49. Geothermal: Drilling for Decarbonization (1/2)

In this eye-opening episode (part 1/2), Host Michael Barnard invites Simon Todd, Managing Director of Causeway Energies and a man whose geological expertise spans from the chalk beds of Northern Ireland to the drilling decks of BP. Simon joins the podcast to drag geothermal energy out of its misunderstood niche and into the spotlight it deserves.

Simon, who spent 25 years at BP before pivoting hard into the future, lays out a vision for geothermal that’s far more than volcanic spas and Icelandic outliers. He starts by grounding us (literally) in the Earth’s temperature dynamics: from a molten 6,000°C core to the relatively tame gradients of continental crust. We learn that geothermal isn’t just a matter of poking around tectonic hotspots. With modern drilling and clever thermal engineering, you can tap heat just about anywhere—even in the soggy, non-volcanic soils of the UK and Ireland.

He gets into the mechanics too, explaining how ground source heat pumps use the shallow earth—those top 10–15 meters that swing with the seasons—to store and retrieve heat. He unpacks the performance metric du jour, the Coefficient of Performance (COP), and shows how deeper wells (500 to 700 meters) vastly outperform air-source systems. The returns? In some projects, a sub-3-year payback. That’s not a climate virtue signal—that’s a boardroom greenlight.

But Simon doesn't stop at closed-loop systems. He dives into the real geothermal opportunity hiding beneath our feet: open-loop aquifer systems. These draw warm water from permeable rock formations—‘rock sponges,’ as he puts it—offering faster heat transfer than passive conduction. And yet, while ATES systems thrive across the Netherlands and Belgium, they’re barely used in the UK or Ireland. Why? Bureaucratic inertia, unfamiliarity, and maybe just a lack of storytelling.

With directional drilling tech now able to reach aquifers from a single pad, and real-time data steering drill heads with pinpoint accuracy, Simon argues we have the tools and the data. What’s missing is awareness—and maybe a bit of ambition.

This episode is a geothermal masterclass from someone who’s lived both the legacy fossil past and the clean energy future. If you're still thinking geothermal is just for hot springs and sci-fi, Simon Todd is here to prove otherwise—with numbers, with tech, and with real-world results.

Follow the show for more episodes like this one, where energy myths get debunked, and the future gets explained.