Energy and its classification: conventional and non-conventional sources

Detail

Why energy matters

• Energy (the power to do work) is needed for every activity:
• cooking food at home
• light and heat
• transport (vehicles, trains, ships, aircraft)

• running machines in industry and farms

• Per capita electricity consumption (electricity used per person in a year) is treated as a sign of development. Richer economies use more electricity per person.

• India's per capita electricity consumption went up from 780 kWh in FY 2015-16 to 1,153 kWh in FY 2024-25, a rise of about 48% in 10 years [6].
• India's per capita energy consumption (all fuels, not only electricity) went up from 15,296 MJ in FY 2015-16 to 18,096 MJ in FY 2024-25, a rise of over 19% [6].

Fossil fuels: the base of the conventional mix

• Fossil fuel: a fuel formed from the remains of plants and animals that were buried long ago. The three fossil fuels are coal, petroleum and natural gas.
• How fossil fuels form:
• Plants and animals die and are buried under layers of sediment (mud and sand).
• Over geological time (millions of years), heat and pressure act on them, with little oxygen.

• The remains turn into coal (mostly from plants) or petroleum and natural gas (mostly from tiny sea organisms).

• Classification as minerals: fossil fuels are organic (made of carbon from living things), non-metallic and exhaustible (they cannot be replaced within a human lifetime).

• Mineral fuels in Class 12 NCERT are coal, petroleum, natural gas and nuclear minerals (uranium, thorium). All four are called conventional and exhaustible.
• Fossil fuels are the main source of CO₂ (carbon dioxide). Burning them releases the carbon that was stored in them, and this drives global warming.
• India's Total Primary Energy Supply (TPES) mix, FY 2024-25 [6]:

Source	Share of TPES (FY 2024-25)
Coal (including lignite)	59.21%
Crude oil	29.79%
Natural gas	7.12%
All others (hydro, nuclear, renewables, etc.)	about 3.9%

• About 96% of India's primary energy still comes from fossil fuels (FY 2024-25). Coal alone supplies nearly three-fifths [6].

Classification of energy resources

• Conventional energy sources: sources that have been used for a long time. Most are exhaustible and polluting.
• Non-conventional energy sources: newer sources. Most are renewable (refilled by nature, such as sunlight and wind), spread more evenly across regions, eco-friendly, and cheaper once the first set-up cost is paid.

Feature	Conventional	Non-conventional
Examples (Class 10)	Firewood, cattle dung cake, coal, petroleum, natural gas, electricity (hydel and thermal)	Solar, wind, tidal, geothermal, biogas, atomic energy
Can it run out?	Yes (exhaustible); firewood is renewable only if forests regrow	Mostly renewable (atomic energy is not)
Pollution	High (smoke, CO₂, ash)	Low
Spread across regions	Uneven (e.g. coal is concentrated in Jharkhand, Odisha, Chhattisgarh)	More even (sun and wind are found almost everywhere)
Cost	Recurring fuel cost	High first cost, low running cost

• Key terms:
• Hydel electricity: electricity made by falling water turning turbines at dams. It is listed as conventional in Class 10.
• Thermal electricity: electricity made by burning coal, petroleum or natural gas to make steam that turns turbines.
• Tidal energy: energy from the rise and fall of sea tides.
• Geothermal energy: heat from inside the Earth.
• Biogas: gas (mostly methane) made when dung and farm waste rot without air.
• Atomic (nuclear) energy: energy released when atoms of uranium or thorium are split.

Trap: where does nuclear energy belong?

• Class 12 NCERT lists nuclear minerals among conventional, exhaustible mineral fuels, but it discusses nuclear energy under the "Non-conventional Energy Sources" heading.
• Class 10 NCERT lists atomic energy as non-conventional.
• How to read it:
• By fuel type, nuclear is exhaustible, because uranium and thorium are limited minerals.

• By technology and newness, nuclear is non-conventional.

• Official policy usage: the Government counts nuclear together with renewables as "non-fossil" capacity. The 500 GW target for 2030 is for renewable energy + nuclear [5][2].

• So non-fossil ≠ renewable. Nuclear is non-fossil but not renewable.

Firewood and dung cake: the rural energy problem

• Firewood and cattle dung cake are traditional biomass fuels (fuels taken directly from plants and animals).
• They meet over 70% of rural household energy needs (NCERT, Class 10 estimate).
• Problems:
• Firewood: forests are shrinking → firewood is getting scarce → women and children walk longer distances to collect it.
• Dung cake: dung burnt as fuel → it is lost as manure (natural fertiliser) → soil fertility falls.

• Indoor smoke from both fuels harms health, mostly for women who cook.

• Policy response: Pradhan Mantri Ujjwala Yojana (PMUY)

• Launched in May 2016 to give deposit-free LPG connections to poor households. The first target of 8 crore connections was reached in September 2019 [8].
• Ujjwala 2.0 was launched in August 2021 for 1 crore more connections, reached by January 2022. Later rounds added 60 lakh connections (reached December 2022) and 75 lakh (reached July 2024) [8].
• 10.33 crore PMUY connections had been released by 1 July 2024 [8].
• 25 lakh more connections were approved for FY 2025-26 [7].
• Clean cooking is still not universal. Having a connection does not always mean the cylinder is refilled regularly, so many homes still use some firewood or dung.

Energy security

• Energy security: steady access to enough energy at an affordable price.
• Why it is a worry for India:
• India imported about 89.44% of its crude oil in FY 2024-25, up from about 89% in FY 2023-24 [6].
• India also imports much of its natural gas (as LNG, liquefied natural gas) and coking coal (high-grade coal needed for making steel).

• Imports expose India to global price shocks, supply cuts and a higher import bill (a bigger current account deficit).

• Policy answer: shift to non-fossil sources

• At COP26 (Glasgow, 2021), India set a target of 500 GW of non-fossil (renewable + nuclear) installed electricity capacity by 2030 [5].
• The plan is to add about 50 GW of renewable capacity every year for 5 years [9].

• NDC milestone: India's NDC (Nationally Determined Contribution: a country's climate pledge under the Paris Agreement) aimed for 50% non-fossil installed capacity by 2030. India reached it in June 2025, five years early [4]. (An earlier target of 40% was met in November 2021, when non-fossil capacity stood at 157.32 GW [10].)

• Non-fossil installed capacity as on 31 March 2026: 283.46 GW [2]:

Source	Capacity (GW, 31.03.2026)
Solar	150.26
Large hydro	51.41
Wind	56.09
Bio-energy	11.75
Small hydro	5.17
Renewable total	274.68
Nuclear	8.78
Non-fossil total	283.46

• By 31 July 2026: non-fossil capacity reached 300.50 GW, over 54% of total installed capacity. Total installed power capacity was about 552 GW, up from 249 GW in 2014 [3].
• Installed capacity ≠ generation. Solar and wind work only when the sun shines or the wind blows. That is why coal still supplies most of the actual electricity and about 59% of primary energy [6].

Prelims Hooks

• Class 10 NCERT lists electricity (hydel and thermal), firewood and cattle dung cake as conventional, and biogas and atomic energy as non-conventional.
• Nuclear trap: nuclear is non-fossil but not renewable. Class 12 calls nuclear minerals conventional (exhaustible) yet discusses them under non-conventional sources.
• Fossil fuels (coal, petroleum, natural gas) are organic, non-metallic, exhaustible minerals and the main source of CO₂.
• The 500 GW by 2030 target covers renewable + nuclear (non-fossil) capacity and was announced at COP26, 2021 [5].
• India reached 50% non-fossil installed capacity in June 2025, five years ahead of its 2030 NDC goal [4].
• Largest non-fossil source by installed capacity (31.03.2026): solar (150.26 GW) > wind (56.09 GW) > large hydro (51.41 GW) > bio-energy > nuclear (8.78 GW) > small hydro [2].
• India's TPES share, FY 2024-25: coal 59.21% > crude oil 29.79% > natural gas 7.12% [6].
• Crude oil import dependence, FY 2024-25: about 89.44% [6].
• PMUY was launched in May 2016, and Ujjwala 2.0 in August 2021 [8].
• Per capita electricity consumption, FY 2024-25: 1,153 kWh [6].

Mains Points

• Energy transition and energy security (GS-III): about 96% of primary energy comes from fossil fuels and about 89% of crude oil is imported (FY 2024-25) [6]. Non-fossil capacity reached 300.50 GW by July 2026 [3] and is aimed at 500 GW by 2030 [5]. This cuts the import bill and CO₂ emissions. But it needs storage, grid upgrades and coal-belt transition planning, because solar and wind are intermittent.
• Classification confusion and policy language: the textbook split (conventional vs non-conventional) differs from the policy split (fossil vs non-fossil vs renewable). Nuclear is the swing case. In answers, define the basis of classification (exhaustibility, technology or carbon content) before you classify a source.
• Rural cooking energy and health: firewood and dung cake supplied over 70% of rural household energy (NCERT). They drive deforestation, loss of manure and indoor air pollution. PMUY (10.33 crore connections by July 2024 [8]; 25 lakh more for 2025-26 [7]) improved access. Refill affordability decides whether households actually switch to LPG. Biogas and improved cookstoves are local, renewable alternatives.
• Distribution advantage of non-conventional sources: coal and oil are found only in a few places (Chota Nagpur Plateau coalfields, offshore Mumbai High, Assam), so energy has to be carried long distances. Sun, wind and biomass are available in most regions, so electricity can be generated locally and closer to remote and rural areas.