Biomass has been, historically, the main source of global energy, primarily for cooking, heating, and small cottage industries. It is witnessing a strong revival and is currently used in a multitude of applications. It provides between 10 and 14% of world energy, with the potential to provide 30-40 + % and is an integral component of all energy scenarios. Biomass energy is providing multiple energy, environmental, and socio-economic benefits, both modern and traditional, ranging from electricity, heat, to transportation fuels.This review provides a critical assessment of biomass energy literature. It is not an analysis of biomass energy production and conversion methods. The main themes covered are: (i) biomass energy potential and its uses; (ii) liquid biofuels for transportation; (iii) land use changes implications; (iv) the food versus fuel debate; (v) environmental and sustainability, subsidies and energy balance issues; and (vi) international biomass energy trade. An additional key concern of this review has been to identify the main shortcomings and concerns affecting biomass energy of themes stated above, e.g. problems posed by poor scientific data, land use change, food versus biofuel debate; environmental and sustainability implications, or potential impacts of international biomass energy trade. Given the broad nature of biomass energy, and the need to embraces all major issues, this review paper is in many ways an overview. © 2016 Society of Chemical Industry Keywords: biomass energy; bioenergy; biofuels; land use; food versus fuel; international biomass energy trade
GENERAL BACKGROUND
Biomass energy† is a large renewable source with the potential for making a significant contribution to the world energy needs, environmentally and sustainably. Currently it contributes between 10 and 14% ‡ of the world primary energy, including about 3% of the world's transport, but with the potential to contribute up to 30-40 + % in 2050, depending on the source. Biomass energy is providing multiple energy, environmental, and socio-economic benefits, both modern and traditional, ranging from electricity, heat to transportation.Given the broad nature of biomass energy and the need to embrace the major issues, it would be impossible to encapsulate so much information and hence it is inevitable that data has to be largely abridged. This review is not concerned with technological production methods of biomass energy for two main reasons: (i) there are already excellent reviews; 1 and (ii) production and conversion technologies are many and varied and this, in itself, will require a specific review which is beyond the scope of this paper. The main themes covered are: (i) biomass energy † Biomass energy denotes bioenergy and biofuels; bioenergy refers to solid biomass used primarily for domestic uses (heating, cooking) and industrial applications (heat and power), for both small and large scale uses; biofuels refer to liquid biofuels (biodiesel and bioethanol) used primarily in road transport. Biogas is covered separ...