Pertamina, PLN sign geothermal power tariff agreement for Lahendong Bottoming Unit, Indonesia

Steamfield at Lahendong geothermal plant, Indonesia (source: Sumitomo Corp.)

Carlo Cariaga 15 Apr 2026

The consortium of PT Pertamina Geothermal Energy (PGEO) and PT PLN Indonesia Power (PLN IP) has finalized an electricity tariff agreement with PT PLN (Persero) for the 15-MW Lahendong Bottoming Unit geothermal power plant, located in North Sulawesi, Indonesia. The facility is expected to be operational by 2028.

With the tariff now signed, the project will now proceed to the next phase. The project partners will form a joint venture, sign an Engineering, Procurement, Construction, and Commissioning (EPCC) service provider, and prepare a Power Purchase Agreement.

The Lahendong Bottoming Unit will utilize residual heat from the existing Lahendong geothermal power facility using binary power plant technology. This optimizes energy utilization, generating additional electricity without having to drill new wells. The Lahendong geothermal field currently has an installed capacity of 120 MW across 6 units, and has been operating since 2001.

“Through this technology, previously untapped waste heat can be converted back into electricity, thereby increasing generation efficiency and strengthening geothermal’s contribution to the national clean energy mix,” said PGEO President Director Ahmad Yani.

PGEO had recently submitted technical documents for further expansion plans in Lahendong, with Units 7 and 8 aiming to provide additional capacity of 40 MW (2 x 20 MW). Earlier this year, the consortium of PGEO and PLN IP also signed a tariff agreement for the 30-MW Ulubelu Bottoming Unit. The two bottoming unit projects, in Ulubelu and Lahendong, had already been identified as priority locations for co-generation based on a Joint Study Agreement signed between the two partners in 2024.

Source: Katadata