Alternative Energy Sources. Fuels for the Future OR Weaning Ourselves Off Fossil Fuels OR Alternative Energy Sources Can Be Fun!. Why Alternative Energy?. Energy sources provide us with heat for our homes, electricity to power just about everything we own, and fuels for our cars.
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Alternative Energy Sources Fuels for the Future OR Weaning Ourselves Off Fossil Fuels OR Alternative Energy Sources Can Be Fun!
Why Alternative Energy? • Energy sources provide us with heat for our homes, electricity to power just about everything we own, and fuels for our cars. • People have always relied on alternative energy sources. • Alternative energy sources are those sources that are not based on the burning of fossil fuels. htt • www.west-norfolk.gov.uk
Why bother with alternatives? • Fossil fuels cause pollution that result in environmental pollution and illness. • Burning fossil fuels releases carbon dioxide, which some scientists such as Al Gore believe could cause global warming. • Fossil fuels that can be harvested economically exist in limited amounts. • Most of the world supply of oil is in the Middle East, a politically unstable region. www.politicsonline.com • www.npr.org
Types of alternative energy • Solar • Nuclear • Wind • Hydro (water) or hydroelectric power • Tidal power • Biomass • Geothermal • Hydrogen – fuel cells
Why are fossil fuels accepted by consumers? • They are abundant. • They are low cost. • They are safeto use.
Alternative energy sources replace… Fossil fuels! www.ngdir.ir/.../nonrewnewables-mm.jpg
Solar Energy • Solar energy uses energy from the sun. • The main expense is collecting, storing and converting the sun’s rays into useful forms of energy. • Environmental impacts/risks are negligible. Solar power is clean and quiet! http://www.astronomy.com/asy/objects/images/sun_full_disk_soho_09_14_1997.jpg
Solar Energy Produces Electricity in One of Two Ways … Photovoltaic … • A photovoltaic cell produces energy when it is exposed to light. • The light excites the electrons in the silicon and that produces electricity. • Silicon (from sand) is the material from which a PV cell is made. http://www.acmegreen.com/page2/page7/files/page7_2.jpg
Solar Energy - PV (photovoltaic) panels http://en.wikipedia.org/wiki/Solar_power
Solar Energy Produces Electricity in One of Two Ways … Thermosolar … http://www.solarnavigator.net/spanish_solar_generating_station.htm Thermosolar power stations provide another method for producing electricity. Here is a thermosolar power station in Spain
Solar Energy Powers … • Small PV cells are used to power solar calculators and emergency roadside phones. • A roof-top solar collector is used to heat water that heats the air in the house. • A solar power plant produces electricity on a large scale – for many homes. • To provide electricity for a satellite, space station, or typical home, the PV cell would have to be as large as 10 square meters! • The high cost of solar power prevents its use on a wide-scale. http://www.abc.net.au http://media.popularmechanics.com
Solar Energy … An Application The CIS Tower, Manchester, England, was clad in PV (photovoltaic) panels at a cost of $11 million. It started feeding electricity to the national grid in November 2005. http://en.wikipedia.org/wiki/Photovoltaics
Nuclear Energy • Two ways that nuclear energy can be produced… fission and fusion • Fission – the breaking apart of atomic nuclei hyperphysics.phy-astr.gsu.edu/hbase/nucene/im...
Nuclear Energy Produces Electricity… • www.comedition.com
Nuclear Energy Fission reactions are used to supply significant amounts of energy for… • Electricity • Heating • Military use- for nuclear submarines! encarta.msn.com
Nuclear Energy • Two advantages of nuclear energy: • It produces huge amounts of energy from small amounts of nuclear fuel (uranium and plutonium). • Earth contains enough nuclear fuel to meet all present and future needs. www.pollutionissues.com
Nuclear Energy • Nuclear energy produces wastes in the form of heat and spent (used) fuel – which can remain radioactive for thousands of years. • Disposing of this radioactive spent fuel is a major problem. • One proposed disposal site is Yucca Mountain in Nevada. • http://www.ocrwm.doe.gov/repository/index.shtml • www.nrc.gov
Nuclear Energy www.amargosavalley.com
Nuclear Energy Four reasons why nuclear power is not as widely used as it could be… • High cost • Peoples’ fear of exposure to radiation • The threat of a meltdown (nuclear explosion) • The fear that nuclear weapons could be developed using this technology Stable, highly centralized governmental control is necessary for the safe operation of nuclear power. http://todayspictures.slate.com/inmotion/essay_chernobyl/ www.answers.com
Nuclear Energy • Two ways that nuclear energy can be produced are fusion and fission. • Fusion – the combining of atomic nuclei – such as in the stars (and sun!) – generates energy http://www.aa.washington.edu
Nuclear Energy – Fusion Reactor • “The power produced by a fusion reactor will be converted to electric energy or other goods like hydrogen or desalinised water. • Neutrons produced in the D-T fusion process carry 4/5 of the energy. • One or two fluids circulate in the blanket and in the diverter/FW to extract the energy and to provide stable operational temperature of the components. • The fluids must flow at high velocity (often in conditions of turbulent flow) while structural materials, pipes, junctions must withstand neutron bombardment, corrosion/erosion, high operational temperature, high heat flux.” • What??!! http://www.isfrt-erice.enea.it/Page2.htm
China claims fusion reactor test a success Government hopes fusion provides clean, limitless energy source … • “BEIJING - Scientists on Thursday carried out China's first successful test of an experimental fusion reactor, powered by the process that fuels the sun, a research institute spokeswoman said. • China, the United States and other governments are pursuing fusion research in hopes that it could become a clean, potentially limitless energy source. • Fusion produces little radioactive waste, unlike fission, which powers conventional nuclear reactors.” http://www.msnbc.msn.com/id/15043462/ updated 3:22 p.m. ET, Thurs., Sept. 28, 2006
Nuclear Energy • Fusion reactions are not currently a practical alternative energy source because… • Scientists have not yet been able to initiate a controlled, long-lasting fusion reaction suitable for producing heat and electricity. • Fusion reactions produce intense radiation that bombards all the materials in the reactor – making them intensely radioactive. • Fusion reactors are very expensive to build. • http://science.howstuffworks.com/fusion-reactor.htm
Hydroelectric Power • photo.e-khmer.net The advantages of hydropower are: It can provide power on demand It is clean – no fossil fuels are burned The reservoirs formed by the dams can be used for entertainment and water. This is the Hoover Dam and several of the turbines that spin to produce electricity. http://www.usbr.gov/lc/hooverdam/
Hydroelectric Power • library.thinkquest.org
Hydroelectric Power • Four drawbacks to hydroelectric power… • Inability to store energy • Large initial investment for facilities • Covers large geographic areas • Contributes to habitat destruction These drawbacks also apply to wind power. www.worldproutassembly.org
Hydroelectric Power • Three problems associated with dams include… • Dams can gradually fill with silt which reduces the water stored in the reservoir. • Dams can disrupt the local ecosystems and prevent the migration of some species of fish. • Dams have the potential to break and cause catastrophic floods. This is what is left of the Hadlock dam in the Adirondacks. • thecommunicator.org
Hydroelectric Power home.clara.net • Other forms of hydroelectric power include: • Tidal power – dams or turbines are constructed to capture the energy of incoming or outgoing tides • Wave power – turbines are situated to catch the power of the rising and falling water. www.logicalscience.com
Tidal Power - The Bay of Fundy http://commons.wikimedia.org/wiki/File:Bay_of_Fundy.jpg
Microhydropower • http://www.microhydropower.net/ • This type of hydropower is much more environmentally- friendly because it doesn’t attempt to change the course or flow of the waterways from which its power is derived.
Wind power – old to new Wind power has been used to pump water for centuries A modern wind turbine produces electricity.
Wind Power • Wind power is the fastest growing segment of the alternative energy business. • Wind mills act as giant turbines that spin with the energy of the wind and generate electricity. (This only happens when the wind blows!) • A large group of wind turbines that produce electricity for an entire community is called a wind farm. www.eere.energy.gov
Wind Power • Wind power has some of the same disadvantages of hydroelectric power. (See slide 20.) • Wind farms can also be noisy (a giant swooshing sound!), unsightly (modern windmills are HUGE!), and can kill migrating birds. rochsolartech.itcstore.com
Biomass • Biomass is organic material that can be “combusted” for energy. • Biomass includes municipal wastes, crop residues, manure, lumber and paper by-products. www.nrcan.gc.ca
Biomass • To be used for energy, biomass can be… • burned directly • gasified into methane and hydrogen (the by-products of which can be used as fertilizer) • fermented into ethanol • anaerobically digested to produce biogas (a mixture containing methane and CO2). sitemaker.umich.edu
Biomass • This is switchgrass, a hardy, fast growing plant that can be used as biomass http://en.wikipedia.org/wiki/Image:Panicum_virgatum.jpg
What is Biodiesel? http://www.wisegeek.com/what-is-biodiesel-fuel.htm http://www.learnbiodiesel.com/site-images/biodiesel-flow-chart.gif
Biomass • Two major drawbacks of biomass energy include… • The use of farm and forest residue prevents the recycling of nutrients back into the ecosystem. • Pollution is generated in the process of converting biomass to energy. www.ctahr.hawaii.edu
Geothermal Energy Remember, geo means Earth • Geothermal energy is “Earth heat” which is present everywhere beneath the Earth’s surface • The highest temperature and thus the most desirable resources are concentrated in regions of active or geologically young volcanoes. • This is the Old Faithful geyser – atop the supervolcano of Yellowstone! zebu.uoregon.edu/2001/ph162/special/oldfaith.gif
Geothermal Energy www.geothermal.ch/bilder/obp0zjs6.jpg
Geothermal Energy • Three major drawbacks to geothermal power include… • Geographic restrictions – not every place has geothermal energy sources near the surface • The cost of drilling down into hot rocks (as deep as 6 miles!) is very high • The environmental impact of habitat disturbance and the need to dispose of large quantities of noxious gases and very salty water.
Geothermal Iceland is on the North Atlantic Volcanic Rift Valley, so it is a prime location for using geothermal energy. Over 90% of homes in Iceland are heated with this energy source. Here is the Bjarnarflag Geothermal Station in northeast Iceland.
The Geysers in California … http://www.inforse.dk/europe/dieret/Geothermal/geot
Hydrogen • Hydrogen and oxygen chemically combine to form water • This reaction can be used to generate electricity using fuel cell technology. • A fuel cell is somewhat similar to a battery but with a fuel cell, chemicals constantly flow into the cell so it never goes dead. As long as there is a flow of chemicals into the cell, the electricity flows out of the cell. • Hydrogen must be in the proper form to be used as a fuel. Most hydrogen used in today’s fuel cells comes from methane • Fuel cell reactions produce no pollution.
Hydrogen • A typical hydrogen fuel cell http://en.wikipedia.org/wiki/Image:Fuel_cell_still.gif
Hydrogen • Other materials can also supply the fuel for a fuel cell. • This is a methanol fuel cell • The actual fuel cell stack is the layered cubic structure in the center of the image http://en.wikipedia.org/wiki/Fuel_cell
A Hydrogen-powered Car… September 2006 - BMW will lease Hydrogen Cars • BMW is going to make a limited number of Hydrogen Series 7 sedans available for lease starting next year. This is the first fleet of hydrogen powered vehicles. • The cars will have tanks for storing liquid hydrogen and gasoline. The BMW Hydrogen 7 will emit only water vapor when burning hydrogen in the combustion engine. • The vehicle has a 260 hp twelve-cylinder engine and will accelerate from 0-62 mph in 9.5 seconds and tops out at 143 mph, according to BMW
Another Hydrogen-powered Car… http://automobiles.honda.com/fcx-clarity/ The Honda Clarity
Hydrogen • Current disadvantages of using hydrogen as a fuel… • Currently it is expensive. Large-scale production will reduce its costs • Driving range is limited with current fuel storage options • Current small distribution channels - California is making some progress • It is extremely flammable – Remember the Hindenburg! • Many improvements are expected as this technology develops!
The Hindenburg… wellington.pm.org/.../hindenberg_strict.jpg