Elsevier has published the second edition of its comprehensive book Geothermal Power Generation: Developments and Innovation, available at:

https://shop.elsevier.com/books/geothermal-power-generation/dipippo/978-0-443-24750-7

ISBN: Hardback, 9780443247507; eBook, 9780443247514

The original edition, published in 2016, was edited by Ronald DiPippo; the new one was edited by DiPippo along with Luis C.A. Gutiérrez-Negrín and Andrew Chiasson. The book comprises 28 chapters written by 40 authors from 12 countries, namely, Chile, Costa Rica, Germany, Iceland, Indonesia, Italy, Kenya, Mexico, New Zealand, Philippines, United Kingdom and United States. There is also an appendix with data on installed geothermal power plants across the world showing trends and projections for the near-term.

In the eight years following the first edition, geothermal power has continued to be a steady and reliable source of electricity to nearly 70 million people around the world. The number of countries served by geothermal power plants has risen from 24 in 2015 to 32, with another 11 poised to join the geothermal club of nations. In 2015, about 12 GW of geothermal power was installed, whereas now the total exceeds 16 GW, representing nearly 4% annual growth.

The book is organized into four sections:

Part One - Resource Exploration, Characterization, and Evaluation

Part Two - Energy Conversion Systems

Part Three - Design and Economic Considerations

Part Four - Case Studies

The first three sections follow the typical chronological order in the development of a resource, from the beginning of exploration through to the options for engineering a power plant, including environmental, economic, social and cultural considerations.

The chapters are descriptive while giving enough analytical material to allow readers to apply scientific principles to understand the design and performance of various plants. The last section includes eight chapters describing actual plants operating around the world, from the earliest ones in Italy, now over 120 years ago, to recent developments in Kenya, and several other countries and regions.

Throughout the book, color photographs and diagrams are used to convey the nature of geothermal resources and a physical sense of different power plant designs, including dry steam, single-, double-, and triple-flash, to a variety of binary and hybrid plants. Extensive reference lists and bibliographies accompany each chapter for further in-depth reading and research.

The second edition includes several new chapters dealing with developments in the Philippines, Central America and the Caribbean, Chile, and Kenya. Another new chapter presents a case study of the large geothermal field at Cerro Prieto in Mexico that has been in continuous operation for over 50 years since 1973.

Innovations and emerging technologies include Advanced Deep Drilling (ADD) and Mineral Recovery (MR) from geothermal brines. While neither of these emerging technologies has been brought to the commercial stage, they promise results in the near term. So far, ADD has demonstrated that existing productive fields can be enhanced, but no power plant has been developed solely by using ADD techniques. Likewise, mineral recovery, in particular the recovery of lithium, has been demonstrated in laboratory tests using simulated brines, and pilot demonstration plants have been designed, however extending the concepts to full-scale operation at a real power plant, or as a stand-alone mineral recovery plant, has so far proven highly challenging.

The following is excerpted from a book review by Susan Fox Hodgson, California Div. of Oil, Gas and Geothermal, retired.

Geothermal Power Generation: Developments and Innovation, Second Edition, includes 958 pages of first-rate geothermal information emphasizing advanced energy technologies. The exceptionally well-organized text is backed by a 30-page index. The front and back covers show geothermal power plants sited in naturally green areas, environmentally in sync with the "green" nature of geothermal power production.

Some chapters touch on geothermal history. An example is Chapter 21, titled “Larderello, Italy: The Oldest Geothermal Field in Operation in the World.” The chapter begins with a Prologue, “...an historical outline, beginning in Prehistory, of Italian geothermal development up to 1960, with particular reference to the Boraciferous Region.” The Prologue, by Raffaele Cataldi, is followed by technical information from authors, Roberto Parri, Franco Lazzeri, and Alessandro Lenzi. The issues they discuss include “...studies and pilot tests on new materials and/or alloys for turbines and auxiliary equipment.”

It doesn't matter if you work in geothermal or don't know the first thing about it. The book is for you. If you are unfamiliar with geothermal power plants, someday you may need a few geothermal facts. Say out of the blue, a developer suggests building a geothermal power plant in your area. You and other residents want to understand the project. Reading through the chapter titles can help guide you to the information you need. Geothermal developers will find the book useful, as well. Talking to (or teaching) community groups about geothermal energy and answering their questions is part of the job.

The results of Geothermal Rising’s’ workshop, facilitated by BiaTech Corporation: “Explore Geothermal Power Digital Solutions to Increase Operational Productivity and Longevity,” offer great insight into the current state of geothermal power generation, operational considerations, and critical areas in which data can be applied to increase productivity and longevity of the power plant. By using tools such as AI, machine learning, and digital twins, improved operational decisions can extend geothermal plant life, reduce costs, and improve performance.

We explored factors that may reduce the life of the reservoir, plant, or infrastructure and shared ways to extend life and mapped it into a framework for engineers and data scientists alike, streamlining decision making processes.

So how was it done? And what are the critical areas for improvement? Let’s explore.

First, we conducted an exercise to understand perceptions around digital tools and what the outlook for the future is. The consistent themes unearthed through this exercise were that presently, perceptions around data and digital tools are enigmatic, but the vision for the future is optimistic. Two case studies were also presented and discussed to identify and investigate root causes of problems associated with aging plants and facilities, and to prime participants for further discussion.

Then, we broke into group exercises to understand operational decisions from daily, cyclic, and long-term strategies, what data is used to make those decisions, and the systems utilized. The groups analyzed decisions from the perspective of plant operations, engineering, and leadership. By devoting time to analyzing day-to-day challenges, engineers were able to brainstorm fresh ideas and prioritize goals in making data driven decisions.

Following the group exercise was a brainstorming session in which participants used BiaTech’s Geothermal Issue Tree Analysis to create a framework that evaluated plant performance. The results of this analysis enumerated factors affecting functioning, including operational costs, capital expenses, maintenance, regulations, and market volatility, among many others. This led to ascertaining specific areas in which digital solutions can be applied for optimal performance.

The workshop identified five areas of high importance that can leverage digital solutions:

• Using AI digital reality to map geothermal plants for operational optimization
• Using data to improve dashboards of plant performance, steamfields, and reservoirs
• Using AI models for historical analysis and measurement of seismicity
• Identifying areas of high risk, including pipeline conditions like corrosion
• Monitoring support for operator walk and thermal trending via drone computer vision
• Explore advanced sensor retrofit for reservoir and well monitoring
• Assess the health of current systems and options to integrate digital solutions

The world is undergoing a digital revolution, but many companies are ill equipped to benefit from the transformation, missing the eight core principles of digital success. Data-driven organizations, especially asset-heavy companies, are 19 times more likely to be profitable and sustainable. Companies that invest in machine learning and AI can increase their revenues by 38%. Clearly, there is potential for geothermal companies to leverage AI to increase productivity and extend asset life.

The team concluded that the value for geothermal companies deploying digital solutions include:

• Lower Operations & Maintenance Costs
• Increase efficiency & output
• Increase life of plant and assets
• Decrease safety and health incidents on-site
• Increase the reservoir health

For geothermal companies, the problem is not the existence of data; it is the challenge to make data available quickly, and improve the quality of the data. High volumes of data currently exist in the geothermal industry, which makes it a prime candidate for renovation using AI and machine learning.

Through BiaTech’s data maturity assessments and prioritization matrix, we prioritized the digital solutions that would have the highest impact with the lowest degree of difficulty of implementation. A key take-away from this workshop is how many of the key pain points for geothermal operators can be positively impacted by relatively simple digital solutions! 

This summary only scratches the surface of what was accomplished in the workshop. If you’d like more information about how digital solutions can transform and empower your business, attend the second offering of this workshop in Reno on April 16th!

Special thanks to Calpine for hosting, and to BiaTech for facilitating this workshop! For more information, contact info@BiaTech.com.

It is extraordinary to think that just beneath our feet there’s enough energy to meet all the world’s energy needs. It is an abundant resource that can be harnessed for human use. Geothermal is a clean and renewable energy source that remains underutilized despite it being a mature and proven resource. Geothermal is the most environmentally friendly energy technology, has the ability to decarbonize heating and cooling of buildings and industry, and can generate dispatchable and baseload electricity all from ample and local geothermal resources. Geothermal presents a compelling case for widespread adoption, and it must become one of the leading protagonists if we are to genuinely address the ongoing climate crisis and successfully transform into a clean energy economy.

The primary energy associated with geothermal is the heat energy that naturally exists beneath the Earth's surface! There are different ways to use the natural heat of the earth. Geothermal heat pumps (also known as ground source) utilize temperatures about two meters below the ground to heat AND cool buildings. Other geothermal technologies use heat energy several kilometres below that is at very high temperatures and is produced by the natural decay of materials within the Earth's crust. Importantly, geothermal energy is constantly replenished, therefore renewable!

Deep within the earth is the hottest part of our planet, the core, which is about 2,900 kilometres below our feet. The extremely high temperature of the core (5,200°C or 9,392°F) serves as limitless battery, recharging the heat beneath our feet that can be used to create geothermal heating, cooling, and power capabilities.

Here are some of the advantages of geothermal:

1. Geothermal is always available: Like other renewable energy sources, geothermal is essentially unlimited, but unlike intermittent renewables it is not affected by season, climate or weather conditions. This is referred to a having high capacity factor of which geothermal has the highest of all renewable energy sources making geothermal a more stable, reliable, and consistent technology. Energy generated from this resource is easy to predict with a high degree of accuracy as it doesn’t fluctuate in the same way as other renewable energy sources, such as solar, hydro, and wind. Geothermal energy is both renewable and sustainable due to the hot reservoirs within the earth being continually and naturally replenished.
2. Geothermal energy plants have a small footprint: Geothermal power plants as well as heating and cooling systems only require modest amounts of space, in contrast with the wide-ranging expanses of land and mining operations needed for intermittent, oil and gas, nuclear and coal energy. Whether it’s a domestic geothermal heat pump system or a large-scale geothermal power plant, most of the components, including the heat exchangers, are buried underground with very little remaining above ground. In homes, a geothermal heat pump is about the size of a household appliance while in geothermal power plants the largest components are the cooling towers and the turbines. Large geothermal power plants can have a visual impact on the landscape, but these days newer architectural designs minimize the visual impact on the landscape.
3. Geothermal energy provides more energy: Aside from time for maintenance, geothermal energy can work at full capacity non-stop because delivery is constant. This is very different to photovoltaic, hydroelectric and wind systems which rarely work at full capacity due to technical and environmental limitations. This means that more power is generated using less land and for the same nominal power. For example, a 9 MW geothermal plant will on average generate energy for about 5,500 homes a year whereas the average 9 MW solar plant can power only 1,800 homes per year. This translates into a lower impact on the environment, less mining for critical minerals, and reduced risk of geopolitical conflict.
4. Geothermal power plants are quiet: While working at full capacity, geothermal power plants run at negligible noise levels. As with all construction, during the building phase of the plants there will be some noise but once the construction is complete, everything runs quietly. This applies to not only geothermal heat pump systems but to larger power stations where several turbines are spinning.
5. Geothermal energy is environmentally friendly: The carbon impact of a geothermal power plant is very low. According to the National Renewable Energy Laboratory, geothermal has the smallest lifecycle carbon footprint of all renewable energy technologies, including wind and solar. Geothermal power generation produces little—if any—nitrous oxide, methane, or sulphur dioxide in contrast with other generation technologies. Binary-cycle geothermal plants, which operate in a closed cycle, release essentially zero emissions, according to the U.S. Department of Energy Geothermal Technologies Office. By utilising the earth’s natural heat, geothermal energy significantly decreases our carbon footprint contributing to cleaner air and a healthier planet.
6. Geothermal power optimises resources: Geothermal plants have components that can be salvaged and reused at the end of the installation’s lifecycle. Furthermore, during operation, the flows of energy are optimized in such a way as utilize any heat that can’t be used immediately for power generation back into the circuit using the steam pipes that power the plant, leading to greater energy efficiency. Geothermal does not require any critical minerals and all materials needed (steel and cement) are easily sourced from North America.
7. Geothermal plants are long-lasting, safe, and reliable: Geothermal heat pumps have an operating life span of over 20 years whereas a traditional furnace last just 7 to 10 years. Geothermal power plants have very long life spans, with some lasting up to 80 and even over 100 years. Geothermal power plants such as Lardarello in Italy (1913), Wairakei in New Zealand (1958), and The Geysers in California (1960) still use original operational infrastructure and wells. This is remarkable longevity when compared to a natural gas combined-cycle plant which normally lasts around 30 years. Because there are no fuels involved there is no risk of fire and overall, this type of system guarantees excellent reliability. Additionally, geothermal power plants have low operating costs once the initial infrastructure is in place making them economically competitive in the long run.
8. Geothermal plants require very little maintenance: Especially when it comes to geothermal heat pumps, geothermal applications don’t need any special maintenance. Because geothermal heat pumps are closed systems, the pressure of the fluid in the piping self-regulates and the number of electrical and mechanical elements that can break down is also minimal.
9. Geothermal can be used to both heat and cool: Geothermal systems can be installed in almost any type of building: from homes to shopping malls, public buildings, and sports centres. A geothermal heat pump is actually a two-in-one HVAC system used for both heating and cooling. Despite the misleading name, geothermal “heat pumps” are just as effective at cooling your home or office in the summer as they are at heating it in the winter!
10. Geothermal heat pumps can reduce overall energy consumption in your home: As well as providing air conditioning in the summer and heating in the winter, geothermal has other advantages when used in the home. For example, it can reduce energy consumption by between 30% and 70% because it can also do the job of a boiler by heating water for use in the kitchen and bathroom.
11. Geothermal improves public health: Traditional air-conditioning removes dangerous heat from buildings and provides life-saving shelter and comfort. Unfortunately, air-conditioning systems worsen two other problems. First, heat is not so much removed or eliminated as it is moved from one location to another. When a building interior is cooled, that thermal energy is transferred to the exterior surroundings. In dense urban areas, this effect increases local temperatures, exacerbating the heat wave in places that are already heat islands as a result of urbanization. A geothermal heating and cooling system can reduce building interior temperatures without heating the surrounding air space by storing and dissipating heat underground. Additionally, geothermal heat pumps are 40% more efficient than their air-source counterparts, especially at high and low temperatures. 
12. Geothermal energy creates record numbers of jobs: Geothermal creates more jobs per megawatt hour than all other renewable energy technologies, according to the National Renewable Energy Laboratory. For the same installed power, geothermal energy creates more direct and indirect employment than any other type of renewable. Geothermal creates 34 jobs per installed megawatt compared to 19 created by wind power and 12 by photovoltaic energy.
13. Geothermal pays local communities: Over the course of 30 to 50 years an average 20 MW geothermal generation facility will pay nearly $6.3 to $11 million dollars in property taxes plus $12 to $22 million in annual royalties. Seventy-five percent of these royalties ($9.2 to $16.6M) go directly back to the state and county.
14. Geothermal energy can improve energy independence and security: Geothermal energy can contribute to enhancing a nation's energy independence and security. By utilising domestic and locally sourced geothermal resources, countries can reduce their dependence on imported fossil fuels and critical minerals, minimizing geopolitical risks associated with energy supply chains. Developing geothermal projects can strengthen a nation's energy portfolio and provide a stable and secure source of energy for future generations.
15. Geothermal energy has huge potential: Currently, worldwide energy consumption from geothermal resources is around 15 terawatts but the total potential energy from geothermal sources is far greater. While most of the geothermal potential is still yet untapped, there is robust research and development happening in the industry that will increase the number of recoverable geothermal resources in the future. It is estimated that new technologies to create Engineered, or Enhanced Geothermal Systems (EGS), can add 100 gigawatts of geothermal power to the grid (Office of Energy Efficiency & Renewable Energy). The 2019 GeoVision analysis concluded that, with advancements in EGS, geothermal could power more than 40 million U.S. homes by 2050 and provide heating and cooling solutions nationwide. Advancements in closed-loop or Advanced Geothermal Systems (AGS) will unlock even more opportunity for geothermal. Additionally, super-hot rock (SHR) technologies have the potential to generate terawatts of power.
16. Geothermal energy use is rapidly evolving: There is growing interest and new research into geothermal innovations. New technologies, such as refined heat pumps, EGS, closed loop systems (AGS), SHR, improved drilling techniques, and more efficient turbines, are being created all the time to improve the energy process. There are an ever-increasing number of projects to improve and grow this area of industry. Within the last few years there have been over 40 geothermal energy start-ups founded in North America.

Geothermal energy has numerous advantages that make it an ideal option for a sustainable transformation to a healthier, more equitable, vibrant economy. With its renewable and clean nature, consistent availability, long-term viability, and versatile applications, geothermal energy offers a path towards a greener and more resilient and stable energy future. By embracing this remarkable resource, we can reduce our carbon footprint, combat climate change, and ensure a more sustainable and just planet for generations to come.

To learn more about harnessing the power of geothermal energy, contact Geothermal Rising, a community that advocates for the growth and deployment of geothermal energy. Founded in 1972, Geothermal Rising is a community of geologists, climate activists, oil and gas professionals, drill rig operators, environmentalists, geochemists, subsurface reservoir modelers and more. Geothermal Rising represents and speaks for an aligned geothermal industry. The non-profit is a renewable energy think tank designed to familiarize and inform audiences about the value and benefits of geothermal energy for heating and cooling as well as electricity generation. Please visit www.geothermal.org.

To learn more about renewable energy technology and how they can be deployed please visit: https://www.renewableenergyhub.co.uk/

We recently used this space to look at the variety of ways that geothermal energy can be utilized. Today, let's hone in specifically on geothermal power production and look at the different ways that electricity can be generated from geothermal energy.

There are primarily three types of geothermal power plants: dry steam, flash steam, and binary cycle. Each of them uses hot water, steam, or a combination of the two to create power.

Dry steam power plants use steam from underground to operate a turbine, which produces power. Dry steam plants were the earliest type of geothermal power plants built, the first of which was built in Larderello, Italy in 1904.

You can see dry steam power production in action at The Geysers in California. The Geysers are the world’s largest single source of geothermal power.

Flash steam power plants are the most common type of geothermal power plants in use today. Hot water (ranging from 360°-700°F) is pressurized at high levels and pumped from the earth into a tank at the surface with much lower pressure. When the pressure is reduced, it causes the water to turn to steam, or "flash". This steam drives the turbine, which produces power.

Flash steam plants come in single, double and triple varieties, denoting the number of times the water is "flashed" into steam.

In a binary power plant, pressurized hot water (below 400°F ) passes through a heat exchanger along with a second fluid (hence, the term binary) that has a much lower boiling point. This causes the second fluid to "flash" into vapor, which drives the turbine and generates electricity.

This type of power plant is considered a closed loop system because almost nothing except water vapor is emitted into the atmosphere. Because it’s such a clean source of energy, much of the geothermal electricity in the future could come from binary power plants. In fact, the vast majority of new geothermal plants in the U.S. since the year 2000 have been binary cycle plants.

There are three types of geothermal energy:
•    Geothermal power plants that produce electricity
•    Direct use and direct heating systems
•    Geothermal heat pumps
Let’s explore each of these exciting natural possibilities. Why? So, we can use the earth to save the earth.

Across the United States and around the world, there are reservoirs of hot water. This water can be found near the earth’s surface, or deeper down. The water is extremely hot, with temperatures ranging from 300° to 700°F. Geothermal power plants use the steam from the hot water to produce electricity.

It’s a simple process. The steam creates energy that rotates a turbine. The turbine activates a generator and electricity is produced. And this is a natural resource, so we’re using these reservoirs in the earth to power the earth.

Geothermal power plants are built where the reservoirs of hot water are located. In the U.S., most of the reservoirs are in the western states, but there are also reservoirs in the South, Midwest, and East Coast. This means that we can be using this natural resource more than we are currently.

And scientists and engineers are working on innovative technologies that will allow geothermal power plants to be built anywhere around the world, serving clean and renewable electricity at any time!

There’s another kind of geothermal energy that’s readily available called geothermal direct heat. It’s a simple process: direct heat comes from the water found in rock beneath the earth’s surface. The hot water in the rock reservoirs produces heat and steam, but isn’t hot enough to be economical to generate electricity. This water is captured and piped into buildings to provide heat, melt ice on roads and sidewalks, and warm fishing farms, greenhouses, and swimming pools.

Direct heat systems are already in use all around the world to make our lives better. For example, direct heat systems provide heat for most of the buildings in Reykjavik, Iceland. Direct heat is also used for food dehydration, pasteurizing milk, and mining gold. It’s an easily accessible and effective geothermal energy source.             

Finally, there are geothermal heat pumps. These heat pumps work by using the heat that naturally occurs in the ground. Did you know that temperatures in the earth 10 feet below ground range from 50°F to 60°F. This means that soil temperatures are typically warmer in the winter and cooler in the summer than the air. Geothermal heat pumps use the earth’s temperature to heat and cool buildings. How? During the winter, heat pumps take the heat from the ground into buildings. The process is and reversed during the summer.

According to the U.S. Environmental Protection Agency (EPA), “geothermal heat pumps are the most energy-efficient, environmentally clean, and cost-effective systems for heating and cooling buildings. All types of buildings, including homes, office buildings, schools, and hospitals, can use geothermal heat pumps.” In addition to heating and cooling buildings, geothermal heat pumps can provide hot water. Best of all, this is clean, renewable energy.

As demand for energy increases, geothermal energy will become an increasingly important energy source.  Right now, California has 43 operating geothermal generating plants, and plans to build more. A 2019 U.S. Department of Energy (DOE) report, GeoVision: Harnessing the Heat Beneath Our Feet, says, “generating electricity through geothermal methods could increase 26-fold by 2050, providing 8.5 percent of the United States’ electricity, as well as direct heat.” And, in Boise, Idaho, geothermal energy is heating 92 of biggest buildings in the city.

Let’s all embrace geothermal energy: a clean, green, renewable energy that uses the earth to power the earth.

https://www.eia.gov/energyexplained/geothermal/geothermal-heat-pumps.php

https://www.eia.gov/energyexplained/geothermal/use-of-geothermal-energy.php

https://www.go-gba.org/resources/green-building-methods/geothermal-energy/

https://www.energy.gov/eere/geothermal/electricity-generation

https://e360.yale.edu/features/can-geothermal-power-play-a-key-role-in-the-energy-transition

https://www.energy.gov/eere/geothermal/downloads/geovision-harnessing-heat-beneath-our-feet