Understanding Sustainable and Conventional Energy Sources

Posted on May 31, 2025 in Geology

Renewable and Non-Conventional Energy Sources

The increasing energy demands have compelled countries worldwide to consider an energy policy and explore the possibility of an energy system with minimal environmental impact. Coal and oil deposits are finite. The energy crisis highlights the need for sustainable energy development, urging replacement with non-polluting renewable sources and conservation. Efforts are being made to develop new sources of energy. These are called renewable sources of energy and include solar, wind, ocean, and geothermal energy, as well as energy from urban and agricultural waste, and energy plantations. They are non-polluting, environmentally clean, and socially relevant. Furthermore, no nation can afford to rely on a single energy form; a diverse energy mix is essential.

Non-Renewable and Conventional Energy Sources

Resources accumulated over long geological periods that cannot be quickly replenished are known as non-renewable energy sources. Examples include coal, petroleum, natural gas, and nuclear fuels like uranium and thorium.

Advantages of Renewable Energy Sources

  • Renewable energy is abundant and often free to harness.
  • It has low or zero carbon emissions, making it green and eco-friendly.
  • It fosters energy self-reliance, reducing dependence on foreign energy supplies.
  • In some cases, renewable sources can be more cost-effective than local grid electricity.

Advantages of Non-Renewable Energy Sources

  • Non-renewable sources are generally cheaper and easier to utilize.
  • They release a large amount of energy from a small quantity of resource (e.g., uranium).

Disadvantages of Non-Renewable Energy Sources

  • Non-renewable sources are finite and will eventually deplete, leading to rising prices and reduced accessibility.
  • Their use is not eco-friendly, as they release toxic gases contributing to significant environmental changes.

Disadvantages of Renewable Energy Sources

Despite their numerous benefits, renewable energy sources also have certain limitations:

  • High initial investment cost for plant setup.
  • Intermittency or non-availability (e.g., solar light only on sunny days).
  • Potential loss of biodiversity and forest, along with local environmental modification (e.g., dams for hydroelectric energy).

Solar Energy

The Sun is the ultimate source of energy for all other forms, directly or indirectly.

Advantages of Solar Energy

  • Solar energy is a renewable and free power source.
  • It produces electricity with zero environmental pollution.
  • It can be deployed in remote and isolated areas lacking grid access.
  • Most solar energy systems have a long lifespan of 30 to 40 years.

Disadvantages of Solar Energy

  • Solar energy can only be harnessed during daytime and sunny conditions; cloudy skies reduce effectiveness.
  • Solar energy can be unreliable at times.
  • Sunlight intensity varies by location, time of day, season, and weather.
  • Efficient energy transmission remains a challenge.
  • Installation costs are high due to:
    • Manufacturing expense of solar panels, cells, and collectors.
    • Use of expensive special-grade silicon.
    • Cost of silver for cell connections.
    • Additional cost for DC to AC conversion.

Wind Energy

High-speed winds possess significant kinetic energy. The Sun is the primary driver of wind. Wind energy is captured using windmills. The force of the wind rotates the blades, which can drive machines such as electric generators, flour mills, and water pumps. Large clusters of windmills, known as wind farms, are now common, feeding substantial electricity into utility grids.

Advantages of Wind Energy

  • Wind is free and can be efficiently captured with modern technology.
  • Wind energy can also be used for hydrogen production via water electrolysis.
  • It is suitable for remote and isolated areas without grid access.

Disadvantages of Wind Energy

  • The primary disadvantage is the unreliability of wind.
  • A minimum wind speed of 15 km/hr (4.2 m/s) is required to rotate turbines.
  • Wind is intermittent and unpredictable, necessitating electricity storage and backup systems.

Hydroelectric Energy

Hydropower is defined as electricity generated from the energy of falling or running water, utilized for various purposes. Historically, it has been used for irrigation and operating mechanical devices like watermills, sawmills, textile mills, dock cranes, domestic lifts, powerhouses, and for paint making. Hydroelectricity is the most widely used renewable energy source, accounting for nearly 16% of global electricity generation.

Advantages of Hydroelectric Energy

  • Hydroelectricity is a clean energy source.
  • The water can also be used for irrigation.
  • It can serve as a source of drinking water, particularly for regions like the deserts of Rajasthan and Gujarat.
  • It is non-polluting, has a long operational life, and features very low operating and maintenance costs, unaffected by inflation.

Disadvantages of Hydroelectric Energy

  • Dam construction requires huge financial investment and adherence to very high standards.
  • Large-scale flooding can lead to the destruction of natural environments.

Tidal Energy

The rise and fall of ocean water are known as high tide and low tide. To rotate a turbine, a difference of several meters between high and low tide is required. This tidal difference can be harnessed by constructing a tidal barrage. During high tide, seawater flows into the barrage reservoir, turning turbines and generating electricity. During low tide, the stored seawater flows out into the sea, again rotating turbines and producing electricity.

Non-Renewable Energy Resources

Fossil Fuels

Fossil fuels primarily comprise hydrocarbons, formed from deposits of once-living organisms over centuries. The three main types used for energy are coal, oil, and natural gas.

Coal

Coal formed during the Carboniferous Age, approximately 255-350 million years ago, in hot, damp regions. Plants and animals from this period, found along rivers and swamps, were buried and, under immense heat and pressure over millions of years, gradually converted into peat and then coal. Partially decomposed vegetation, deeply buried in sedimentary environments, slowly transformed into the solid, brittle, carbonaceous rock known as coal. Peat, a soft organic material consisting of partly decayed plants and sometimes deposited mineral matter, is considered the precursor to coal. When subjected to high pressure and heat, peat transforms into coal.

Natural Gas

Natural gas, a fossil fuel, is primarily composed of methane (95%), with small amounts of ethane and propane. It can be found alongside oil deposits or independently. Among fossil fuels, it is considered the cleanest energy source. Natural gas is easily transported via pipelines, burns without smoke, and has a high calorific value. It serves as an energy source for domestic and industrial purposes, power generation, and as a raw material for petrochemical and fertilizer plants.

LPG (Liquefied Petroleum Gas)

LPG (Liquefied Petroleum Gas) is widely used as a domestic cooking fuel. Its main component is odorless butane, to which propane and ethyl mercaptan are added to provide a foul smell for leak detection. It is produced by converting petroleum into liquid form under pressure. Indane and Bharat Petroleum are major distributing agencies for LPG in India.

CNG (Compressed Natural Gas)

CNG (Compressed Natural Gas) is used as a substitute for petrol and diesel in vehicles. The Delhi Transport Corporation (DTC), for example, has fully transitioned its buses and auto-rickshaws to run on CNG, significantly reducing city pollution. CNG is a cleaner fuel than diesel, widely adopted in many cities and for long-distance transport. It primarily contains methane, compressed to 80 atmospheres. CNG is also often more cost-effective (approximately one-third the price) than diesel in the long run due to its stable pricing.

Nuclear Energy

Nuclear energy, while known for its destructive potential (as seen in nuclear weapons), can also be harnessed for commercial power generation. It can be generated through two primary processes:

  • Nuclear Fission: The nucleus of certain heavy isotopes (e.g., Uranium-235) is split into lighter nuclei upon neutron bombardment, releasing immense energy through a chain reaction. To control the reaction rate, only one released neutron is allowed to strike another nucleus.
  • Nuclear Fusion: A heavier nucleus is formed from two isotopes of a lighter element, releasing enormous energy. This process requires extremely high temperatures, nearly 1 billion degrees Celsius.

The heat energy produced by either fission or fusion is used to generate steam, which then drives electric turbines.

Components of a Nuclear Reactor

  • Moderator: Heavy water, Graphite, Deuterium, Paraffin. Moderators slow down fast-moving neutrons (through collisions with protons) to create ‘thermal neutrons,’ which are essential for U-235 fission in the fuel.
  • Control Rods: Boron or Cadmium rods.
  • Coolant: A substance used to remove and transfer heat from the nuclear reactor core to the surroundings.
  • Shielding: Concrete walls (2-25m thick) protect against harmful radiation emitted during nuclear reactions, ensuring safety for personnel.
  • Nuclear Fuel: Uranium-235 (U-235).

Advantages of Nuclear Energy

  • Emits very few greenhouse gases, thus not contributing significantly to global warming.
  • Readily available technology.
  • Generates a high quantity of electricity from a very small amount of fuel.

Disadvantages of Nuclear Energy

  • High installation cost due to stringent radiation containment and safety procedures.
  • Requires a centralized power source with extensive infrastructure.
  • High known and potential risks.

National Solar Mission

The National Solar Mission is one of the eight key National Missions under India’s National Action Plan on Climate Change (NAPCC). Launched on June 30, 2008, NAPCC identified solar energy technology development as a National Mission. To promote ecologically sustainable growth and address India’s energy security challenges, the National Solar Mission was launched by the Government of India and State Governments as a major initiative, officially approved on January 11, 2010. India possesses immense potential for solar energy, with abundant and intense sunshine available for long durations daily, making it crucial for reducing reliance on depleting non-renewable sources. Furthermore, it enables decentralized energy distribution, empowering communities at the grassroots level.

Environmental Impact of Solar Energy

  • Solar energy is environmentally friendly, producing zero emissions during electricity or heat generation, thus preventing environmental pollution.
  • The sun’s energy is a renewable and free power source.
  • It can be deployed in remote and isolated areas lacking power supply.
  • Most solar energy systems have a long lifespan (30 to 40 years).