Biofuels: the good, the bad, the ugly—and the unwise policy

Throughout the world, nations are seeking ways to decrease CO2 emissions and to reduce their dependency on fossil fuels, especially oil, for environmental as well as geopolitical reasons. Being a renewable, CO2-reducing and easily storable energy carrier, biomass is a priority resource for fossil fuel substitution, and biomass is increasingly used for both the road transport and the heat and power sectors, with emerging interest in using it for aviation, sea transport and chemicals production as well. For the road transport sector, the conversion of biomass to the liquid biofuels of bio-diesel and bioethanol is at present a technological pathway promoted by governments in many countries. With the increasing interest in our biomass resource, however, the issue of competition for the biomass and the need for prioritising it has become evident. A review of scientific studies reporting on biomass potentials shows an interval from 75 to 400 EJ/year from the most pessimistic to the most optimistic estimates of the maximum biophysically available potential of biomass for energy purposes in 2030, being capable of around 10–50% fossil fuel substitution. This is what is judged to be biophysically available, and the studies including economic and market oriented considerations find the potential to be lower, i.e. in the interval of 75–150 EJ/year or 10–20% fossil substitution. Further, studies looking at the biomass residue part only, i.e. the biomass potential not in competition with food production, the reported interval lies from 15 to 95 EJ/ year, or around 2–13% fossil substitution in 2030. My personal judgement is that we will never reach a level over 20% fossil substitution by biomass, be it residues or crops, and we will not reach such a level before energy consumption in general has risen more than that. For several decades ahead, we still depend heavily on fossil fuels, and we can only replace them to the extent and at the speed that alternatives become available. As the magnitude of biomass that is or can be made available for energy purposes is small compared to the magnitude of the new potential customers for it, any long-term and largescale prioritisation of biomass for one purpose will imply a loss of alternative uses of the same biomass. If the lost alternatives are, then, significantly more efficient as well as economically more attractive in fossil fuels substitution and CO2 reduction, we lose more than we win. This is the case for most liquid biofuels, including first generation biodiesels (plant bio-diesels) as well as first and second generation bioethanol technologies used in Europe and the USA. When we prioritise biomass for these biofuels, we H. Wenzel (&) Faculty of Engineering, Institute of Chemical Engineering, Biotechnology and Environmental Technology, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark e-mail: henrik.wenzel@kbm.sdu.dk