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Alternative Energy

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Title: Alternative Energy


1
Alternative Energy
2
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

3
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

4
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)

5
Alternative Energy Sources
6
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

7
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?

8
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
9
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

10
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.

11
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).

12
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.

13
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.

14
PV Cell
Photovoltaic Cell
15
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
16
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

17
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
18
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
19
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
20
Solar Electric Power
Power Tower System
Dish-Engine System
21
Solar Water Heaters
Solar water heaters, water temperatures can be
around 170F
22
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.

23
Solar Heating
24
Solar Heating
Summer sun is at a higher angle
Winter sun is at a lower angle
25
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

26
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.

27
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.

28
Wind Turbines
http//www.nrel.gov/learning/re_wind.html
29
(No Transcript)
30
Wind Turbines
31
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?

32
(No Transcript)
33
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).

34
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.

35
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
36
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.

37
Geothermal Power
  • The following is from the DOE website
    http//www1.eere.energy.gov/geothermal/egs_animati
    on.html

38
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.

39
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.

40
Tidal Power
www.darvill.clara.net/.../MarineTurbines.jpg
http//rhapody2000.free.fr/images/wallpapers/Findi
ng-Nemo-4_800X600.jpg
41
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.

42
Hybrid Cars
Photos from fueleconomy.gov
43
Hybrid SUVs
Ford Escape
Mercury Mariner
Saturn Vue
Toyota Highlander
Photos from fueleconomy.gov
44
Hybrid Electric Design
http//www.fueleconomy.gov/feg/hybridtech.shtml
45
Fuel Economy in Hybrid Cars miles per gallon
Source fueleconomy.gov
46
Fuel Economy Hybrid SUVsmiles per gallon
Source fueleconomy.gov
47
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

48
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

49
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?).

50
Hybrid Sales
  • The number of hybrids sold has skyrocketed since
    2000
  • 2006 projected sales are 250,000

August, 2006
Source hybridcars.com
51
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.

52
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.

53
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

54
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.

55
Synopsis?
  • Yes, there are viable alternative energy sources
  • Are they economically feasible?
  • Diffuse
  • Widely scattered
  • Expensive
  • Solutions
  • Support research
  • Support products
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