Renewable Energy System: Alternative Fuel Usage in the Energy Market of the US Public Transportation System

Abstract

The U.S. transportation sector is the second largest energy consumer in 2020 with about a 35% usage rate. However, the sector accounted for the largest proportion (29%) of the total greenhouse gas emissions in 2019. Compared with the use of personal automobiles, public transportation is believed to be cost-effective and provides low emissions, which tends to reduce the need to travel long distances and lower the carbon footprints of transit operations. This study examined the impact of alternative fuels (various blends of biodiesel, hydrogen, methanol, and ethanol) versus conventional fuels on greenhouse gas emissions in the U.S. public transit system. The research was anchored by three regression models to analyze the joint and individual impact of both conventional fuel and alternative fuel. Secondary data were extracted from the American Public Transit Association 2021 Fact Book, the U.S. Bureau of Transportation Statistics, and the Inventory of U.S. Greenhouse Gas Emissions and Sinks 1999-2019 (EPA 2021). The descriptive statistics, correlation, and stationarity tests were established on the variables, and the regression models were estimated using ordinary least squares. The findings revealed that while conventional fuel expands the flow of carbon emissions, alternative fuel is a drag on the total emissions from public transportation. However, it was concluded that the utilization of alternative fuels in the U.S. transportation industry is still very low, thus there is a need to put all machinery in motion to embrace this fuel type to reverse climate change issues, especially in the public transit system.