Since 1970 the U.S. Department of Energy (DOE) has supported scientists and engineers at Berkeley Lab to stimulate industrial development of geothermal resources. The primary mission of our DOE supported R&D program is twofold: to reduce uncertainties associated with finding, characterizing, and evaluating natural geothermal resources; and to develop and understand the enhancement of permeability and fluid flow to increase fluid production through subsurface engineering, i.e., Enhanced Geothermal Systems (EGS).
Research in geothermal energy exploration at Berkeley Lab fully began in the former Earth Sciences Division (in 1977) as a key research focus which encompassed geophysical characterization and numerical modeling of fracture flow. Today, the Geothermal Systems Program is one of four Programs in the Energy Geosciences Division’s Energy Resources Program Domain.
Our Research Thrusts
The Geothermal Systems Program is focused on two research thrusts.
- Developing innovative technologies for identifying and characterizing conventional and hidden natural hydrothermal systems.
- Characterizing, developing, and sustaining enhanced geothermal systems, through the use of coupled process models, MEQ monitoring, and laboratory studies.
The first thrust focuses on developing innovative technologies for identifying and characterizing both conventional and hidden natural hydrothermal systems. Typically, “hidden” systems are deep, fault-hosted circulating systems in which surface manifestations have either been modified (obscuring deeper high temperatures) or are nonexistent. Our main research avenues include: chemical geothermometry through multicomponent analysis; subsurface characterization using joint inversion of coupled geophysical attributes; locating and mapping surface fluid flux; and play fairway analysis of prospective geothermal regions to identify geothermal systems and to better constrain resource potential.
The second thrust, developing approaches to implement, monitor and model enhanced geothermal systems, involves a form of heat mining, in which hot rock permeability is artificially created or enhanced through hydraulic and/or chemical stimulation. LBNL has played a major role in coupled process modeling and induced seismicity monitoring of several DOE-EGS demonstration projects. We are the lead lab for the EGS Collab Project, which combines field experiments, numerical simulations, and laboratory measurements to improve our understanding of the relations between permeability creation, induced seismicity, and heat production in crystalline rocks under relevant stress (and temperature) conditions for Enhanced Geothermal Systems (EGS). To allow comparison between field data and model results, we are performing intermediate-scale field tests and conducting well-controlled in-situ experiments focused on rock fracture behavior and permeability enhancement being conducted at the Sanford Underground Research Facility (SURF) in Lead, SD. This project will help support the Frontier Observatory for Research in Geothermal Energy (FORGE) EGS field laboratory.
In addition, scientists in the Geothermal Systems Program have previously evaluated the feasibility of using CO2 as an alternative working fluid in EGS, with projects focused on geothermal energy coupled to Carbon Capture and Sequestration and experimental-based research into chemical reactions and heat extraction efficiency under supercritical CO2 conditions.
Expertise, Techniques, and Equipment
Our expertise, techniques, and equipment is categorized into three main areas and encompasses theoretical, laboratory, and field studies, with an emphasis on multidisciplinary approaches.
Geophysical techniques for subsurface imaging and joint inversion
- Imaging reservoir stimulation, subsurface structures, alteration, and fluids
- Improved imaging resolution
- Coupled data inversion and analysis (acoustic, EM, rock physics)
- Monitoring, analysis, and mitigation of induced seismicity
Geochemical, geomechanical, and isotope techniques for tracing fluid-rock histories (fluid flow)
- Multicomponent geothermometry to predict subsurface reservoir temperatures
- Isotopic signatures to identify sources of geothermal fluids
- Reactive transport in fractured media
- Geochemical impact on permeability, physical properties of rocks
- Flow path engineering (creation, mitigation)
- Improved tracer technology (natural and injected tracers)
Reservoir engineering and coupled process modeling
- Predictive, inverse, and process models
- Coupled Thermal-Hydrologic-Mechanical-Chemical processes
- TOUGH family of codes
Support for the Geothermal Systems Program is provided principally by the DOE Energy Efficiency and Renewable Energy, Geothermal Technologies Office, with additional contributions from other sponsors contracted with industry partners.