Increasing energy demand has led to excessive depletion of fossil fuels, significant emission of pollutants and climate change. It is an urgent task to secure clean alternative energy sources to ensure sustainable development. Bioenergy derived from biomass can play a major role in the future energy system due to its renewability, and sustainability. The wide distribution of biomass provides rich sources of raw materials, while the significant development in bioenergy conversion technology improves its competitiveness. Bioenergy, which is used to produce biofuel, heat, and electricity, may be generated via various routes such as thermo-chemical, biological, and bio-electrochemical processes. An energy-efficient and eco-friendly biomass pre-treatment process may effectively enhance bioenergy conversion. Biomass-based heat and electricity can constitute an important fraction of energy in industrial and household sectors; while biofuels may provide energy supply in transportation particularly for heavy goods vehicles and aviation. The biofuel system must be optimised to ensure sustainability, maximise efficiency and minimise cost. It is important to fully understand the mechanisms and the correct combination of biomass pre-treatment, bioenergy conversion, and upgrading technologies. Particular attention should be paid to establishing effective policies to promote the bioenergy and biofuel industries.