Green Hydrogen: Clean Fuel for Hard-to-Decarbonise Sectors
Hydrogen is the universe's most abundant element — and when produced usingrenewable energy, it becomes a versatile, zero-emission fuel that could decarbonise the sectors that electricity alone cannot reach. Green hydrogen is emerging as a cornerstone of global climate strategies, with over $500 billion in announced projects worldwide.
The Hydrogen Colour Spectrum
Not all hydrogen is equal. The industry uses colours to distinguish production methods:
- Grey hydrogen: Produced from natural gas via steam methane reforming — accounts for 95% of current production, emitting 10 tonnes of CO₂ per tonne of hydrogen
- Blue hydrogen: Grey hydrogen with carbon capture applied — reduces but doesn't eliminate emissions
- Green hydrogen: Produced by splitting water (electrolysis) using renewable electricity — truly zero-emission
- Pink/purple hydrogen: Electrolysis powered by nuclear energy
How Electrolysis Works
Green hydrogen production uses electrolysers to split water (H₂O) into hydrogen (H₂) and oxygen (O₂) using electricity. The three main electrolyser technologies are alkaline (mature, lowest cost), proton exchange membrane or PEM (faster response, compact), and solid oxide (highest efficiency, but operates at high temperatures). When powered by solar orwind energy, the entire process produces zero greenhouse gas emissions.
Applications: Where Green Hydrogen Matters Most
Green hydrogen's value lies in replacing fossil fuels where direct electrification isn't feasible:
- Steel production: Hydrogen replaces coal as the reducing agent in iron ore processing — SSAB's HYBRIT project already produces fossil-free steel
- Shipping: Hydrogen-derived ammonia and methanol can power container ships that can't run on batteries
- Aviation: Synthetic kerosene produced from hydrogen and captured CO₂ offers a drop-in replacement for jet fuel
- Chemical production: Green hydrogen replaces grey hydrogen in ammonia (fertiliser) and methanol manufacturing
- Long-duration energy storage: Excess renewable energy converts to hydrogen for storage, reconverted to electricity during shortages
The Cost Challenge
Green hydrogen currently costs $3-6 per kilogram, compared to $1-2 for grey hydrogen. The gap is closing fast: electrolyser costs have fallen 60% since 2020, renewable electricity prices continue declining, and economies of scale from gigawatt-scale projects are kicking in. TheInternational Renewable Energy Agency (IRENA) projects green hydrogen reaching cost parity with grey by 2030 in regions with excellent renewable resources (Middle East, Australia, Chile, North Africa).
Infrastructure Requirements
Scaling green hydrogen requires massive infrastructure investment: electrolyser manufacturing capacity (from ~1 GW today to hundreds of GW), dedicated renewable energy generation (producing one tonne of hydrogen requires ~50 MWh of electricity), hydrogen pipelines and storage facilities, and port infrastructure for international hydrogen trade. The EU's hydrogen backbone plan envisions 40,000 km of hydrogen pipelines by 2040, partly repurposing existing natural gas networks.
Green Hydrogen and Energy Storage
One of hydrogen's most compelling roles is as a medium forlong-duration energy storage. While batteries excel at storing energy for hours, hydrogen can store energy for weeks or months in underground salt caverns. This seasonal storage capability is crucial for renewable-heavy grids that produce surplus energy in summer but face deficits in winter. Hydrogen fills the gap that batteries cannot.
Global Hydrogen Strategies
Over 40 countries have published national hydrogen strategies. The EU targets 10 million tonnes of domestic green hydrogen production by 2030. The US Inflation Reduction Act offers production tax credits up to $3/kg. Saudi Arabia is building NEOM Green Hydrogen, a $8.4 billion facility targeting 600 tonnes per day. Australia, Chile, and Morocco are positioning as major hydrogen exporters, leveraging abundant renewable resources.
Challenges and Uncertainties
Green hydrogen faces real challenges. Electrolysis efficiency losses mean 30-40% of input energy is lost in conversion. Water consumption is significant — roughly 9 litres per kilogram of hydrogen. Hydrogen is difficult to store and transport (small molecules leak through conventional materials). And competition from direct electrification is fierce — wherever a battery or heat pump works, it's more efficient than a hydrogen pathway. Green hydrogen must focus where it has no alternative, not try to compete everywhere.
The Hydrogen Economy Ahead
Green hydrogen won't replace fossil fuels everywhere — but it doesn't need to. If it successfully decarbonises steel, shipping, aviation, and chemical production, it would address roughly 15-20% of global emissions that electricity alone cannot reach. Combined withcarbon capture for residual emissions and renewable energy for everything else, green hydrogen completes the decarbonisation puzzle. The technology works. The economics are converging. The question is whether investment and infrastructure can scale fast enough.