Green hydrogen


  • The number and scale of projects using and making hydrogen, a gas that releases energy when burned without emitting carbon dioxide, is rapidly growing.

International Efforts

  • If its construction goes to plan, a Euro 2.5 billion (GBP 2.18 billion) undersea pipeline will convey “green hydrogen” from Spain to France from 2030.
  • In the US, some power stations are being upgraded to allow hydrogen to be blended with fossil gas, and the Norwegian oil company Equinor is teaming up with Thermal SSE to build a 1,800 megawatt (MW) “blue hydrogen” power plant in Britain.
  • Meanwhile, China unveiled a plan in which includes deploying 50,000 hydrogen vehicles by 2025 and early December saw the first hydrogen-fuelled tractors and forklifts leave the assembly line at a new plant in Guangdong province.

Hydrogen is produced in multiple ways. A colour spectrum is used to render it simple.

  • “Grey” and “brown/black” hydrogen come from fossil gas (methane) and coal (brown or black coal) respectively – a process that, for every tonne of hydrogen, emits between ten and 12 tonnes of CO₂ for grey hydrogen and 18 to 20 for brown.

    Green hydrogen
    Photo Credit: Getty Images/iStockphoto
  • “Blue” is the same process except the carbon dioxide is supposed to be captured and stored underground. And “green” hydrogen is conventionally defined as generated from splitting water into hydrogen and oxygen using renewable electricity.
  • But only 0.04% of hydrogen is green, and blue hydrogen is less than 1%.
  • The rest is grey or brown, most of which is used in oil refineries and for manufacturing ammonia and methanol.

What is green hydrogen?

  • A colourless, odourless, tasteless, non-toxic and highly combustible gaseous substance, hydrogen is the lightest, simplest and most abundant member of the family of chemical elements in the universe.
  • But a colour green prefixed to it makes hydrogen the “fuel of the future”.
  • The ‘green’ depends on how the electricity is generated to obtain the hydrogen, which does not emit greenhouse gas when burned.
  • Green hydrogen is produced through electrolysis using renewable sources of energy such as solar, wind or hydel power.
  • Hydrogen can be ‘grey’ and ‘blue’ too.
    • Grey hydrogen is generated through fossil fuels such as coal and gas and currently accounts for 95% of the total production in South Asia.
    • Blue hydrogen, too, is produced using electricity generated by burning fossil fuels but with technologies to prevent the carbon released in the process from entering the atmosphere.
  • Other types
    • Brown hydrogen is produced using coal where the emissions are released to the air.
    • Pink hydrogen is generated through electrolysis powered by nuclear energy. Nuclear-produced hydrogen can also be referred to as purple hydrogen or red hydrogen.
    • Turquoise hydrogen is made using a process called methane pyrolysis to produce hydrogen and solid carbon. In the future, turquoise hydrogen may be valued as a low-emission hydrogen, dependent on the thermal process being powered with renewable energy and the carbon being permanently stored or used.
    • Yellow hydrogen is a relatively new phrase for hydrogen made through electrolysis using solar power.
    • White hydrogen is a naturally-occurring geological hydrogen found in underground deposits and created through fracking.

How much green hydrogen is India producing?

  • India has just begun to generate green hydrogen with the objective of raising non-fossil energy capacity to 500 gigawatts by 2030.
  • It was on April 20, 2022 that the public sector OIL, which is headquartered in eastern Assam’s Duliajan, set up India’s first 99.99% pure green hydrogen pilot plant in keeping with the goal of “making the country ready for the pilot-scale production of hydrogen and its use in various applications” while “research and development efforts are ongoing for a reduction in the cost of production, storage and the transportation” of hydrogen.
  • The plant was set up at the petroleum exploration major’s Jorhat pump station, also in eastern Assam.
  • Powered by a 500 KW solar plant, the green hydrogen unit has an installed capacity to produce 10 kg of hydrogen per day and scale it up to 30 kg per day.

What are the advantages of hydrogen as a fuel?

  • The intermittent nature of renewable energy, especially wind, leads to grid instability.
  • Green hydrogen can be stored for long periods of time.
  • The stored hydrogen can be used to produce electricity using fuel cells.
  • In a fuel cell, a device that converts the energy of a chemical into electricity, hydrogen gas reacts with oxygen to produce electricity and water vapour.
  • Hydrogen, thus, can act as an energy storage device and contribute to grid stability.
  • The oxygen, produced as a by-product (8 kg of oxygen is produced per 1 kg of hydrogen), can also be monetised by using it for industrial and medical applications or for enriching the environment.
  • The possibilities of hydrogen have made many countries pledge investments with Portugal having unveiled a national hydrogen strategy worth $7.7 billion in May.
  • Renewable developers see green hydrogen as an emerging market and some have targeted the transport sector, although electric vehicles have begun to catch the imagination of consumers today.

Dark Side of green hydrogen

  • Hydrogen’s true colours Green hydrogen is essential for decarbonisation: to replace fossil fuels in steelmaking, ammonia production for fertilisers and possibly shipping and trucking – processes which are difficult to electrify.
  • Some green hydrogen is crosshatched with dirtier hues. So it’s not simply that in its production a lot of energy is wasted in the double transformation from electricity to gas and then fuel.
  • But burning hydrogen also emits nitrogen oxides, air pollutants linked to respiratory illnesses and acid rain.
  • If green hydrogen production is scaled up to play a significant economic role by 2050, its freshwater demand will exceed one-quarter of today’s global annual consumption, risking water scarcity in some regions.
  • Above all, hydrogen is meaningfully green only if the renewable energy that generates it cannot be fed into the grid to replace power from gas or coal plants.
  • Blue hydrogen relies on a similar – but much more harmful – trick of the light. 
  • During sunny or windy spells, a glut of renewable energy generation can slash electricity prices, freeing them from the grip of natural gas prices for a few hours at a time.
  • This is often not enough to justify investments in the electrolysers which produce green hydrogen. Green hydrogen won’t gain the necessary price advantage over blue hydrogen and fossil gas until electricity markets are restructured.

Way Forward

  • For hydrogen to be true blue, the emissions must be captured and securely stored (CCUS).
  • Tackling this stalling operation requires public policy.
  • Governments will need to regulate or tax carbon out of the market while simultaneously ramping up renewables.
  • The approach to electricity pricing also needs to shift, to decouple the prices of electricity generated from renewables and fossil gas.
  • The marginal pricing system hugely benefits renewable project owners, since they profit from high electricity prices and effectively zero input costs.
  • An alternative market structure would set rewards for generators according to their average costs plus a slight surplus which could be reinvested into deploying more renewables and other green technologies, providing consumers with cheap electricity. This can only be achieved through a robustly regulated market or by nationalising energy companies and setting prices and production.


  • In any future energy system, hydrogen will have a role. But its expansion must be carefully designed, to prevent the promise of green hydrogen disguising the risks of its blue and grey cousins.


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