Greenhouse Gases

1
Assignment 4, Exercise 1 The impact of material
choice on automotive life cycle GHG emissions
Greenhouse Gases
Materials Production
Vehicle Manufacturing
Vehicle Use
Vehicle Disposal
Material Choice
2
Calculation of the material composition of the
vehicles
Material composition of baseline vehicle
Vehicle weight of baseline vehicle
Amount of BIW material in vehicle design l
Amount of other material in vehicle design l
Vehicle weight of vehicle design l
Replaced Material
Replacement coefficient of vehicle design l
Secondary mass savings
3
Calculation of GHG emissions during vehicle use
phase
Total distance driven during use phase
GHG emissions from fuel production and combustion
Baseline fuel economy
Fuel economy improvement
Fuel savings per mass savings
Secondary mass savings
Primary mass savings of vehicle design l
Replaced material
4
Calculation of GHG emissions from material
production and recycling
BIW material
Avoided burden of prompt scrap recycling
Avoided burden of eol scrap recycling
Secondary savings in other material
Avoided burden of prompt scrap recycling
Avoided burden of eol scrap recycling
5
The avoided burden method
Vehicle
400 kg
Vehicle Life Cycle
BF/BOF 2.63 kgCO2/kg
400 kg
EAF 0.99 kgCO2/kg
400 kg
Building Life Cycle
BF/BOF 2.63 kgCO2/kg
400 kg
Building
Credit for scrap generation requires debit for
scrap use!
6
Assignment 4, Exercise 2 Biofuels
7
What are Biofuels?

• Fuels derived from biological sources are called
  biofuels.
• Examples are
• Grains, sugar crops and other starches can be
  fermented into ethanol, which can be burnt
  pure or blended with conventional gasoline.
• Cellulosic material, including grasses, trees
  and green waste, can also be converted into
  alcohol.
• Oil-seed crops (e.g. rapeseed, soybean and
  sunflower) can be converted into methyl
  esters, which can be burnt pure or blended with
  conventional diesel.
• Other organic wastes with high calorific
  content, like waste oil, animal manure,
  organic household waste

8
Global production of fuel ethanol, 1975-2003(in
million liters per year)
Source International Energy Agency, 2004
9
Global production capacity of biodiesel,
1991-2003(in million liters per year)
Source International Energy Agency, 2004
10
Ethanol production
Harvest Technique
Feedstock Conversion
Process Heat
Sugar Conversion
Feedstock
Co-Products
Fermentation distillation of alcohol
Sugarcane
Cut wholecane stalk
Crush cane,heat, treatchemically
Mainlycrushedcane
Heat, electricity,molasses
Separatestarch, mill, applyenzymes
Graincrops
Take starchy parts only, leave stalks
Mainlyfossilfuel
Animalfeed, sweetener
Cellulosiccrops
Harvestentireplant
Heat,electricity,animal feed,bioplastic,etc.
Convert tosugar viaenzymatic hydrolysis
Mainly lignin cellulose
Wastebiomass
Collect,separate,clean
11
Range of estimated GHG reductions from
biofuels (well-to-wheels CO2eq compared to
gasoline/diesel)
Biodiesel from soy 44
E90 from corn -2
E90 from grass -44
Source International Energy Agency, 2004
Source Delucchi, ITS UC Davis, 2006
12
Summary of industrial ecology in one convenient
slide
Most environmental impacts are caused by the
quantity and quality of the material and energy
flows through the economy.
To make good environmental decisions it is
necessary to identify and assess the trade-offs
across all impacted life cycle stages and the
trade-offs across all impacted environmental
concerns.