Energy Resources of India

India's Drainage Systems and Mineral Resources covers the country's metallic mineral belts, named iron and bauxite deposits, and the major-versus-minor minerals legal distinction. This note covers the other half of the same NCERT chapter: energy resources specifically, coal, petroleum and natural gas, shale gas, nuclear power and the renewable sources, the ground UPSC has already tested through a statement-based shale gas question and a coastal minerals question.

Energy minerals sit apart from metallic ores in one basic way: coal and petroleum are fossil fuels, formed from buried organic matter over geological time, so their location depends on where sedimentary basins of a particular age happen to sit, not on the crystalline rock that hosts iron or manganese. This is why India's coal and oil geography reads so differently from its metallic mineral belts, coal sits in old river valleys of the peninsula while petroleum sits almost entirely in younger coastal and offshore sedimentary basins.

Coal: two geological ages, two separate geographies

India's coal occurs in rocks of two distinct ages, and NCERT is explicit that this is the basic organising fact for the whole topic. About four fifths of Indian coal is of the bituminous type and is non-coking, meaning most of it is suited to power generation rather than to metallurgical coking use.

Gondwana coalfields supply the overwhelming bulk of the country's coal and sit in river valleys across the peninsular plateau, chiefly the Damodar valley, along with the Godavari, Mahanadi and Sone valleys. The Damodar valley alone forms the Jharkhand-Bengal coal belt, home to the country's best known named coalfields: Jharia (the single largest coalfield), Raniganj (the next largest), Bokaro, Giridih and Karanpura. Beyond this belt, the major coal mining centres worth remembering by state are Singrauli in Madhya Pradesh (part of a coalfield that straddles the Madhya Pradesh, Uttar Pradesh border), Korba in Chhattisgarh, Talcher and Rampur in Odisha, Chanda-Wardha and Kamptee in Maharashtra, and Singareni in Telangana. Because these deposits sit in Gondwana age rock, geologically far older than the Tertiary coal described below, they are structurally and chemically a different resource, not merely a different location.

Tertiary coalfields form the second, geologically much younger source, confined to the country's north-east: Assam, Arunachal Pradesh, Meghalaya and Nagaland. Named extraction sites include Cherrapunji, Darangiri, Mewlong and Langrin in Meghalaya, Makum, Jaipur and Nazira in upper Assam, Namchik-Namphuk in Arunachal Pradesh, and a further deposit at Kalakot in Jammu and Kashmir. This regional split, Gondwana coal dominating the peninsula versus Tertiary coal confined to the north-east, is exactly the kind of geography-plus-geology pairing UPSC likes to test through matching questions.

A third, smaller category is lignite (brown coal), a lower grade coal found in younger, softer deposits along coastal tracts rather than in the Gondwana river valleys or the north-eastern hills. India's lignite occurs in the coastal areas of Tamil Nadu, Puducherry, Gujarat and Jammu and Kashmir, with Tamil Nadu's Neyveli deposit the country's best known lignite mining centre, feeding a dedicated lignite based power complex rather than the thermal plants that run on Gondwana coal.

Petroleum and natural gas: from a single Assam field to three coastlines

Crude petroleum in India occurs in sedimentary rocks of the Tertiary period, a geologically recent formation compared with the Gondwana coal belt. Organised exploration effectively began only after the Oil and Natural Gas Commission was set up in 1956; before that, Digboi in Assam had been the country's only significant producing region for decades. The picture changed substantially once exploration widened to the country's western and eastern margins.

Assam remains a genuine onshore producer beyond Digboi, with Naharkatiya and Moran as the other established fields in the state. Gujarat built up a cluster of onshore fields associated with the Cambay basin: Ankleshwar, Kalol, Mehsana, Nawagam and Lunej are the names worth retaining, since UPSC has a habit of testing whether a candidate can place a named oilfield in its correct state.

The bigger shift, though, was offshore. Mumbai High, roughly 160 kilometres off the coast of Mumbai, was discovered in 1973 and began production in 1976; it remains the anchor of India's offshore output and sits within the broader Bombay basin. On the east coast, exploratory drilling later opened up two further offshore basins, the Krishna-Godavari basin off Andhra Pradesh and the Cauvery basin off Tamil Nadu, both of which have since yielded both oil and gas finds and continue to see fresh exploration activity by ONGC and private operators. Natural gas typically occurs alongside petroleum rather than as an independent deposit, and India's largest reserves sit in the Mumbai High region and its neighbouring fields, supplemented by finds in the Cambay basin onshore and, more recently, by discoveries in the Krishna-Godavari basin on the east coast.

Crude extracted from a well is not usable directly and must pass through a refinery. India runs two structurally different kinds: a field-based refinery built at the site of production itself, of which Digboi is the classic example, and a market-based refinery built instead near the point of consumption or export, connected to crude sources by pipeline or tanker, of which Barauni in Bihar is the standard textbook example. Most of India's refining capacity added since independence follows the market-based model, visible in the spread of refineries far from any oilfield, at Mathura, Panipat, Bina, Haldia and several coastal cities.

Shale gas: the basin geography UPSC has already tested directly

Shale gas is natural gas trapped within fine grained shale rock rather than in the porous reservoir rock that yields conventional gas, and extracting it needs hydraulic fracturing rather than a simple well. India's Ministry of Petroleum and Natural Gas has flagged several sedimentary basins as carrying shale gas and shale oil potential, based on separate assessments run at different times by the US Geological Survey, by ONGC and by the Central Mine Planning and Design Institute. The basins that recur across these assessments, and that UPSC has already drawn a question from, are the Cambay basin in Gujarat, the Krishna-Godavari basin on the east coast, and the Cauvery basin further south, with the Damodar Valley basin in the east also showing shale potential linked to its established Gondwana coal geology. A national policy issued in October 2013 assigned the right to explore and develop shale gas and oil within existing nomination-regime blocks to the national oil companies, meaning ONGC and Oil India Limited rather than private operators, a detail that distinguishes India's shale gas regime from the open-licensing model used for conventional exploration blocks. This remains a resource identified and assessed rather than commercially produced at scale, which is itself worth remembering: potential and production are two different things, and UPSC's question tested only the former.

Nuclear power: the minerals behind it and why plants sit where they do

Two minerals underpin India's nuclear power programme, and each has its own distinct geography. Uranium is associated with the Dharwar rock system and is mined chiefly along the Singhbhum belt in Jharkhand, with further deposits in Rajasthan's Udaipur, Alwar and Jhunjhunu districts, Chhattisgarh's Durg district, Maharashtra's Bhandara district and Himachal Pradesh's Kullu district. Thorium, by contrast, comes almost entirely from monazite sands rather than hard rock mining, concentrated in the beach placer deposits running along the coasts of Kerala and Tamil Nadu, with further monazite-rich stretches near Odisha's Mahanadi delta and near Visakhapatnam in Andhra Pradesh. India's institutional nuclear programme traces back to the Atomic Energy Commission, set up in 1948, followed by an Atomic Energy Institute at Trombay in 1954 that was renamed the Bhabha Atomic Research Centre in 1967.

India currently runs its commercial nuclear fleet through the Nuclear Power Corporation of India Limited across seven sites: Tarapur in Maharashtra (the country's first commercial station), Rawatbhata near Kota in Rajasthan, Kalpakkam (Madras Atomic Power Station) and Kudankulam, both in Tamil Nadu, Narora in Uttar Pradesh, Kakrapar in Gujarat, and Kaiga in Karnataka. Kudankulam, built with Russian collaboration, is now the single largest station by capacity in the fleet.

The siting logic across every one of these stations comes down to a single engineering constraint: a nuclear reactor needs a continuous, very large supply of water for cooling, so every site is chosen for guaranteed access to that volume rather than for proximity to the uranium or thorium deposits that fuel it (unlike coal power, which clusters near coalfields to cut transport cost, nuclear fuel is compact enough that its own mineral geography barely constrains where a plant can be built). Coastal stations such as Tarapur, Kalpakkam and Kudankulam draw on effectively unlimited seawater. Inland stations solve the same problem with a major river or reservoir instead: Rawatbhata sits by the Rana Pratap Sagar reservoir on the Chambal, Narora sits directly on the Ganga, Kaiga draws from the Kali river in Karnataka, and Kakrapar, despite being in a coastal state, is actually an inland riverine site drawing its cooling water from the Tapi through the Ukai reservoir rather than from the sea. The pattern to retain is the underlying requirement, assured cooling water at scale, not any one type of water body; a coastal state does not guarantee a coastal nuclear site, and an inland state is no obstacle at all as long as a large river or reservoir sits nearby.

Hydroelectric and renewable energy: a regional survey

India's multipurpose river valley projects, Bhakra-Nangal, Hirakud, the Damodar Valley scheme and Nagarjuna Sagar among them, already carry most of the country's installed hydroelectric capacity and are covered by name in the companion note on drainage systems; this section instead sketches where the newer, non-conventional sources concentrate.

Solar energy is harvested through two distinct routes, photovoltaic cells that convert sunlight directly into electricity, and solar thermal systems that instead capture heat. NCERT itself frames solar's advantage in efficiency terms: it rates solar generation as roughly seven per cent more effective than a comparable coal or oil based plant, and roughly ten per cent more effective than a nuclear plant. Geographically, western India carries the greatest solar potential, concentrated above all in Gujarat and Rajasthan, both benefiting from a dry climate and consistently high solar insolation.

Wind energy follows a different regional pattern, concentrated instead in Rajasthan, Gujarat, Maharashtra and Karnataka, states whose terrain and seasonal wind systems, including the monsoon's own wind patterns alongside permanent systems like the trade winds and westerlies, make turbine generation viable.

Tidal energy remains almost entirely unrealised in India despite real physical potential: large tidal waves occur specifically along the west coast, most notably in the Gulf of Kutch and the Gulf of Khambhat, but this potential has not yet been converted into significant installed capacity, a genuine gap between resource and infrastructure that is itself worth knowing as a fact in its own right.

Geothermal energy, tapped from heat escaping the earth's interior through hot springs and geysers, has a single operating example in India, a plant commissioned at Manikaran in Himachal Pradesh, making it more a proof of concept than a meaningful share of the country's power mix.

Bio-energy, generation from agricultural, municipal and industrial waste, is exemplified by the Okhla plant in Delhi, which converts municipal solid waste into power, a model aimed as much at waste management as at electricity generation.

Across all of these renewable categories, India's installed capacity has grown fast enough in recent years that any specific figure quoted here would likely be stale within a year; the durable exam fact is the regional pattern, not the current gigawatt count; solar and wind cluster heavily in the western and southern states with the right combination of insolation, open land and consistent wind, while hydro remains tied to the river basins already dammed for irrigation and multipurpose use.

Quick revision points

• Coal has two distinct geological sources: Gondwana coalfields (dominant, peninsular river valleys, Jharia the largest followed by Raniganj, Bokaro, Giridih, Karanpura) and Tertiary coalfields (Assam, Arunachal Pradesh, Meghalaya, Nagaland).
• Lignite: coastal Tamil Nadu (Neyveli), Puducherry, Gujarat and Jammu and Kashmir.
• Petroleum: onshore in Assam (Digboi, Naharkatiya, Moran) and Gujarat (Ankleshwar, Kalol, Mehsana, Nawagam, Lunej); offshore at Mumbai High (found 1973, producing 1976) and in the newer Krishna-Godavari and Cauvery offshore basins.
• Refineries: field-based (Digboi) versus market-based (Barauni), a distinction based on location relative to the crude source, not on ownership or capacity.
• Shale gas basins UPSC has tested directly: Cambay, Krishna-Godavari and Cauvery, with the Damodar Valley basin also assessed as prospective; development rights sit with ONGC and Oil India under a 2013 national oil company policy.
• Nuclear minerals: uranium (Dharwar rocks, Singhbhum belt) and thorium (monazite beach sands, Kerala and Tamil Nadu coasts).
• Nuclear stations: Tarapur (Maharashtra, first), Rawatbhata (Rajasthan), Kalpakkam and Kudankulam (Tamil Nadu), Narora (Uttar Pradesh), Kakrapar (Gujarat), Kaiga (Karnataka), all sited for assured cooling water, coastal or riverine, not for mineral proximity.
• Renewables by region: solar and wind concentrate in Gujarat, Rajasthan, Maharashtra and Karnataka; tidal potential (Gulf of Kutch, Gulf of Khambhat) remains largely untapped; geothermal has one working example, Manikaran (Himachal Pradesh); bio-energy is exemplified by Delhi's Okhla waste-to-energy plant.

Once the coal, petroleum and nuclear geography is fixed by name, practise the statement-based and matching-pair formats UPSC actually sets on this chapter, since a single correct-sounding basin or coalfield dropped into an otherwise accurate list is exactly the trap this topic is built around.