Techno-economic analysis of a grape pomace biorefinery: Production of seed oil, polyphenols, and biochar

Processing grape pomace (GP), a major waste from the wine industry, into multiple value-added products based on the biorefinery concept has a potential to reduce waste disposal and promote a sustainable bioeconomy. However, its economic feasibility at a commercial scale remains unknown. The present study aims to evaluate the economics of a biorefinery process of GP, by performing comparative techno-economic analysis of three processing scenarios: (1) a whole biorefinery process that fully utilizes GP biomass and produces grape seed oil, polyphenols, and biochar (GSO + GSKP + GB), (2) a process that produces grape seed oil and polyphenols (GSO + GSKP), and (3) a process that produces only grape seed oil (GSO). A plant capacity of about 33,000 metric tons/year was considered in the analysis. Among the three scenarios, the whole biorefinery process (GSO + GSKP + GB) showed the highest economic performance with the net present value (NPV), internal rate of return (IRR), and payback period of 111.7 million US-$, 34.3%, and 2.5 years, respectively, due to the diverse revenues and minimized waste disposal cost. The GSO plant showed the lowest economic performance with a negative NPV. Sensitivity analysis revealed that plant capacity, polyphenol price, polyphenol concentration (percentage) in grape pomace, and biochar price had dominating influences on the economic performance of the biorefinery process.