The default approaches and emission factors shown in the ICFPA/NCASI calculation tools have been selected to be applicable to an international audience; however, in many cases, mills will need to substitute values that are better suited to their particular regulatory or technical situations. To meet these needs, NCASI developed an enhanced version of the calculation tools spreadsheet that is tailored specifically for mills in the US. This enhanced version of the Microsoft Excel-based tool includes an easier-to-use Visual Basic interface that guides the user through the process of completing a GHG inventory. In addition, the new version includes default emission factors and units appropriate for mills in the US.

The enhanced version of the calculation tools for US mills employs the same mathematical estimation methods as the tools prepared for ICFPA, but includes a set of Visual Basic macros that facilitate entering data related to emissions calculations in a variety of formats and reporting units.

The primary features of the enhanced version include:

• The ability to enter fuel consumption data in a variety of units, including mass or volume units of measure for many fuels.
• The ability to use custom (fuel or combustion technology specific) emission factors in a variety of units.
• Automatic selection of "default" emission factors for a variety of fuels (emission factors drawn predominately from IPCC publications).
• Inclusion of state-specific (and US average) emission factors for electrical power purchased from utilities, drawn from the Department of Energy's 1605(b) program and from EPA's EGrid database, in an electronic data set for easy selection and use.
• A simple and easy to use method for allocating emissions from combined heat and power (CHP) systems, for use in estimating emissions associated with imported (purchased) or exported (sold) electrical power or steam.

The tools have been extensively tested, however some (but not all) computers with the Microsoft Windows 98 operating system combined with Excel 97 have problems when running the workbook. The problems manifest by Windows closing the Excel application. NCASI is soliciting reports of any problems encountered when using the tools, and is developing a version of the enhanced calculation tools that function robustly on all versions of Excel from 97 onward. When complete, this version will be available to NCASI members free of charge, and will be available to non-members for a nominal fee.