Day 31: Geothermal Energy

Today you will learn from expert guest Roland Horne about geothermal energy, why it may or may not help solve climate change, how it works and what needs to still be done for it to be an effective solution to climate change.

Summary

Guest: Roland Horne

Roland N. Horne is the Thomas Davies Barrow Professor of Earth Sciences at Stanford University, and Senior Fellow in the Precourt Institute for Energy. He holds BE, PhD and DSc degrees from the University of Auckland, New Zealand, all in Engineering Science.

He is best known for his work in well test interpretation, production optimization, and analysis of fractured reservoirs. So far in his academic career he has supervised the graduate research of 60 PhD and 135 MS students. He is an Honorary Member of the Society of Petroleum Engineers (SPE), and a member of the US National Academy of Engineering. He served on the International Geothermal Association (IGA) Board 1998-2001, 2001-2004, and 2007-2010, and was the 2010-2013 President of IGA.

He was the Technical Program chair of the World Geothermal Congress in 2005, 2010, 2015 and 2020.Horne has been an SPE Distinguished Lecturer (1998, 2009 and 2020), and has been awarded the SPE Distinguished Achievement Award for Petroleum Engineering Faculty, the Lester C. Uren Award, and the John Franklin Carl Award. From Society of Exploration Geophysicists (SEG), he received the Best Paper in “Geophysics” in 2011, and from SPE he received Best Paper in Journal of Petroleum Technology (1992) and Best Paper in SPE Formation Evaluation (1993). He has also received five Best Paper awards from Geothermal Resources Council (GRC). He is a Fellow of the School of Engineering, University of Tokyo (2016) and also an Honorary Professor of China University of Petroleum – East China (2016).

Follow Roland Horne:

• LinkedIn
• Website

Explain succinctly what geothermal energy is from first principles.

Geothermal energy is recovering the heat of the earth and converting it to useful applications, in the form of electricity or as a second path using the heat directly.

Why does geothermal energy help to solve climate change?

Geothermal energy is a renewable energy which has very low carbon emissions.  

It's also a different format of renewable energy than the intermittent sources like wind and solar, so it can be can be operated anytime, day or night, any month and any year.

Steel man the other side. Why would geothermal energy NOT work to solve climate change?

There are some aspects to the deployment of geothermal energy that can be something that we need to work around.

• Geothermal is base load, which 20 years ago was a good thing because it meant that you could keep it on the grid all the time. However, in today's  grids where we have large amounts of wind and solar, both intermittent, baseload power is no longer what the grids actually want.  They want variable power and dispatchable power. Being baseload, at the moment at least, limits the application.
• So those kind of base load sources in a largely intermittent grid are going to require storage of some kind as we go forward in the future.

Who benefits most by implementing geothermal energy as a solution?

• Consumers
• Earth Inhabitants

Who is harmed most by implementing geothermal energy  as a solution?

There is a concern in some cases for induced seismicity. But that generally just affects people who are just close to it.

How does geothermal energy work as a solution to climate change?

Almost all rock everywhere in the world is saturated with water.  And so that water, which is sitting inside of the permeable rocks is heated up by the geothermal source and is either in place as hot water or in some cases directly a steam.

So the way that we deploy a geothermal electrical generation system is:

• drill wells into the ground 2000-3000 meters, or about 8,000 feet.  
• use the water to bring steam to the surface.
• steam turns a turbine to generate electricity

For geothermal energy as a solution to work, what innovation or policy needs to be created?

Storage is the main technological innovation needed.

In policy we need to address the uncertainty and lead time issue. A geothermal power plant takes several years to actually bring into operation. That ends up costing quite a lot of money because of the duration. You're spending money for that process but you're not getting anything back until a power plant is actually built.

So, in terms of policy and legislation what has been useful in a number of places, including here in the US, is mechanisms to actually encourage that process,  either by mitigating some of the risk for example, in the form of feed in tariffs that actually provides some certainty to what the actual income is going to be, or in some cases, legislation that actually obliges the grids to accept a certain amount of  power of certain kinds.

Additional Resources

• Geothermal Rising

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Top Skills To Learn

Our guest recommends learning the following skills:

• Engineering: measure, quantify, analyze, understand, and project what the geothermal resource will do in the future and design a system that will be suitable for that. Other enginners needed are mechanical, drilling, plant, and civil.
• Geoscience: people who explore for the geothermal resource in the first place
• Business: financing, permitting, the community relationship issues

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Activity

Activity: Geothermal Resource Assessment

Description: Research geothermal potential in your region or a specific country. Explore available maps and data to identify potential geothermal hotspots. Discuss the feasibility of tapping into this resource.

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Skill Lesson Mastered

Demonstrate mastery of the knowledge and skills presented in this lesson by applying it to the above activity. If, and only if, you have a full understanding and have mastered the knowledge and skills presented in this lesson, select the next lesson in the navigation.