Energy in Context

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Energy in Context

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Overview

• Magnitude of Energy Use
• Implications to human living
• Implications to global climate change
• Technological Cycles
• Impact of human practices on energy use

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Magnitude of Energy Use
Energy Required to raise 100 kg a distance of 1 m. 1000 Joules
Energy required for 60 Watt light bulb operating 1 hours 216,000 Joules
Energy required to heat 5 kg pan of water to boiling temperature 1,670,000 Joules
Energy required to process 1 kg wood products 2,000,000 Joules
Energy required to process 1 kg of plastic products 100,000,000
Energy required to mine/smelt 1 kg aluminum 220,000,000 Joules
Energy required to drive an SUV 25 miles 200,000,000 Joules
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• Implications for how we live?

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Connection to Global ClimateChange

(gCO2 per 3,600,000 Joules) (gCO2 per 3,600,000 Joules) (gCO2 per 3,600,000 Joules) (gCO2 per 3,600,000 Joules) (gCO2 per 3,600,000 Joules) (gCO2 per 3,600,000 Joules) (gCO2 per 3,600,000 Joules)
Energy Source Coal Oil Gas Hydro Nuclear Solar PV
Current technology 972 684 684 18 21.6 126
Next generation technology 288 504 504 18 10.8 28.8
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Energy Efficiency of Industrialized Economy

• Est. 1-3
• Why so low?

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Product Life Cycle

Consider life cycle energy impact of a 1 kg of
aluminum being used in an aluminum wheel of a
Ford Excursion over a 150,000 mile life.
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• Case A No Recycling

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•  

1 Ford Excursion 3000 kg, 15 mpg, 150,000
miles/lifeUseful energy from I.C. engine
overcomes rolling resistance, inertia, drag. 75
of this is dependent upon weight. Therefore the
mass consumed in the burning of gasoline over
life due to the 1 kg mass on the vehicle
is (150,000 miles/life)/(15 miles/gallon) x (3
kg-fuel/gallon) / 3000 kg-al x 0.75 7.5 kg
fuel/kg-al Energy consumed 7.5 kg-fuel/kg-al x
( 50 MJ/kg-fuel) 375 MJ/kg-al
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1 Source American Metals, amm.com
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• Case B Recycling r of the aluminum

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• Same energy use as in Case A except that the
  mining energy and material processing energy are
  reduced by
• r(Emining Ematerials)
• where r is the fraction of recycled aluminum
  going into the making of a new wheel

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1 Ford Excursion 3000 kg, 15 mpg, 150,000
miles/lifeUseful exergy from I.C. engine
overcomes rolling resistance, inertia, drag. 75
of this is dependent upon weight. Therefore the
mass consumed in the burning of gasoline over
life due to the 1 kg mass on the vehicle
is (150,000 miles/life)/(15 miles/gallon) x (3
kg/gallon) x 0.75 / 3000 7.5 kg fuel Exergy
consumed 7.5 kg-fuel x ( 50 MJ/kg-fuel) 375
MJ/kg-al
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• Comparison

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• Cost Comparision
• If 100 recycle and given a cost of
• 0.10 / (3.6 MJ), a 230 MJ reduction in energy
  yields a
• 6.30 savings per kg
• Note This is 4 times more expensive than it
  would seem because aluminum companies have been
  given cheap access to hydroelectric energy!!!!!

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Energy Generation Efficiency
Process Efficiency
Coal?Electricity ? transmission 20
Natural gas ? electricity ? transmission 25
Fuel Cell 40 (70-80) if heat used
Solar PV 20 typical
Wind 30