Route Based Fuel Savings of Freight Train Hybridization

Abstract

Abstract Adding battery locomotives to traditional diesel locomotives to form a hybrid consist has the potential to reduce fuel consumption and emissions in freight rail operations. This paper provides round trip, route-based estimates of diesel (hpd/ton) and battery (hpb/ton) power requirements and diesel (gal/ton) and battery (hpbhr/ton) energy requirements for hybrid consist. Given the route-specific power profile, the power split between the battery pack and the diesel engine is optimized to minimize fuel consumption by running the diesel engine at maximum efficiency during the entire trip. The results from 100-mile out/back routes between Chicago and Harrisburg indicate that the required diesel power for hybrid consist is maximum in low-gradient regions at 1.17 (hpd/ton) and the required battery power is maximum in hilly regions at 2.04 (hpb/ton) for discharge and 9.43 (hpb/ton) for charge. Maximum fuel efficiency gains of approximately 60% are seen in hilly routes, where 2.09 (hpbhr/ton) of battery energy is needed. Minimum fuel economy gains are observed in flat regions, with a 20% fuel consumption reduction. This ideal case analysis of hybrid consist can serve as an easy-to-use tool for the US freight rail sector to estimate fuel savings and sort routes based on the potential results for electrification, without requiring substantial computation.