Advances in Geothermal Energy Research at LLNL: Exploring Hidden Systems and Enhanced Technologies

1. LLNL FY2003 Geothermal Activities Paul Kasameyer Carol Bruton Geothermal Program , Lawrence Livermore National Lab Presentation to Roy Mink Berkeley, March 20, 2003 UCRL-PRES-152558 This work was performed under the auspices of the U. S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48.

2. LLNL has projects in Geosciences and ESR&T • Paul Kasameyer will discuss geosciences • Hidden geothermal systems • Fracture characterization • Carol Bruton will discuss Energy Systems research and Technologies • Cost reduction by treatment of fluids

3. LLNL has Geoscience Funding in two areas • Core Research: $600K • Localized Strain As a Discriminator of Hidden Geothermal Systems, Bill Foxall: $210K • Prediction and Detection of the Attributes of Induced Fractures in Enhanced Geothermal Systems, Jeff Roberts: $300K • Reinjection of Chemically Modified Geothermal Brines, Carol Bruton: $50K • Origins of Geothermal Fluids Based on Low-abundance Isotopes, Greg Nimz: $40K • Detection and Mapping: $300K • Remote Sensing for Hidden Geothermal Resources, Bill Pickles: $300K

4. Exploration technology to expand the geothermal resource • Geosciences Goal: Develop innovative exploration techniques to expand the geothermal resource by reducing costs or enable the finding of new systems • LLNL contribution focuses on finding “hidden’ geothermal systems in the Basin and Range / eastern California • Learn why non-volcanic geothermal systems occur where they do, and how to screen large areas for targets • Evaluate imaging, strain and hydrologic methods for screening large areas for potential targets • Input into estimates of the ‘undiscovered’ resource • Expand resource so that more geothermal could be used

5. Current LLNL projects in exploration • Attributes and screening methods for favorable sites for hidden systems • Localized Strain As a Discriminator of Hidden Geothermal Systems, Bill Foxall: $210K • Remote Sensing for Hidden Geothermal Resources, Bill Pickles: $300K • Origins of Geothermal Fluids Based on Low-abundance Isotopes, Greg Nimz: $40K

6. InSAR shows a prominent lineament at the Dixie Valley geothermal Field

7. Our team is examining hyper-spectral data from Dixie Meadows, a new area that will be drilled Do features in the range indicate that a geothermal system exists in the valley? • LLNL, Bill Pickles, UNR, Wendy Calvin, UU, Greg Nash and Dharminder Pal, UC Santa Cruz, Eli Silver and Ty Kennedy-Bowdoin, • HyVista Corp., Brigette Martini, • LLNL/UCSC mapping alteration at range-front boundaries and lineaments in range

8. Technologies for enhanced geothermal system development • Geosciences Goal: Create or engineer geothermal reservoirs • LLNL contribution focuses on technical capabilities needed to predict and detect the mechanical, thermal and chemical effects of reservoir fracture manipulation • Improve modeling and measurement of fracture behavior in near-well mechanical and chemical environment • Use commercial code PulsFrac, geochemical modeling codes and laboratory measurements to design optimal frac procedures • Identify what material properties are needed for optimization • Evaluate relevance of “oilpatch” frac experience • Measure geophysical properties of fractured rocks for diagnoses • Apply in support of industry EGS projects.

9. Current LLNL Projects in EGS Technologies • Predicting mechanical, thermal and chemical behavior of induced fractures • Prediction and Detection of the Attributes of Induced Fractures in Enhanced Geothermal Systems, Jeff Roberts: (Modeling and core properties part, ~$200K) • Reinjection of Chemically Modified Geothermal Brines, Carol Bruton: $50K • Detection of fractures • Prediction and Detection of the Attributes of Induced Fractures in Enhanced Geothermal Systems, Jeff Roberts: (Lab studies of fractured rock, ~$100K) • Test of GeoBILT, a long, multi-component EM logging tool at the Geysers. (Funded by EMI, INC., ~$40K)

10. Detection of fractures and properties of fractured reservoir rocks is a current focus

11. LLNL Geosciences future • Screening strategy for sites to explore for hidden geothermal or potential EGS sites • Evaluate imaging approaches at a number of developed and undeveloped site, including relationship of known B&R geothermal fields to cross-cutting trends • Determine if there are areas of large localized strain that might lead to hidden systems • Understand relationship between regional groundwater and geothermal waters • Develop and test means to predict and control mechanical, chemical and thermal frac process in geothermal wells • Experiments at DOE-sponsored EGS sites.

12. Energy Systems Research and TestingWork at LLNL • ESR&T Goal: Maximize cost effectiveness of conversion plants to help make geothermal energy cost-competitive with fossil-fueled systems • LLNL contribution focuses on chemical issues • Understand and manipulate the chemistry and physics of geothermal fluids to • reduce maintenance and operating costs • allow more efficient utilization of geothermal heat • increase use of low temperature resources • create additional revenue streams through cascaded use

13. Current LLNL Projects • Prevent fouling and precipitation in power plants to reduce O&M costs and allow extraction of more heat • Silica scale inhibition - L. Burton P.I., FY03 $200K • Convert dissolved minerals and metals into valuable by-products to produce additional revenue streams • Silica extraction (joint DOE/California Energy Commission funding) - B. Bourcier P.I., FY03 $100K • Metals extraction (DOE funding) - B. Bourcier P.I., FY03 $25K

14. Low salinity brine Medium salinity brine Inhibitortestingin lab Isolating variables Scale inhibition: Develop a predictive model of silica polymerization and deposition using lab and field data Increasingsupersatn. • Controlling variables: • SiO2 concentration • temperature • pH • salinity • inhibitor dosage Silica deposition rate, log Decreasingsalinity pH

15. Future plans in scaling • Validate the model at field sites • Improve model by iterating between the field and lab • Extend to other types of scale (e.g carbonates, sulfates) and mixed scales

16. Silica and metals extractionat Mammoth Lakes, California Silica extraction Goal: Develop processes to produce high value mineral by-products with properties matching those of commercial materials 600-900 ppm SiO2 Metals extraction ~1 ppm Cs, Rb, W ~6 ppm Li Geothermal fluid 100-200 ppm TDS To evaporative cooler 1200 ppm TDS 250 ppm SiO2 Reverse osmosis separation Potential Value (gross, annual, in millions) Silica $8.6 Lithium $1.5 Rubidium $90 Cesium $100 Tungsten $2.6

17. Current CEC funding ends Silica Mammoth Process development Pilot plant Commercial process • Science basis • Lab and field tests • Market testing • CEC funding? New site Process development Pilot plant Commercial process Future plans for silica and metals extraction Metals Mammoth Process development Pilot plant Commercial process • Use existing • technologies • Apply new • separation/extraction • technologies