Technical Document and User Guide for the Multi-Modal Passenger Simulation Model for Comparing Passenger Rail Energy Consumption with Competing Modes (2015)

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61 6 Air Mode Simulation Module 6.1 Overview The air simulation module simulates the air leg of a full door-to-door passenger trip generating the energy and emissions intensities of the air leg of the passenger trip. The air module is unlike the other modal simulation modules as it does not ‘simulate’ the movement of an aircraft but uses energy intensity characterization data that are published each year by the US Bureau of Transportation Statistics [Research and Innovation Technology Administration, Bureau of Transportation Statistics, 2013]. The default characterization data provided with the model are based on 2011-2012 operations of domestic US scheduled air carriers and can be updated by the user as desired in future years as air technology and operations practices change. The following five types of aircraft were assessed: 1. Turboprops (TP) 2. Small Regional Jets (SRJ) (defined here as jet aircraft with less than 50 seats) 3. Regional Jets (RJ) (defined here as jet aircraft with 50 to 89 seats) 4. Narrow Body Jets (NBJ) (defined here as jet aircraft with greater than 89 seats in a single aisle configuration) 5. Wide Body Jets (WRJ) (defined here as jet aircraft with greater than 89 seats configured with more than one aisle) The data were analyzed to provide an indication of the mix of aircraft used in meeting the demand for different trip lengths. Each aircraft type was analyzed to provide an indication of its average load factor, its per-seat fuel intensity during the landing and takeoff cycle (kg/seat-LTO) and for the cruise segment (kg/seat-GC-mi). The default coefficients used in the Air Simulation sheet are presented in the Air Mode Methodology (Section 2.4). 6.2 Air Module Layout 6.2.1 User Inputs The overall model structure was illustrated in Figure 1 of Chapter 3. Those worksheets specific to simulating the air passenger mode are discussed in more detail here. The minimum input data required to make an air simulation run are the coordinates for the origin, destination and any intermediate airports involved in the trip. A database of airport coordinates is not published; however, the data can be obtained for individual airports from publicly available websites. The co-ordinates for a sample of airports (i.e. those involved in our case study locations) are included with the model and the user can build an internal dataset as new trips are defined and simulated. With the airport coordinates specified, the model calculates the GC-distance for each leg of the trip, applies the average proportions of each aircraft type used for the trip distance involved and then calculates the aircraft specific energy and emissions intensities for the air legs of the trip.

62 The ‘Air-Simulation’ worksheet simulates the energy intensity of an air mode trip using a default distribution of aircraft types typical of the trip leg distances. A user can specify a single aircraft type or alternative mix of aircraft types. Similarly, representative proportions of direct and indirect (hub and spoke or multi-stop) trips can be specified or a 100% allocation to one or the other trip scenario can be made. Also, the default mirror-image return trip can be overridden with a user-specified trip if desired. The default data are presented in Subsection 2.4.2. 6.2.2 Air Simulation Worksheet Layout The structure of the ‘Air-Simulation’ worksheet and its direct interface to default datasets is illustrated in Figure 16. The areas of the worksheet are color coded to reflect their primary purpose: green indicates it is a user input, yellow indicates technical default data that can be optionally modified by the user, orange indicates calculation procedures at the core of the simulation, and blue indicates interim output data for transfer and/or aggregation by the ‘Macro’. The LTO and cruise legs of the air trip are calculated separately such that the differentiated impact of cruise-altitude emissions can be applied. The following fuel, energy and GHG intensities are calculated for the defined origin-destination trip:  kg-fuel consumed per seat-Great Circle-km traveled (kg/sGCkm),  kg-fuel consumed per passenger-Great Circle-km traveled (kg/pGCkm),  kg-fuel consumed per passenger-trip (kg/trip),  kJ of energy consumed per seat-Great Circle-km traveled (kJ/sGCkm),  kJ of energy consumed per passenger-Great Circle-km traveled (kJ/pGCkm),  kJ of energy consumed per passenger-trip (kJ/trip).  Grams CO2e emitted per seat-Great Circle-km traveled (g/sGCkm),  Grams CO2e emitted per passenger-Great Circle-km traveled (g/pGCkm), and  kilograms CO2e emitted per passenger-trip (kg/trip). In addition, the travel time of the air leg(s) of the trip is calculated, including dwell time at intermediate stops and airport arrival / departure processing/waiting times.

63 Figure 16. Air-Simulation Worksheet Layout color legend (primary purpose of Sheet): User input, Calculation processing Sheets/Macro; Optional User overrides of technical defaults; Output