Science and Technology › Energy technology
हिन्दी — Read in HindiHydrogen and bioenergy
Fuel cells, ethanol blending and its feedstock, biogas, and aviation fuel made from biomass. Prelims has asked about the raw materials allowed under the National Policy on Biofuels and how green hydrogen is produced.
Foundation note: The colours of hydrogen
UPSC has asked
- Prelims 2025: battery electric and fuel cell vehicles as alternative powertrains
- Prelims 2023: uses of green hydrogen as fuel and in fuel cells
- Prelims 2020: raw materials allowed under the National Policy on Biofuels
Showing 3 of 6 articles, those that changed from 1 to 30 June 2026.Show all
Hydrogen from nuclear heat: the copper chlorine cycle
Copy link to Hydrogen from nuclear heat: the copper chlorine cyclePrelims
The copper chlorine cycle is a thermochemical cycle that splits water using heat rather than electricity.
- It is considered promising because it runs at relatively lower temperatures with higher thermodynamic efficiency.
- Using nuclear process heat avoids the fossil fuel use and emissions of conventional hydrogen production and extends nuclear energy to non electric uses.
- The Fast Breeder Test Reactor at the Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, is India's only operating fast reactor research facility.
What changed
26 Jun 2026BriefThe Department of Atomic Energy inaugurated at Kalpakkam on 26 June a technology demonstrator of the Bhabha Atomic Research Centre's indigenous copper chlorine process using process heat from the Fast Breeder Test Reactor, described as the world's first such facility. PIB, 26 Jun 2026: DAE Inaugurates World's First Hydrogen Production Facility Based on Copper–Chlorine Thermochemical Cycle Using Nuclear Heat from Fast Breeder Test Reactor (opens in a new tab)
See also: The Prototype Fast Breeder Reactor
Biofuels
Compressed biogas
Copy link to Compressed biogasPrelims and Mains
Compressed biogas is the gas of anaerobic digestion, in which bacteria break down wet organic matter without oxygen, stripped of its carbon dioxide and other impurities to leave almost pure methane.
- It is chemically what natural gas is, so it can 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.
What changed
13 Jun 2026BriefA Harohalli plant turns Bengaluru wet waste into compressed biogas, and in April its gas entered the GAIL pipeline for the first time. Mains: Biogas needs a sustained price signal, as solar had, to attract investment; India's target of 5,000 plants compares with Germany's 9,000. The Indian Express, 13 Jun 2026: 50 tonnes in, 1 tonne out: Bengaluru startup turns city garbage into green energy amid LPG crisis (opens in a new tab) · The Hindu, 3 Jun 2026: Can kitchen waste replace LPG? This Indian startup thinks so (opens in a new tab)
Green hydrogen
National Green Hydrogen Mission
Copy link to National Green Hydrogen MissionPrelims and Mains
- Green hydrogen
- Hydrogen made by splitting water with electricity from renewable sources, so the making of it releases no carbon dioxide, unlike hydrogen reformed from natural gas.
The National Green Hydrogen Mission is the money and the architecture India has put behind making hydrogen from water instead of fossil gas.
- Green hydrogen matters because hydrogen is already an industrial raw material, made today from fossil gas.
- 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.
- Twelve pilot projects in road transport try both fuel cells and hydrogen internal combustion engines.
The Mission's value chain
Renewable power
Dedicated renewable capacity supplies the electricity
Electrolysers
Domestically made electrolysers split water, with incentives for manufacturing
Green hydrogen
Production capacity supported under the SIGHT incentives
Certification: The Green Hydrogen Certification Scheme certifies the hydrogen as green across the chain, through its portal launched in June 2026
Uses
Refineries, fertiliser through green ammonia, steel and mobility
What changed
17 Jun 2026
- The Ministry of New and Renewable Energy launched the Green Hydrogen Certification Portal of India on 17 June for certification and compliance under the Green Hydrogen Certification Scheme.
- Standards for green ammonia and green methanol are finalised, and 6.7 lakh tonnes a year of green ammonia is contracted for fertiliser plants.
Background reading: PIB, 29 Jul 2026: Centre Launches 12 Pilot Projects Under National Green Hydrogen Mission for Deployment of 70 Hydrogen-Powered Vehicles Across 21 Routes (opens in a new tab)
UPSC has asked
- Prelims 2026: how green hydrogen is produced and the Mission's 2030 target
Further reading: National Green Hydrogen Mission (MNRE)
- E20
- Petrol blended with 20 per cent anhydrous ethanol by volume. The number is the ethanol share, so E20 (20 per cent) is a stronger blend than E10 (10 per cent).
- second generation ethanol
- Ethanol made from non-food biomass such as crop stubble or bagasse, by breaking down cellulose, so it does not compete with the food plate.
- carburettor
- An older fuel mixing device that cannot sense the extra oxygen ethanol brings and adjust for it, so the engine runs lean, with too little fuel for the air it draws in.
- Flex fuel vehicle
- A vehicle that runs on any ethanol petrol blend from E20 to E100.