Hydrogen and bioenergy

Prelims and MainsAdded 20 September

Hydrogen has to be made, and the colours are a shorthand for how. Grey, nearly all of today's supply, comes from natural gas reacted with steam, releasing roughly 10 kilograms of carbon dioxide per kilogram of hydrogen. Blue is the same with the carbon dioxide captured. Green is made by electrolysis of water on renewable electricity, with no carbon dioxide at the point of production. Brown and black come from coal, pink from nuclear electricity, turquoise from methane pyrolysis, white from rock. India's rule for what counts as green is an emissions limit, not a route: at most 2 kilograms of carbon dioxide equivalent per kilogram of hydrogen, well to gate.

• Emissions by route, on the accounting of the International Energy Agency (IEA): grey about 10 to 12 kg CO2e per kg at the plant and 10 to 14 once upstream methane is counted; coal about 22 to 26, roughly double gas; green near zero. The first market for green hydrogen is replacing the grey hydrogen refineries and fertiliser plants already use. The IEA is moving from colours to measured intensity, which is the Mains point: a colour says nothing about actual emissions.
• Two electrolyser types: alkaline, cheaper and more mature, and proton exchange membrane, more compact and better at following variable wind and solar. India's Strategic Interventions for Green Hydrogen Transition (SIGHT) programme funds electrolyser manufacturing regardless of type, 3,000 MW a year allocated so far, with a carve out for indigenous technology.
• India's standard, set by MNRE on 18 August 2023, is the 2 kg limit above, with the scope defined separately for the electrolysis and biomass routes; matching standards followed for green ammonia and green methanol.
• Demand today is grey and sits in refineries and fertiliser: about 5 million tonnes a year in the mission document, almost 6 million on NITI Aayog's 2020 basis. The National Green Hydrogen Mission, approved on 4 January 2023 with Rs 19,744 crore, targets at least 5 million tonnes a year of production capacity by 2030 with about 125 GW of added renewable capacity; the 60 to 100 GW of electrolysers often quoted is a ministerial estimate, not a mission target.
• Cost is the barrier: green hydrogen in India runs at three to four times grey, Rs 300 to 400 per kg in 2025 against a target of Rs 100. A consumption obligation is enabled by the mission but not notified, so demand rests on public sector procurement; the order of use is refining and ammonia first, then steel by direct reduction, then shipping and aviation, and road transport last.

Mains: Green hydrogen is a way to store and move renewable electricity as a fuel; it is worth making only where the electricity is cheap and the alternative is fossil hydrogen already in use, which is why refineries and fertiliser come first and road vehicles last.

See also: National Green Hydrogen Mission · Photocatalytic water splitting · Hydrogen fuel cell train · Steelmaking routes · Coal gasification

Prelims and Mains

Compressed biogas comes from rot rather than from fermentation, and from material nobody wants to eat. Bacteria break down wet organic matter without oxygen, in the anaerobic digestion that gives off a gas of mostly methane and carbon dioxide.

• Stripping out the carbon dioxide and the other impurities leaves almost pure methane, chemically what natural gas is.
• It can therefore be blended into the compressed natural gas (CNG) sold to vehicles and into the gas piped to homes.
• The feedstock is non-food material: crop residue, cattle dung, press mud from sugar mills and municipal organic waste.
• Crop residue otherwise burnt in the field becomes a feedstock with a buyer, which is the link to stubble burning.
• The binding constraint is the collection chain, in harvest windows, storage and the distance the material can be carried.

Prelims and Mains

A gas made from waste is only worth making if somebody is obliged to buy it at a price that covers the plant. GOBARdhan is the scheme that arranges both, and gathers a scattered effort under one ministry.

• The Cabinet approved GOBARdhan, the National Circular Bioenergy Scheme, at ₹23,731 crore to 2035-36, to raise compressed biogas output almost tenfold.
• It gathers programmes spread across four ministries under the Ministry of Petroleum and Natural Gas.
• GOBARdhan itself began in 2018 under the Swachh Bharat Mission (Grameen), and supply was first sought through SATAT (Sustainable Alternative Towards Affordable Transportation), which left more than 200 plants running.
• City gas distributors must blend compressed biogas at 3 per cent in 2026-27, 4 per cent in 2027-28 and 5 per cent from 2028-29.
• An administered price of ₹2,110 per million British thermal units (MMBtu) is fixed for at least ten years, alongside capital subsidies and pipeline support.
• The government says the revised offtake framework has no material price impact and lets plants operate sustainably.
• Every unit blended is natural gas India does not import, which is the energy security argument for the scheme.

Background reading: PIB, 6 Aug 2026: Cabinet approves GOBARdhan, the National Circular Bioenergy Scheme (opens in a new tab)

Prelims and Mains

Green hydrogen is worth a mission because hydrogen is already an industrial raw material, made today from fossil gas. The Mission is the money and the architecture India has put behind making it from water instead.

• The Mission, approved in 2023 and run by the Ministry of New and Renewable Energy (MNRE), targets 5 million tonnes of green hydrogen a year by 2030.
• Electrolysis passes electricity through water to separate hydrogen from oxygen, and is the route the Mission's money is built around.
• SIGHT, Strategic Interventions for Green Hydrogen Transition, is the Mission's incentive arm, and pays separately for making electrolysers and for making hydrogen.
• Hydrogen production is awarded in modes, and Mode-2B is the route under which refineries are allotted capacity.

Background reading: PIB, 11 Aug 2026: Green hydrogen in refineries, battery storage and EV schemes (opens in a new tab)

Prelims and Mains

Electrolysis has to be given electricity before it can split anything, and that electricity is most of the cost. Photocatalysis skips the step: a photocatalyst absorbs sunlight and uses that energy directly to pull the water molecule apart.

• The catalyst has to separate the charges that light creates before they recombine, which is what limits the yield.
• Most photocatalysts that work are built on costly inorganic semiconductors or on precious metals, so the cost sits in the catalyst.
• The Centre for Nano and Soft Matter Sciences (CeNS), Bengaluru, has made a metal-free organic photocatalyst for splitting water with sunlight.
• It pairs aspartic acid, an amino acid, with perylene diimide, a light absorbing organic molecule, in place of a precious metal.
• In water the pair self-assembles into two dimensional nanosheets, which give nearly 18 per cent more photocurrent than the bulk form.

Mains

India's first hydrogen train runs between Jind and Sonipat in Haryana on proton exchange membrane fuel cells, which combine hydrogen with oxygen from the air to make electricity and leave only water vapour and heat.