Batteries, hydrogen fuel cells, and bioethanol in passenger cars

Fuel-efficient, low-emission powertrains and alternative, low-carbon fuels for road transport, particularly advanced biofuels, electricity, and hydrogen are essential to mitigating global climate change, urban air pollution, and energy security issues. Several high-profile comparative assessments of these technologies have been conducted over the last 2 decades to inform policymakers and other stakeholders on which to support. The studies have generated a tremendous amount of knowledge and greatly improved our understanding of the relative roles of the different technologies. They show that all technologies are potentially required and support to all of them should therefore be granted. Sustainable, cost-competitive bioethanol in particular has a potentially important role to play in the short to medium term. Moreover, bioethanol and batteries should not be seen as antagonistic as they can work together in plug-in hybrid electric vehicles. In the long term, if internal combustion engines are phased out, sustainable biomass production routes to bioethanol can continue to be exploited for the production of bio-hydrogen for fuel cell powertrains.