Mitigation of Greenhouse Gas Emissions Through the Shift From Fossil Fuels to Electricity in the Mass Transport System in Guayaquil, Ecuador

Abstract

Climate change is a serious threat to sustainability. Anthropogenic climate change is due to the accumulation of greenhouse gases (GHG) in the atmosphere beyond natural levels. Anthropogenic GHG emissions are mostly associated with carbon-dioxide (CO2) originated in the combustion of fossil fuels used for heat, power, and transportation. Globally, transportation contributes to 14% of the global GHG emissions. The transport sector is one of the main contributors to the greenhouse gas emissions of Ecuador. In Guayaquil, the road mass transportation system comprises regular buses and the bus rapid transit (BRT) system. Electricity in Ecuador is mostly derived from hydropower, hence incurs relatively low GHG emissions along its life cycle. Therefore, electrification of transport has been seen as an opportunity for mitigation of GHG emissions. In this study, the effect of partial replacement of the bus rapid system fleet is investigated. Feeders have been chosen as the replacement target in five different scenarios. GHG emissions from diesel-based feeders have been calculated using the GREET Fleet Footprint Calculator tool. The GHG emissions associated with the electricity used for transportation is calculated using the life cycle inventory of the electricity generation system of Ecuador. Three energy mix scenarios are used for this purpose. The 2012 mix which had 61% hydropower; the mix of 85% hydropower and the marginal electricity scenario, which supposed the extreme case when the new demand for electricity occurs during peak demand periods. Results indicate that mitigation of GHG emissions is possible for almost all scenarios of percentage fleet replacement and all mix scenarios. Electric buses efficiency and the carbon intensity of the electricity mix are critical for GHG mitigation.