A series of reactive-transport models of Enhanced Geothermal Systems (EGS) were constructed using the reactive transport code PFLOTRAN to examine the effect of matrix thermal contraction and mineral dissolution/precipitation on fracture flow in the context of grid cell size and model complexity. It was found that for thermal drawdown at production well, the impact of fracture zone grid cell size is negligible.
This report summarizes important nuances in local water concerns and potential climate impacts that could influence the roll-out of technologies associated with energy transitions. Current investments in clean energy technologies are very high, which is driving a lot of investments in related manufacturing (i.e., hydrogen, solar, wind, and batteries) and mining (e.g., lithium, copper, and graphite) around the world. To understand how water and climate dynamics could be influencing these activities, we conducted a phased literature review for three countries: China, Germany, and France. China was selected due to its global dominance in manufacturing of solar panels, batteries, and electrolyzers as well as production of rare earth elements while Germany and France were selected due to their emerging leadership in energy transitions-related manufacturing within the European Union. For each of these three nations, we identified areas where manufacturing is occurring within the country and then evaluated relevant water resources and climate impacts. Multiple sources were consulted for this review, including BloombergNEF, international reports, industry sources, peer-reviewed literature, climate data, and media coverage.
An existing shared risk framework designed for assessing and comparing threat-based risks to water utilities is being extended to incorporate electric power. An important differentiating characteristic of this framework is the use of a system-centric rather than an asset-centric approach. This approach allows anonymous sharing of results and enables comparison of assessments across different utilities within an infrastructure sector. By allowing utility owners to compare their assessments with others, they can improve their self-assessments and identification of "unknown unknowns". This document provides an approach for extension of the framework to electric power, including treatment of dependencies and interdependencies. The systems, threats, and mathematical description of associated risks used in a prototype framework are provided. The method is extensible so that additional infrastructure sectors can be incorporated. Preliminary results for a proof of concept calculation are provided.
Schwering, Paul C.; Lowry, Thomas S.; Hinz, Nicholas; Matson, Gabe; Sabin, Andrew; Blake, Kelly; Zimmerman, Jade; Sewell, Steven; Cumming, William
The Basin & Range Investigations for Developing Geothermal Energy (BRIDGE) Project kicked off in the Autumn of 2021. The Department of Energy Geothermal Technologies Office (GTO) funded BRIDGE as part of a broader GTO initiative to advance the identification and development of hidden, or “blind”, geothermal energy resources in the Basin and Range Province (Basin & Range) of the western USA. The BRIDGE Team is a collaboration being led by Sandia National Laboratories (Sandia) with partners from Geologica Geothermal Group, the US Navy Geothermal Program Office, and others that will contribute to various stages of the project. The focus of this project is on Western Nevada with areas of interest, identified chiefly from the prior Nevada Play Fairway Analysis (PFA) study, located primarily in Churchill and Mineral Counties including lands managed by the Department of Defense (DOD). The first stage of BRIDGE is focused on reconnaissance of PFA targets that are suspected or known to be associated with hidden geothermal resources on DOD and surrounding lands. Helicopter-borne transient electromagnetism (HTEM) surveying is being used in a novel conceptual approach for optimizing shallow and deep well targeting in Basin & Range geothermal exploration. This reconnaissance phase is part of the overall BRIDGE workflow: 1. Assess the pre-survey likelihood of geothermal systems in the study area based on PFA reviews and a reanalysis of existing information to constrain subsurface temperature, structure, hydrology, and thermal manifestations. 2. Design and execute HTEM resistivity surveying to image the depth to the low resistivity and low permeability clay cap, within which a thermally conductive (linear) temperature gradient could be targeted for drilling, and potentially image the underlying higher resistivity associated with shallow aquifers hosting outflows from deeper geothermal systems. 3. Drill temperature gradient (TG) wells that penetrate a thick enough section of the clay cap detected by HTEM surveying to provide a linear thermal gradient that could be reliably extrapolated to the base of the cap. 4. In areas where the TG wells detected a prospective temperature gradient but where the HTEM survey did not penetrate to the base of the cap, conduct surface magnetotelluric (MT) resistivity surveys to image the base of the cap to identify the depth to which the linear TG well gradient could be reliably extrapolated. 5. On the most prospective target(s), drill at least one testable slim hole well to discover the resource associated with the interpreted geothermal reservoir upflow source. The first stage of the project and the second stage HTEM survey have been completed. Preliminary results are being analyzed with respect to potential TG targets and plans for followup surveys, geophysical joint inversion, conceptual model development, and interpretation.
There are an estimated 48,745 wells producing oil or gas in New Mexico as of August 8, 2020 and with advances in drilling and oil recovery technology the use of hydraulic fracturing has become more commonplace. With a typical well requiring 1.5 to 16 million gallons of water, there is an increased demand for water in the Permian Basin and concern over the regions ability to meet this demand. This report is an addendum to the 2018 report Water Resource Assessment in the New Mexico Permian Basin (SAND2018-12018) to monitor baseline water level and chemistry data established in the original report. Results from this addendum can be used to further understand regional water supply and demands and aid in the BLMs mission of sustainably meeting the needs of water users while protecting human and environmental health.
Significant costs can be related to losing circulation of drilling fluids in geothermal drilling. This paper is the second of four case studies of geothermal fields operated by Ormat Technologies, directed at forming a comprehensive strategy to characterize and address lost circulation in varying conditions, and examines the geologic context of and common responses to lost circulation in the loosely consolidated, shallow sedimentary reservoir of the Don A. Campbell geothermal field. The Don A. Campbell Geothermal Field is in the SW portion of Gabbs Valley in NV, along the eastern margin of the Central Walker Lane shear zone. The reservoir here is shallow and primarily in the basin fill, which is hydrothermally altered along fault zones. Wells in this reservoir are highly productive (250-315 L/s) with moderate temperatures (120-125 °C) and were drilled to an average depth of ~1500 ft (450 m). Lost circulation is frequently reported beginning at depths of about 800 ft, slightly shallower than the average casing shoe depth of 900- 1000 ft (275-305 m). Reports of lost circulation frequently coincide with drilling through silicified basin fill. Strategies to address lost circulation differ above and below the cased interval; bentonite chips were used at shallow depths and aerated, gelled drilling fluids were used in the production intervals. Further study of this and other areas will contribute to developing a systematic understanding of geologic contextual-informed lost circulation mitigation strategies.
For over 50 years, performance assessment (PA) has been used throughout the world to inform decisions concerning the storage and management of radioactive waste. Some of the applications of PA include environmental assessments of nuclear disposal sites, development of methodologies and regulations for the long-term storage of nuclear waste, regulatory assessment for site selection and licensing at the Waste Isolation Pilot Plant and Yucca Mountain, and safety assessments for nuclear reactors. PA begins with asking the following questions: 1) What can happen? 2) How likely is it to happen? 3) What are the consequences when it does happen? and 4) What is the uncertainty of the first three questions? This work presents an approach for applying PA methodologies to geothermal resource evaluation that is adaptable and conformable to all phases of geothermal energy production. It provides a consistent and transparent framework for organizing data and information in a manner that supports decision making and accounts for uncertainties. The process provides a better understanding of the underlying risks that can jeopardize the development and/or performance of a geothermal project and identifies the best pathways for reducing or eliminating those risks. The approach is demonstrated through hypothetical examples of both hydrothermal and enhanced geothermal systems (EGS).
Significant costs can be related to losing circulation of drilling fluids in geothermal drilling. This paper is the second of four case studies of geothermal fields operated by Ormat Technologies, directed at forming a comprehensive strategy to characterize and address lost circulation in varying conditions, and examines the geologic context of and common responses to lost circulation in the loosely consolidated, shallow sedimentary reservoir of the Don A. Campbell geothermal field. The Don A. Campbell Geothermal Field is in the SW portion of Gabbs Valley in NV, along the eastern margin of the Central Walker Lane shear zone. The reservoir here is shallow and primarily in the basin fill, which is hydrothermally altered along fault zones. Wells in this reservoir are highly productive (250-315 L/s) with moderate temperatures (120-125 °C) and were drilled to an average depth of ~1500 ft (450 m). Lost circulation is frequently reported beginning at depths of about 800 ft, slightly shallower than the average casing shoe depth of 900- 1000 ft (275-305 m). Reports of lost circulation frequently coincide with drilling through silicified basin fill. Strategies to address lost circulation differ above and below the cased interval; bentonite chips were used at shallow depths and aerated, gelled drilling fluids were used in the production intervals. Further study of this and other areas will contribute to developing a systematic understanding of geologic contextual-informed lost circulation mitigation strategies.