Indonesian government has set an ambitious target of 23% renewable energy mix in 2025 as stated in National Energy Policy. For that purpose, geothermal is expected to contribute 7.2 GW. Efforts from both government and contractors are needed to reach this goal. From government side, supporting policies to stimulate geothermal development activities are necessary. Government has initiated an effort by establishing Geothermal Fund, an investment fund from the government for the purpose to help financing geothermal projects in Indonesia. On the other hand, contractors also need to conduct a comprehensive feasibility study in order to have a successful geothermal project.
In this study, a technical and economic feasibility study with geothermal fund involvement is conducted for a power plant project of geothermal field X located in eastern part of Indonesia. Based on the previous study, probabilistic reserves distribution is obtained as follows: 10% probability (pessimistic) of 43 MW, 50% probability (moderate) of 74 MW, and 90% probability (optimistic) of 118 MW (Sugianto, 2018).
In the technical aspect, the technical requirements needed for field development are determined for each probability reserve. Assuming exploration well with 50% success rate and both development and make up well have 80% success rate while all the wells have the capacity of 6 MW/Well, the number of total wells for each probability are as follow: 24 wells for pessimistic, 37 wells for moderate, and 57 wells for optimistic scenario.
In the economic aspect, feasibility study is conducted through economic model for each development model based on three probability reserves. The study is conducted for 2 scenarios, one with geothermal fund and one without. with minimum acceptable rate of return (MARR) of 8%, the project without geothermal fund will only be desirable in moderate and optimistic scenario while geothermal fund improve project’s IRR across different scenarios, increasing IRR points of 1-3% and making all scenario to be desirable.