COMPREHENSIVE ASSESSMENT OF THE ENERGY EFFICIENCY, PAYBACK PERIOD AND ENVIRONMENTAL IMPACT OF A HYBRID BIOGAS PLANT COMPREHENSIVE ASSESSMENT OF THE ENERGY EFFICIENCY, PAYBACK PERIOD AND ENVIRONMENTAL IMPACT OF A HYBRID BIOGAS PLANT

Abstract

This paper presents the results of a comprehensive evaluation of a small-scale hybrid biogas plant for farms in Uzbekistan. The system under study includes a 0.5 m³ bioreactor, a 2 m² solar collector, and a 0.55 kW photovoltaic panel, providing thermal and electrical energy for the bioreactor with minimal external input.

Performance was evaluated using an energy balance approach accounting for all subsystem efficiencies.

The overall energy efficiency of the plant is about 37% (i.e., roughly one-third of the input renewable energy is converted into useful heat and electricity). The hybrid system can supply up to 96% of its energy needs from renewable sources, demonstrating a high level of energy autonomy. Economic analysis indicates an annual benefit of approximately 1.8 million UZS by replacing grid electricity and natural gas with renewable energy and utilizing the produced biofertilizer. The simple payback period is about 7 years. Environmentally, the plant reduces CO₂ emissions by 2.0 tons per year (roughly 20 tons over 10 years) through the substitution of fossil fuels with biogas and solar energy.

Thus, the hybrid solar-biogas system represents an effective solution for supplying energy to remote farming communities in Uzbekistan. It enables the efficient utilization of livestock waste while simultaneously producing heat, electricity, and valuable biofertilizer, thereby enhancing the energy autonomy and environmental sustainability of the agricultural sector. The obtained results demonstrate the high potential for implementing such small-scale systems in agriculture, contributing to the development of renewable energy and the reduction of the carbon footprint in the region.