purchases starting this tax year,
  January 2006. The tax credit for a particular
  model will be offered up until 60,000 vehicles
  are sold for that model. I guess this means that
  the first 60,000 customers that purchase a Toyota
  Prius will receive 3150, if you buy the vehicle
  between January and September 2006. After October
  1, 2006 the tax credit is reduced to only 1575.
  The Ford, Chevy, and Honda hybrids dont yet
  have a cut off time period I am not sure why?
• Check out the Federal Income Tax table that
  reports the amount of tax credit for the
  different hybrid vehicles fueleconomy.gov

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Hybrid Sales continued

• In 2005, hybrids represented 1.2 of all vehicles
  sold (hybridcars.com)
• In 2006, hybrids are projected to be 10 of all
  vehicles sold. This percentage will continue to
  rise, eventually most cars will employ some sort
  of hybrid engine
• The Toyota Prius was the most sold (52 of all
  hybrids)
• IN 2005, hybrid sales per state are as follows
• California (52,000, 50 of these were sold in LA)
• Florida (10,470)
• Texas (9632)
• New York (9372)
• Virginia (8650 probably D.C. residents?).

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Hybrid Sales

• The number of hybrids sold has skyrocketed since
  2000
• 2006 projected sales are 250,000

August, 2006
Source hybridcars.com
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Electric Cars

• During the late 1990s and early 2000 several
  manufactures spent millions of dollars
  researching and designing electric cars. The
  advent of the hybrid blew the electric car out of
  the water. Electric cars are thought of
  negatively because (from DIDIK.com)
• Maximum mileage from one charge is short (about
  40 miles)
• It takes up to 7 hours to charge the battery and
  you need a high voltage charger. A
• They arent very fast
• They create pollution from the burning of fossil
  fuels.

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Hydrogen Fuel Cells

• CAVS is also on the cutting edge for designing
  Hydrogen Fuel Cells.
• Hydrogen is used to generate electricity to power
  the vehicle via a catalyst. The energy
  conversion rate is unbelievable, up to 60.
  Combustion engine efficiency is about 20. Plus,
  the only waste products are water and heat.
• Fuel cell technology relies on a platinum
  catalyst, which is expensive and a precious
  metal. As of yet, this is not cost effective.
  Sources of hydrogen gas are not readily available.

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Biodiesel Is Made From

• Feedstock - the primary source for biodiesel.
  Oil from both vegetable and animal stocks can be
  converted into fuel.
• Soybean oil is the most dominant
• But it can also be made from
• Vegetable oil (french-fry oil)
• Chicken oil
• Catfish oil
• Tallowtree oil
• Acidulated fatty acids

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Advantages and Limitations of Biodiesel

• Advantages
• Low cost and domestically available
• Can be made from domestic agriculture, no
  reliance on foreign oil
• Many car engines can be easily converted into a
  Biodiesel engine
• Biodiesel burns very clean and doesnt produce
  nearly as much pollution as gasoline engines
• One major limitation to biodiesel right now is
  storage bacteria decompose organics.

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Synopsis?

• Yes, there are viable alternative energy sources
• Are they economically feasible?
• Diffuse
• Widely scattered
• Expensive
• Solutions
• Support research
• Support products