Prime Minister Modi’s flagging-off of India’s first hydrogen-powered train, on the 89-km Jind–Sonipat section in Haryana, deserves to be recorded as a genuine engineering achievement. The ten-coach trainset, designed and built indigenously, will carry some 2,600 passengers on a fuel-cell system that generates its own electricity on board. It is backed by a dedicated hydrogen production facility at Jind — a 1 MW electrolyser producing roughly 430 kg of hydrogen a day, using water drawn from rainwater harvested on station rooftops. This is not a token gesture; it is a working piece of infrastructure.
India joins a small club here. Germany’s Coradia iLint began commercial hydrogen rail service in 2018; France, Britain and China have their own pilots running. That India has now done this with a train built at home, rather than imported, is worth saying plainly, before any of the caveats that follow.
And the caveats do follow — not to take away from the achievement, but because the public conversation around this launch has, almost without exception, reached for two words that do not quite hold up: “zero pollution,” and “the ultimate green fuel.” An educated readership deserves to understand why.
II. What “Zero Emission” Actually Means
Here is a simple, everyday comparison. Consider an electric car charged overnight in your garage. At the point of use — on the road — it emits nothing. No exhaust, no smoke, no smell. But the electricity that charged it came from somewhere: quite possibly a coal or gas-fired power station many kilometres away, sending power down high-tension transmission lines, losing some of it as heat along the way, before it ever reached your charging point. The car is clean. The question of whether the journey was clean depends entirely on what happened at the power station, well before the car left your driveway. And when the battery eventually wears out, its disposal raises a separate set of environmental concerns that have nothing to do with tailpipes at all.
Exactly the same logic applies to an electric train running on overhead wires. The train itself pollutes nothing. But the grid supplying it may include thermal power stations burning coal, somewhere upstream of the tracks.
This distinction — between where you don’t see the pollution and whether pollution occurred at all — is the single most important thing to hold in mind while reading about the hydrogen train. “Zero emission at the point of use” is a true and creditable claim. “Zero pollution,” full stop, is a different and much larger claim — and it is not one that any fuel chain, hydrogen included, can currently make with a straight face.
III. Following the Hydrogen, Step by Step
So where does the hydrogen train’s energy actually come from, and what happens to it along the way? It helps to walk through the chain in plain steps, the way one might trace a rupee through several hands before it reaches its final destination — losing a little at every stop.
Step one: making the hydrogen. Hydrogen does not occur freely in nature the way coal or oil does; it has to be extracted, typically by splitting water into hydrogen and oxygen using electricity, a process called electrolysis. This is the “green” route the Jind plant uses, and it is the right way to do it — cleaner by far than the more common global practice of extracting hydrogen from natural gas. But electrolysis is inherently a one-way street: you must always put in more electrical energy than you will later get back out of the hydrogen. Some energy is lost as heat in the process itself, the way a kettle loses some heat to the air around it even as it boils your water.
Step two: where that electricity came from. The electricity fed into the Jind electrolyser has to be generated somewhere in the first place — ideally from solar or wind, but drawn, as the reports indicate, from assured grid supply. Unless that grid supply is itself verifiably renewable, the same upstream question that applies to electric trains and electric cars applies here too, one step earlier in the chain.
Step three: storing and moving the hydrogen. Once produced, hydrogen has to be compressed and stored — at the Jind facility, around 3,000 kg of on-site storage — and this compression itself consumes energy. Hydrogen is a notoriously difficult gas to handle efficiently; it is light, it needs high pressure to store in useful quantities, and every stage of handling it costs something.
Step four: converting it back to electricity. Finally, aboard the train, the hydrogen is fed into a fuel cell, where it recombines with oxygen from the air to generate electricity — releasing only water vapour as a by-product. This is the stage most reporting stops at, and understandably so, because it is genuinely impressive: no smoke, no soot, just water. Fuel cells convert hydrogen’s stored energy to electricity at roughly 50 to 60 per cent efficiency in real-world operation — respectable, and better than a diesel engine.
But here is the point that gets lost: that 50–60 per cent efficiency is only for the last step. Add up the losses at every earlier stage — generating the electricity, electrolysing the water, compressing and storing the gas — and credible engineering studies put the overall efficiency of the full chain, from original electricity to final electricity delivered to the wheels, at somewhere around 38 to 40 per cent. Put differently: for every unit of electricity that went into making the hydrogen in the first place, more than half is lost before the train ever moves an inch. This is not a design flaw or a failure of Indian engineering — it is simply what elementary thermodynamics permits. Energy changes form each time it moves from one stage to the next, and at every such change, some of it escapes as unusable heat. No fuel cell, however well made, is exempt from this rule.
IV. A Word on Safety
There is one further caveat worth stating plainly, quite apart from questions of efficiency: hydrogen is a highly inflammable gas. It ignites easily, burns almost invisibly in daylight, and — when mixed with air in the wrong proportion and exposed to even a small spark or source of static electricity — can explode. This is not a reason to be alarmed about the passenger train itself, which is engineered with multiple layers of safety systems precisely because this risk is well understood. But it is a reason why the electrolysis plant at Jind, and any facility that produces, compresses and stores hydrogen in tanks or cylinders, must treat safety as paramount rather than incidental. Leak detection, proper ventilation, spark-proof fittings, and rigorous protocols around every valve and joint are not optional extras in a hydrogen facility — they are the difference between a green energy success story and a serious industrial accident. This too deserves a mention whenever hydrogen is described, as it often is, as a simple and benign fuel.
V. The Comparison That Actually Matters
The honest comparison, then, is not hydrogen versus diesel. Against diesel, hydrogen wins easily — lower local pollution, no particulate matter, no NOx at the platform. The comparison that matters, and the one rarely made in the celebratory coverage, is hydrogen versus direct electrification: simply running the same electricity through overhead wires straight to the train, without the detour through electrolysis, storage and a fuel cell. That direct route is markedly more efficient, because it skips the conversion losses at each intermediate step.
Why, then, choose hydrogen at all? Because not every route can be electrified economically — putting up overhead wires and substations along every branch line in the country is expensive and slow. Hydrogen trains offer a genuine advantage precisely where electrification is impractical: they deliver clean local operation without new wires. That is a real and valuable use case. It is simply a different case from “the most efficient possible technology,” and the two should not be confused.
VI. What This Means for Policy Discourse
None of the above is an argument against the hydrogen train, or against green hydrogen more broadly. Quite the opposite: pursuing genuinely renewable-sourced hydrogen, as the Jind plant claims to do, is the right long-term direction, and far preferable to the grey and blue hydrogen — derived from natural gas — that still dominates global hydrogen production today. The Jind–Sonipat launch is a creditable first step, and India’s ability to build the trainset indigenously adds to its credit.
But a democracy debating its energy future deserves accuracy over slogans. “Zero pollution at the point of use” is true and worth celebrating. “The ultimate green fuel,” “thermodynamically most efficient,” or simply “zero pollution” without qualification are claims the physics does not support. An educated citizenry does not need advanced mathematics to understand this — only the same everyday logic that applies to the electric car in the driveway: what you don’t see at one end of the wire was very likely produced, and paid for, at the other.