Fervo Energy's May 2026 IPO was the largest clean-energy listing on record, and the market read it as proof that enhanced geothermal works. Thomas Giehm, Investment Manager at Underground Ventures, Europe's only VC fund dedicated to geothermal technology, invests one layer beneath developers like Fervo: the drilling tools, downhole electronics, and completion technology that have to perform before any well produces power. From that seat, he separates what the IPO actually validates, investor appetite for firm clean power and a demonstrated cost curve on a still-small well count, from what remains open: whether a 35% learning rate holds across thousands of wells drilled into deeper, hotter rock.

We trace geothermal's borrowed playbook from shale, the one place that analogy breaks, and why Europe, despite real geothermal resources, hasn't produced its own Fervo yet. We close on what a background in commodity trading sees in an energy bet that a traditional VC might miss, and one early belief about geothermal Thomas has had to revise.

In this episode:

• 02:42 — Origin story: commodity trading to geothermal, via a cold email to Torsten Kolind
• 05:02 — What the Fervo IPO actually validates, and what it doesn't
• 10:45 — The picks-and-shovels thesis: why back the tech layer, not the developers
• 16:23 — Mapping the five-segment value chain, and a new name in it: Terraferno
• 23:04 — The ten-year cost curve: which technologies actually bend it
• 31:38 — Could Europe build its own Fervo?
• 41:19 — Personal: what a trader's instinct sees, and one early belief revised

Links:

• Fervo Energy S-1 / IPO prospectus (Nasdaq: FRVO)
• Underground Ventures — ugventures.com

Guest: Thomas Giehm, Investment Manager at Underground Ventures.

Stranded is a podcast on climate finance and the energy transition: what it costs, who carries the risk, and what gets left behind. New episodes every three weeks. Subscribe wherever you listen.

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