Handbook for Evaluating Emissions and Costs of APUs and Alternative Systems (2012)

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E-1 A p p e n d i x e In developing this Handbook, many assumptions were made related to the emission char- acteristics and operating parameters for APUs and alternative systems. These assumptions are discussed in detail in Chapters 1–4. Key assumptions are repeated here for clarity: • APU TIM values were obtained from ICAO and are used as a starting point for the quantitative assessments described in Chapter 3. • In Chapter 3, TIM values for APUs are assumed to be identical to usage times for alternative systems. That is, airlines will operate the alternative systems for the same amount of time they would have operated APUs if an alternative system were not available. However, it is antici- pated that APU and alternative system usage times at remote RON locations are not the same. At remote RON parking positions, APUs are usually shut down at night whereas alternative systems are often used all night. Therefore, different usage times (different TIM values) may be needed to accurately compare emissions associated with the use of APUs and/or alternative systems at remote aircraft parking positions. • Data from the FAA’s VALE technical manual were used to define the three ambient tempera- ture conditions described in Chapter 3 (e.g., hot, neutral, and cold). The three ambient temper- ature conditions in turn define if aircraft cooling is required (hot), aircraft heating is required (cold), or no aircraft cooling or heating is required (neutral). • The research team assumed that the “APU Start” and the “Main Engine Start” modes are com- mon for the use of APUs and alternative systems. In other words the research team assumed that aircraft APUs are operated during the “APU Start” and “Main Engine Start” modes regardless of whether an alternative ground power and PCA system is available. For simplicity, the research team assumed that no other ground support equipment is required to support aircraft during these modes (e.g., an air start unit). • Since total hydrocarbons (THC) emission factors for electricity consumption were not avail- able, an approximate volatile organic compounds (VOC) emission factor was derived from existing VOC species data maintained by the USEPA. • A 40% diversity factor was used to account for the average percent of the full power loads consumed by aircraft. • All cost data and results are presented in 2010 dollars. No specifications are provided to reconcile the impacts of inflation and other economic factors. • As indicated in the various cost tables, the source of all capital and maintenance costs is AERO Systems Engineering, Inc. The capital costs for alternative system power and PCA are conser- vatively based on the highest capacity for each power (kVA) and PCA (tonnage) ranges that are applicable to each aircraft category. • The average cost of electricity ($/KWh) and natural gas ($/mmBTU) are nominal average values derived from various internet searches. Assumptions

Abbreviations and acronyms used without definitions in TRB publications: AAAE American Association of Airport Executives AASHO American Association of State Highway Officials AASHTO American Association of State Highway and Transportation Officials ACI–NA Airports Council International–North America ACRP Airport Cooperative Research Program ADA Americans with Disabilities Act APTA American Public Transportation Association ASCE American Society of Civil Engineers ASME American Society of Mechanical Engineers ASTM American Society for Testing and Materials ATA American Trucking Associations CTAA Community Transportation Association of America CTBSSP Commercial Truck and Bus Safety Synthesis Program DHS Department of Homeland Security DOE Department of Energy EPA Environmental Protection Agency FAA Federal Aviation Administration FHWA Federal Highway Administration FMCSA Federal Motor Carrier Safety Administration FRA Federal Railroad Administration FTA Federal Transit Administration HMCRP Hazardous Materials Cooperative Research Program IEEE Institute of Electrical and Electronics Engineers ISTEA Intermodal Surface Transportation Efficiency Act of 1991 ITE Institute of Transportation Engineers NASA National Aeronautics and Space Administration NASAO National Association of State Aviation Officials NCFRP National Cooperative Freight Research Program NCHRP National Cooperative Highway Research Program NHTSA National Highway Traffic Safety Administration NTSB National Transportation Safety Board PHMSA Pipeline and Hazardous Materials Safety Administration RITA Research and Innovative Technology Administration SAE Society of Automotive Engineers SAFETEA-LU Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (2005) TCRP Transit Cooperative Research Program TEA-21 Transportation Equity Act for the 21st Century (1998) TRB Transportation Research Board TSA Transportation Security Administration U.S.DOT United States Department of Transportation