Researchers at Texas A&M University have concluded that the MixAlco process (developed there) to convert biomass to fuels and chemicals—under a base-case capacity of 40 dry tonne feedstock per hour— requires a total capital investment of $5.54/annual gallon of hydrocarbon fuels (US $3.79/annual gallon of ethanol equivalent). The minimum selling price (with 10% ROI), internal hydrogen production, and US $60/tonne biomass] is US $2.56/gal hydrocarbon, which is equivalent to US $1.75/gal ethanol.
If plant capacity is increased to 400 tph, the minimum selling price of biomass-derived hydrocarbon fuels is US $1.76/gal hydrocarbon (US $1.20/gal ethanol equivalent), which can compete without subsidies with petroleum-derived hydrocarbons when crude oil sells for about US $65/bbl. At 40 tph, using the average tipping fee for municipal solid waste (US $45/dry tonne) and current price of external hydrogen (US $1/kg), the minimum selling price is only US $1.24/gal hydrocarbon (US $0.85/gal ethanol equivalent).
A key feature of the MixAlco process is the fermentation, which employs a mixed culture of acid-forming microorganisms to convert biomass components (carbohydrates, proteins, and fats) to carboxylate salts. Subsequently, these intermediate salts are chemically converted to hydrocarbon fuels (gasoline, jet fuel, and diesel).
Terrabon LLC has licensed and is working to commercialize the process. (Earlier post.)
Viet Pham, Mark Holtzapple and Mahmoud El-Halwagi (2010)Techno-economic analysis of biomass to fuel conversion via the MixAlco process. Journal of Industrial Microbiology and Biotechnology doi: 10.1007/s10295-010-0763-0