Techno-economic and environmental feasibility analysis of rice husks fired energy system for application in a cluster of rice mills

The agro-processing industries can play a critical role in the development of sustainable and clean energy systems. The lack of knowledge about the technical and economic viability of agro-waste to energy is a major barrier to the successful implementation of such energy systems in developing countries, especially sub-Saharan Africa countries. This paper presents the techno-economic-environmental assessment of a cluster of rice mills located in Abakaliki, Nigeria, as a provider of clean energy. The cluster of rice mills can sustainably fulfil its energy needs through the application of organic Rankine cycle based combined heat and power plant fired by rice husks. Three scenarios of the plant were proposed and investigated for complete information. The rice husk from the cluster can provide daily 20–30 MWh and 4–91 MWh of electrical power and thermal power, respectively, at 14.5–21% efficiency. A tonne of rice husk can provide 0.45–0.65 MWh of electricity; that the unit cost of electricity from the proposed system is between 0.12 and 0.159$/kWh, which is better than 0.947 US$/kWh for the diesel generator currently in use. About 270–483 kg of CO2/MWh can be saved by the proposed combined heat and power system in relation to the current use of Lister diesel generators. The proposed plant has the potentials to support the Nigerian Nationally Determined Contributions to the Paris Agreement. The work also presents an appropriate business model and policy pathway for sustainable cottage rice processing industries.