Geothermal power and nuclear siting, at a glance
Two technologies, the same question: does the ground allow it?
Heat near the surface
Geothermal power needs Earth’s heat close enough to reach.
Puga Valley, Ladakh
India’s first geothermal project, over 14,000 feet up.
Kudankulam, Zone II
India’s lowest seismic hazard zone, by design.
Sept 2026, Andaman SMRs
BARC scouts Zone V, India’s highest seismic hazard, for small reactors.
What Do Geothermal Power and Nuclear Siting Have in Common?
Why does geography control both technologies?
- Geothermal power draws on heat stored inside the Earth, most accessible near tectonic plate boundaries and volcanic or geologically active regions.
- It counts as renewable and low-carbon, since it taps existing heat instead of burning fuel.
- Nuclear power plants need careful siting to limit risk from earthquakes, tsunamis, and other geophysical hazards.
- Coastal nuclear sites face a specific tension. They need coastal access for cooling water, but the coast is also where tsunami risk concentrates.
- Both technologies show the same underlying pattern: where the ground allows, and where it doesn’t, shapes these choices as much as the engineering does.
Q1. True or False: geothermal power is most accessible near tectonic plate boundaries and volcanic regions.
Q2. True or False: coastal nuclear sites are chosen for cooling water access and face no added tsunami risk from being on the coast.
Where Is India’s Geothermal Potential, and How Are Nuclear Plants Sited?
What is India’s biggest geothermal project?
- India has limited high-potential geothermal sites, concentrated mainly in Ladakh, Himachal Pradesh, and parts of the Andaman Islands.
- The most-cited site is Puga Valley in Ladakh, where state-run ONGC is building India’s first geothermal power project, also the world’s highest-altitude one, at over 14,000 feet.
- On 17 July 2026, Ladakh’s Lieutenant Governor commissioned two wells there, each drilled 1,000 metres deep, meant to support a planned 1 MW pilot plant drawing on underground temperatures above 200°C.
- Early estimates suggest a 5 sq km area of the valley could eventually support up to 200 MW of clean power. That scale is still years away.
Where are India’s nuclear plants sited, and why?
- The 2011 Fukushima disaster in Japan intensified global scrutiny of nuclear plants sited near seismically active coastlines.
- Kudankulam, on the Tamil Nadu coast, sits in Seismic Zone II, India’s lowest official hazard classification. Regulators cite no active faults nearby and low tsunami potential, alongside its coastal access for cooling water.
- Tarapur, on Maharashtra’s coast, sits in Seismic Zone III and draws cooling water directly from the Arabian Sea.
- Every Indian nuclear plant’s structures are engineered for the specific maximum earthquake considered possible at that site, not one single national standard.
Q3. True or False: Puga Valley, in Ladakh, is the site of India’s first geothermal power project.
Think it through, before reading on. In September 2026, BARC scouted sites in the Andaman and Nicobar Islands for Small Modular Reactors. Which seismic zone are these islands in, and why would anyone propose a nuclear reactor there at all?
Show the explanation
Seismic Zone V, India’s highest hazard classification. Officials cited other Zone V countries already running similar reactors, including offshore barge-mounted floating plants, as precedent. The pitch isn’t that the ground is safe. It’s that a smaller, more resilient SMR design can manage a risk a conventional plant like Kudankulam or Tarapur never had to face at their own, far gentler sites.
Remember the trap. Kudankulam sits in Zone II, India’s lowest seismic hazard. The Andaman and Nicobar Islands sit in Zone V, the highest. Don’t mix these up: lower zone number means lower hazard, not higher.
What Does a Real Earthquake Reveal About Nuclear Siting?
How did a real earthquake test these siting assumptions?
- On 26 January 2001, a magnitude-7.7 earthquake struck Bhuj, in Gujarat’s Kutch region, killing over 13,000 people.
- Gujarat spans nearly the full range of India’s seismic zones within one state, from low-hazard Zone II to the highest, Zone V, near Kutch itself.
- Kakrapar Atomic Power Station, elsewhere in Gujarat and further from the epicentre, continued functioning through the quake. That doesn’t prove every design assumption is correct, but it does show the plant’s safety systems held under an actual major earthquake, not just a modelled one.
- The 1993 Latur earthquake, which struck the supposedly “stable” Deccan Plateau, along with the 2001 Bhuj quake, pushed India to significantly revise its seismic zoning map upward.
- Geothermal power’s limited global adoption, despite being low-carbon, shows the same lesson from the opposite direction: geographic availability, not just demand, constrains what a technology can actually do.
Q4. True or False: Kakrapar Atomic Power Station continued functioning through the 2001 Bhuj earthquake.
Q5. True or False: the 1993 Latur earthquake and the 2001 Bhuj earthquake together led India to revise its seismic zoning map upward.
Q6. True or False: because geothermal power is low-carbon, geography places no real limit on how widely it can be adopted.
Quick Q&A
What does India’s first geothermal power project depend on?
Underground heat above 200°C at Puga Valley, Ladakh, over 14,000 feet up.
Which seismic zone is Kudankulam sited in?
Zone II, India’s lowest official hazard classification.
What happened to Kakrapar during the 2001 Bhuj earthquake?
It kept functioning through the magnitude-7.7 quake.
Why is BARC scouting the Andaman Islands, Zone V, for reactors?
Small Modular Reactors are designed to be resilient enough to go where a conventional plant could not.
BARC scouts Andaman sites for small reactors, in Seismic Zone V. A BARC team ran a five-day site assessment across the Andaman and Nicobar Islands, 4-8 September 2026, to scout locations for Small Modular Reactors. Lieutenant Governor Admiral D.K. Joshi met the team. Source: The Week.
The driver is the Great Nicobar mega-project, a container terminal, airport, and township across 16,610 hectares, which will sharply raise electricity demand currently met mostly by diesel generators.
Officials cited other Zone V countries already running similar reactors, including offshore barge-mounted floating plants, as precedent. This is this article’s own siting tension playing out in real time: SMRs are proposed specifically because they can go where a conventional plant like Kudankulam or Tarapur could not.
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