Stefan Unnasch


Low Carbon Fuel Standards, Renewable Hydrogen, Economic Due Diligence, Mass Energy Balance, Air Permitting

Stefan received his Bachelor of Science degree in Mechanical Engineering from the University of California, Berkeley in 1983. He has over 70 publications in the area of alternative fuels and has presented and lectured at technical conferences and universities around the world.  He has performed fuel cycle analysis studies since 1987, developing analytical approaches that take into account the environmental constraints that apply to California. He develops models of well-to-wheel energy impacts and emissions, such as criteria pollutants, toxics, greenhouse gases. These analyses have included assessing the resource mix and transportation modes for fuel production, process modeling of fuel production plants, and vehicle drive cycle analysis. He has developed spreadsheet and database models that enable the calculation of regional specific emissions as part of a full fuel cycle analysis. His work on California fuel cycle analysis efforts includes serving as the Co-Chairman of the Societal Benefits Topic Team for the California Hydrogen Highway Blueprint Plan, support of California AB1007, and work on the California Low Carbon Fuel Standard.

Stefan led the development of the California GREET model used in support of the Low Carbon Fuel Standard. He has also performed life cycle analyses for over 80 advanced biofuels developers to provide custom life cycle analysis for fuel pathways that are not supported by the GREET, GHGenius, and BioGrace models.  Sefan has worked on a number of projects and economic impact studies involving alternative fuels and renewable power production in California.  He led teams that performed technical and economic analyses of ethanol production facilities that could be built in California, focusing on cellulosic conversion technologies covering a variety of feedstocks, including forest material, waste paper, rice straw, and urban waste. Contact Stefan.