1. Centre
for Environmental Policy, Imperial College London, London SW7 1NA, United Kingdom
2. MATGAS Research Center, Campus
de la UAB, Bellaterra, Barcelona 08193, Spain
3. Joint
BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National Laboratory, Emeryville, California 94608, United States
4. Biomass
Science and Conversion Technology Department, Sandia National Laboratories, Livermore, California 94550, United States
5. Carburos Metálicos/Air Products Group, C/Aragón, 300, 08009 Barcelona, Spain