The significant increase in global population has driven unprecedented increases in energy demand and waste generation, resulting in higher fossil fuel consumption. The escalating use of fossil fuels also results in substantial greenhouse gas emissions, contributing to global warming and environmental degradation. A strategic transition toward renewable energy sources is essential to counter these challenges. This shift aims to reduce our reliance on fossil fuels, mitigate carbon emissions, and facilitate effective management of organic waste. This article reviews various thermochemical technologies, including torrefaction, pyrolysis, gasification, and liquefaction, that can transform waste biomass into solid, liquid, and gaseous biofuels. Operational parameters, including temperature, heating rate, pressure, reaction time, feedstock composition, and catalysts, influence these biorefinery conversion processes. Moreover, the intricate interplay between primary and secondary chemical reactions significantly affects the product distribution from the thermochemical processing of biomass. In addition to exploring the technical aspects of these technologies, this review article also addresses the practical challenges and opportunities associated with biomass conversion. The article also reviews the pragmatic challenges and opportunities associated with biomass conversion for process scale-up and commercialization. • Biofuels can address clean energy security and mitigate greenhouse gas emissions. • Torrefaction, pyrolysis, liquefaction, and gasification are scalable waste-to-energy processes. • Temperature, heating rate, reaction time, reactor design, and feed concentration impact biomass conversion. • Biofuels require upgrading to remove impurities and improve their performance. • Integrating biorefinery technologies demonstrates a closed-loop circular economy approach.
Talwar et al. (2026) studied this question.