chapter 18 renewable energy 18.1 renewable energy today (2004) 18.2 alternative energy and...
TRANSCRIPT
Chapter 18 renewable Energy 1
Chapter 18 Renewable Energy
18.1 Renewable Energy Today (2004)18.2 Alternative Energy and
Conservation p455-473
Chapter 18 renewable Energy 2
Key terms
• Renewable energy• Passive solar hearing• Active solar heating • Biomass fuel• Hydroelectric energy• Geothermal energy• Alternative energy• Ocean thermal energy conversion (OTEC)• Fuel cell• Energy efficiency• Energy conservation
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18.1 renewable Energy Today
• List 6 forms of renewable energy, and compare their advantages and disadvantages
• Describe the differences between passive solar heating, active solar heating and photovoltaic energy
• Describe the current sate of wind energy technology• Explain the differences in biomass fuel used between
developed and developing nations• Describe how hydroelectric energy, geothermal
energy and geothermal heat pumps work
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Renewable Energy -today
• Energy from sources that are constantly being formed – (wind, sun, water and Earth’s heat)
• Europe planned to increase use by 2010 to reduce the impact on nonrenewable energy
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Solar Energy-
Power from the sun- Produces energy by nuclear fusion reaction in
its core, only small part reaches Earth- All life's energy is directly or indirectly
powered by the sun2 types
1. passive 2. Active
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Passive Solar Heating
• The use of the sun’s energy to heat something directly• Simplest form of energy• Sun hitting the window and heating a room• Building who use this form of heat must be well insulated
with thick walls and floors to prevent heat loss at night• Building is designed based on how the sun shines during
the day or seasons (windows)• http://www.youtube.com/watch?v=lzGaLw__kdk(8 mins)
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Active Solar Heating
• Energy from that sun that is gathered by collectors and used to heat water or to heat a building
• More than 1 million homes in US use active solar energy to heat water (2004)
• Most are found on roof tops• Liquid is heated by sun as it flows through the solar
collectors, the hot liquid is then pumped through a heat exchanger, which heats water fro the building
• About 8% of the energy used in the US is fused to heat water this type of energy could save $$ and energy
• http://www.ehow.com/video_4908308_active-solar-heating-work.html
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Photovoltaic Cells
• (FOHT oh vahl TAY ik) – convert sun’s energy into electricity• Invented more than 120 years ago• Used to power everything from calculators to space satiations• No moving parts, non polluting power• Only produce small amounts of energy• Have become more efficient and less expensive• More efficient in developing countries who need less energy • http://www.youtube.com/watch?v=x2zjdtxrisc (2mins)• http://www.youtube.com/watch?v=fixI-xZ3U_M (4 mins)
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Wind Power- Cheap and Abundant
• Energy from sun warms the Earth’s surface unevenly causes air masses to flow in the atmosphere aka wind
• Converts the movement of wind into electric energy
• Fastest growing energy source in the world• Turbines are cost effective and can be built in
3 months• http://www.nrel.gov/learning/re_wind.html (6 mins)
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Wind Farms
• Large arrays of wind turbines • In California one wind farm can supply enough
energy for 280,00 homes • Farmers are adding them to their land and selling
the energy to local utility• Seen as future of energy but..Difficult to transport the energyThere is potential to produce hydrogen from water
and then pipe that to cities for fuelhttp://www.voanews.com/content/wind-turbines-take-steep-toll-on-birds-and-bats/1524387.html
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Biomass- Power from Living Things
• Plant material, wood, manure, or any organic material
• (fossil fuels are not biomass because they are nonrenewable)
• Methane and Alcohol• http://www.youtube.com/user/smarterfuels?
v=9bKAA3riLcI
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Methane- Biomass
• Methane- is the result of bacteria decomposing organic waste, is burned to generate heat or electricity
• China more than 6 million households use biogas digester to ferment manure and produce gas for used for heating and cooking
• 2002 Britain’s first dung-fired power station started to produce electricity
• Landfills in the US
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Alcohol- Biomass
• Liquid fuels, ethanol/ alcohol can be made by fermenting fruit or agricultural waste
• Corn is used in the US• Cars and trucks can run on ethanol or gasohol,
blend of gasoline and ethanol• Produces less air pollution than fossil fuels• http://guides.seattleacademy.org/content.php?pid=211050&sid=1756553 (6mins)• http://www.youtube.com/watch?v=KW1MbmmEVxI (7mins)
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Hydroelectricity- Power from Moving Water
• Energy produced from moving water• 20% of worlds energy• Canada, US, Brazil, China, Russia and Norway• Large power plants have dam that is built across a river
to hold back a reservoir of water the water gets released to turn a turbine generates electricity
Advantages:• Expensive to build but inexpensive to run, no air
pollution, last longer, flood control, drinking water, agriculture, industry and recreation
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Hydroelectricity- Power from Moving Water
Disadvantages- • Changes a river flow, reservoir floods, water below the dam is
lowered, affect Salmon fisheries no longer swim up stream to spawn, human displacement due to flooding, dam failure, greenhouse gases from decomposing plant matter trapped in reservoirs
Modern Trends• - US is done, Brazil, India and China still constructing, • micro-hydropower (no dam required) located on small streams,
turbines float on the water, no longer blocking river, cheaper • http://www.youtube.com/watch?v=iHBRf2bUNXU
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How does it work (2mins)http://www.youtube.com/watch?v=rnPEtwQtmGQ
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Geothermal Energy- Power from the Earth
• Water in the Earth is heated to generate electricity• Pump heated water or steam from rock formations
and use the water or steam to power a turbine that generates electricity, water is returned to earth where it can be heated again
• US is worlds largest producer, The Geysers in California and it produces energy for about 1.7 million homes,
• Philippines, Iceland, Japan, Mexico, Italy and New Zealand
• Must be managed carefully so it is not depleted
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Geothermal Energy- Power from the Earth
• Energy for Homes- uses stable underground temps to war and cool homes
• More than 600,000 homes in the US are heated and cooled using Geothermal heat pumps
• Temperature in the ground is consistent year round
• In summer ground is cooler and in the winter the ground is warmer
• http://www.youtube.com/watch?v=uVDBRQvBVso
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18.2 Alternative Energy and Conservation
• Describe 3 alternative energy technologies• ID 2 ways that hydrogen could be used a s a fuel
source in the future• Explain the difference between energy
efficiency and energy conservation• Describe 2 forms of energy-efficient
transportation• ID 3 ways that you can conserve energy in your
daily life
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18.2 Alternative Energy and Conservation
• Alternative Energy- energy sources that are still being developed, the source must be proven to be cost effective, environmental impacts must be acceptable,
• Government usually is the ones who invest for research
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Tidal Power
• Once used to power mills thousand of years ago in France and Britain
• Today- France, Russia, Canada• Works similar to a hydroelectric dam• As the tides rise water flows behind a dam and when
the tides lower the water is trapped and used to run a turbine that will generate electricity
• It is renewable and non polluting but cost of building and maintaining is high, only a few locations are suitable
• http://www.youtube.com/watch?v=4Iq-h4ShZ8s
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Ocean Thermal Energy Conservation
• Hawaii uses the temperature difference in the ocean to generate electricity- OTEC or Ocean Thermal Energy Conversion
• Warm surface water is used to boil sea water, boiling water turns to steam and turns the turbine runs an electric generator, the cold water will cool the steam so that the water can be used again
Problem- the power required to pump the cold water from deep in the ocean uses 1/3 of t he energy produced, environmental impact is unknown
http://www.youtube.com/watch?v=qGwsvuxuK7g (4mins)
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Hydrogen- A Future Fuel Source?
• Most abundant element in the universe• Can be burned as fuel• no pollutants – water is the only byproduct• Splitting of water or the use of plants to
produce hydrogenChallenge- takes a lot of energy to produce, use
wind or solar to produce energy to split waterhttp://www.proactiveinvestors.co.uk/companies/stocktube/1723/afc-energy-continues-to-drive-its-hydrogen-fuel-cell-technology-forward--1723.html
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Fuel Cell-
• like a battery, produces electricity chemically, by combining hydrogen fuel with oxygen from the air, water is byproduct
• Can be natural gas, alcohol or gasoline• Space shuttles have internal combustion
engines powered by fuel cells• By 2010 portable phones and games could be
powered for fuel cells (??)
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Energy Efficiency
• 2 main ways to reduce energy use lifestyle changes and increase in energy efficiency
• The percentage of energy put into a system that does useful work
• EF%= (Energy out/ energy in) X100• Most of our devices are inefficient• More than 40% of all commercial energy used
in US is wasted but require sacrifices or investments in new technologies
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Efficient Transportation
• Key is to develop transportation that is energy efficient and increase public transportation
• In 2004 gas prices were still low• Hybrid Cars- small, efficient gasoline engine
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Cogeneration
• Production of 2 useful forms of energy from the same fuel source
• Example: waste heat from an industrial furnace can power a steam turbine that produces electricity and then they can use the electricity or sell it
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Energy Conservation
• Saving energy• Cities and Towns Saving Energy- Osage, Iowa
of 3,600 people, can save more $1 million each year
• Conservation around the home- average home spends more than $1200 on energy bills each year, most of which the energy is wasted, poor windows, door, walls and roof, new windows could reduce your energy bill by 15%
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Conservation in Daily Life
• Walk or ride a bike• Carpool• Use fuel efficient autos• Energy star products• Recycle• Turn or unplug appliances when not at home