Enriched Methane for City Public Transport Buses

Abstract

Hydrogen is seen as an alternative strategy to overcome the energy dependence on fossil fuels. The epochal change recognized by the “hydrogen revolution” has not yet occurred; however, many efforts toward carbon-free energy development have been made. In the world of transportation, hydrogen as a fuel, has demonstrated reduction of pollutant emissions and better energy efficiency. Although low temperature fuel cells (FC) allow using FC generators on board of vehicles, there are still some open issues regarding FC generator durability and hydrogen storage. Furthermore, some manufacturers have already designed and produced vehicles powered by internal combustion engines fueled with hydrogen. As a matter of fact for both technologies, the major obstacle consists in the lack of a hydrogen distribution network. While awaiting for satisfactory solutions to the large availability of hydrogen at gas stations an intermediate step toward a carbon- free mobility is achievable with the mixtures of hydrogen and methane. These blends represent an interesting application to take advantage of conventional combustion engines and to promote the transition toward hydrogen mobility. The higher combustion characteristics of hydrogen result in a higher combustion efficiency that is able to reduce energy consumption and CO₂ emission due to the lower presence of carbon in the mixture. The Mhybus project demonstrates the feasibility of using hydrogen-methane blends as fuel in public transportation and highlights energy and environmental advantages.