Biomass resources assessment and pretreatment technologies

Biomass, a renewable organic matter of plant, animal, and waste origin, is emerging as a major pillar of the global energy shift to renewable energy. This chapter explains biomass's tremendous potential as a sustainable feedstock for the generation of bioenergy to replace fossil fuels, lower greenhouse gas emissions, and contribute to net-zero targets. The study critically evaluates biomass types (woody, agricultural residues, energy crops, algae, and municipal wastes), compositions, and energy potentials. Large-scale frameworks such as thermochemical, biochemical, and mechanical pretreatment methods were discussed, with key numerical facts: 60% of renewable energy in the EU is supplied by biomass energy production, with an estimated 1260EJ/year biomass production globally. Novelty lies in the cumulative evaluation of biomass supply chains, pretreatment technology, energy densification (for instance, torrefied briquettes with transportation efficiency up to 85%), and environmental impacts (for example, algae-based biomass with minimum greenhouse gas emissions of 5-15g CO2/kWh). The research also highlights biomass densification innovations such as pelletizing and briquetting with energy densities up to 25MJ/m3. Emerging contributions are critically assessing biomass ash management, pelletizing, lifecycle emissions, and possible valorization avenues in the future, such as sustainable, eco-friendly recycling of ash, and biorefinery concepts. Emerging future markets include advanced biofuels (diesel, aviation), decentralized renewable energy systems, and circular low-carbon and sustainability-based bioeconomies. This chapter is an interdisciplinary roadmap for scholars and policymakers to sketch out robust, low-carbon bioenergy systems complementing global action toward decarbonization.