Turning waste biomass into energy is a sustainable replacement for fossil fuels while addressing waste management problems. Thermochemical conversion processes, such as pyrolysis, gasification, and hydrothermal liquefaction, as well as biochemical conversion processes such as fermentation and anaerobic digestion, can generate sustainable biofuels, biogas, biochar, and syngas from biomass. For both thermochemical and biochemical processes, constant and stable efficiency parameters such as temperature, pH, residence time, and biomass feedstock composition are critical to the efficiency of the technologies. Even with its immense potential, converting biomass to fuels faces barriers associated with available feedstock, economic feasibility, policy decisions, and environmental assessment regarding land use, emissions, and waste products. Innovations to improve biomass to energy viability include nanocatalysts, biochar applications, artificial intelligence-based process optimization, and developing circular bioeconomy approaches to biomass conversion. Well-designed policy choices, economic incentives, and global partnerships could enhance biomass energy to become a core part of the international renewable energy shift. Overall, the information contained within this chapter demonstrates that globally biomass is a viable option, or option of transition, to advance to renewable energy.