Techno-Financial Analysis of Bio-Compressed Natural Gas as an Alternative Cooking Fuel: A Case Study of Gandaki Urja

Abstract

Nepal generates around 2500 tons of solid waste each day. These wastes are collected from the sources and dumped directly at different landfill sites throughout the country without proper segregation and scientific methods. These unscientific dumping of the wastes, emissions from the combustion of petroleum products and excessive use of chemical fertilizers in the agricultural field are mainly responsible for spreading diseases in human beings and creates huge negative impacts in the whole ecosystem while playing the major role in rapid increasing national trade deficit. Thus, our research emphasize on the technical and financial aspects of the largest BioCNG plant in Nepal, Gandaki Urja Pvt. Ltd. with a focus on the technical process of waste collection, anaerobic digestion, gas purification, compression, storage and fertilization. This study also includes a commercial viability and future of BioCNG as an alternative fuel. From the field study of Gandaki Urja, it is found that the total waste processing capacity of the plant is 45 TPD leading to the formation of 2500 m3 of raw biogas, 1125 Kg of BioCNG and 2000 Kg of organic fertilizer per day. Due to the covid pandemic and lockdown, the demand of gas and fertilizer were reduced drastically. This minimized the feedstock in the plant to 18 TPD leading to generation of 1014 m3 of raw biogas, 456 Kg of BioCNG and 1000 Kg of organic fertilizer per day. Organic fertilizer from biogas plant has proved to be high quality manure rich in humus with pH 7.78, moisture 30%, nitrogen 1.5%, phosphorous 0.5% and potassium 1.5%. About 4.8 GJ/day energy is required for the complete production and storage of BioCNG and organic fertilizer which is about 20% of the total energy generated at 18 TPD capacity and about 9% of the full capacity of 45 TPD. At 18 TPD capacity, produced BioCNG can replace 518 Kg, 495 L and 570 L of LPG, diesel and petrol respectively. Similarly, 1152 Kg, 1102 L and 1268 L of LPG, diesel and petrol respectively at 45 TPD capacity. From the production and use of BioCNG, LPG has been replaced for cooking purpose. This will reduce around 320 TPY of CO2 emission with 18 TPD capacity and 715 TPY with 45 TPD capacity. Similarly, comparing with diesel and petrol 1086 TPY and 1018 TPY CO2 emission will be reduced at full capacity. The financial feasibility of the project was also assessed taking 10 years as the analysis period. The total yearly sale revenue projected is NRs. 58.993 Million at 100% capacity. The annual net profit of the company is calculated to be Rs. 22,682,125.00. Taking the 40% government subsidy in capital expenditure, with annual profit of Rs. 22,682,125.00, the payback period will be in 7th yr of selling of products. Taking without 40% government subsidy in capital expenditure, with annual profit of Rs. 22,682,125.00, the payback period will be in 11th yr of selling of products. The debt/equity/subsidy ration was found to be 32%/28%/40%.