This guide is designed to provide O&G professionals, graduates, and those currently pursuing undergraduate education with a general overview of the geothermal industry and how O&G can help its continued growth. It also provides a curated list of resources for those looking to expand their knowledge of the geothermal sector and its similarities to O&G (including skills and technology). The EnergyGigs Team produces this guide under the direction of our geothermal subject matter expert. The recommendations made here are because our SMEs have found them valuable and not because we are being paid to recommend them. EnergyGigs is a Houston-based energy marketplace where the energy industry finds the experts they need to scale business for the future. EnergyGigs is focused on supporting the energy future across all energy resources, using a variety of hiring solutions, including Projects, Job Boards, Temporary to Permanent, and Strategic Searches.
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What is Geothermal Energy?
Geothermal Energy is heat in the subsurface and is a firm, flexible source of clean, secure, and reliable energy that can be utilized across industrial, commercial, and residential sectors. Geothermal energy offers essential benefits to nations across the globe, including grid stability, diversity of energy options, efficient heating and cooling, key technology and workforce pathways from O&G to geothermal development, and lower carbon emissions.
Types of Geothermal Energy
Hydrothermal systems are geothermal resources where heat is harnessed from hot water/brine and steam for power generation (> 150°C 300°F) or direct use (<150°C/300°F). These are referred to as conventional geothermal resources. These are limited to areas with the right geological conditions. The key components of hydrothermal systems are:
-Large heat source
-Permeable reservoir
-Supply of water and a reliable recharge mechanism
Evidence of hydrothermal systems may be present on the surface as hot springs or geysers. However, where there is a lack of surface evidence, it is referred to as a blind geothermal system.
Key technologies used to harness heat/power from hydrothermal systems are flash steam, dry steam, or binary cycle power plants (utilizing the organic Rankine cycle); modular binary cycle units(operating the organic Rankine cycle); and heat exchange systems for direct use and district heating.
Unconventional geothermal resources are those that lack key components of hydrothermal systems. The key unconventional geothermal resources are:
-Those that lack water supply and permeable reservoirs - are often referred to as petrothermal resources.
-Super hot rock - geothermal resources that lack water supply and permeable reservoirs with temperatures >400°C/752°F.
-Supercritical resources - where geothermal fluids have temperatures >400°C/752°F and pressures of 221 bar.
Key technologies used to harness heat/power from these resources include Enhanced/Engineered Geothermal Systems (EGS), where permeable reservoirs are created using stimulation techniques, and Closed Loop Geothermal (CLG)/ Advanced Geothermal Systems (AGS), where heat is harnessed by creating a closed loop where a working fluid harnesses the heat.
What are the Advantages of Geothermal Energy?
-Small Footprint - Geothermal power plants are compact, using less land per gigawatt-hour than comparable- power capacity solar photovoltaic, wind, and coal.
-Emissions- Modern geothermal power plants emit no greenhouse gasses and have life cycle emissions four times lower than solar PV and six to 20 times lower than natural gas. Geothermal power plants consume less water on average over the lifetime energy output than most conventional electricity-generation technologies.
-Reliability - The geothermal heat sources are not significantly affected by seasonal fluctuations in the temperature, i.e., they are a reliable and consistent source of power/heat that can be accessed at any time.
-Renewable -The heat flowing from Earth's interior is continually replenished by the decay of naturally occurring radioactive elements.
-Widespread globally - Geothermal resources are available globally at various temperatures and depths.
What are the Disadvantages of Geothermal Energy?
-Cost - The initial cost for exploration (including high drilling costs) and installation of geothermal power technologies is significantly higher than other renewable and fossil fuel-driven power sources.
-Geothermal resource risk (geological uncertainties) - There is a need to reduce risk and uncertainty, particularly at the exploration stage.
-Earthquake risk - Induced seismicity can occur due to hydraulic stimulation in EGS or during reinjection.
-Solid waste - Geothermal power does not generate the amounts of solid wastes of coal mining, but it does generate solid waste from well drilling operations and wastes from power plant operations. This waste may include naturally occurring radioactive materials.
Oil & Gas to Geothermal
The O&G Industry's years of experience and hundreds of thousands of wells have led to a rich history of developing game-changing technologies (including tools in the exploration, data processing, and drilling sectors). This has led to an extensive understanding of the subsurface and the development of previously inaccessible and uneconomical hydrocarbon resources. The development and successes of technologies such as horizontal drilling, hydraulic fracturing, and microseismic fracturing mapping contributed significantly to the US Shale Revolution.
EGS is similar to hydrocarbon shale resources as flow pathways need to be created via stimulation to harness the resources. As such, the technologies that contributed to the US Shale Revolution can be utilized to develop further and scale EGS. This idea has been proven with the successful EGS pilot project by Fervo Energy, utilizing oil and gas drilling technology to produce geothermal power from a pair of horizontal wells.
Outside of the EGS and Shale similarity, the geothermal energy industry requires many of the same knowledge and skill sets used in the O&G industry. These include an understanding of subsurface conditions to identify ideal locations for resource exploration and support drilling operations; skills and best practices for managing hydraulic fracturing and wastewater injection; mitigating or dealing with potential induced seismicity; and skills and experience for completion and operation of wells. Currently, many developers creating and adapting technologies for geothermal applications are professionals from the O&G industry, applying their knowledge and experience of the challenges and solutions from O&G to geothermal.
Key Resources for Transitioning from Oil and Gas to Geothermal
Books, Academic Resources, Journal Articles
-Huenges, E. and Ledru, P. eds., 2011. Geothermal energy systems: exploration, development, and utilization. John Wiley & Sons.
-Geothermal Reservoir Engineering, Editor(s): Malcolm A. Grant, Paul F. Bixley, Geothermal Reservoir Engineering (Second Edition), Academic Press, 2011, Page iii,
-ISBN 9780123838803, https://doi.org/10.1016/B978-0-12-383880-3.10022-8.
-"Introduction to Enhanced Geothermal Systems" by John W. Lund and Tonya L. Boyd
-Avato, P.A., Basarir, N., Beardsmore, G., Gehringer, M., Harding-Newman, T., Harvey, C. and Pantelias, A., 2013. Geothermal exploration best practices: guide to resource data collection, analysis, and presentation for geothermal projects. World Bank Group, Washington DC.
-Finger, JT and Blankenship, D.A., 2012. Handbook of best practices for geothermal drilling (No. SAND2011-6478). Sandia National Lab. (SNL-NM), Albuquerque, NM (United States).
-Sanyal, S.K., 2003. One Discipline, Two Arenas–Reservoir Engineering In Geothermal and Petroleum Industries. In Proc., Twenty-Eighth Workshop on Geothermal Reservoir Engineering, Stanford University (pp. 1697-1702).
-Okoroafor, E.R., Offor, C.P. and Prince, E.I., 2022, August. Mapping Relevant Petroleum Engineering Skill Sets for the Transition to Renewable Energy and Sustainable Energy. In SPE Nigeria Annual International Conference and Exhibition(p. D031S017R005). SPE
Industry Associations and Conferences
-Geothermal Rising - Focuses on raising public awareness of geothermal energy, championing innovation, and building an enabling environment for geothermal energy. The organization provides a number of geothermal resources for students, professionals, and companies.
-Geothermal Rising Annual Conference - A premier geothermal conference that features an exhibit hall, informative panel sessions, and technical sessions showcasing the latest geothermal research; the opportunity to nurture/expand your geothermal network; and includes field trips and workshops
-International Geothermal Association (IGA) - Is a platform to promote and support global geothermal development. The flagship event is the World Geothermal Congress, held every three years, and numerous regional events every year focused on policies, the regulatory framework, financial mechanisms, and technology development. The IGA hosts a database for geothermal power and heating/cooling, geothermal research papers, and geothermal tools and always offers courses throughout the year.
-Stanford Geothermal Workshop - The conference brings together engineers, scientists, and managers involved in geothermal reservoir studies.
-Society of Petroleum Engineers (SPE) Geothermal Technical Session: This Technical Section seeks to collect, disseminate, and exchange technical knowledge concerning geothermal energy and demonstrate its proximity to more traditional oil and gas disciplines.
Online Courses, Training Programs, and Webinars
-Stanford Energy-Understanding Energy Learning Hub: Lecture on Geothermal Energy https://understand-energy.Stanford.edu/energy-resources/renewable-energy/geothermal-energy
-Stanford Geothermal Program - Focuses on developing reservoir engineering techniques to facilitate the efficient production of geothermal resources. The program offers graduate study programs leading to the degrees of MS or PhD.
-Introduction to Geothermal - Presented by Teverra LLC, introduces the audience to what geothermal is, how geothermal resources are discovered, and how to produce energy once found.
-GeoLogica - offers several courses on geothermal energy in their "Training for a GeoEnergy Transition" course series.
-Seequent on-demand webinars - Leapfrog Energy is a geomodelling technology used to understand the complexities of the subsurface. This tool has been used globally in the geothermal space, and they offer on-demand webinars and a free online course on Leapfrog for geothermal.
-University of Aberdeen - Short Course on Geothermal and Hydro Energy focuses on studying geothermal and hydro energy's fundamentals and advanced concepts. https://on.abdn.ac.uk/courses/geothermal-and-hydro-energy/
News & Research
-ThinkGeoEnergy - Is the leading news and research platform for the global geothermal energy sector. https://www.thinkgeoenergy.com/
-Utah Forge - A dedicated underground field laboratory sponsored by the United States Department of Energy (DOE) for developing, testing, and accelerating breakthroughs in EGS technologies to advance the utilization of geothermal resources worldwide. https://utahforge.com/
Sources
-Clean Air Task Force, Superhot Rock Energy: A Vision for Firm, Global Zero-Carbon Energy (November 2022) https://www.catf.us/resource/superhot-rock-energy-a-vision-for-firm-global-zero-carbon-energy/
-Clean Air Task ForceSuperhot Rock Geothermal: A Vision for Zero-Carbon Energy "Everywhere" (October 2021) https://www.catf.us/resource/superhot-rock-energy-a-vision-for-firm-global-zero-carbon-energy/
-Fervo Energy Announces Technology Breakthrough in Next-Generation Geothermal, July 18, 2023 https://fervoenergy.com/fervo-energy-announces-technology-breakthrough-in-next-generationgeothermal/
-GeothermEx, Inc.- Ann Robertson-Tait, Roger Henneberger and Subir Sanyal, Workshop On Geological Risk Insurance, World Bank Geothermal Energy Development Program (GEOFUND), 11-12 November 2008, Karlsruhe, Germany.
-Geothermal Technologies Office, Office of Energy Efficiency & Renewable Energy (USA) Geothermal Basics https://www.energy.gov/eere/geothermal/geothermal-basics
-James Pethokoukis, "Can Geothermal Energy Replace Oil and Gas? My Long-Read Q&A with Jamie Beard," American Enterprise Institute, October 21, 2021, https://www.aei.org/economics/can-geothermalenergy-replace-oil-and-gas-my-long-read-qa-with-jamie-beard/.
-James Pethokoukis, "Can Geothermal Energy Replace Oil and Gas? My Long-Read Q&A with Jamie Beard," American Enterprise Institute, October 21, 2021, https://www.aei.org/economics/can-geothermalenergy-replace-oil-and-gas-my-long-read-qa-with-jamie-beard/.
