Production of solid biofuels from organic waste in developing countries: A review from sustainability and economic feasibility perspectives

The current increase in the world population and its energy demand promotes the study and implementation of cleaner energy forms since the traditional energy recovery systems are seriously affecting the environment. Biofuels and especially biomass or solid biofuels represent a sustainable energy source for developed and developing countries. This review aims to discuss the characteristics and advantages of solid biofuels, analyse the pretreatments and thermal treatments required to recover energy, and compare them with traditional fossil fuels. Other areas such as the sustainability and economic feasibility of solid biofuels are likewise addressed by explaining frequently used tools to evaluate the environmental impact as Life Cycle Assessment (LCA). Comparatively, more recent methodologies are examined as efforts for accomplishing sustainability in the biofuel industry, namely Life Cycle Sustainability Assessment (LCSA) and certification schemes like the Roundtable on Sustainable Biomaterials (RSB), the Inter-American Development Bank Sustainability Scorecard, and initiatives like the Roundtable for Sustainable Palm Oil (RSPO). Finally, it was revealed that the economic feasibility and competitiveness of solid biofuels differ among developing countries but represent a notable contribution to their energy matrix. [Display omitted] •Properties of solid biofuels (SB) make them competitive with conventional fuels.•Pretreatment and handling of feedstock have a higher impact on SB feasibility.•Could yield very low GHG emissions, heightening sustainability in developing countries.•State-interventions may be required for solid biofuels to access the fuels market.•Solid biofuels from biowaste are essential to circularity for developing countries.