Feasibility Study of Integrating Green Hydrogen Plant with Geothermal Power Plants in Renewable Energy Microgrid

Abstract

In alignment with Indonesia’s national energy transition goals, PT PLN (Persero) has initiated a de-dieselization program aimed at replacing diesel generators with renewable energy sources, such as photovoltaic (PV) and geothermal power, as outlined in the Electricity Supply Business Plan (RUPTL 2021). This study investigates the economic feasibility of the proposed 10 MW Atadei Geothermal Power Plant (GPP), located within the Lembata microgrid in East Nusa Tenggara, a system currently challenged by increased PV penetration and the resulting “duck curve” phenomenon. This condition significantly reduces net load during midday, thereby constraining the minimum operational thresholds of geothermal generation. Two operational scenarios are evaluated: (1) reduced-capacity baseload operation, and (2) the integration of green hydrogen production to utilize excess power. Based on a post-dispatch average capacity factor of 77%, approximately 13% of geothermal generation remains unutilized. Incorporating green hydrogen production with Proton Electrolyzer Membrane (PEM) as a demand-response strategy enhances system flexibility, resulting in a net present value (NPV) of USD 0.16 million and an internal rate of return (IRR) of 12.5%. To maintain project viability, a minimum hydrogen price of USD 6.9 per kilogram is required. The findings underscore the potential of flexible, demand-side applications—particularly hydrogen production—to support both operational reliability and economic sustainability in isolated renewable energy systems