This innovative configuration combines the power of two turbines into a single high-capacity unit delivering up to 60 MW. Conceived and developed entirely in-house by Exergy’s Turbine team in Italy, the Gemini sets a new benchmark for efficiency, scalability, and competitiveness in large-scale geothermal power generation, making it the ideal match for next- generation Enhanced and Advanced Geothermal Systems (EGS and AGS).
At the heart of Gemini’s innovation lies an evolution of Exergy’s proprietary ROT architecture. The turbine features a dual-inlet design that allows the working fluid to enter symmetrically from both sides and expand radially outward through a central rotor disk equipped with dual mirrored rotor stages. After its radial expansion, the fluid converges toward a central exhaust flange for discharge.
In this new configuration, stator blades are mounted on lateral stator disks, while the rotor is supported in a between-bearings arrangement, replacing the traditional overhung setup. This structural advancement significantly enhances the turbine’s mechanical stability, reduces vibration, and improves operational reliability.
The Gemini turbine’s unique configuration delivers a series of technical, operational and economic advantages providing real value for developers and operators:
The Gemini Turbine opens new possibilities for harnessing geothermal resources with very high flow rates more efficiently, replacing traditional configurations that use two ROT turbines operating in parallel. It provides a competitive, cost-effective, and high-performance solution for large-scale geothermal power plants in the 30–60 MW range.
Gemini is particularly suited to next-generation geothermal systems based on EGS and AGS technologies, which are emerging as the most promising frontier of global geothermal development. These systems enable power generation in regions previously considered unsuitable for geothermal use.
Luca Pozzoni, Deputy CEO of Exergy International commented, “The Gemini turbine marks a major milestone in Exergy’s technological evolution. It showcases the strength of our engineering expertise and the creativity of our team, who constantly push the boundaries of what our technology can achieve. With Gemini, we deliver a solution that offers higher performance, lower costs, and a reduced environmental footprint — all essential for the future of large-scale geothermal power”.
