Energy Resources: Conventional and Non-Conventional - TNPSC - Environmental Scientist

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Energy Resources: Conventional and Non-Conventional Energy – Study Notes 

Energy is the backbone of modern civilization. It powers industries, transportation, agriculture, healthcare, communication, and daily life. As the global population grows and technology advances, energy demand continues to rise. Energy resources can be broadly classified into conventional and non-conventional (also called renewable) sources, depending on their availability, sustainability, and environmental impact.

1. Conventional Energy Resources

Conventional energy resources are traditional sources of energy that have been used for decades. They are mostly non-renewable, meaning they exist in finite quantities and cannot be replenished quickly.

A. Fossil Fuels

Fossil fuels are formed from the remains of ancient plants and animals buried for millions of years under pressure and heat.

1. Coal

  • Origin: Dead plant material accumulated in swamps and over time turned into coal.

  • Uses: Electricity generation, steel production, cement industry.

  • Types: Anthracite, bituminous, sub-bituminous, lignite.

  • Advantages: Abundant, established technology.

  • Disadvantages: Major source of CO₂, SO₂, and particulate matter; causes air pollution and acid rain.

2. Petroleum (Crude Oil)

  • Origin: Marine organisms buried under sedimentary rock layers.

  • Uses: Fuels (petrol, diesel, kerosene), plastics, lubricants.

  • Advantages: High energy content, easy transport.

  • Disadvantages: Limited reserves, oil spills, greenhouse gas emissions.

3. Natural Gas

  • Components: Mainly methane (CH₄).

  • Uses: Cooking, electricity generation, fertilizers.

  • Advantages: Cleaner than coal and oil, high efficiency.

  • Disadvantages: Methane is a potent greenhouse gas; extraction may cause land degradation.

B. Nuclear Energy

  • Source: Uranium-235 and Plutonium-239 used in nuclear reactors.

  • Process: Nuclear fission – atoms split to release energy.

  • Uses: Base-load electricity generation.

  • Advantages: Low carbon emissions, high energy yield.

  • Disadvantages: Radioactive waste disposal, risk of accidents (Chernobyl, Fukushima), high initial cost.

Environmental Impacts of Conventional Energy

  • Air pollution: Emission of CO₂, NOx, SO₂ from fossil fuels.

  • Water pollution: Oil spills, contamination from mining.

  • Land degradation: Deforestation, open-pit mining.

  • Climate change: Greenhouse gas accumulation.

  • Resource depletion: Non-renewable and will exhaust eventually.

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2. Non-Conventional (Renewable) Energy Resources

Non-conventional or renewable energy sources are naturally replenished and sustainable over the long term. They are considered eco-friendly as they emit little or no greenhouse gases.

A. Solar Energy

1. Solar Photovoltaic (PV)

  • Converts sunlight directly into electricity using solar panels.

  • Uses: Homes, street lights, calculators, off-grid systems.

2. Solar Thermal

  • Uses sunlight to heat water or air.

  • Uses: Water heaters, power plants (CSP – Concentrated Solar Power).

Advantages:

  • Abundant and free.

  • No pollution during use.

  • Low maintenance cost.

Disadvantages:

  • High installation cost.

  • Efficiency depends on weather and location.

  • Energy storage is needed for night use.

B. Wind Energy

  • Mechanism: Wind turns turbine blades connected to a generator.

  • Ideal locations: Coastal areas, hilltops, open plains.

  • Advantages: Clean, renewable, cost-effective in the long term.

  • Disadvantages: Intermittent supply, noise pollution, visual impact, threat to birds.

C. Hydropower

  • Source: Energy of flowing or falling water, typically using dams.

  • Types:

    • Large hydroelectric projects (e.g., Bhakra-Nangal, Tehri Dam)

    • Small hydropower plants (up to 25 MW)

Advantages:

  • Reliable, efficient, long life span.

  • Provides water for irrigation and drinking.

Disadvantages:

  • Large-scale displacement of people.

  • Ecological damage to river ecosystems.

  • Risk of dam failure.

D. Biomass Energy

  • Source: Organic matter like wood, crop residue, animal waste.

  • Forms: Biogas, biodiesel, ethanol.

  • Biogas Plants: Use cow dung, kitchen waste in anaerobic digesters to produce methane.

Advantages:

  • Utilizes waste, reduces landfill.

  • Renewable and widely available.

  • Generates rural employment.

Disadvantages:

  • Land use competition with food crops.

  • Air pollution if not efficiently burned.

E. Geothermal Energy

  • Source: Heat from the Earth’s interior.

  • Uses: Electricity generation, heating systems.

  • Locations: Geothermal hotspots (e.g., Iceland, parts of India like Manikaran in Himachal Pradesh).

Advantages:

  • Reliable and continuous.

  • Low emissions.

Disadvantages:

  • Geographically limited.

  • High setup cost and potential groundwater contamination.

F. Tidal and Wave Energy

  • Tidal Energy: Generated from rise and fall of tides using turbines.

  • Wave Energy: Extracted from surface motion of the ocean.

Advantages:

  • Predictable and renewable.

  • Minimal land use.

Disadvantages:

  • Technology still under development.

  • High cost and ecological disturbance to marine life.

Comparison: Conventional vs Non-Conventional Energy

FeatureConventional EnergyNon-Conventional Energy
AvailabilityLimited (non-renewable)Unlimited (renewable)
PollutionHigh (air, water, land)Low or negligible
CostLow initial but high long-termHigh initial but low operational
Resource DepletionYesNo
Carbon EmissionsHighLow to zero
Environmental ImpactSignificantMinimal

Need for a Shift Towards Renewable Energy

  • Environmental protection: Reduces greenhouse gas emissions and pollution.

  • Energy security: Decreases dependence on imported fuels.

  • Sustainability: Ensures long-term energy availability.

  • Job creation: Renewable sector offers large employment potential.

  • Rural development: Decentralized energy systems like solar and biogas can empower villages.

Government Initiatives in India

India has made significant strides in promoting renewable energy through various policies:

  • National Solar Mission: Aims to install 100 GW of solar capacity.

  • Wind Energy Mission

  • Renewable Energy Investment Promotion

  • Subsidies and tax incentives for solar rooftops, biogas plants

  • International Solar Alliance (ISA): India-led initiative to promote solar globally.

Challenges in Renewable Energy Adoption

  • High capital investment

  • Intermittency and storage issues

  • Grid integration and transmission infrastructure

  • Technological limitations in some sectors

  • Lack of public awareness in rural areas

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