Energy Resources of India: Conventional and Non-conventional

1. Energy and its classification: conventional and non-conventional sources

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• Every activity needs energy: cooking, light, heat, transport and machines. Electricity use per person is treated as a sign of development (Class 10).
• Fossil fuel: coal, petroleum and natural gas. They formed from buried plant and animal remains over geological time. They are exhaustible organic non-metallic minerals and the main source of CO2.
• Classification of energy resources (Class 10):

Conventional energy sources	Non-conventional energy sources
Firewood, cattle dung cake, coal, petroleum, natural gas, electricity (hydel and thermal)	Solar, wind, tidal, geothermal, biogas, atomic energy
Exhaustible and polluting	Renewable, more evenly spread, eco-friendly, cheaper once set up

• Trap: Class 12 calls nuclear minerals conventional (exhaustible) but discusses them under the non-conventional heading. Class 10 lists atomic energy as non-conventional.
• Firewood and dung cake meet over 70 per cent of rural household energy needs (Class 10 estimate). Forests are shrinking, and burning dung wastes manure. LPG under PM Ujjwala Yojana (2016) is the alternative, but clean cooking is still not universal (verify current).
• Energy security is a worry because India imports most of its crude oil and much of its gas and coking coal.

2. Coal: formation, grades and the Gondwana-Tertiary divide

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• Coal forms when plant material is pressed together over millions of years. Its grade depends on how hard it was pressed, how deep it was buried and for how long.
• Grades, from lowest to highest carbon:
• Peat: decaying swamp plants. Low carbon, high moisture, little heat.
• Lignite: soft brown coal with high moisture.
• Bituminous coal: buried deep at higher temperatures. It is the most common commercial coal.

• Anthracite: the best hard coal and almost smokeless. India has very little of it, mainly in Jammu and Kashmir.

• Coking coal (metallurgical coal) is high-grade bituminous coal that turns into coke for blast furnaces. It is scarce in India (mainly Jharia), and much of it is imported, chiefly from Australia (verify current).

• Gondwana coal is about 250–300 million years old (Class 10: "a little over 200 million"). It makes up about 98 per cent of reserves and is mostly bituminous. About 80 per cent of Indian coal is non-coking. Ash content is high, often 30–45 per cent.
• Tertiary coal is about 15–60 million years old (Class 10: about 55 million). It has less carbon and more sulphur. Fields: Darangiri, Cherrapunji, Mewlong and Langrin (Meghalaya); Makum, Jaipur and Nazira (upper Assam); Namchik-Namphuk (Arunachal Pradesh); Kalakot (Jammu and Kashmir). Rat-hole mining (narrow family-dug tunnels) at Jowai and Cherrapunjee was banned by the NGT in 2014.
• Lignite is found in Tamil Nadu, Puducherry, Gujarat (Kutch, Bhavnagar), Rajasthan (Barmer, Bikaner) and Jammu and Kashmir. Neyveli lignite (Cuddalore district, Tamil Nadu) is the largest deposit. NLC India mines it for pithead power stations, and it is the only notable fuel in the south-western mineral belt.

3. Coalfields: distribution, problems and the future of coal

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• Coal reserves distribution: over 97 per cent of reserves lie in the Damodar, Sone, Mahanadi and Godavari valleys (Class 10 adds the Wardha). Odisha, Jharkhand and Chhattisgarh hold about 70 per cent (verify current).
• Damodar valley (Jharkhand–West Bengal):
• Jharia coalfield (Dhanbad): the largest coalfield and the main source of coking coal.
• Raniganj coalfield (West Bengal): the second largest and the oldest, mined since 1774. It feeds the Durgapur–Asansol industries.

• Bokaro, Giridih and Karanpura.

• Other fields: Singrauli coalfield (Madhya Pradesh–Uttar Pradesh border), called the "energy capital" for its pithead plants such as NTPC Vindhyachal. Also Korba (Chhattisgarh), Talcher and Ib valley/Rampur (Odisha), Chanda–Wardha, Kamptee and Bander (Maharashtra), Singareni (Telangana) and Pandur (Andhra Pradesh).

• Why plants sit on coalfields: coal is bulky and turns to ash when burnt, so it loses weight. Steel mills and thermal plants therefore cluster on the north-eastern plateau.
• Problems: fires have burnt under Jharia since about 1916, and people are being moved under the Jharia Master Plan (2009, revised 2025). Miners face unsafe pits, methane blasts and lung disease. Hasdeo Arand coalfield (north Chhattisgarh) lies under dense sal forest that is an elephant corridor and home to Gond villages. Mining there for Rajasthan's state power company has faced long protests.
• Beyond NCERT: output passed 1 billion tonnes in 2024-25. Coal India produces most of it, and commercial auctions of coal blocks began in 2020 (verify current).
• Coal-bed methane is gas drawn out of coal seams. The first commercial output came from Raniganj in 2007.
• Coal gasification turns coal into syngas. The National Coal Gasification Mission aims to gasify 100 million tonnes by 2030.

4. Petroleum: occurrence, oilfields, refineries and reserves

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• Petroleum is a mix of liquid and gaseous hydrocarbons found in Tertiary sedimentary rocks. It is called "liquid gold" because it is scarce and has many uses: fuel for vehicles, trains and aircraft, plus fertiliser, synthetic rubber and fibre, medicines and wax. Refineries are a "nodal industry" (Class 10), meaning many other industries depend on them.
• Anticline trap: oil collects at the top of an upfold in porous limestone or sandstone. Non-porous layers seal it, and gas sits above the oil. Fault traps form where porous and non-porous rocks meet along a fault.
• The Oil and Natural Gas Commission was set up in 1956 (a corporation since 1994). Before 1956, the Digboi oilfield (Assam, oil struck 1889) was the only producing area. Digboi also has Asia's oldest working refinery (1901).
• Assam: Digboi, Naharkatiya oilfield (1953) and Moran-Hugrijan.
• Gujarat (Cambay basin): Ankleshwar (1960, the most important), Kalol, Mehsana, Nawagam, Kosamba and Lunej.
• Mumbai High: about 160 km offshore in the Arabian Sea. Found in 1974 (NCERT: 1973), producing since 1976. It is India's largest offshore field.
• Barmer oil fields (Rajasthan): Mangala, found by Cairn in 2004. HPCL's refinery is at Pachpadra. The Krishna-Godavari basin and Kaveri basin are the main east-coast sources.
• Field-based and market-based refineries: Digboi stands near its oilfield. Barauni, Mathura and Panipat stand near markets and get crude by pipeline. India imports about 85–88 per cent of its crude but is a net exporter of petroleum products (verify current).
• Strategic Petroleum Reserve (ISPRL): underground rock caverns holding 5.33 million tonnes at Visakhapatnam, Mangaluru and Padur. Phase II is planned at Chandikhol (Odisha) and Padur (verify current).

5. Natural gas and the national gas grid

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• Natural gas is found with petroleum and comes out when crude is brought up. It is used for power, industrial heat, fertilisers (urea) and petrochemicals.
• City gas distribution networks supply CNG to vehicles and PNG (piped gas) to homes.
• Reserves: Mumbai High and allied west-coast fields (Bassein), the Cambay basin, and the KG basin (deep-water KG-D6, producing since 2009).
• Pipelines: GAIL's 1,700 km Hazira–Vijaipur–Jagdishpur (HVJ) line was the first trunk pipeline. It carried Mumbai High gas to fertiliser and power plants in the west and north.
• National Gas Grid ("One Nation One Grid") will link all gas sources and markets, including the North-East. The network grew from 1,700 km to 18,500 km (Class 10). About 25,900 km was operational in 2025 and about 34,000 km is authorised (verify current).
• Pradhan Mantri Urja Ganga (about 3,300 km, Jagdishpur–Haldia–Bokaro–Dhamra) brings gas to eastern India. The Indradhanush grid links the eight NE states (verify current).
• Beyond NCERT: India aims for a 15 per cent gas share in its energy mix by 2030. About half of its gas is imported as LNG through Dahej, Hazira, Dabhol, Kochi, Ennore and Mundra (verify current).
• Gas hydrates are ice-like solids holding methane in seabed sediments. Expeditions NGHP-01 (2006) and NGHP-02 (2015) found rich deposits in the KG basin, but they are not yet mined commercially.

6. Electricity: thermal and hydel power

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• Electricity comes from running water (hydel) or from burning coal, oil or gas (thermal). Once made, it is exactly the same (Class 10).
• Thermal power is non-renewable and polluting, but it is India's main source.
• Pithead plants sit on coalfields: Singrauli, Korba, Talcher, Neyveli.
• Port-based plants burn imported coal: Mundra, Krishnapatnam.

• Coal still produces about three-quarters of India's electricity (verify current).

• Hydroelectric power comes from fast-flowing water turning turbines. It is renewable and clean to run, but it displaces people and traps sediment. Examples are multipurpose projects such as Bhakra Nangal, the Damodar Valley Corporation and Kopili (Assam). Most untapped potential is in Himalayan rivers; Arunachal Pradesh has the largest share. Large hydro was declared renewable in 2019.

• Subansiri Lower Hydroelectric Project (2,000 MW, NHPC) lies on the Arunachal–Assam border. It is India's largest hydro project, and its units began running from 2024 after years of protests downstream (verify current).
• Pumped storage hydropower works like a giant battery:
• Water is pumped uphill when power is cheap or solar is plentiful.
• At peak demand, it flows down through turbines.

• New projects are planned in the Western Ghats, Andhra Pradesh and elsewhere (verify current).

• Hydel essay frame (Class 12 exercise): potential, Himalayan versus Peninsular spread, and limits (earthquakes, glacial lake outburst floods or GLOFs, resettling displaced people, shared rivers).

7. Nuclear energy: minerals, power stations and the three-stage programme

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• Nuclear energy is released when atoms of uranium or thorium split (fission).
• Uranium occurs in Dharwar rocks along the Singhbhum copper belt (Jaduguda, Jharkhand; first mine 1967). Other sources are Udaipur, Alwar and Jhunjhunu (Rajasthan), Durg (Chhattisgarh), Bhandara (Maharashtra), Kullu (Himachal Pradesh) and the large Tummalapalle deposit (Andhra Pradesh). India has little uranium and imports it; the 2008 NSG waiver allowed these imports.
• Thorium comes from monazite and ilmenite in beach sands of Kerala (Palakkad and Kollam), Tamil Nadu, near Visakhapatnam and the Mahanadi delta. India has among the world's largest reserves.
• Institutions: Atomic Energy Commission (1948). The Bhabha Atomic Research Centre (Trombay) began in 1954 and was renamed in 1967.
• Stations:
• Tarapur Atomic Power Station (Maharashtra): the first, 1969, with US-built boiling water reactors.
• Others: Rawatbhata (Rajasthan), Kalpakkam (Tamil Nadu), Narora (Uttar Pradesh), Kaiga (Karnataka), Kakrapar (Gujarat).
• Kudankulam Nuclear Power Plant (Tirunelveli, Tamil Nadu): Russian VVER-1000 reactors. Units 1 and 2 run since 2013 and 2016, and four more are being built.
• Jaitapur nuclear project (Ratnagiri, Maharashtra): six planned French EPRs, stalled.
• Installed nuclear capacity is about 8.8 GW (verify current).

Three-stage nuclear power programme (Homi Bhabha, 1950s)	Reactor	Fuel
Stage 1	Pressurised heavy water reactor (heavy water slows the reaction and carries away heat; first indigenous 700 MWe units at Kakrapar, 2023)	Natural uranium
Stage 2	Fast breeder: the Prototype Fast Breeder Reactor (500 MWe, sodium-cooled, Kalpakkam, BHAVINI; core loading began March 2024, verify current)	Plutonium
Stage 3	Thorium reactors	U-233 made from thorium

• Nuclear Energy Mission (Budget 2025-26) targets 100 GW by 2047. It sets aside ₹20,000 crore for small modular reactors (up to about 300 MWe, made from factory-built modules) and aims for at least five indigenous ones by 2033. Bharat Small Reactors are based on the 220 MWe PHWR. A 2025 law opens civil nuclear power to private firms (verify current).

8. Solar energy: potential, parks and schemes

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• Solar energy is captured in two ways:
• Photovoltaic cells turn sunlight directly into electricity.

• Solar thermal technology uses the heat for water heaters, crop dryers and cookers.

• India is tropical, with about 300 clear days in much of the country. Rajasthan and Gujarat have the most potential (Class 12). Solar is spreading in rural areas and cutting the use of firewood and dung (Class 10).

• Trap: Class 12 says solar is "7 per cent more effective than coal or oil". This is an odd textbook line, so do not build answers on it.
• The National Solar Mission began in 2010, and its target was raised to 100 GW in 2015. Solar is now the largest renewable source, at over 100 GW (verify current).
• Solar parks:
• Bhadla Solar Park: about 2,245 MW on some 5,700 ha in Jodhpur district (Thar).
• Pavagada (Karnataka), Kurnool (Andhra Pradesh), Rewa (Madhya Pradesh).

• Khavda Renewable Energy Park (Rann of Kutch, Gujarat): solar plus wind, about 30 GW over 538 sq km. It is set to be the world's largest renewable plant (verify current).

• Floating solar saves land and cuts evaporation from reservoirs. Examples: Omkareshwar on the Narmada (Madhya Pradesh) and NTPC Ramagundam (Telangana).

• Schemes:
• PM-KUSUM (2019): solar pumps and small plants on barren or farm land.

• PM Surya Ghar Muft Bijli Yojana (February 2024, ₹75,021 crore): rooftop solar for 1 crore homes, with up to 300 free units a month.

• Limits: land; power lines that kill the Great Indian Bustard (Supreme Court orders since 2021); imported modules (a PLI scheme now backs local manufacturing); storage and grid stability (verify current).

9. Wind, tidal, ocean and geothermal energy

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• Wind energy is pollution-free. Turbines turn the moving energy of wind into electricity. Trade winds, westerlies, monsoon winds and land and sea breezes can all be used (Class 12).
• The largest cluster runs from Nagercoil to Madurai in Tamil Nadu. Muppandal gets winds funnelled through the Aralvaimozhi gap.
• Jaisalmer is also well known. Gujarat, Maharashtra and Karnataka are major states.

• India has the world's fourth-largest wind capacity, led by Gujarat and Tamil Nadu (verify current).

• Offshore wind energy uses turbines at sea, where winds are stronger and steadier. The target is 30 GW by 2030, with zones off Gujarat and Tamil Nadu. Viability gap funding was approved in 2024 (verify current).

• Tidal energy works in three steps:
• A floodgate dam is built across an inlet.
• High-tide water flows in and is trapped.
• As the tide falls, the water flows back to the sea through turbines.

• The best sites are the Gulfs of Khambhat and Kachchh (Gujarat) and the Sundarbans (West Bengal). No large plant has been built yet.

• Ocean thermal energy conversion uses the gap of about 20°C between warm surface water and cold deep water. NIOT is building a demonstration plant at Kavaratti (Lakshadweep).

• Geothermal energy works where the ground heats up quickly with depth (a high geothermal gradient):
• Groundwater absorbs heat from hot rocks.
• It rises to the surface as steam.
• The steam drives turbines.
• Experimental sites are Manikaran in the Parvati valley (Himachal Pradesh) and Puga valley (Ladakh, ONGC drilling). Tattapani (Chhattisgarh) is another hot-spring site. India has several hundred hot springs, and a geothermal policy was notified in 2025 (verify current).
• The first successful use was in Boise, Idaho (USA), in 1890 (Class 12).

10. Bio-energy, biogas and biofuels

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• Bio-energy comes from crop residues and from city, industrial and other wastes. It can become electricity, heat or cooking gas. It gets rid of waste, raises rural incomes, cuts pollution and reduces pressure on fuelwood. Example: the Okhla waste-to-energy plant in Delhi, which faces local complaints about emissions (Class 12).
• Biogas works like this:
• Shrubs, farm waste and animal and human waste rot.
• The rotting gives off gas that is mostly methane.
• This gas gives more heat than kerosene, dung cake or charcoal.

• Plants run at municipal, cooperative and household levels.

• Gobar gas plants run on cattle dung. They give the farmer both fuel and better manure, which makes them the most efficient use of dung (Class 10).

• Compressed biogas is purified biogas sold as vehicle and industrial fuel. It is promoted under SATAT (2018) with a target of 5,000 plants; GOBARdhan (2018) backs village biogas (verify current).
• Ethanol blending means mixing ethanol into petrol under the National Policy on Biofuels (2018, amended 2022).
• Ethanol comes from molasses, cane juice, damaged grains and maize.
• E20 (20 per cent blending) was reached in 2025, ahead of the original 2030 target (verify current).

• Second-generation ethanol is made from crop residue at IOCL Panipat (2022).

• Trade-offs: sugarcane needs a lot of water, maize gets diverted from animal feed (the food-versus-fuel debate), and older vehicles may not handle high blends.

11. Energy transition: green hydrogen, grids, targets, the International Solar Alliance and conservation

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• Green hydrogen is made by splitting water (electrolysis) using renewable power. Grey hydrogen is made from natural gas. India's 2023 standard caps emissions at 2 kg CO2 per kg of hydrogen.
• National Green Hydrogen Mission (January 2023, ₹19,744 crore) aims for 5 million tonnes a year by 2030, backed by about 125 GW of renewables. It offers SIGHT incentives and plans hubs at ports such as Kandla, Paradip and Thoothukudi (verify current). Users would include refineries, fertiliser plants, steel and shipping.
• The Green Energy Corridor (2015) carries renewable power from Rajasthan, Gujarat, Tamil Nadu, Karnataka and other states into the national grid. A separate line will bring 13 GW from Ladakh.
• Targets:
• 500 GW of non-fossil capacity by 2030.
• Updated NDC (2022): 50 per cent non-fossil capacity and a 45 per cent cut in emission intensity from the 2005 level.

• Net zero by 2070.

• Non-fossil share of power capacity crossed 50 per cent in June 2025, five years early. Yet coal still makes about three-quarters of the electricity (verify current).

• Just energy transition means protecting coal workers and coal districts in Jharkhand, Chhattisgarh and Odisha through retraining, new industries and reuse of mine land. JETP funding (Just Energy Transition Partnerships) goes to South Africa, Indonesia and Vietnam, not India.
• International Solar Alliance was launched by India and France at COP21, Paris, on 30 November 2015. It is treaty-based with its headquarters in Gurugram, and all UN members could join from 2020. One Sun One World One Grid (India, 2018) proposes cross-border solar grids across time zones. It was launched with the UK as the Green Grids Initiative at COP26 (2021).
• Conservation: "energy saved is energy produced" (Class 10). NCERT says India is among the least energy-efficient countries. It urges public transport, switching off unused lights and fans, power-saving devices and recycling. Beyond NCERT: Energy Conservation Act 2001, the Bureau of Energy Efficiency (2002), star labels, the PAT scheme, UJALA LEDs (2015), and the 2022 amendment that allows carbon credit trading.

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Exam angles

Prelims — high-yield facts and traps

• Coal grades by carbon, lowest to highest: peat < lignite < bituminous < anthracite. Anthracite is mainly in Jammu and Kashmir. Neyveli lignite is in Tamil Nadu.
• Gondwana coal is about 98 per cent of reserves and is found in the Damodar, Sone, Mahanadi and Godavari valleys. Tertiary coal is in Meghalaya, Assam, Arunachal and Kalakot.
• Jharia is the largest coalfield and gives coking coal. Raniganj is the oldest (1774). "Most Indian coal is coking" is FALSE: about 80 per cent is non-coking.
• Oilfields: Digboi (1889, Assam), Naharkatiya (1953), Ankleshwar (1960, Gujarat), Mumbai High (1974; NCERT says 1973), Mangala (Barmer, 2004), KG-D6 (east coast).
• Digboi is a field-based refinery; Barauni, Mathura and Panipat are market-based.
• SPR caverns: Visakhapatnam, Mangaluru, Padur. Phase II: Chandikhol and Padur. In an anticline trap, gas lies above oil.
• Uranium: Jaduguda (Singhbhum) and Tummalapalle. Thorium: monazite beach sands of Kerala, Tamil Nadu, Andhra Pradesh and Odisha.
• Three stages: PHWR on natural uranium → fast breeder on plutonium (PFBR, Kalpakkam) → thorium and U-233.
• Nuclear stations by state: Tarapur (Maharashtra, first, 1969), Rawatbhata (Rajasthan), Kalpakkam and Kudankulam (Tamil Nadu), Narora (UP), Kaiga (Karnataka), Kakrapar (Gujarat). Jaitapur is planned in Maharashtra.
• Geothermal: Manikaran (HP), Puga (Ladakh), Tattapani (Chhattisgarh). Tidal: Khambhat, Kachchh, Sundarbans. OTEC: Kavaratti. Wind: Muppandal–Nagercoil and Jaisalmer.
• Solar parks: Bhadla (Rajasthan), Pavagada (Karnataka), Kurnool (AP), Rewa (MP), Khavda (Gujarat). Floating solar: Omkareshwar.
• Scheme years: PM-KUSUM 2019, PM Surya Ghar 2024, SATAT and GOBARdhan 2018, Biofuels Policy 2018 (amended 2022).
• ISA: COP21, 2015, India and France, HQ Gurugram. OSOWOG 2018, and the Green Grids Initiative at COP26.
• NGHM: 2023, 5 MMT by 2030. Green hydrogen limit: 2 kg CO2 per kg H2.
• Trap: "Atomic energy is conventional in both NCERT books" is FALSE. Class 10 lists it as non-conventional.

Mains — GS-I and GS-III themes

1. Spatial pattern of coal and why thermal and steel plants sit on coalfields (bulky coal that loses weight on burning).
2. "Coal will remain India's mainstay for decades": energy security against just transition and climate commitments.
3. Hydel power in India: potential, Himalayan versus Peninsular spread, and limits (earthquakes, GLOFs, displacement, downstream effects).
4. Why solar has a bright future in India, and its trade-offs: land, storage, grid, manufacturing, the Great Indian Bustard.
5. The thorium logic of the three-stage programme, and the role of SMRs and private firms.
6. Ethanol blending: energy security against water, food and land.
7. Where green hydrogen hubs will grow (ports, renewable-rich deserts) and why.

Current-affairs hooks

• CEA and MNRE capacity milestones: non-fossil share and progress toward 500 GW (verify current).
• Coal output records, block auctions, Hasdeo protests, Jharia rehabilitation.
• PFBR criticality, new PHWR units, the Nuclear Energy Mission, private nuclear players, Kudankulam and Jaitapur progress.
• Gas grid work in the North-East, LNG deals, city gas growth, KG basin output.
• Green hydrogen tenders and hubs; green steel pilots.
• ISA Assembly meetings and new members; NDC updates at COPs.
• Summer peak power demand and coal-stock alerts at power plants.