Feasibility of alternatives to driving on diesel and petrol

Abstract

Globally, our road transport sector is powered almost exclusively by internal combustion engines (ICE) and more than 90% of these engines are powered by fuels derived from crude oil. Both the current cost and projected future costs of crude oil have risen sharply in the last years. Doubts about of security of imported crude oil supplies remain, and prices are expected to remain volatile but higher than in the past. Road transport is also a major source of greenhouse gases (GHG) and air pollutants such as NOx, PM10 and volatile organic compounds. In the European Union (EU), it is responsible for 18% of GHG emissions. Changing the cars, fuels and related infrastructure we use today is a complicated and expensive transition. To reduce dependence on crude oil in transport, the use of electricity and hydrogen in cars has been advocated. However, hydrogen and battery powered cars were found to be uncompetitive by a large margin: even if the cost of fuel cells would come down to 120 €/kW or the cost of batteries to €150/kWh, advanced hybrid cars are found to have a lower cost of driving. Due to increased efficiency, series hybrid cars can reduce emissions of CO2 by 34%-47% compared to regular diesel and petrol cars. Plug-in hybrid cars and fully battery powered cars can further reduce GHG emissions, depending on the source of electricity used. Based on the generation capacity projected for the Netherlands in 2015, electricity for electric vehicle (EV) charging would be generated using natural gas, and this would mean a reduction of GHG emissions of 51%-78% compared to current cars and fuels. If off-peak charging is successfully introduced, electric driving need not strain infrastructure even in case of a 100% switch to electric vehicles. Reduction of oil dependence and, possibly, GHG emissions can also be achieved by using alternative fuels. Synthetic fuel may be competitive with oil-based diesel, and for gas-to-liquids (GTL), coal-to-liquids (CTL) and biomass-to-liquids (BTL) oil price should be above 33, 60 and 75 $/bbl, respectively. However, CTL is found to increase our transport-related GHG emissions per km driven by 25%-110%. Diesel from synthetic crude oil (SCO) increases GHG emissions by 13%-60% and GTL chains without CCS by 10%. GTL with CCS is found to reduce GHG emissions by around 5% compared to fossil diesel. The net emissions from BTL can be an order of magnitude smaller and can even be made negative by application of CCS. When necessary GHG reductions in road transportation and electricity generation are considered together, lowest overall costs are achieved by using hybrid cars and both biomass and CCS to maximum potential, and by using the least-cost CO2 emissions reduction options in road transportation, even if that reduces biomass and CO2 storage capacity available for electricity generation. However, significant uncertainties remain in the cost of alternative fuels, as well as fuel cells and batteries. EU regulation on car emissions will presumably force a shift to hybrid vehicles by 2020 unless fuel cells or batteries become very cheap very soon, with additional GHG emissions reductions achieved through use of biofuels if sufficient supply of sustainable biomass feedstock can be secured. However, non-cost barriers, such as lack of familiarity and impact on car performance, to public adoption of alternative fuels remain. Simulations of the co-evolution of motorist demand and production capacity indicate that multiple barriers to adoption of alternative fuels reinforce each other. All else being equal, sustainable biofuels and hybrid cars may be adopted by motorists on grounds of GHG emissions reductions and economic arguments. Furthermore, these alternatives can also be implemented without dramatic changes in vehicle fleets and energy infrastructure.