The default approaches and emission factors used in the original calculation tools released in 2002 were selected to be applicable to an international audience. In many cases, however, 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 workbook tailored specifically for mills in the US, which was announced in July 2003. Since then, it has become clear that the DOE 1605(b) Voluntary Reporting program includes reporting guidance that could be inconvenient to follow when using existing versions of the tools. It has also become clear that the DOE guidelines are likely to become the standard reporting guidance in the U.S.

In May 2004, NCASI released an additional enhanced version of the Excel-based tool specifically to conform to the requirements of DOE’s current guidelines for the Voluntary Reporting of Greenhouse Gases (the 1605(b) program). This version includes an easy-to-use Visual Basic user interface that guides the user through the process of completing a GHG inventory, as well as default emission factors and units appropriate for the DOE program. (The user may use factors different than the defaults.) The DOE 1605(b) version of the calculation tools will produce the same results as earlier versions if the same emission factors are used, although the results may be expressed differently in some cases.

Both of the enhanced versions of the calculation tools for US mills (the version released in July 2003 and the new version specific for the DOE Voluntary Reporting program) employ the same mathematical estimation methods as the tools prepared for ICFPA, but include 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 versions 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
• Inclusion of state-specific (and US average) emission factors for electrical power purchased from utilities 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.

In addition, the newly released version specific for the DOE Voluntary Reporting program includes the following features and enhancements:

• The ability to estimate emissions of each of the three primary greenhouse gases of interest to the industry (carbon dioxide, methane, and nitrous oxide) separately, in a speciated manner, from independent emission factors.
• Incorporation of DOE specified emission factors as default values (users still have the ability to use custom emission factors in a variety of units).
• Incorporation of an inventory summary page tailored to meet the reporting requirements of the DOE Voluntary Reporting program (e.g., methane emissions from waste management operations are reported as quantities of methane rather than as carbon dioxide equivalents).
• Various features designed to ease both the data entry process and the examination of calculation results.
• The ability to estimate emissions of "climate neutral" carbon dioxide from biomass combustion without having to enter biomass fuel consumption data twice. (Estimates of climate neutral CO2 from biomass combustion are not included in the inventory results. Rather, these emissions are reported separately, as "supporting information.")

The DOE has recently proposed to modify the General Guidelines for reporting greenhouse gas emissions under Section 1605(b) of the Energy Policy Act of 1992. (See NCASI Corporate Correspondent Memorandum 04-04.) DOE expects to propose companion Technical Guidelines soon, which will provide more detailed instructions for reporting sources and sinks of greenhouse gases. Once finalized, NCASI will update the GHG Calculation Tools to reflect the modified guidelines.