February 1, 2010

MEMORANDUM

TO: 			Air Docket EPA-HQ-OAR-2005-0161

SUBJECT:	Lifecycle Greenhouse Gas (GHG) Impacts Calculations

This memorandum accompanies spreadsheets placed on the docket that
calculate GHG emissions per british thermal unit of renewable fuel. 
These spreadsheets integrate the results from modeling of each stage of
the renewable fuel lifecycle (e.g., feedstock production, domestic and
international agricultural emissions, fuel transport and distribution). 
The only piece of the lifecycle analysis not calculated in these
spreadsheets are the emissions from international land use change.  The
results from these impact calculation spreadsheets were used in
spreadsheets that compare the lifecycle GHG emissions of renewable fuels
with the 2005 petroleum baseline, which are docketed separately.

For more information about the calculation of lifecycle GHG emissions
and the data contained in these spreadsheets refer to the RIA Chapter 2.

