The objective of this research is to prepare a workbook for airport, airline, and environmental planners that can be used to evaluate alternatives to aircraft auxiliary power units (APUs) for power, heating, and air conditioning. The workbook should include tools to quantify the general emissions benefits of alternatives and to provide appropriate quantitative and/or qualitative analyses of the financial (e.g., capital, operating, and maintenance expenses) and operational implications, as well as any potential noise reductions that may occur. The workbook is intended to be a set of tools that will provide general emission information for various types of APUs, options, costs, and other considerations that can be applied.