Hydrogen and bioenergy

Prelims and Mains

Every litre of petrol sold in India has been one fifth ethanol since April, when the last unblended pump ran dry. Five months on, the argument is over what the blend saves and what it costs in water, in food and at the fuel gauge.

• Since 1 April 2026 all petrol sold in India must be E20 with a minimum Research Octane Number (RON) of 95, and unblended petrol is no longer sold.
• Ethanol is made by fermenting sugars, whether from sugarcane juice or from the starch of maize and rice, and is blended into petrol.
• Blending began as a pilot in 2001, reached 10 per cent in 2021-22 and 19.2 per cent in 2024-25, and hit 20 per cent in 2025-26.
• A blending mandate fixes the percentage the seller must blend, which creates demand a costlier fuel could not win on price.
• A first-generation biofuel is made from a food crop, so it competes for land, water and the plate.
• Maize supplies about 45 per cent of this year's blending ethanol, rice from the Food Corporation of India 22 per cent and sugarcane juice 16 per cent.
• Government estimates put E20 above petrol in cost while crude is below about $70 a barrel, so buyers lose mileage with no lower price for it.
• The Chief Economic Adviser would hold at E20 until the food versus fuel trade-off has been costed.
• The remedy urged is to count blue water and life-cycle emissions feedstock by feedstock, and to move to second-generation ethanol.

Background reading: The Indian Express, 23 Aug 2026: E20 can save India money. Why doesn't the consumer see the benefit? (opens in a new tab)

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.