Chapter in a nutshell: Energy sources are conventional (coal, petroleum, natural gas, hydel — limited/polluting, mostly non-renewable) and non-conventional/renewable (solar, wind, tidal, geothermal, biogas, nuclear — clean and inexhaustible). India relies heavily on coal and oil but is expanding renewables to cut pollution and conserve fuels.
1. Conventional Sources
Long-used sources: coal, petroleum, natural gas and hydel power. Except hydel, the fossil fuels are limited, exhaustible, and cause air pollution + global warming.2. Coal
- A fossil fuel from sedimentary rocks; India is among the top producers.
- Types (increasing carbon/quality): Peat → Lignite (brown) → Bituminous → Anthracite (best, ~90% carbon).
- Distribution: Jharkhand (Jharia, Bokaro — largest), Odisha (Talcher), Chhattisgarh (Korba), West Bengal (Raniganj), MP (Singrauli). Most reserves are in the Damodar valley / Gondwana rocks.
- Uses: thermal power, iron & steel (coking coal), industry, railways.
- Merits: abundant, easy to use, high energy. Demerits: pollution, dangerous mining, non-renewable, land degradation.
3. Petroleum (Mineral Oil)
- "Rock oil" — a mixture of hydrocarbons in sedimentary basins; refined into petrol, diesel, kerosene, LPG, paraffin wax, lubricants.
- Distribution: Assam (Digboi — oldest, Naharkatiya), Mumbai High (offshore, largest), Gujarat (Ankleshwar), Krishna-Godavari basin.
- Refineries: Digboi, Mathura, Koyali, Jamnagar (world's largest).
- India imports most of its oil → energy security concern.
4. Natural Gas & Hydel Power
- Natural gas: found with/near petroleum; cleaner fuel — CNG for vehicles, LPG/PNG for cooking, fertiliser feedstock. Sources: Mumbai High, KG basin, Gujarat; transported by the HBJ pipeline.
- Hydel (hydro-electric) power: electricity from falling water at dams — renewable, clean; from multipurpose projects (Bhakra, Hirakud). Limited by suitable sites and seasonal flow.
5. Non-Conventional / Renewable Sources
| Source | Note |
|---|---|
| Solar | abundant sunshine; solar cells/panels, cookers, water heaters (Gujarat, Rajasthan) |
| Wind | wind farms in coastal/open areas (Tamil Nadu, Gujarat) |
| Tidal | energy of sea tides (Gulf of Kutch/Khambhat potential) |
| Geothermal | heat from inside the Earth (hot springs — Manikaran) |
| Biogas | gas from decomposing dung/waste (rural cooking, gobar gas) |
| Nuclear | from uranium/thorium fission (Tarapur, Kalpakkam); huge energy, but radioactive waste |
6. Conservation of Energy
Fossil fuels are exhaustible, so: use energy-efficient appliances; switch to renewables; use public transport/CNG; avoid wastage; promote biogas/solar in villages.7. Worked / Structured Examples (ICSE pattern)
Q1. Name the best variety of coal and its carbon content. Solution: Anthracite (~90% carbon). Q2. Differentiate conventional and non-conventional energy. Solution: Conventional = long-used, mostly non-renewable/polluting (coal, oil); non-conventional = renewable, clean (solar, wind). Q3. Name India's oldest oil field and the largest offshore one. Solution: Digboi (Assam); Mumbai High. Q4. Why is hydel power called renewable? Solution: It uses flowing water, replenished by the water cycle. Q5. Give two advantages of natural gas over coal. Solution: It is cleaner (less pollution) and more efficient.8. Key Terms — Quick Glossary
| Term | One-line definition |
|---|---|
| Conventional energy | long-used source (coal, oil, gas, hydel). |
| Non-conventional energy | newer renewable source (solar, wind…). |
| Fossil fuel | fuel from buried organic matter (coal, oil, gas). |
| Anthracite | the highest-grade coal. |
| Hydel power | electricity from falling water. |
| Biogas | gas from decomposing organic waste. |
| Renewable | source that is naturally replenished. |
| Non-renewable | exhaustible source. |
| Thermal power | electricity from burning coal/gas. |
9. Common Mistakes to Avoid
- Calling coal/petroleum renewable — they are non-renewable fossil fuels.
- Saying hydel/solar pollute — they are clean sources.
- Confusing coal grades — anthracite is best, peat is lowest.
- Forgetting Mumbai High is offshore oil (not coal).
- Treating nuclear as pollution-free — it produces radioactive waste.
10. Likely Exam Questions (with crisp answers)
- Classify energy resources. → Conventional (coal, oil, gas, hydel) and non-conventional (solar, wind, tidal, geothermal, biogas, nuclear).
- Name the four types of coal. → Peat, lignite, bituminous, anthracite.
- Which state has the largest coal reserves? → Jharkhand.
- Name two products of petroleum. → Petrol and diesel (also kerosene, LPG).
- Name India's largest offshore oil field. → Mumbai High.
- Why is natural gas an eco-friendly fuel? → It burns cleanly with less pollution.
- Give two renewable energy sources. → Solar and wind.
- Name a state with major wind farms. → Tamil Nadu (also Gujarat).
- From which minerals is nuclear energy obtained? → Uranium and thorium.
- State one advantage and one disadvantage of coal. → Abundant/high energy; pollution/non-renewable.
- Why must fossil fuels be conserved? → They are exhaustible and polluting.
- Name a geothermal site in India. → Manikaran (hot springs).
- What is biogas and its rural use? → Gas from decomposing dung/waste; used for cooking and lighting.
- Name India's largest oil refinery. → Jamnagar (Gujarat).
11. Coal Types Compared
| Type | Carbon | Quality |
|---|---|---|
| Peat | lowest | poor, smoky |
| Lignite (brown coal) | low | moderate |
| Bituminous | high | most used (coking coal for steel) |
| Anthracite | ~90% | best, hard, clean-burning |
12. Oil & Gas Fields (reference)
| Region | Fields |
|---|---|
| Assam (NE) | Digboi (oldest), Naharkatiya, Moran |
| Offshore | Mumbai High (largest), Bassein |
| Gujarat | Ankleshwar, Kalol |
| East coast | Krishna-Godavari (KG) basin |
13. Renewable Sources — why they matter
Fossil fuels are running out and pollute, so India is investing in solar, wind, hydel, biogas and nuclear energy. These are clean and inexhaustible, reduce import dependence and cut greenhouse gases — key to sustainable development.14. More Worked / Structured Examples
Q6. Why is coking (bituminous) coal important for industry? Solution: It is used to make coke for smelting iron in the steel industry. Q7. Why does India import large amounts of petroleum? Solution: Its domestic reserves are limited compared to its high demand. Q8. Name two clean alternatives to petrol for vehicles. Solution: CNG (natural gas) and electricity (also biofuels). Q9. Why is solar energy especially suitable for Rajasthan? Solution: It receives abundant, year-round sunshine.15. More Exam Questions (with crisp answers)
- Name a thermal-power fuel and a clean alternative. → Coal (thermal); solar/wind (clean).
- Which coalfield is in West Bengal? → Raniganj.
- Name two states that produce most of India's coal. → Jharkhand and Odisha.
- What does CNG stand for and one use? → Compressed Natural Gas; clean fuel for vehicles.
- Name India's two nuclear power stations. → Tarapur and Kalpakkam.
- Why is hydel power eco-friendly? → It is renewable and produces no air pollution.
- State two disadvantages of fossil fuels. → They pollute the air and are non-renewable.
- Name the gas pipeline carrying natural gas in India. → The HBJ pipeline.
- Give one rural benefit of biogas plants. → Clean cooking gas plus manure from the slurry.
16. Sources at a Glance
| Source | Renewable? | Pollution |
|---|---|---|
| Coal | No | High |
| Petroleum/Gas | No | High/Medium |
| Hydel | Yes | Low |
| Solar/Wind/Tidal | Yes | None |
| Biogas | Yes | Low |
| Nuclear | No (fuel limited) | Radioactive waste |
17. Final Quick-Revision Q&A
- Which is the cleanest fossil fuel? → Natural gas.
- Name the lowest grade of coal. → Peat.
- Define a fossil fuel. → A fuel formed from buried organic remains over millions of years.
- Why is nuclear energy not fully clean? → It produces hazardous radioactive waste.
- Name a tidal-energy potential site in India. → Gulf of Kutch/Khambhat.
- Why promote renewable energy? → To cut pollution, conserve fossil fuels and ensure sustainability.
- Name two petroleum products used as fuel. → Petrol and diesel (also LPG, kerosene).
- Name the oldest oil field in India. → Digboi (Assam).
- Which coal is used to make coke for steel? → Bituminous (coking) coal.
- Name the largest oil refinery in India. → Jamnagar (Gujarat).
- Give one disadvantage of hydel power. → It depends on suitable river sites and seasonal water flow.
- Name the rule-of-thumb for the best to worst coal. → Anthracite > bituminous > lignite > peat.
- Why is energy conservation a national priority? → Fossil fuels are limited and largely imported, and burning them pollutes.
- Name two states with major solar-power potential. → Rajasthan and Gujarat.
- What is thermal power? → Electricity generated by burning coal or gas to make steam that drives turbines.
- Name a non-conventional source using the Earth internal heat. → Geothermal energy.
- Why is petroleum called rock oil? → It is found trapped in sedimentary rocks (petra = rock, oleum = oil).
- Name the gas supplied to homes by pipeline for cooking. → PNG (piped natural gas); LPG in cylinders.
- Which energy source is stored chemical energy of the Sun from long ago? → Coal/petroleum (fossil fuels).