| Parallel life cycle assessments (LCAs) of energy use and greenhouse gas (GHG) emissions of baseline mass transit systems in the U.S. and India are conducted. The LCAs focus on bus and electrified urban rail transit systems in Denver, USA and Chennai, India. The life cycle GHG analysis is then applied to evaluate GHG mitigation in the transportation sector in Denver. A major difficulty in using life cycle data for transport policy decision-making is that baseline LCAs of buses and electrified urban rail have not been conducted in either India or the U.S. The contribution of this thesis is to begin filling this important data gap on the life cycle impacts of transit systems in each country, providing for the first time a side-by-side comparison of life cycle energy use and GHG emissions of mass transit systems in the developed and developing world. The analysis is relevant for GHG mitigation for climate actions as well as urban infrastructure planning for a carbon-constrained future.; The analysis found that established life cycle inventory databases from industrialized nations cannot be used for developing country vehicle manufacturing and operation analyses without explicitly accounting for significant process differences. For buses, Indian buses have an energy and GHG advantage over U.S. buses [11 vs 24 MJ/v-km; 0.9 vs 1.8 kgCO2e/v-km] due to lighter vehicles, fewer auxiliaries, better fuel economy, and higher ridership. For electrified urban rail, the results are reversed with U.S. systems being lighter and having greater energy efficiency [12 vs 26 MJ/v-km; 3.0 vs 6.4 kgCO2e/v-km]. Incorporating ridership amplifies these results on a per passenger basis yielding kgCO2e/p-km factors of 0.02, 0.2, 0.4 and 0.2 for India bus, U.S. bus, India rail, and U.S. rail respectively. GHG emission factors of electric grids are shown to be up to three times greater than for diesel fuel, comparatively disadvantaging electrified urban rail systems. Finally, analysis of GHG reduction options for the transportation sector in Denver shows that mass transit system supply must be coupled with market-based and City policies to reduce travel demand, along with state-level initiatives to improve fuel-propulsion systems, to achieve even moderate GHG reductions. |
