Track: Sustainability and Green Systems

Abstract

This study is a review of the role of biogas from agricultural biomass in the energy transition in a multipurpose application for supply of electricity, heat energy and fertilizer to support agriculture. The global concerns and commitment to reduce greenhouse gas emissions and the related global warming has set in motion effort to identify and promote renewable energy sources like biogas. Biogas can be produced from any biodegradable biomass under suitable conditions making it possible for rural based smallholder farmers to effectively participate in the global energy transition to renewable and low carbon grid electricity. With development of decentralization of grid power generation, smallholder farmers can generate biogas and use it to run grid connected electricity generator to earn revenue and reduce the demand on grid s electricity. However  many digesters fail and remain idle in developing countries due to lack of adequate operation and maintenance knowledge while conversion technologies available remain advanced and complex for the smallholder farmers. With proper process management, the digestate will substitute chemical fertilizers with additional financial benefits and fertility management. The farmers will also meet their entire heating requirements from a well-designed and sized biogas plant.  The overall objective of this study was to identify measures and technologies that can be adopted by farmers to generate power for own use and export to the power grid while meeting other energy and farming requirements for sustainable agriculture. The study showed that biogas from agricultural wastes can play a leading role in the energy transition to green and low carbon sources for grid electricity, but a sustainable biogas system has to be multipurpose to make social economic sense to smallholder farmers.   The study recommends modifications on bio-digesters and the use of the Stirling engine to generate electricity at farm level though other feasible conversion technologies are available. For viability of grid supply, state incentives like attractive feed in tariffs are necessary.