UNAIR NEWS – The Society of Renewable Energy (SRE) Universitas Airlangga (UNAIR) held an online webinar on geothermal energy on Sunday (May 31, 2026), titled Voice of Energy: The Geothermal Career You Never Knew Existed. The event highlighted the role of geothermal power in Indonesia’s energy transition and featured Adrian Tawakal, S.T., M.T., a geothermal researcher at PT Pertamina, as the guest speaker.
Understanding how geothermal energy works
Tawakal described geothermal energy as a renewable resource generated from the Earth’s natural heat. Geothermal systems are formed through the interaction of heat sources, underground fluids, reservoirs, and cap rocks, which allow heat to accumulate beneath the surface and be transferred upward.
“Geothermal energy is a clean and reliable source of power that can provide a continuous electricity supply, making it an important component of the energy transition and national energy security,” Tawakal said.
Indonesia holds one of the largest geothermal reserves in the world due to its location along the Pacific Ring of Fire, a region known for intense volcanic activity, he explained. Adrian likened the geothermal process to a kettle sitting on a stove. The stove represents hot rocks created by tectonic plate movements, while the water inside the kettle symbolizes underground reservoirs heated naturally by the Earth. As the water turns into steam, it rises through production wells. The process is contained by a cap rock, comparable to a kettle lid, which traps heat and pressure within the reservoir. Together, these elements make electricity generation possible.
During geothermal operations, steam and water are first separated using a separator. The steam then passes through a scrubber before being condensed. While the steam is used to drive turbines that generate electricity, the water undergoes additional treatment and is ultimately reinjected into the reservoir rather than discarded.
Benefits of geothermal energy
Tawakal said geothermal power is considered a highly dependable energy source because it can operate continuously around the clock throughout the year. With proper management, geothermal facilities have demonstrated the ability to remain productive for more than 100 years.
“Indonesia has an estimated geothermal resource potential of 23.76 gigawatts, yet only 2.13 gigawatts have been utilized for electricity generation,” Tawakal said. “This underscores the need to develop geothermal energy in ways that are both environmentally sustainable and economically feasible so that its vast potential can be fully harnessed.”
Author: Fauziah Kandela
Editor: Khefti Al Mawalia
