| Title | The Gemini Turbine: A Boost for Power Generation in Large-Scale ORC Geothermal Plants |
|---|---|
| Authors | Giorgia Ruffato, Davide Elia Lattuada |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | |
| Abstract | Geothermal plants using Organic Rankine Cycle (ORC) technology face high volumetric flow rates combined with medium enthalpy drops. While increasing the size of heat exchangers and piping can easily accommodate higher flow rates on the heat exchange side, the expansion phase presents more challenges, especially for radial outflow turbines (ROT). For ROTs, there is a critical volumetric flow rate threshold, typically around 50 m³/s. Beyond this, the blade height plays a crucial role in maintaining mechanical integrity, as it is directly related to the volumetric flow rate. The traditional approach of Exergy to manage these higher flow rates has been to split the flow into two turbines, each handling a portion of the flow. This study outlines a significant innovation in the realm of large-scale geothermal power generation: the Gemini Turbine, a ROT design developed by Exergy to address the challenges posed by high volumetric flow rates in ORC. The core of the innovation lies in the ability of the Gemini Turbine to handle large geothermal resources—up to 50–60 MW—without the need to split the flow into two turbines, as is traditionally done in these systems. The paper likely includes a case study demonstrating how the Gemini Turbine could be applied in real-world geothermal power plants. This case study would help illustrate the potential benefits, such as more efficient operations, greater reliability, and more compact plant layouts. |