Energy District

The geothermal programme deploys XGS (eXtended Geothermal System) solid-state closed-loop technology — a next-generation approach that circulates working fluid through sealed boreholes drilled into hot dry rock, eliminating the need to extract geothermal brine and removing the risk of induced seismicity, surface contamination, or aquifer disruption. Development begins with an initial 8.5MW demonstration plant to prove reservoir performance and de-risk the subsequent scale-up to full commercial capacity of 150–200MW. Waste heat recovered from the generation cycle is routed directly to the brine valorisation crystallisation units, reducing the thermal energy requirement for mineral processing.

The green hydrogen facility operates PEM (Proton Exchange Membrane) electrolysers at 70–80% conversion efficiency, powered entirely by geothermal electricity. Target production capacity is 10,000 tonnes per year. The electrolysis load — ranging from 55 to 140MW — serves as a flexible demand balancer for the internal grid: when geothermal output exceeds immediate district consumption, excess power is directed to hydrogen production rather than curtailed. Hydrogen is stored at 350–700 bar in on-site pressure vessels. Oxygen produced as a co-product is recovered and supplied to downstream industrial processes, eliminating another external input.

The mainland district includes a dedicated facility for the manufacture of HVDC (High-Voltage Direct Current) submarine cables — one of the most critical and supply-constrained components in the global clean energy transition. The cable transmission programme is planned in three phases: an initial 150MW capacity connection between the mainland district and Siberut Island, expanding to 300MW, and reaching a full 400MW transmission capacity in the third phase. The manufacturing facility serves both the internal programme and the wider regional market — Indonesia's national electrification drive and ASEAN's appetite for cross-border renewable energy trade create sustained demand.

The Energy District does not exist to sell electricity alone. It exists to make every other operation in the mainland district more competitive, more sustainable, and more resilient. Renewable baseload power eliminates exposure to fossil fuel price volatility. On-site hydrogen production enables clean industrial processes and transport. HVDC manufacturing demonstrates and supplies the infrastructure of the energy transition itself. Together, these three capabilities position the mainland district as both a beneficiary and a producer of Southeast Asia's clean energy future.