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This Geothermal Technologies Program presentation was delivered on June 6, 2011 at a Program Peer Review meeting. It contains annual budget, Recovery Act, funding opportunities, upcoming program activities, and more.
The Geothermal Technologies Program assembled a geothermal Blue Ribbon Panel on March 22-23, 2011 in Albuquerque, New Mexico for a guided discussion on the future of geothermal energy in the United States and the role of the DOE Program. The Geothermal Blue Ribbon Panel Report captures the discussions and recommendations of the experts. An addendum is available here: http://www.eere.energy.gov/geothermal/pdfs/gtp_blue_ribbon_panel_report_addendum10-2011.pdf
Geothermal Technologies Program fiscal year 2012 budget request PowerPoint presentation, March 8, 2011.
Geothermal Technologies Program fiscal year 2103 budget request presentation by Doug Hollett, Program Manager.
Geothermal Technologies Program 2012 Peer Review slide presentation by Doug Hollett, Program Manager, on May 7, 2012.
Abstract not provided.
On June 6-10, 2011, the U.S. Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy (EERE), Geothermal Technologies Program (GTP or the Program) conducted its annual program peer review in Bethesda, Maryland. In accordance with the EERE Peer Review Guide, the review provides an independent, expert evaluation of the strategic goals and direction of the program and is a forum for feedback and recommendations on future program planning. The purpose of the review was to evaluate DOE-funded projects for their contribution to the mission and goals of the Program and to assess progress made against stated objectives.
The primary objective of this project was to improve our ability to predict performance of an Enhanced Geothermal System (EGS) reservoir over time by relating, in a quantitative manner, microseismic imaging with fluid and temperature changes within the reservoir. Historically, microseismic data have been used qualitatively to place bounds on the growth of EGS reservoirs created by large hydraulic fracturing experiments. Previous investigators used an experimentally based fracture opening relationship (fracture aperture as a function of pressure), the spatial extent of microseismic events, and some assumptions about fracture frequency to determine the size of an EGS reservoir created during large pumping tests. We addressed a number of issues (1) locating microearthquakes that occur during hydraulic fracturing, (2) obtaining more information about a reservoir than the microearthquake locations from the microearthquake data, for example, information about the seismic velocity structure of the reservoir or the scattering of seismic waves within the reservoir, (3) developing an improved methodology for estimating properties of fractures that intersect wellbores in a reservoir, and (4) developing a conceptual model for explaining the downward growth of observed seismicity that accompanies some hydraulic injections into geothermal reservoirs. We used two primary microseismic datasets for our work. The work was motivated by a dataset from the Salak Geothermal Field in Indonesia where seismicity accompanying a hydraulic injection was observed to migrate downward. We also used data from the Soultz EGS site in France. We also used Vertical Seismic Profiling data from a well in the United States. The work conducted is of benefit for characterizing reservoirs that are created by hydraulic fracturing for both EGS and for petroleum recovery.
A large centralized geothermal heat pump system was installed to provide ice making, space cooling, space heating, process water heating, and domestic hot water heating for an ice arena in Eagan Minnesota. This paper provides information related to the design and construction of the project. Additionally, operating conditions for 12 months after start-up are provided.
This paper discusses opportunities and challenges related to the technical and economic feasibility of developing power generation from geothermal resources at temperatures of 150 degrees C and lower. Insights from projects funded by the U.S. Department of Energy (DOE), Geothermal Technologies Office inform these discussions and provide the basis for some lessons learned to help guide decisions by DOE and the industry in further developing this resource. The technical basis for low-temperature geothermal energy is well established and the systems can be economic today in certain situations. However, these applications are far from a 'plug and play' product; successful development today requires a good knowledge of geothermal system design and operation.
This paper discusses opportunities and challenges related to the technical and economic feasibility of developing power generation from geothermal resources at temperatures of 150 degrees C and lower. Insights from projects funded by the U.S. Department of Energy (DOE), Geothermal Technologies Office inform these discussions and provide the basis for some lessons learned to help guide decisions by DOE and the industry in further developing this resource. The technical basis for low-temperature geothermal energy is well established and the systems can be economic today in certain situations. However, these applications are far from a 'plug and play' product; successful development today requires a good knowledge of geothermal system design and operation.
This fact sheet is an overview of the Department of Energy's Geothermal Technologies program.
This project utilizes Silicon Carbide (SiC) materials platform to fabricate advanced sensors to be used as high-temperature downhole instrumentation for the DOE’s Geothermal Technologies Program on Enhanced Geothermal Systems. The scope of the proposed research is to 1) develop a SiC pressure sensor that can operate in harsh supercritical conditions, 2) develop a SiC temperature sensor that can operate in harsh supercritical conditions, 3) develop a bonding process for adhering SiC sensor die to well casing couplers, and 4) perform experimental exposure testing of sensor materials and the sensor devices.
Geothermal energy has been underutilized in the U.S., primarily due to the high cost of drilling in the harsh environments encountered during the development of geothermal resources. Drilling depths can approach 5,000 m with temperatures reaching 170 C. In situ geothermal fluids are up to ten times more saline than seawater and highly corrosive, and hard rock formations often exceed 240 MPa compressive strength. This combination of extreme conditions pushes the limits of most conventional drilling equipment. Furthermore, enhanced geothermal systems are expected to reach depths of 10,000 m and temperatures more than 300 °C. To address these drilling challenges, Sandia developed a proof-of-concept tool called the auto indexer under an annual operating plan task funded by the Geothermal Technologies Program (GTP) of the U.S. Department of Energy Geothermal Technologies Office. The auto indexer is a relatively simple, elastomer-free motor that was shown previously to be compatible with pneumatic hammers in bench-top testing. Pneumatic hammers can improve penetration rates and potentially reduce drilling costs when deployed in appropriate conditions. The current effort, also funded by DOE GTP, increased the technology readiness level of the auto indexer, producing a scaled prototype for drilling larger diameter boreholes using pneumatic hammers. The results presented herein include design details, modeling and simulation results, and testing results, as well as background on percussive hammers and downhole rotation.
The U.S. Department of Energy (DOE) Geothermal Technologies Program (GTP) tasked the National Renewable Energy Laboratory (NREL) with conducting the annual geothermal supply curve update. This report documents the approach taken to identify geothermal resources, determine the electrical producing potential of these resources, and estimate the levelized cost of electricity (LCOE), capital costs, and operating and maintenance costs from these geothermal resources at present and future timeframes under various GTP funding levels. Finally, this report discusses the resulting supply curve representation and how improvements can be made to future supply curve updates.
Geothermal Technologies Program presentation by Jay Nathwani on the National Geothermal Data System, 9-30-2011.
Numerical simulation codes have become critical tools for understanding complex geologic processes, as applied to technology assessment, system design, monitoring, and operational guidance. Recently the need for quantitatively evaluating coupled Thermodynamic, Hydrologic, geoMechanical, and geoChemical (THMC) processes has grown, driven by new applications such as geologic sequestration of greenhouse gases and development of unconventional energy sources. Here we focus on Enhanced Geothermal Systems (EGS), which are man-made geothermal reservoirs created where hot rock exists but there is insufficient natural permeability and/or pore fluids to allow efficient energy extraction. In an EGS, carefully controlled subsurface fluid injection is performed to enhance the permeability of pre-existing fractures, which facilitates fluid circulation and heat transport. EGS technologies are relatively new, and pose significant simulation challenges. To become a trusted analytical tool for EGS, numerical simulation codes must be tested to demonstrate that they adequately represent the coupled THMC processes of concern. This presentation describes the approach and status of a benchmarking and code intercomparison effort currently underway, supported by the U. S. Department of Energy’s Geothermal Technologies Program. This study is being closely coordinated with a parallel international effort sponsored by the International Partnership for Geothermal Technology (IPGT). We have defined an extensive suite of benchmark problems, test cases, and challenge problems, ranging in complexity and difficulty, and a number of modeling teams are applying various simulation tools to these problems. The descriptions of the problems and modeling results are being compiled using the Velo framework, a scientific workflow and data management environment accessible through a simple web-based interface.
This report is the third in a series of reports sponsored by the U.S. Department of Energy Geothermal Technologies Program in which a range of water-related issues surrounding geothermal power production are evaluated. The first report made an initial attempt at quantifying the life cycle fresh water requirements of geothermal power-generating systems and explored operational and environmental concerns related to the geochemical composition of geothermal fluids. The initial analysis of life cycle fresh water consumption of geothermal power-generating systems identified that operational water requirements consumed the vast majority of water across the life cycle. However, it relied upon limited operational water consumption data and did not account for belowground operational losses for enhanced geothermal systems (EGSs). A second report presented an initial assessment of fresh water demand for future growth in utility-scale geothermal power generation. The current analysis builds upon this work to improve life cycle fresh water consumption estimates and incorporates regional water availability into the resource assessment to improve the identification of areas where future growth in geothermal electricity generation may encounter water challenges. This report is divided into nine chapters. Chapter 1 gives the background of the project and its purpose, which is to assess the water consumption of geothermal technologies and identify areas where water availability may present a challenge to utility-scale geothermal development. Water consumption refers to the water that is withdrawn from a resource such as a river, lake, or nongeothermal aquifer that is not returned to that resource. The geothermal electricity generation technologies evaluated in this study include conventional hydrothermal flash and binary systems, as well as EGSs that rely on engineering a productive reservoir where heat exists, but where water availability or permeability may be limited. Chapter 2 describes the approach and methods for this work and identifies the four power plant scenarios evaluated: a 20-MW EGS binary plant, a 50-MW EGS binary plant, a 10-MW hydrothermal binary plant, and a 50-MW hydrothermal flash plant. The methods focus on (1) the collection of data to improve estimation of EGS stimulation volumes, aboveground operational consumption for all geothermal technologies, and belowground operational consumption for EGS; and (2) the mapping of the geothermal and water resources of the western United States to assist in the identification of potential water challenges to geothermal growth. Chapters 3 and 4 present the water requirements for the power plant life cycle. Chapter 3 presents the results of the current data collection effort, and Chapter 4 presents the normalized volume of fresh water consumed at each life cycle stage per lifetime energy output for the power plant scenarios evaluated. Over the life cycle of a geothermal power plant, from construction through 30 years of operation, the majority of water is consumed by plant operations. For the EGS binary scenarios, where dry cooling was assumed, belowground operational water loss is the greatest contributor depending upon the physical and operational conditions of the reservoir. Total life cycle water consumption requirements for air-cooled EGS binary scenarios vary between 0.22 and 1.85 gal/kWh, depending upon the extent of belowground operational water consumption. The air-cooled hydrothermal binary and flash plants experience far less fresh water consumption over the life cycle, at 0.04 gal/kWh. Fresh water requirements associated with air- cooled binary operations are primarily from aboveground water needs, including dust control, maintenance, and domestic use. Although wet-cooled hydrothermal flash systems require water for cooling, these plants generally rely upon the geofluid, fluid from the geothermal reservoir, which typically has high salinity and total dissolved solids concentration and is much warmer than normal groundwater sources, for their cooling water needs; thus, while there is considerable geofluid loss at 2.7 gal/kWh, fresh water consumption during operations is similar to that of aircooled binary systems. Chapter 5 presents the assessment of water demand for future growth in deployment of utility-scale geothermal power generation. The approach combines the life cycle analysis of geothermal water consumption with a geothermal supply curve according to resource type, levelized cost of electricity (LCOE), and potential growth scenarios. A total of 17 growth scenarios were evaluated. In general, the scenarios that assumed lower costs for EGSs as a result of learning and technological improvements resulted in greater geothermal potential, but also significantly greater water demand due to the higher water consumption by EGSs. It was shown, however, that this effect could be largely mitigated if nonpotable water sources were used for belowground operational water demands. The geographical areas that showed the highest water demand for most growth scenarios were southern and northern California, as well as most of Nevada. In addition to water demand by geothermal power production, Chapter 5 includes data on water availability for geothermal development areas. A qualitative analysis is included that identifies some of the basins where the limited availability of water is most likely to affect the development of geothermal resources. The data indicate that water availability is fairly limited, especially under drought conditions, in most of the areas with significant near- and medium-term geothermal potential. Southern California was found to have the greatest potential for water-related challenges with its combination of high geothermal potential and limited water availability. The results of this work are summarized in Chapter 6. Overall, this work highlights the importance of utilizing dry cooling systems for binary and EGS systems and minimizing fresh water consumption throughout the life cycle of geothermal power development. The large resource base for EGSs represents a major opportunity for the geothermal industry; however, depending upon geology, these systems can require large quantities of makeup water due to belowground reservoir losses. Identifying potential sources of compatible degraded or low-quality water for use for makeup injection for EGS and flash systems represents an important opportunity to reduce the impacts of geothermal development on fresh water resources. The importance of identifying alternative water sources for geothermal systems is heightened by the fact that a large fraction of the geothermal resource is located in areas already experiencing water stress. Chapter 7 is a glossary of the technical terms used in the report, and Chapters 8 and 9 provide references and a bibliography, respectively.