PLN to Powering Bacan Island with Geothermal

Geological Agency data end of 2019 showed that there were 15 geothermal locations in North Maluku province, the 15 locations are classified as 5 high temperature systems, 4 medium and 6 low. While from the survey status, 4 locations have been carried out reconnaissance surveys, 6 preliminary surveys, and 5 detailed surveys. 4 of these locations have been designated as Geothermal Working Area (WKP) namely, Songa Wayaua 42 MW – assignment WKP to PLN, WKP Gunung Hamiding 175 MW – Pre Survey & Exploration Assignment (PSPE) to Star Energy, WKP Jailolo 75 MW will be drilled by the government (Government Drilling program) and WKP Telaga Ranu 72 MW which will be tendered soon.

The WKP Songa Wayaua was established in 2008 on Bacan Island, South Halmahera Regency with an area of 42,540 Ha. An earlier survey by Central Geology Resources yielded an estimated reserve of 140 MW, with geothermal manifestations hot springs and fumaroles. The Songa-Wayua geothermal system is the water dominated system with an estimated reservoir temperature ranging from 180-260 °C (Giggenbach Na-K geothermometer) which is included in the intermediate-high enthalpy.

In 2017, PLN received an assignment for this WKP with an initial development plan of 2 x 5 MW. The current electricity condition of Bacan Island with a capacity of about 6.2 MW is fully supported by PLTD (diesel) and several small-centralized PLTS. The presence of PLTP Songa Wayaua 2 x 5 MW will make electricity on Bacan Island more stable and reliable. This is one of the considerations for PLN to accept the WKP Songa Wayaua assignment.

PLN’s initial steps in managing this WKP were increasing the quantity and quality of data through a Pre-Feasibility Study conducted by PT NewQuest Geotechnology in 2018-2019. The scopes of the Pre-FS includes evaluation of the existing of 3G data, Remote Sensing Analysis, Reprocessing and 3-D Modeling of Existing MT-Gravity Data. Then followed up with additional survey covering LiDAR Survey, Geological Mapping and Rock Analysis, Geochemical Studies and Water/ Gas/ Isotope Analysis, Geophysical Survey (Gravity, MT, and TDEM). All of the data were further analyzed by performing Conceptual Modeling and Resources Assessment, Well Targeting and Drilling Design, Well Pad Selection, Infrastructure Design (Access Road, Well Pad, and Water Distribution System), Power Plant Design (Process Flow Diagram, Technology Selection, and FCRS Design), Transmission Line Design, and Economic Analysis as well as Financial Evaluation.

Bacan Island is a very beautiful island with promising tourism potential, there are 3 gold and silver mining companies. ESDM One Map shows solar energy potency is 4.6 kWh/m2/day and there are 2 other potential geothermal locations namely Labuha and Indari.

In the near future, PLN will determine partners for the development and utilization of geothermal energy in the Songa Wayaua. Good Luck.