The units will be tested at a Pertamina geothermal site in Kamojang, leveraging its low-cost, baseload power.

The companies will use HyET’s proton-conducting solid oxide electrolysis-based technologies (p-SOEC) to turn geothermal steam into green hydrogen, and single-step CO2 electrolysis to turn geothermal CO2 into carbon monoxide using renewable electricity.

The hydrogen and CO2 can then be combined to make e-fuels such as e-methanol and sustainable aviation fuel (e-SAF), which could be used in the aviation, shipping, and other hard-to-abate sectors.

“Together, these technologies can enable cost-effective production of green hydrogen, carbon monoxide, and ultimately green synthetic fuel, positioning Indonesia as a competitive hub for the regional e-fuels and green chemicals market,” Pertamina said in a statement.

The pilot will run throughout 2026, and if it meets its targets, the partners plan to move directly into scaling and commercialisation. It will generate the technical and financial data needed to scale the technologies to a 10MW e-chemicals facility in Indonesia.

A Dutch impact investor, Invest International, has issued a letter of intent to support the project.