Wood residues are often treated as waste in Nordic countries and are incinerated for energy recovery,leading to the release of pollutants such as carbon monoxide, particulate matter, and volatile organiccompounds. These emissions have adverse effects on human health and contribute to climate changeimpact [1]. In this study, a wood-based biorefinery plant is analyzed from a sustainability perspective,where 2,3-butanediol (BDO), hydrochar, and pyrochar are among the valuable products generated fromwood residues.The biological conversion of wood residues through the integration of pretreatment, hydrolysis, andfermentation processes offers a pathway to convert lignocellulosic woody materials into BDO. Theenvironmental aspects of such processes were scrutinized in our previous study, considering impacts suchas climate change, resource depletion, and ecosystem quality. This revealed that refraining from woodcombustion and instead utilizing wood residues for BDO production leads to significant environmentalbenefits [2]. To fully assess the viability of a biorefinery platform, it is mandatory to employ acomprehensive techno-economic analysis (TEA) for each stage in the production chain, scrutinizing capitaland production costs, and revenue streams [3]. Economic viability is a pivotal factor for the successfultransformation and must be considered for all emerging value chains toward a feasible and carbon-neutraleconomy [4]. This analysis needs to take into account essential factors such as process efficiency, variouscosts, and process income.Key findings underscore the dual benefits of wood-based biorefinery systems. Firstly, the production of2,3-BDO, hydrochar, and pyrochar offers promising solutions for valorizing wood residues, improvingwaste treatment strategies, and reducing dependency on fossil resources. Secondly, economic analysesreveal favorable returns on investment, minimum selling price, potential for market competitiveness, andlong-term sustainability. For instance, in the case of BDO production, a biorefinery plant was modeled witha daily processing capacity of 100 metric tons of wood residues in the form of wood chips. This analysisencompassed three different scenarios (Sc.). Sc. 1, where BDO is the sole product; Sc. 2, where BDO isproduced alongside methane and biofertilizer; and Sc. 3, which incorporates a combined heat and powersystem using biogas from the waste stream. The analysis emphasizes the minimum selling price (MSP) ofBDO, revealing it to be lowest in Sc. 1 at USD 2.97/kg, compared to USD 3.20/kg and USD 3.48/kg for Sc. 2and Sc. 3, respectively. It can be concluded from Fig. 2 that while the vaporization of the biorefinery’swaste stream can lead to a higher net present value, the associated costs may affect the profitability ofthe BDO biorefinery, leading to a longer payback period.In addition to BDO production, biochar production and utilization as a soil amendment in agriculture andforestry were also investigated from LCA and TEA perspectives. The goal was to investigate thesustainability impact of using wood residues to produce biochars as a soil amendment and to generatebioenergy for captive consumption in kraft pulp mills. The evaluated thermochemical treatmenttechnologies for utilizing sludge for soil improvement are pyrolysis and hydrothermal carbonization (HTC).These two alternative systems have been compared with the reference case, i.e., incineration, which is themost common end-of-life handling method for woody biomass in Sweden, in order to examine alternativeuses for biomass treatment.

This study demonstrates the substantial environmental and economic advantages of shifting fromtraditional incineration to innovative wood-based biorefinery processes. By focusing on the production ofhigh-value chemicals and materials like BDO, hydrochar, and pyrochar, the biorefinery approach not onlymitigates pollution and supports sustainable waste management but also contributes to the developmentof a carbon-neutral economy. These findings underscore the potential of biorefineries to play a crucial rolein the circular bioeconomy, transforming waste into valuable resources and fostering long-termenvironmental and economic sustainability.AcknowledgementsThe authors express gratitude to FORMAS, the funding agency, for supporting the Swedish segment of theWoodPro project with grant number 2022-01942.