Introduction & Summary
Conventional energy sources, primarily fossil fuels like coal, petroleum, and natural gas, have historically formed the backbone of global energy supply, fueling industrialization and economic growth. Despite growing concerns about climate change and environmental degradation, these sources continue to dominate India's energy mix due to their abundance and established infrastructure.
This module delves into the characteristics, reserves, and associated environmental and economic issues of coal, petroleum, and natural gas. It explores the working principles of thermal power plants and the technologies employed for pollution control. Crucially, it examines emerging "Clean Coal Technologies" (CCT) like Integrated Gasification Combined Cycle (IGCC) and Carbon Capture Utilization & Storage (CCUS), which aim to mitigate the environmental impact of coal, highlighting the ongoing efforts to balance energy security with sustainability.
Coal: The Dominant Fossil Fuel
Coal is the most abundant fossil fuel globally and a dominant energy source in India.
Types of Coal (by Carbon Content & Heat Value)
Anthracite
Highest carbon (~87-97%), highest heat value. Hard, shiny. Rare in India.
Bituminous
High carbon (~45-86%), high heat. Most common, used in power plants. Found in India.
Sub-bituminous
Lower carbon, moderate heat value.
Lignite
Lowest carbon (~25-35%), lowest heat. Brownish, high moisture. Found in India (e.g., Neyveli).
Source: NCERT Class XII Geography; D.R. Khullar.
Coal Reserves in India
- Abundant: India has the fifth largest coal reserves in the world.
- Distribution: Concentrated in Gondwana coalfields (Damodar Valley - Jharkhand, West Bengal, Odisha, Chhattisgarh, Madhya Pradesh) and Tertiary coalfields (Northeast India).
- Quality: Predominantly bituminous and lignite. Indian coal generally has high ash content and low sulfur content.
Issues Associated with Coal
- Land Degradation: Open-cast mining causes deforestation, loss of agricultural land, soil erosion.
- Displacement: Forced displacement of local communities, often tribal populations.
- Water Pollution: Acid mine drainage, heavy metal contamination.
- Air Pollution: Dust pollution.
- Particulate Matter (PM): Fine dust causing smog and respiratory diseases.
- Sulfur Dioxide (SO₂): Causes acid rain and respiratory problems.
- Nitrogen Oxides (NOx): Contribute to acid rain and smog.
- Heavy Metals: Mercury, lead, arsenic released.
- Greenhouse Gas (GHG) Emissions: Largest single source of CO₂ emissions globally.
Thermal power plants generate enormous quantities of fly ash, posing disposal challenges and environmental concerns (e.g., contamination of soil and water).
Coal Liquefaction & Gasification
Coal Gasification
Process of converting coal into syngas (mainly H₂ and CO) by reacting it with steam, oxygen, and/or air under high pressure and temperature.
Applications: Electricity (IGCC), chemicals, fuels.
Benefits: Cleaner than direct combustion, easier pollutant capture.
Coal Liquefaction
Process of converting coal into liquid hydrocarbons (synthetic crude oil or fuels).
Methods: Direct Liquefaction, Indirect Liquefaction (Fischer-Tropsch).
Benefits: Reduces crude oil import dependence.
India is exploring these technologies to diversify coal's use and reduce import dependence. (Source: Ministry of Coal, CPCB, NITI Aayog)
Petroleum & Natural Gas
Crucial for transportation, industry, and power generation, formed from ancient marine organisms.
Reserves & Refining in India
Petroleum Reserves
Relatively limited. Major fields: Mumbai High (offshore), Assam, Gujarat, Rajasthan.
Natural Gas Reserves
Limited. Major fields: Krishna-Godavari (KG) Basin, Assam, Gujarat.
High Import Dependence: India is ~85% import dependent for crude oil and significantly for natural gas.
Refining Capacity
India has significant refining capacity, often exceeding domestic production, making it a refining hub.
Unconventional Hydrocarbons & Issues
Unconventional Hydrocarbons
- Shale Gas: Natural gas in shale formations (requires "fracking").
- Coal Bed Methane (CBM): Natural gas in coal seams.
- India has potential reserves and is exploring commercial exploitation.
Key Issues
Highly susceptible to global geopolitics, impacting import bills, inflation, and energy security.
- GHG Emissions: CO₂ release (natural gas cleaner than coal).
- Air Pollution: NOx, VOCs.
- Oil Spills: Marine pollution.
- Fracking Concerns (Shale Gas): Water contamination, seismic activity.
Source: MoPNG, ONGC, GAIL, DGH, Economic Survey.
Thermal Power Plants
Dominant in India's electricity generation, primarily coal-based.
Working Principle (Coal-based)
Efficiency
Typical: 30-40%. Modern supercritical/ultra-supercritical plants: 40-45%+.
Higher efficiency means less coal per unit of electricity, reducing emissions.
Pollution Control Technologies
Electrostatic Precipitators (ESP)
Remove particulate matter (fly ash, dust) using electrostatic forces.
Flue Gas Desulphurization (FGD)
Remove Sulfur Dioxide (SO₂) using limestone/lime, forming gypsum.
SCR / SNCR
Reduce Nitrogen Oxides (NOx) by converting them to N₂ and H₂O.
Tall Stacks
Disperse pollutants over a wider area, reducing local concentrations but contributing to regional/global pollution. Not a removal technology.
Source: Ministry of Power, CEA, CPCB.
Clean Coal Technologies (CCT)
Aiming to mitigate the environmental impact of coal, particularly GHG emissions.
Integrated Gasification Combined Cycle (IGCC)
Converts coal into syngas (clean gas). Syngas fuels a combined cycle power plant (gas turbine + steam turbine).
Working:- Coal gasified to syngas.
- Impurities removed from syngas.
- Cleaned syngas burned in gas turbine (electricity).
- Exhaust heat generates steam for steam turbine (more electricity).
- Higher thermal efficiency.
- Lower pollutant emissions (SO₂, NOx, PM, mercury).
- Carbon Capture Ready.
Status: Commercially viable, higher capital costs. Limited global operation.
Carbon Capture Utilization & Storage (CCUS)
Technologies to capture CO₂ emissions from large point sources, then utilize or store it permanently.
Components:- Capture: Separating CO₂ (Post-combustion, Pre-combustion, Oxy-fuel).
- Utilization (CCU): Value-added products (EOR, chemicals, fuels, algae).
- Storage (CCS): Deep geological formations (saline aquifers, depleted reservoirs).
Significantly reduces GHG emissions, pathway for industrial decarbonization.
Challenges:- High cost (energy penalty, capital/operating).
- Scalability, storage site availability & safety.
- Public acceptance, regulatory framework.
Status: Active R&D, pilot projects, some commercial scale. India has draft CCUS policy. (Source: NITI Aayog, IEA)
Exam Focus: Analytical Notes
Prelims-ready Quick Facts
Coal
- Types: Anthracite (highest C), Bituminous (common in India), Lignite (lowest C).
- Reserves (India): 5th largest. High ash, low sulfur.
- Issues: Mining, Pollution (PM, SO₂, NOx, CO₂), Ash.
- Gasification: Coal to Syngas (H₂, CO).
Petroleum & Natural Gas
- Reserves (India): Limited, ~85% oil import dependent.
- Unconventional: Shale Gas (fracking), CBM.
- Issues: Price volatility, Import dependence, GHG, Spills.
Thermal Power Plants
- Working: Coal -> Heat -> Steam -> Turbine -> Electricity.
- Efficiency: 30-40% (conv.), 40-45%+ (supercritical).
- Pollution Control: ESP (PM), FGD (SO₂), SCR/SNCR (NOx).
Clean Coal Technologies
- IGCC: Coal -> Syngas -> Combined Cycle. Higher efficiency.
- CCUS: Capture CO₂, Utilize/Store. Reduces GHG. Challenges: Cost, scale.
Mains-ready Analytical Insights
- Coal's Future in India: Energy security vs. climate commitments (Net Zero 2070). Role of CCT vs. phase-out.
- Energy Trilemma: Balancing security, sustainability, and affordability.
- Fracking Debate: Environmental/social concerns of shale gas/CBM.
- CCUS Viability: Genuine solution or costly distraction prolonging fossil fuel reliance?
Early Industrialization
Dominance of fossil fuels begins, driving growth.
Mid-20th Century
Shift to global energy markets, oil/gas reliance increases.
Late 20th - Early 21st Century
Growing environmental awareness; pollution control (ESP, FGD) to decarbonization (CCT, CCUS).
India's Trajectory
Continued coal dependence; policy focus on reducing imports and promoting clean tech.
- Energy Security: Conventional sources critical for India; oil/gas import dependence a vulnerability.
- Climate Change: Fossil fuels largest GHG contributor; decarbonization (CCUS, renewables) vital for Net Zero 2070.
- Economic Impact: Oil/gas price volatility affects inflation, fiscal deficit.
- Public Health: Air pollution from thermal plants.
- Geopolitics: Fossil fuel access drives global politics.
- Russia-Ukraine Conflict: Highlighted energy price volatility.
- India's Coal Production Targets: Push to increase domestic output.
- Mandatory FGD Installation: Directives for thermal plants.
- NITI Aayog's Carbon Capture Policy Framework (2022).
- Reliance Industries' investment in CCUS.
Value-added Points
Energy Mix: Proportion of different energy sources in total supply.
Energy Intensity: Energy consumed per unit of GDP.
Just Transition: Equitable transition away from coal for workers/communities.
Further Resources & Practice
Current Affairs (Last 1 Year)
Continued Coal Reliance (2023-24): India's coal-fired power capacity expanded amidst rising energy demand. (Source: Ministry of Power)
Mandatory FGD Installation: Ongoing push by MoEFCC for FGD systems, implementation delays persist. (Source: MoEFCC, CPCB)
CCUS Policy Progress: Post NITI Aayog's 2022 framework, pilot projects and discussions continue. (Source: NITI Aayog)
Focus on Domestic Oil/Gas Production: Intensified efforts by ONGC etc. to boost domestic output. (Source: MoPNG)
Adoption of Supercritical/Ultra-Supercritical Tech: New thermal plants adopt more efficient technologies. (Source: CEA)
UPSC Previous Year Questions (PYQs)
Prelims
Q. (UPSC Prelims 2020) With reference to 'Coal Bed Methane (CBM)' and 'Shale Gas', consider the following statements: ...
Answer: (d) 1, 2 and 3
Hint: Tests knowledge of unconventional fossil fuels. All statements are correct.
Q. (UPSC Prelims 2017) The term 'Clean Coal Technologies' refers to: ...
Answer: (d) 1, 2 and 3
Hint: Directly tests CCT knowledge including gasification and CCUS.
Mains
Q. (UPSC Mains 2023) "The development of technologies for producing 'Green Hydrogen' is crucial for India to achieve its target of Net Zero by 2070." Discuss.
Direction: Discuss challenges of fossil fuels as background, mention CCUS as mitigation for fossil fuels.
Q. (UPSC Mains 2020) With growing energy needs, should India pursue its Nuclear Energy Programme? Discuss the facts and fears associated with it.
Direction: Discuss challenges of fossil fuels as justification for diversifying into nuclear.
Original Practice Questions
MCQs for Prelims
1. Which of the following statements about 'Coal Gasification' is/are correct? ...
Answer: (c) 1 and 3 only
Explanation: Statement 2 is incorrect; coal gasification is cleaner than direct combustion.
2. Consider the following pairs of pollution control technologies ... How many pairs correctly matched? ...
Answer: (a) Only one
Explanation: Only Pair 2 (FGD: SO₂) is correct. ESP targets PM; SCR targets NOx.
Descriptive Questions for Mains
1. "Despite India's ambitious renewable energy targets, coal continues to be the dominant source... In this context, 'Clean Coal Technologies' (CCT) offer a pragmatic pathway..." Discuss. (15 marks, 250 words)
2. "India's high import dependence for crude oil and natural gas poses significant energy security and economic challenges..." Discuss. (10 marks, 150 words)