The reduction of CO2e emissions in the transportation sector: Plug-in electric vehicles and biofuels

Abstract

The global transport sector is the second largest energy consumer and strongly relies on fossil fuels. Efforts for reducing GHG emissions on this sector depend on energy efficiency improvement and the use of renewable fuels and electrification. All these technologies are commercially available and each one faces some barriers to overcame environmental and financial issues. Complete vehicle electrification is still expensive, and its use as an environmentally sound solution relies on decarbonization of the electricity supply. Vehicles equipped with internal combustion engines running on renewable liquid fuels are less expensive than battery electric vehicles but its energy intensity by land area (MJ/ha) is low. We have examined an alternative where both solutions are combined through the deployment of Plug -in Hybrid Vehicles, using renewable fuel and renewable electricity. Selecting sugar cane as a source of ethanol, we can take advantage of its coproduct – electricity, used for battery charging. We have determined the well to wheel lifecycle carbon balance of PHEV consuming sugarcane-based electricity and ethanol for several scenarios being the lowest one 67gCO2e/mile. We have demonstrated that this technology is a viable alternative for climate mitigation goals. Based on published forecasts for efficiency improvements, on existing vehicle and fuel production pathways, we have shown that a car fleet of one billion units in operation by 2030 can be fueled through harvesting 125.2 million hectares of land with sugar cane and eucalyptus. Considering that ethanol and gasoline have the same performance, on miles per gallon based on their respective energy content, the total harvested area decreases to 103.7 Mha.