Enhanced Geothermal Systems (EGS) with CO2 as Heat Transmission Fluid Geothermal Lab Call Project

From Open Energy Information

Last modified on July 22, 2011.

Project Title Enhanced Geothermal Systems (EGS) with CO2 as Heat Transmission Fluid
Project Type / Topic 1 Laboratory Call for Submission of Applications for Research, Development and Analysis of Geothermal Technologies
Project Type / Topic 2 Supercritical Carbon Dioxide / Reservoir Rock Chemical Interactions
Project Description Previous and current attempts to develop EGS in the U.S., Japan, Europe and Australia have all employed water as a heat transmission fluid. Water has many properties that make it a favorable medium for heat extraction, but it also has serious drawbacks. The use of supercritical CO2 (scCO2) instead of water as heat extraction fluid was suggested by Donald Brown of Los Alamos National Laboratory as a “game changing” alternative that can avoid the problems of aqueous fluids, make heretofore inaccessible energy resources available for human use, and provide ancillary benefits by using and storing CO2.

A CO2-based EGS is expected to comprise three distinct zones.

- Zone 1 - The inner zone or "core" of the system, from which all water has been removed by dissolution into the flowing CO2 stream, so that the fluid consists of a single super-critical CO2 phase. This is the main volume from which thermal energy is extracted by the flowing CO2.
- Zone 2 - Surrounding the inner zone is an intermediate region that contains a two-phase mixture of CO2 and aqueous fluid.
- Zone 3 - The outer region affected by the EGS activities. The fluid is a single aqueous phase with dissolved and chemically active CO2.

Process behavior and issues are expected to be quite different in the different zones. This is especially true for chemical interactions. Little is known about the geochemistry of non-aqueous systems, and the absence of water in the inner zone poses unique questions to be addressed by experiments and modeling

State California
Objectives Achieve a rational, science-based design that tests and interrogates critical process elements of EGS with CO2.
Awardees (Company / Institution) Lawrence Berkeley National Laboratory

Partner 1 Idaho National Laboratory

Funding Opportunity Announcement DE-PS36-09GO99017
DOE Funding Level (total award amount) $956,000.00
Total Project Cost $956,000.00

Principal Investigator(s) Karsten Pruess, Lawrence Berkeley National Laboratory
Other Principal Investigators George Redden, Idaho National Laboratory
Targets / Milestones - Test crucial predictions from theoretical models about the heat transfer and fluid flow properties of CO2;

- Obtain essential data to be incorporated into mathematical models;
- Determine how water is removed from a permeable medium by continuous circulation of dry anhydrous CO2;
- Build mathematical models for EGS with CO2 that allow to analyze, optimize, and scale-up all aspects of stimulation, development, and operation of EGS with CO2; and
- Identify favorable as well as unfavorable geologic conditions for a field test of EGS with CO2. Specific research tasks include the following.

Location of Project Berkeley, CA, Idaho Falls, ID
37.8717°, -122.2728°,

Funding Source American Recovery and Reinvestment Act of 2009
References EERE Geothermal Technologies Programs[1]


  1. EERE Geothermal Technologies Programs