Green Hydrogen: Fueling the Hardest-to-Decarbonize Sectors

There is a contradiction at the heart of the clean energy transition. For electricity, the answer is clear: solar, wind, and batteries can power almost everything that plugs into a grid. But there is a part of the economy that does not plug in — the part that burns things. The furnaces that melt steel, the kilns that make cement, the ships that cross oceans, the aircraft that fly continents, and the chemical plants that make ammonia for fertilizer all need fuel, and they need it in forms that batteries cannot easily provide. A steel furnace requires temperatures that electricity can reach but that a battery cannot sustain at scale; a container ship crossing the Pacific cannot carry the weight of batteries that would be needed. For these sectors, the transition needs a different answer, and the answer increasingly looks like hydrogen.

Hydrogen is the most abundant element in the universe and the simplest of all fuels: burn it and it combines with oxygen to make nothing but water. But hydrogen does not occur naturally in usable form on Earth; it must be manufactured, and the way it is manufactured determines whether it is clean or dirty. Green hydrogen — produced by splitting water into hydrogen and oxygen using electricity from renewable sources — is the clean form, and it is emerging as the fuel of the hard-to-decarbonize future. This article explores what green hydrogen is, which sectors need it, the challenges of scaling it up, and whether it can deliver on its promise.

The Hydrogen Spectrum

Not all hydrogen is created equal, and the terms used to describe it are a color-coded map of its climate credentials. Grey hydrogen, the most common today, is made from natural gas through a process that releases carbon dioxide — it is effectively a fossil fuel in another form. Blue hydrogen is grey hydrogen with the carbon captured and stored, reducing — though not eliminating — its emissions. Green hydrogen is made by electrolysis, splitting water using electricity from renewable sources, producing no carbon emissions at all. There are also less common varieties — pink hydrogen from nuclear power, turquoise hydrogen from pyrolysis — but the divide that matters is between the hydrogen that emits carbon and the hydrogen that does not. Green hydrogen is the destination; the question is how fast the world can get there and at what cost.

Why Green Hydrogen?

Green hydrogen is attractive because it solves the storage problem that plagues renewables and the combustion problem that plagues industry. It can be stored in large quantities for long periods, transported in ships and pipelines, and burned or converted into fuel cells to provide energy on demand. It can substitute for fossil fuels in processes that need intense heat or dense energy. And it can be made anywhere there is renewable electricity and water — which is to say, almost anywhere. The vision is a hydrogen economy in which the sun and wind of the great renewable regions — the deserts, the coasts, the windy steppes — are converted into a fuel that can be shipped to the industries and sectors that cannot be electrified.

The Sectors That Need It

Green hydrogen is not needed everywhere, and the honest assessment is that electricity should be the answer where it works. Hydrogen is expensive and inefficient compared with direct electrification — it takes more energy to make, store, and convert hydrogen than to use electricity directly. The sectors that genuinely need hydrogen are those where electrification fails.

Industry

Heavy industry is the most important market. Steel, cement, chemicals, and fertilizers are responsible for a substantial share of global emissions, and their processes demand either extreme heat or hydrogen as a chemical input. Green hydrogen can replace the coal that reduces iron ore to iron in steelmaking — a process that, using hydrogen, produces water instead of carbon dioxide. It can provide the high-temperature heat for cement and glass kilns. And it is the essential ingredient of green ammonia, made from nitrogen and hydrogen, which can replace the fossil-derived ammonia that is the basis of modern fertilizer. The industrial transition to green hydrogen is the deepest and most durable market for the fuel.

Shipping and Aviation

For shipping and aviation, hydrogen and its derivatives are among the few credible paths to decarbonization. Ships can run on green ammonia, made from green hydrogen, which is energy-dense enough for long ocean voyages and produces no carbon when burned. Aviation is harder still: the energy density of hydrogen makes it difficult for long-haul flight, so the more likely path is sustainable aviation fuel — made from hydrogen and captured carbon — alongside hydrogen combustion for shorter routes. Neither sector is easy, and both are far from scaled solutions, but hydrogen-based fuels are the leading candidates for the fuels of the future.

Long-Duration Storage

Beyond industry and transport, hydrogen offers the promise of long-duration energy storage. Batteries store energy for hours to days; hydrogen can store it for weeks to seasons. Renewable power generated in a windy spring can be converted to hydrogen and stored until a still winter evening. As the share of variable renewables rises, this seasonal storage role is becoming increasingly important, and hydrogen is the most credible technology for it.

The Challenges

The obstacles to a hydrogen economy are formidable, and the history of hydrogen is littered with promises that exceeded delivery. The challenges cluster in three areas.

Cost

Green hydrogen is today significantly more expensive than the fossil fuels it must replace, and much more expensive than grey hydrogen. The cost is driven by the price of renewable electricity, the capital cost of electrolysers, and the inefficiency of the conversion process. The trajectory, however, is encouraging: the cost of electrolysers is falling, renewable electricity is the cheapest it has ever been, and projections suggest green hydrogen could reach cost parity with fossil fuels within a decade or two with continued deployment and policy support. Like solar and wind before it, hydrogen needs to travel down the learning curve, and that requires early markets and investment.

Infrastructure

Hydrogen is difficult to handle. It is a tiny molecule that leaks easily, it embrittles metals, and it is highly flammable. The infrastructure to produce, store, transport, and dispense hydrogen at scale — pipelines, compressors, storage caverns, and ports — barely exists, and building it is a multi-decade, multibillion-dollar undertaking. The challenge is not just technical but geographic: the best renewable resources and the largest industrial consumers are often far apart, requiring the transport of hydrogen across borders and oceans.

Efficiency and Priorities

The most sobering critique of hydrogen is efficiency. The chain from renewable electricity to hydrogen to useful energy loses a large share of the energy at each step. Using electricity directly is almost always more efficient than converting it to hydrogen and back. This is why the priority order matters: electrify everything that can be electrified first, and reserve hydrogen for the sectors that genuinely need it. A hydrogen economy that overreaches — powering cars and heating homes with hydrogen where electricity would do — would be a costly detour. The discipline of the transition is to use hydrogen where it is necessary, not where it is merely fashionable.

Policy and Momentum

Despite the challenges, the momentum behind green hydrogen is real and growing. Governments have committed billions to hydrogen strategies, from the European Union's hydrogen bank and targets, to the United States' clean hydrogen hubs, to the industrial policies of China, Japan, and Korea. The private sector is investing in electrolyser manufacturing, hydrogen projects, and the first green ammonia and green steel plants. The economics are improving, the technology is advancing, and the demonstration projects are beginning to prove the concept at industrial scale. The pattern resembles the early days of solar and wind: expensive, small, and contested — but on a trajectory that can, with sustained support, become mainstream.

Conclusion: The Fuel That Isn't Here Yet — But Could Be

Green hydrogen is not a silver bullet, and it is not the answer to every part of the energy transition. But it is the answer to a specific and essential set of problems: the furnaces that cannot plug in, the ships and planes that cannot carry batteries, and the chemicals that the modern world cannot do without. For those sectors, hydrogen is not an option among many; it is the leading path to zero emissions. The technology is real, the economics are improving, and the infrastructure challenge is large but not insurmountable. The hydrogen economy will not arrive quickly, and it will not arrive everywhere at once. But it is arriving, and for the hardest parts of the economy, it may be the difference between a world that reaches net zero and a world that cannot.

Frequently Asked Questions

What is green hydrogen?

Green hydrogen is hydrogen produced by electrolysis — splitting water into hydrogen and oxygen — using electricity from renewable sources. Burning it produces only water, making it a zero-carbon fuel.

Why do some sectors need hydrogen?

Industry, shipping, and aviation need hydrogen because they require intense heat or dense energy that batteries cannot practically provide. Steel, cement, chemicals, long-haul ships, and aircraft are among the hardest to decarbonize, and hydrogen-based fuels are leading solutions.

How is green hydrogen different from grey and blue hydrogen?

Grey hydrogen is made from natural gas and emits carbon. Blue hydrogen is grey hydrogen with carbon capture, reducing emissions. Green hydrogen is made from renewable electricity and water, producing no carbon emissions.

Is green hydrogen efficient?

Direct electrification is generally more efficient than hydrogen, which loses energy at each step of production, storage, and conversion. This is why hydrogen should be reserved for sectors that cannot be electrified, rather than used where electricity would work.

How expensive is green hydrogen?

Green hydrogen is currently more expensive than fossil fuels, but costs are falling as electrolysers scale and renewable electricity gets cheaper. With continued investment and policy support, it could approach cost parity within a decade or two.

Related Articles

The Energy Transition: How the World Is Powering Down on Fossil Fuels — The broader transformation that green hydrogen is a part of.

Renewable Energy: Powering a Cleaner Future — The clean electricity that green hydrogen is made from.

Net Zero Explained: What It Means and How to Get There — Why hydrogen matters for reaching net zero across the whole economy.