Techno-Economic Feasibility Study of a Combined Cycle Power Plant Utilizing Natural Gas and Biogas from Cattle Manure Co-firing in South Central Timor

Abstract

The low electrification ratio in East Nusa Tenggara, particularly in South Central Timor Regency, poses a significant issue. Despite reaching an electrification rate of 92.33%, efforts to achieve 100% are ongoing. South Central Timor as one of the largest cattle farming areas in Indonesia, with its large grasslands and dry climate ideal for cattle farming, has substantial biogas potential from beef cattle manure through anaerobic digestion. Biogas from beef cattle manure has a net calorific value of 18.36 MJ/kg. Based on projections for 2027 using best fit regression, the average daily manure production capacity from 260,217 cattle in South Central Timor is 7.55 kilotons, which is equivalent to approximately 301,852 m³ of biogas. A small-scale combined cycle power plant (CCPP) is proposed to capitalize on this, with a capacity of 20.73 MW and a net thermal efficiency of 55.33%. The plant’s fuel mix will consist of 30% biogas and 70% natural gas by mass, with a fuel mass flow rate of 1 kg/s. The levelized cost of electricity (LCOE), internal rate of return (IRR), and net present value (NPV) obtained from the economic calculations are Rp1,126.76/kWh, 9.62%, and 222 billion IDR with assumptions of a 20-year plant lifetime, an electricity selling price of Rp1,352/kWh, and a discount rate of 6%. The plant is expected to reduce carbon emissions by 61 kilotons annually, while creating new job opportunities in the energy, livestock, and logistics sectors.