Tapping the Earth’s heat
With Petroleum Engineering about to launch its Masters in Geothermal Engineering, program leader Stuart Walsh explains the importance of geothermal in the future energy mix and why he loves the subject so much.
My first question is very basic: what is geothermal engineering?
Geothermal engineering is a discipline that involves designing and building systems that use the Earth’s heat to do useful work. It includes producing energy in the form of electricity, but there are other forms of geothermal energy use as well. There’s geothermal heating and cooling, lithium and rare earth mining, and energy storage; even geothermal refrigeration and desalination fall under the category of geothermal engineering.
What is your role at Petroleum Engineering?
I have two roles. In a teaching capacity, I’m one of the leads for the new geothermal masters stream, which is a really exciting opportunity. I’m also a researcher and my long-term interest centres on new geothermal drilling technologies.
Geothermal resources tend to be located in hard basement rocks, which are a bit different from the rocks we are used to drilling for oil and gas, and can be difficult to drill with conventional means. As a result, drilling is a major component of the costs that go into geothermal energy. If we can improve our ability to drill, we can lower those costs and make geothermal power cheaper and more widely available.
What got you into geothermal engineering?
“I’m an applied mathematician by training and love working on complex, multidisciplinary challenges and, frankly, geothermal engineering has that in spades. There’s geology, thermodynamics, rock mechanics, fluid mechanics, heat and mass transfer, chemistry, electric power, economics – you name it.
Stuart Walsh, Deputy Head (Marketing & Industry) and Lecturer, Petroleum Engineering
I’m an applied mathematician by training and love working on complex, multidisciplinary challenges and, frankly, geothermal engineering has that in spades. There’s geology, thermodynamics, rock mechanics, fluid mechanics, heat and mass transfer, chemistry, electric power, economics – you name it.
I also like working on problems that are important from a global perspective. Currently, I think we face two major problems: we need to increase our production of energy while reducing the amount of carbon we’re putting into the atmosphere. Geothermal energy, unlike other renewable energies, provides constant or baseload power, so it’s a reliable form of sustainable energy that solves both of these problems.
Just from a personal perspective, I also love studying volcanoes, and by working on geothermal energy I get an excuse to do that, too.
What are you working on at the moment?
I’m interested in a technique called thermal spallation, which is a way of breaking up hard rocks using heat. I’m also working on a project using microwave spallation – again, a way of breaking up these hard rocks but using microwave radiation. Both techniques are aimed at increasing the drilling rate to reduce the cost of geothermal wells.
I’m also looking into the economics of hybrid or unconventional geothermal operations, for example lithium production as well as geothermal energy, or optimising production from geothermal desalination plants, or even geothermal energy storage.
Finally, I have a project examining the geochemistry of geothermal resources, in particular how we model the physical properties of geothermal brines based on their chemical composition.
Why is the new masters program significant?
We’re called the School of Petroleum Engineering, but we think about ourselves as being a school of energy resources. We’re looking at ways to apply the technologies and know-how we’ve learnt through many years of petroleum engineering in different fields. The new masters program fits into this vision of where we’re going with the School in the future.
Who might be interested in doing the new masters program?
If you’re interested in interdisciplinary challenges, if you’re interested in questions around energy, if you’re interested in geology, then you’ll probably enjoy geothermal engineering. Also, if you like getting out in nature, it’s a great field to be in. One of the wonderful things about geothermal energy is that geothermal plants are often located in some of the most beautiful places in the world.
Learn more about the Masters Program In Geothermal Engineering.