Bellwork 3/22/12

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Bellwork 3/22/12

• Define
• Elevation, Flow Rate, Fluid, Fluid Dynamics,
  Force, Hydrodynamics, Pressure

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Evaluating Energy Resources

• Renewable
• Future availability
• Net energy yield
• It takes energy to get energy
• Habitat degradation
• Cost (initial and ongoing)
• Community disruption
• Political or international issues
• Suitability in different locations
• Polluting (air, water, noise, visual)

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Important Nonrenewable Energy Sources
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Fossil Fuels

• What are the fossil fuels?

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FOSSIL FUELS 85 of the worldscommercial
energy
COAL
OIL
NATURAL GAS
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(No Transcript)
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20 richest countries consume

• 50 of coal
• 80 of natural gas
• 65 of oil

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North American Energy Resources
US has only 2.4 of worlds oil reserves
Average American uses in one day what a person in
the poorest countries use in one year
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COAL

Fossilized, condensed carbon-rich fuel

10 X reserves of oil/gas, last 200 years at
present rate
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Coal What is it?

• Solid fossil fuel formed in several stages
• Land plants that lived 300-400 million years ago
• Subjected to intense heat and pressure over many
  millions of years
• Mostly carbon, small amounts of sulfur

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Coal Formation and Types
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Coal what do we use it for?

• Stages of coal formation
• 300 million year old forests
• peat gt lignite gt bituminous gt anthracite
• Primarily strip-mined
• Used mostly for generating electricity
• Used to generate 62 of the worlds electricity
• Used to generate 52 of the U.S. electricity
• Enough coal for about 200-1000 years
• U.S. has 25 of worlds reserves
• High environmental impact
• Coal gasification and liquefaction

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Coal Trade-offs
Worlds most abundant fossil fuel Mining and
burning coal has a severe environmental
impact Accounts for over 1/3 of the worlds CO2
emissions
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Discussion Questions?

• How is your classroom lit?
• Where does the electricity come from to power the
  lightbulbs in your classroom?
• How much do you think it costs to light your
  classroom for one hour?

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Calculating Costs

• The electricity needed for the fluorescent tubes
  used to light most classrooms costs approximately
  three-tenths of a cent per hour.
• Can you figure out how much it would cost to
  light our classroom for 1 hour?
• N x 0.003 Cost/hour
• How much would it cost for the entire day? Week?
  Year?

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Coal Costs

• It takes approximately 1 ton of coal to produce
  2,500 kilowatthours (kWh) of electricity (or 1
  pound of coal to produce 1.25 kilowatt-hours)
• The average fluorescent tube uses 18 watts per
  hour or .018 kilowatt-hours of power per bulb.
• How much coal do we use in 1 hour to light the
  school? 1 week? 1 year?