DEEPEN: DErisking Exploration for Geothermal Plays in Magmatic ENvironments: Cooperative Research and Development Final Report, CRADA Number CRD-20-17162

High resource risk and high capital costs are key barriers to scaling up geothermal energy development globally. Reducing both resource risk and costs has for a long time been a priority area of both research institutions and industry, particularly when it comes to new types of geothermal resources. The DErisking Exploration for geothermal Plays in magmatic Environments (DEEPEN) project aimed to contribute to this goal through increasing the probability of success when drilling for geothermal fluids in magmatic systems. “Magmatic” geothermal systems form in volcanic or plutonic settings. The geothermal resource types that may develop in magmatic environments include conventional convective hydrothermal reservoirs, reservoirs of naturally occurring supercritical fluids (>374 degrees C/ >220 bar for pure water), superheated steam reservoirs, and hot rocks suitable for development through enhanced geothermal system (EGS) technology. The latter 3 types are effectively new resource types, since the hottest geothermal fluids exploited for power typically have temperatures between 350 degrees C and 365 degrees C. By developing and testing improved exploration methods and an improved framework for joint interpretation of exploration data in magmatic settings, the DEEPEN project has advanced the development of geothermal energy by reducing resource risk. The project has achieved the following key accomplishments: 1) Ranking and analysis of existing geoscientific methods for detecting and characterizing prospective geothermal resources in magmatic settings, particularly with respect to emerging geothermal resource types such as superhot EGS and supercritical fluids; 2) Development and validation of new geophysical and geochemical methods for discovering and characterizing prospective geothermal resources in magmatic settings. These new tools improve the detection and subsurface imaging of deep and hot bodies and build on results from previous EU-funded efforts (e.g., FP7-IMAGE project); 3) Development of a Play Fairway Analysis (PFA) methodology and framework for joint interpretation of exploration data specific to magmatic plays. The DEEPEN PFA approach drew learnings from 14 international training sites statistical analysis of exploration datasets to produce generalized conceptual models and numerical models for multiple plays within a single magmatic system. Those models were the basis of a fairway analysis framework that includes the root zones of geothermal systems in magmatic environments; 4) Application of the DEEPEN methodology (multi-geophysical inversion and PFA) at two magmatic systems slated for superhot geothermal development: Hengill Volcano, Iceland (which hosts two major geothermal fields currently produced for geothermal power and is the future site of IDDP-3, a deep well that will be drilled with the goal of tapping supercritical geothermal fluids for power) and at Newberry Volcano, USA (a currently undeveloped site that will demonstrate the development of superhot EGS in the near future).