Renewable Energy

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Renewable Energy

• Section 1- Renewable Energy Today

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Renewable Energy

• Energy from sources constantly being formed
• Use needs to be increased

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Solar Power

• Sun
• Passive Solar Heating
• Uses heat from sun directly
• Large windows face directly into sun
• N. hemisphere- south windows

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Solar Power

• Active Solar Heating
• Gathered by collectors
• Usually mounted on roof
• Heats water in collector and transfers throughout
  home

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Solar Power

• Photovoltaic Cells- solar cells
• Use sun energy to produce a small amt. of
  electricity
• Can be stored in batteries
• Efficient and less expensive
• Good for developing countries

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Wind Power- Cheap and Abundant

• Uneven heating from sun causes wind
• Wind turbines can convert into electricity
• Cheap
• Wind Farms- Large arrays of wind turbines
• Problem transporting electricity from rural to
  urban areas

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Wind Farm
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Biomass- Power from Living Things

• Biomass fuel- any organic matter used for energy
• Ex Wood, organic trash and manure
• Burning can release air pollution
• Methane gas from decomposition

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Biomass- Power from Living Things

• Alcohol- Liquid fuel derived from biomass
• Ethanol- from fermenting fruit or agricultural
  waste corn is major source
• Gasohol- gasoline ethanol
• Less air pollution

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Hydroelectricity- Power from Moving Water

• 20 of worlds electricity
• Dams hold water- reservoir
• Released to turn a turbine
• Benefits
• Inexpensive
• No air pollution
• Last longer than power plants
• Provide flood control, drinking water,
  agriculture, industry, and recreation

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Hydroelectricity- Power from Moving Water

• Disadvantages
• Disruption of ecosystems Ex Salmon
• Displacement of people
• Farmland below dams less fertile
• Future
• Micro-hydropower- Floating turbine in a small
  stream

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Geothermal Energy- Power from the Earth

• Energy from heat in the water deposits of the
  earths crust
• Geothermal pumps- heated water to turbine and
  recycle back for reheating
• U.S. worlds largest producer
• Ex The Geysers in CA-1.7 million houses

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Geothermal Energy
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Geothermal Heat Pumps- Energy for Homes

• 600,000 homes in U.S.
• Stable underground temperatures year-round allows
  for heating and cooling all year
• Ground cooler in summer and warmer in winter

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Geothermal Heat Pump
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Chapter 18- Renewable Energy

• Section 2- Alternative Energy and Conservation

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Alternative Energy

• Energy sources that do not use fossil fuels and
  are still in development
• Viable if cost effective and environmental
  effects are acceptable
• Research with govt investment

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Tidal Power

• Tide- movement of water caused by gravitational
  b/w sun, moon and Earth
• Twice a day, rise and fall
• Used to generate electricity in France, Russia
  and Canada
• France and Britain used over 1000 yrs ago

• High tides come in, trapped by a dam
• After low tide, dam opens to allow water to rush
  out spinning a turbine to generate electricity
• Cost is high to build and maintain
• Few siutable locations

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Tidal Power
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Ocean Thermal Energy Conversion

• Warm surface water boils sea water at low temp.
  in a vacuum
• Steam spins a turbine to generate electricity
• Cold water from deep ocean cool steam back into
  liquid to be used again
• Not cost effective and effects of pumping large
  amounts of cold water to surface are unknown

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Ocean Thermal Energy Conversion
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Hydrogen- A Future Fuel Source?

• Most abundant element in universe can be burned
  as fuel
• No carbon-no pollution!
• When burned combines with oxygen to form water
  vapor and nitrogen oxide
• Can split molecules of water or grow plants to
  produce hydrogen cost effectively

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Challenge of Hydrogen Fuel

• Takes a lot of energy to produce
• Use of fossil fuels to split atoms pollutes
• Can use solar or wind power
• Can store in tanks and transport in pipes
• Could use as it is produced in fuel cells

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Fuel Cells

• Produces electricity chemically by combining H
  with O
• Can be fueled by anything w/ large amounts of H,
  such as gasoline, natural gas and alcohol
• Could continue to use gasoline stations

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Energy Efficiency

• Percentage of energy put into a system that does
  useful work
• Energy efficiency
• Energy Out X 100
  Energy In
• First Law of Thermodynamics- Energy in must
  equal energy out much lost as heat

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Energy Efficiency

• Over 40 of commercial energy is wasted
• Fuel-wasting vehicles, furnaces, and appliances
• Leaky, poorly insulated buildings
• Could save by
• Fuel cells instead of internal combustion engines
• Increase public transportation
• Fluorescent instead of incandescent lights

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Hybrid Cars

• Small, efficient gasoline engines with also an
  electric motor for extra power
• Convert braking energy into electricity to store
  in battery
• Shut off gas engine to save fuel when sitting
• Aerodynamics make less energy for acceleration
• Cost a little bit more, but less to refuel and
  pollute less

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Hybrids
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Cogeneration

• Production of two useful forms of energy from
  same fuel source
• Ex Waste heat from an industrial furnace can run
  a steam turbine for electricity
• Can supply heat and electricity to multiple
  buildings
• Small units now available in U.S.

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Energy Conservation-Saving Energy

• Cities and Towns
• Plug leaks around windows and doors
• Replace inefficient furnaces
• Insulate water heaters
• EX Osage, Iowa saved over 1 million a year
  boosted economy

• Around the Home
• 1,200/year per home lost energy through poor
  insulation
• Seal doors and windows (replace w/high efficiency
  windows)

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Save Energy Around the Home
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Conservation in Daily Life

• Conservation Tips
• Walk or ride a bike on short trips
• Carpool or use public transportation
• Drive a fuel-efficient automobile
• Choose ENERGY STAR products
• Recycle and buy recycled products
• Set computers to sleep mode when not in use

• Use less of any resource to save energy
• Wash clothes in cold water for less energy usage
  (25 of heat usage)