About us

GeothermEx is the most comprehensive and longest-established geothermal resource consulting and services firm in the world.

Founded in 1973, our reputation is built on five decades of proven expertise coupled with steadfast objectivity. Whether you need advice on resource viability, risk assessment or economics and timelines, we deliver high-quality, realistic analyses for projects anywhere in the world.

For due diligence work related to geothermal investments, the GeothermEx Report is considered the gold standard, as evidenced by GeothermEx’s work on more than 8.5 GW of clean geothermal electricity and related investments exceeding $14 billion.



Ann Robertson-Tait



Minh Pham

Reservoir Engineering Manager


Logan Hackett

Senior Geochemist / Geologist


Roger Henneberger

Earth Science Manager

Meet the whole team

Our long and varied experience enables efficiencies that allow our customers to get their geothermal projects online quickly. Often starting at the early exploration stage, GeothermEx’s involvement guides projects forward though stakeholder buy-in, well testing and resource confirmation, power cycle optimization and acceptance testing.

After commencing routine operations, our work continues with resource monitoring and management, often developing numerical reservoir models to maximize and maintain power output, and considering options for expansion.

Learn more about what we do and the services we offer.