As renewable energy technologies such as photovoltaics mature and fossil-fuel power plants are decommissioned, an increasingly large proportion of emissions come from energy-intensive industries and the automotive and transportation sectors. An internal combustion engine wastes up to 60 % of its energy as heat, and by recent estimates ~10 % of the greenhouse gas emissions in Europe are from heavy-duty transport vehicles. A coordinated approach to reducing emissions therefore requires technologies to improve the efficiency of existing energy-intensive processes alongside the expansion of primary renewables.