The time has finally come for geothermal energy
Why geothermal hasn’t been a “holy grail”
- Usable high‑temperature resources are geographically patchy (Iceland, rift zones, volcanic regions). In most areas, hot rock is deep, heat flow is tiny (~40–60 mW/m²), and rock is a poor conductor, so you quickly “cool the rock” and must wait for it to reheat.
- Several commenters frame non‑volcanic geothermal as more like a finite hot‑rock “battery” than a continuously renewable source unless drilling is very cheap and very deep.
- Economics are “iffy”: very expensive wells for tens of MW, with high exploration risk and uncertain output. In many cases, solar and wind are already cheaper.
What’s changing
- Oil/gas drilling and fracking have driven costs down and enabled much deeper, more precise wells; some see this as the enabling tech for “deep geothermal” / enhanced geothermal systems.
- Ideas: plasma drilling, fracturing to increase rock contact, branching wells, and reusing orphaned oil wells for geothermal remediation projects. Opinions are mixed on how much this really fixes cost and water‑intrusion issues.
Heat vs power: ground‑source confusion
- Several comments emphasize the difference between:
- Deep geothermal power (hot rock, steam turbines, MW‑scale electricity).
- Ground/pond‑source heat pumps and district heating, which mainly exploit shallow ground as a seasonal heat store, often ultimately solar‑driven.
- Ground‑source heat pumps are praised as effective for buildings, but they don’t solve grid‑scale electricity needs.
Geothermal vs solar, wind, and nuclear
- Pro‑geothermal view: dispatchable, low‑carbon, good complement to intermittent renewables and for district heating (e.g., Munich, Iceland, flooded mines).
- Skeptical view: steam turbines and drilling are fundamentally expensive; with PV module prices plunging and batteries improving, geothermal will remain a niche except in very favorable geology.
- Large side debate: whether nuclear fission should be the core solution (cheap baseload if politics and regulation allowed) vs renewables+batteries outcompeting new nuclear on cost and build speed. No consensus.
Grid integration, storage, and “baseload”
- One camp argues “baseload generation is obsolete”: cheapest energy is now intermittent (solar/wind), and what’s needed is dispatchable capacity and storage (batteries, pumped hydro, demand shifting).
- Others counter that real grids still have large continuous loads and that countries relying heavily on intermittent renewables (e.g., Germany) struggle with costs and coal backup, whereas nuclear‑heavy grids (e.g., France) enjoy cheap, low‑carbon power—though maintaining aging fleets is getting very expensive.
- Several note promising work on large‑scale batteries, thermal storage in rock/soil, and grid‑forming inverters, but long‑duration/seasonal storage remains hard; many expect some continued fossil backup.
Risks and planetary impacts
- Induced earthquakes from enhanced geothermal projects have already shut down some trials, prompting calls for caution, especially in historically seismic regions.
- Concerns about “cooling the core” are dismissed as physically negligible relative to Earth’s internal heat budget, based on figures shared in the thread.