Softwood forest thinnings as a biomass source for ethanol production: A feasibility study for California

A plan has been put forth to strategically thin northern California forests to reduce fire danger and improve forest health. The resulting biomass res idue, instead of being open burned, can be converted into ethanol that can be used as a fuel oxygenate or an octane enhancer. Economic potential for a biomass-to-ethanol facility using this softwood biomass was evaluated for two cases: stand-alone and co-located. The colocated case refers to a speci fic site with an existing biomass power facility near Martell, California. A two-stage dilute acid hydrolysis process is used for the production of et hanol from softwoods, and the residual lignin is used to generate steam and electricity. For a plant processing 800 dry tonnes per day of feedstock, t he co-located case is an economically attractive concept. Total estimated c apital investment is approximately $70 million for the co-located plant, an d the resulting internal rate of return (IRR) is about 24% using 25% equity financing. A sensitivity analysis showed that ethanol selling price and fi xed capital investment have a substantial effect on the IRR. It can be conc luded that such a biomass-to-ethanol plant seems to be an appealing proposi tion for California, if ethanol replaces methyl tert-butyl ether, which is slated for a phaseout.