Environmental Engineering Reference
In-Depth Information
FTP, HFET, US06/SC03, Cold CO, others; (2) for Europe, NEDC and (3) for Asia-
Pacific, mainly Japan, 10-15 mode.
The energy efficiency of converting natural occurring feedstock to energy in
the vehicle's fuel tank has been studied intensely by researchers at the US
Department of Energy's Argonne National Laboratory (ANL) [3,4]. For example,
ANL has developed a model for Greenhouse Gases, Regulated Emissions, and
Energy Use in Transportation (GREET) that has the facility to illustrate the com-
plete energy path of some 30 different fuel processing scenarios. Figure 9.1 illus-
trates some of the fuel processing pathways analysed by the ANL team.
Conv. and reform. gasoline
Crude naphtha
Liquefied petroleum gas
Conv. and LS diesel
Petroleum
Cornpressed natural gas
Liquefied petroleum gas
Dimethyl ether
Liquefied natural gas
FT diesel and naphtha
Natural gas
Methanol
Gaseous and liquid H 2
Liquefied natural gas
FT diesel and naphtha
Dimethyl ether
Methanol
Flared gas
Gaseous and liquid H 2
Landfill gas
Corn
Cellulosic biomass
Soybeans
Various sources
Electricity
Methanol
Ethanol
Biodiesel
Electricity
Gaseous and liquid H 2
Figure 9.1 Fuel processing pathways (from Reference 4)
The pathways listed in Figure 9.1 include (1) feedstock production, transportation
and storage, (2) fuel production, transportation, distribution and storage and (3) vehicle
refuelling operations, fuel combustion/conversion, fuel evaporation and tyre and brake
wear. The processes covering stages 1 and 2 are referred to as wells-to-tank (WTT),
and the last process, stage 3, is referred to as tank-to-wheels (TTW). As an example on
the use of ANL's GREET programme to calculate upstream energy use in fuel pro-
duction, Atkins and Koch [5] tabulate the fuel cycle total energy consumption and
greenhouse gases (GHG) for some representative fuel pathways. Table 9.1 is a listing
of the most prominent fuel pathways in operation today.
It is necessary to quantify the upstream energy use because some fuels have
significantly higher TTW energy efficiency and minimal emissions but may have
rather large upstream energy use and emissions. The ANL approach gives a global
picture of the fuel energy and emissions as a closed system.
Data in Table 9.1 convey several important messages. First, the fuel types
represent both near term and long term solutions. E85 ethanol, for example, is made
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