Project Overview
Mount Olive is a high-temperature geothermal prospect in Lake County, California — the same volcanic field that hosts The Geysers, the world’s largest operating geothermal complex. This is not a new discovery. It is a systematically characterised resource with more than 25 years of exploration data, a legacy deep confirmation well that measured 274°C at depth, and a new 3D magnetotelluric resistivity survey that has resolved three high-priority drilling targets for the first time.
The 9.8 km² prospective reservoir area carries a preliminary pre-drill resource estimate of 88–147 megawatts of electrical generation capacity. Initial development of the highest-confidence target zone alone is expected to support greater than 25 MW, with expansion potential toward approximately 100 MW through phased development of the full prospect.
The exploration science is complete. The next step is confirmation drilling.
In the World’s Best Geothermal Neighbourhood
Lake County, California is the most productive geothermal county in the United States. The Geysers, located approximately 15 kilometres from Mount Olive within the same Clear Lake Volcanic Field, has operated since 1960 and currently produces approximately 725 megawatts of electricity — the most geothermal power produced in a single field anywhere on Earth.
The geological architecture that makes The Geysers work is the same at Mount Olive:
- Heat source: Quaternary volcanic activity within the Clear Lake Volcanic Field
- Reservoir host: Mesozoic Franciscan Complex basement rocks — fractured greenstone and metavolcanics; the identical lithology that produces at The Geysers and at Sulphur Bank, the other producing resource in the CLVF
- Seal: Quaternary Clear Lake Volcanics forming a regional clay cap that contains the pressurised hydrothermal fluids below
The Mount Olive prospect sits within this proven productive geological framework. The question has never been whether the heat exists. The Neasham-1 well settled that in 1980. The question is whether purposefully sited confirmation wells — in the optimal portions of the MT-defined anomaly — can bring it to production. The 2025 3D MT survey defines exactly where those wells should go.
What the 3D MT Survey Revealed
In 2025, Mount Olive Geothermal LLC commissioned a 3D magnetotelluric resistivity survey across approximately 28 km² of the Mount Olive prospect. The survey was conducted and modelled in three dimensions CGG/Viridien RLM-3D inversion software — the industry standard for geothermal resource characterisation.
The result: three distinct resource target areas (A, B, and C), each defined by a dome-like uplift in the base of the regional clay cap conductor. These dome structures are interpreted as zones of active upwelling of high-temperature geothermal fluids within the Franciscan basement reservoir — the same geophysical signature that characterises the productive zones at The Geysers.
The full prospective area across all three targets spans 9.8 km², carrying a preliminary resource estimate of 88–147 MW using empirical power density factors derived from high-temperature hydrothermal fields worldwide (Wilmarth & Stimac, 2014; Wilmarth et al, 2021).
About Lake County and the Clear Lake Volcanic Field
Lake County sits at the heart of one of the most geothermally active regions in the United States. The Clear Lake Volcanic Field has generated commercial geothermal energy since 1960, hosts the world’s largest operating geothermal complex, and is underlain by the same Mesozoic Franciscan Complex reservoir that defines the Mount Olive prospect.
The scientific literature on the CLVF spans decades: from the foundational geothermal reconnaissance work of the 1970s and 1980s (Martin, 1976; Goff & Janik, 1993) through modern resistivity imaging and reservoir characterisation. The Mount Olive exploration program — including the 2025 3D MT survey — builds directly on this published knowledge base and the site-specific legacy dataset accumulated since 1994.
This is proven geothermal territory. The confirmation program is the next chapter.
