Ernst Worrell (Ph.D.) lead the industrial energy assessment work at Lawrence Berkeley National Laboratory for four years previous to taking a position at Ecofys. Until 1998 he co-lead the energy efficiency group at the Department of Science, Technology and Society of Utrecht University, The Netherlands. He was a visiting scientist at the Center for Energy and Environmental Studies at Princeton University (USA) in 1994-1995, and a visiting professor at the Universidade de Sao Paulo, Brazil, in 1996. He joined the Environmental Energy Technologies Division of Lawrence Berkeley National Laboratory, USA, in 1998. His work includes research and evaluation projects in industrial energy efficiency improvement, energy policy, energy and materials, and waste processing. He has experience in multi-national research teams and has lead studies for various governments, European Commission, World Energy Council and the United Nations. He is lead-author of two IPCC special reports (e.g. on Technology Transfer) and the Third Assessment Report. He is (co-) author of over 150 publications. He is Editor-in-Chief of Resources, Conservation and Recycling and associate editor of Energy, the International Journal and editorial board member of Waste Management.