Natural and Energy Resources

Natural resources are materials and conditions provided by nature that people use. They are classified as renewable (replenished on a human timescale, such as solar, wind, hydro, biomass and forests) and non-renewable (fixed stock, such as coal, oil, gas and minerals). Soil sits between the two: it is formed so slowly, often centimetres in hundreds of years, that it is effectively non-renewable on a human timescale. Renewable does not mean inexhaustible or impact-free, because forests can be cut faster than they regrow and hydropower dams change rivers. Energy resources are also grouped as conventional (coal, oil, gas, large hydro, nuclear) and non-conventional or new and renewable (solar, wind, small hydro, biomass, geothermal, tidal and wave).

India has set a target of 500 GW of non-fossil electricity capacity by 2030, and the main drivers are falling solar and wind costs, energy security and climate commitments. The common weaknesses of renewables are intermittency (solar and wind vary with weather), land use, and the need for storage and grid upgrades. Fossil fuels remain dominant because they are dispatchable and energy dense, but they are the main source of CO2 and air pollutants.

Solar energy is used in two ways: photovoltaic (PV) conversion, in which sunlight is directly converted to electricity by semiconductor cells (silicon is the most widely used material), and solar thermal, where sunlight heats water or air or, in concentrated solar power, is focused by mirrors to raise steam for a turbine. The photovoltaic effect is the principle of solar cells. India's advantages are high solar radiation over most of the country and large desert land in Rajasthan and Gujarat.

• Jawaharlal Nehru National Solar Mission launched in 2010

• Bhadla Solar Park in Rajasthan is among the largest in the world

• PM-KUSUM supports solar pumps and solarisation of agriculture; PM Surya Ghar: Muft Bijli Yojana (2024) supports rooftop solar for households

• International Solar Alliance (launched 2015, headquarters Gurugram) works to expand solar use in sunshine countries

Wind turbines convert the kinetic energy of wind into electricity, and the Betz limit says a turbine can extract at most about 59 per cent of the wind's kinetic energy. Wind power is clean in operation but variable, can affect birds and bats, and produces noise and visual impact near habitations. Offshore wind has stronger and steadier winds, and India's National Offshore Wind Energy Policy was notified in 2015 with potential on the Gujarat and Tamil Nadu coasts. Tamil Nadu's Muppandal is a well-known wind farm.

Soil forms from parent material through weathering under the influence of climate, organisms, relief (topography) and time. A soil profile has horizons: O (organic), A (topsoil, rich in organic matter and the most fertile), B (subsoil where materials accumulate), C (weathered parent material) and R (bedrock). Most crops do best at a soil pH of about 6 to 7.

Soil conservation methods include contour ploughing, terracing, strip cropping, shelterbelts, afforestation, check dams for gullies, zero tillage and crop rotation. The Soil Health Card Scheme (2015) gives farmers nutrient status and recommendations.

Hydropower uses the potential energy of stored or flowing water to turn turbines. Run-of-river schemes have little storage and smaller impact, while storage dams give peaking power and irrigation. Pumped-storage plants pump water to a higher reservoir when power is cheap and release it at peak demand, so they function as large batteries. In India, small hydro projects are those up to 25 MW. Hydropower impacts include submergence of land and forest, displacement of people, sedimentation, blocked fish migration, altered downstream flow, and reservoir-induced seismicity (Koyna).

• Tehri Dam on the Bhagirathi (Uttarakhand), the tallest dam in India; Bhakra Nangal on the Sutlej

• Three Gorges Dam in China is the world's largest hydropower station by installed capacity

• Arunachal Pradesh has the largest untapped hydropower potential in India

Geothermal energy is heat from within the Earth, tapped from hot water, steam or hot rock using wells. Conventional hydrothermal plants use natural steam or hot water, while Enhanced Geothermal Systems (EGS) create reservoirs in hot dry rock. It gives steady, round-the-clock power but is site-specific and can release hydrogen sulphide and cause induced seismicity. The world's first geothermal power plant was at Larderello, Italy (1904), Iceland is a leader in geothermal heating, and The Geysers in California is a large field. Indian geothermal provinces include Puga in Ladakh, Manikaran in Himachal Pradesh and Tattapani in Chhattisgarh.

Biomass is organic matter of plant and animal origin that can be burned directly (wood, dung, crop residue), converted to gas, or converted to liquid fuels. It is considered close to carbon neutral because the CO2 released was recently absorbed by plants, but this holds only if harvesting is sustainable. Open burning of residue and traditional stoves cause serious air pollution.

• Biogas (about 55 to 65 per cent methane) is produced by anaerobic digestion of dung and organic waste; gasification of biomass gives producer gas; briquettes and pellets are densified biomass

• Ethanol (blended with petrol) from sugarcane and grains, and biodiesel from non-edible oils such as Jatropha, are biofuels

• GOBARdhan (2018) turns cattle dung and agricultural waste into biogas and compost; SATAT (2018) promotes compressed biogas

Nuclear fission splits heavy nuclei, mainly uranium-235, releasing energy and neutrons that sustain a chain reaction; a moderator (heavy water or graphite) slows neutrons and a coolant removes heat. Nuclear fusion joins light nuclei such as deuterium and tritium, powers the Sun, and is not yet commercial. Nuclear power has very low operating greenhouse gas emissions but raises concerns about accidents (Three Mile Island 1979, Chernobyl 1986, Fukushima 2011), radioactive waste and proliferation. High-level waste is immobilized by vitrification and kept in deep geological repositories.

• India's three-stage nuclear programme, conceived by Homi J. Bhabha, aims to use thorium: Stage 1 pressurized heavy water reactors, Stage 2 fast breeder reactors, Stage 3 thorium-based reactors

• Tarapur (Maharashtra) is India's first nuclear power station (1969); Kudankulam is in Tamil Nadu; the Nuclear Power Corporation of India Limited operates the fleet

Forests provide timber and non-timber products, regulate climate through carbon storage, protect watersheds and soil, support biodiversity, and are home to tribal and forest-dependent communities. Indian forests are broadly of types such as tropical evergreen, tropical dry deciduous (teak), thorn, montane, and mangrove (Sundarbans). Threats include conversion to agriculture, mining, infrastructure, fire, grazing and illegal felling.

• Forest Survey of India publishes the India State of Forest Report every two years

• National Forest Policy, 1988: target of one-third (33 per cent) of the geographical area under forest or tree cover, and two-thirds in hills

• Forest (Conservation) Act, 1980 regulates diversion of forest land; Forest Rights Act, 2006 recognizes the rights of forest-dwelling Scheduled Tribes and other traditional forest dwellers; Joint Forest Management involves local communities in protection

• Madhya Pradesh has the largest forest cover by area; Mizoram has the highest forest cover as a percentage of its area

• REDD+ rewards reduction of emissions from deforestation and forest degradation