Graz Revives Ambitious Geothermal Heating Project as OMV Eyes Exploratory Drilling in 2026 By: Robert Buluma The Austrian city of Graz is once again positioning itself at the forefront of Europe’s geothermal transition after new agreements were successfully renegotiated between the City of Graz, OMV , and Energie Steiermark for a large-scale geothermal heating project that had unexpectedly stalled in late 2025. The revived initiative, centered on supplying renewable heat to Graz’s district heating network, now appears back on track with exploratory drilling potentially beginning before the end of 2026. The development marks a critical moment not only for Austria’s geothermal ambitions but also for Europe’s broader struggle to reduce dependence on fossil fuels amid volatile energy markets, geopolitical instability, and rising heating costs. If successful, the Graz geothermal project could become one of the continent’s most important urban geothermal heating systems, demonstrati...
By: Robert Buluma Rodatherm Energy has done something no other geothermal startup has attempted at commercial scale: swapped water for refrigerant in a closed-loop system. The claim is 50% higher thermal efficiency than water-based binary cycles, achieved by circulating a proprietary phase-change fluid through a fully cased, pressurized wellbore. The company emerged from stealth in September 2025 with a $38 million Series A—the largest first venture raise in geothermal history. Lead investor Evok Innovations was joined by Toyota Ventures, TDK Ventures, and the Grantham Foundation. The engineering thesis is elegant. The execution risks are significant. This is an Alphaxioms examination of both. II. The Thermodynamic Distinction Every geothermal company you've covered moves heat using water or steam. Rodatherm moves heat using a fluid that boils and condenses inside the wellbore. In a conventional closed-loop water system (Eavor's model), water circulates as a single-phase liq...