Impact of Fuel Production Technologies on Energy Consumption and GHG Emissions from Diesel and Electric–Hydrogen Hybrid Buses in Rio de Janeiro, Brazil

In view of the GHG reduction targets to be met, Brazilian researchers are looking for cleaner alternatives to energy sources. These alternatives are primarily to be applied in the transport sector, which presents high energy consumption, as well as high CO2 emissions. In this sense, this research developed an LCI study considering two bus alternatives for the city of Rio de Janeiro: diesel-powered internal combustion buses (ICEB) and a hydrogen-powered polymer fuel cell hybrid bus (FCHB). For the FCHB, three hydrogen production methods were also included: water electrolysis (WE), ethanol steam reforming (ESR) and natural gas steam reforming (NGSR). The research was aimed at estimating energy consumption, including the percentage of energy that is renewable, as well as CO2 emissions. The results show diesel as the energy source with the highest emissions as well as the highest fossil energy consumption. Regarding the alternatives for hydrogen production, water electrolysis stood out with the lowest emissions.