UGC NET Paper One | Unit 9: People, Development and Environment
Focus: Geothermal Energy, Biomass, Nuclear Power, Energy Forestry & Thermal Power
Definition: Geothermal energy is thermal energy extracted from the Earth's crust, combining heat from the planet's formation and radioactive decay. This energy has been used for centuries for various purposes such as heating and electricity generation.
Installed Capacity: As of 2019, there were 13,900 MW of geothermal power available worldwide.
Additional Uses: An additional 28 GW provided heat for district heating, space heating, spas, industrial processes, desalination, and agricultural applications.
Employment: The industry employed about one hundred thousand people in 2019.
Use steam directly from geothermal reservoirs to turn turbines and generate electricity.
Pull high-pressure hot water from the ground and convert it to steam to drive turbines.
Transfer heat from geothermal hot water to another liquid that boils at a lower temperature than water, which then turns the turbines.
Global Presence: As of 2010, geothermal electricity was generated in 26 countries. As of 2019, worldwide geothermal power capacity was 15.4 GW, with the United States contributing 3.68 GW.
Significant Contributors - Countries with High Geothermal Energy Utilization:
Renewable Resource: Geothermal energy is considered renewable because heat extraction rates are negligible compared to the Earth's heat content.
Low Emissions: The greenhouse gas emissions of geothermal electric stations average 45 grams of carbon dioxide per kilowatt-hour of electricity, which is less than 5% of the emissions from coal-fired plants.
Geothermal energy is a reliable and sustainable source of power and heat, with a long history of use and significant potential for future expansion. It provides a constant supply of energy, has low greenhouse gas emissions, and is cost-effective, making it an essential component of the global renewable energy mix. With ongoing technological advancements and increasing capacity, geothermal energy will continue to play a crucial role in meeting the world's energy needs sustainably.
Biomass is organic material derived from plants and animals. It includes things like wood, wood leftovers, energy crops, agricultural waste like straw, and organic waste from homes and industries.
Wood and its residues are the biggest sources of biomass energy today. Wood can be burned directly or processed into pellet fuel or other types of fuel. Other plants like maize, switchgrass, miscanthus, and bamboo can also be used as fuel.
📝 EXAM IMPORTANT
Biomass fuels have the potential to form a sustainable carbon-neutral energy source because they produce as much carbon dioxide on combustion as they consume when they grow.
📝 EXAM IMPORTANT
In terms of energy density, Biomass has the lowest energy content per unit mass.
Leftovers from logging and wood processing.
Crop leftovers like straw.
Organic waste from households.
Organic waste from industries.
📝 EXAM IMPORTANT
Even when solid waste is buried in landfills, it can still provide energy because buried waste produces natural gas which can be captured and burned.
Energy crops are fast-growing, low-cost, and low-maintenance plants cultivated specifically for renewable bioenergy production. These crops are processed into fuels such as biofuel, biodiesel, or biogas.
📝 EXAM IMPORTANT
Energy crops are fast-growing plants and can be converted into gaseous and liquid fuel. They generally have high calorific value.
Raw biomass can be turned into better fuels using different methods:
📝 EXAM IMPORTANT
Producer Gas is the result of the conversion of solid biomass into gaseous fuels. It can be used as fuel in internal combustion engines. Hydrogen and methane present in Producer Gas determine its heating value.
Pyrolysis is a technology used to convert biomass into an intermediate liquid product called Bio-Oil.
📝 EXAM IMPORTANT
Pyrolysis produces bio-oil with minimal waste, and the resulting liquid can replace heating oil.
📝 EXAM IMPORTANT
Biodiesel is a renewable, biodegradable fuel produced domestically. Biodiesel can be created from vegetable oils and animal fats.
It offers an eco-friendly alternative to traditional diesel, though with some differences:
📝 EXAM IMPORTANT
Biodiesel has a higher viscosity compared to petroleum diesel. This higher viscosity can affect the flow characteristics of the fuel in engines.
Biogas is a renewable fuel produced through the anaerobic digestion of organic matter, such as food or animal waste.
Calorific Value: The energy content of biogas is determined by its methane percentage. With a high methane content of around 60%, biogas has a significant calorific value.
Carbon neutrality involves balancing carbon emissions with carbon absorption in carbon sinks.
📝 EXAM IMPORTANT
Energy produced from biomass is considered 'carbon neutral'.
📝 EXAM IMPORTANT
Biomass is considered as carbon neutral because the amount of carbon they emit is equal to the amount of carbon they have consumed during their lifetime.
📝 EXAM IMPORTANT
Energy production from biomass has traditionally been considered carbon neutral because carbon dioxide emissions from combustion of biomass are sequestered by growing biomass.
📝 EXAM IMPORTANT
Consequently, Carbon dioxide emissions from bioenergy production has traditionally been excluded from most emission inventories and climate impact studies.
📝 EXAM IMPORTANT
Biomass adds CO2 to the atmosphere. Burning wood releases carbon dioxide, but this is balanced if new trees are planted.
📝 EXAM IMPORTANT
Carbon dioxide emissions associated with the production of bioenergy are significantly less compared to those from combustion of fossil fuels.
📝 EXAM IMPORTANT
A source of renewable power which can be developed with minimum cost is Biomass power.
Biomass power plants often have lower initial costs compared to wind and tidal energy.
📝 EXAM IMPORTANT
The biggest hindrance in using biomass as a major energy source is large amounts of land required to grow energy crops.
Sustainable land use is crucial for viability.
The use of agricultural resources can impact water bodies. An over-fertile lake experiences excessive nutrient enrichment, particularly from nitrates and phosphates, leading to eutrophication.
📝 EXAM IMPORTANT
This process results in:
While discussing cleaner fuels, it is worth noting:
📝 EXAM IMPORTANT
Natural gas is a very attractive eco-friendly fuel because it produces fewer pollutants and less carbon dioxide per unit energy than any other fossil fuel on combustion.
Nuclear power uses nuclear reactions to produce electricity. It primarily comes from:
Splitting of uranium and plutonium atoms in nuclear power plants.
Used in niche applications like space probes.
Still in the research phase for electricity generation.
Most plants use enriched uranium in a once-through fuel cycle.
Fuel is removed after about three years when it can no longer sustain a chain reaction, then cooled in spent fuel pools before long-term storage.
Uranium-235 (U-235): The most widely used fuel in nuclear power plants for nuclear fission due to its easily split atoms, which release significant energy. This energy heats water to produce steam that drives turbines, generating electricity.
Plutonium-239 (Pu-239): Also used in some reactors, but U-235 remains the primary choice for its efficiency and effectiveness in sustaining a chain reaction.
Spent fuel is high-level radioactive waste and must be isolated for hundreds of thousands of years, although new technologies like fast reactors could reduce this time.
Some countries reprocess spent fuel to extract fissile and fertile elements for new fuel, although this is more expensive and poses proliferation risks due to plutonium-239.
First nuclear power plant built.
Global installed nuclear capacity grew to 300 GW by 1990.
The Three Mile Island (1979) and Chernobyl (1986) disasters increased regulation and public opposition.
📅 April 26, 1986
Location: Reactor No. 4 of the Chernobyl Nuclear Power Plant near Pripyat in the Ukrainian SSR, close to the Byelorussian SSR border.
Impact: An explosion resulted in one of the worst nuclear disasters in history. The explosion released massive amounts of radioactive material into the environment, leading to widespread contamination and long-term health impacts.
📅 March 28, 1979, 4:00 AM
Location: Unit 2 reactor of the Three Mile Island Nuclear Generating Station on the Susquehanna River in Londonderry Township, Pennsylvania, near Harrisburg.
Impact: A partial meltdown occurred, releasing radioactive gases and iodine into the environment, raising concerns about nuclear safety in the United States.
📅 March 11, 2011
Location: Fukushima Daiichi Nuclear Power Plant in Okuma, Fukushima, Japan.
Trigger & Impact: Triggered by a massive earthquake and subsequent tsunami, the disaster led to reactor meltdowns, hydrogen explosions, and the release of radioactive materials, causing significant environmental and health concerns.
Fission is a type of chain reaction where neutrons released during fission cause additional fission in at least one more nucleus, which then releases more neutrons, continuing the cycle.
In nuclear reactors, a moderator is used to slow down neutrons from their fast speeds to facilitate a sustained chain reaction.
Water-Cooled Reactors: Water serves both as the coolant and the moderator.
A breeder reactor is a type of nuclear reactor that generates more fissile material than it consumes. Unlike conventional reactors that use uranium-235, breeder reactors can use more abundant isotopes like uranium-238.
📝 EXAM IMPORTANT - Breeder Reactors in India
India plans to set up six Fast Breeder Reactor units, with the first two units located in Kalpakkam, Tamil Nadu.
Sites for the remaining units are being identified, and all six units are expected to be operational by 2039.
Fewer fatalities per unit of energy compared to coal, petroleum, natural gas, and hydroelectricity.
Emits no greenhouse gases and has lower life-cycle carbon emissions than common renewables.
Average global capacity factor is 89%, indicating efficient and reliable energy production.
Risks of accidents, as evidenced by Fukushima in 2011.
Long-term storage of radioactive waste.
High construction costs and slow deployment compared to other renewable energy sources.
Nuclear power is the fifth-largest source of electricity in India, following coal, gas, hydroelectricity, and wind power.
As of November 2020: India operates 23 nuclear reactors across 8 nuclear power plants
Combined Installed Capacity: 7,380 MW
FY 2020-21 Generation: 43 TWh (3.11% of total)
Under Construction: 10 reactors (8,000 MW)
In October 2010, India planned to reach a nuclear power capacity of 63 GW by 2032.
The 2011 Fukushima nuclear disaster sparked numerous anti-nuclear protests in India:
Historically, India's nuclear power plants have experienced low capacity factors:
Lifetime Weighted Energy Availability Factor (as of 2021): 66.1%
Recent Improvement (2019-2021): 74.4% availability factor
Despite challenges like nuclear fuel shortages
India is advancing thorium-based fuel technologies, aiming to design and develop a prototype atomic reactor using thorium and low-enriched uranium.
This is a key component of India's three-stage nuclear power program.
📝 EXAM IMPORTANT - Recent Development
December 5, 2025: Russia's state-owned nuclear corporation Rosatom delivered the first consignment of nuclear fuel for the initial loading of Kudankulam Nuclear Power Plant's Unit-3 in Tamil Nadu.
Significance: The delivery coincided with President Vladimir Putin's visit to New Delhi, highlighting the strategic importance of Indo-Russian partnership.
Fuel Production: The fuel assemblies were produced by the Novosibirsk Chemical Concentrates Plant and arrived via a cargo flight operated by Rosatom's Nuclear Fuel Division.
Total Shipments: Seven shipments from Russia are planned to supply the full reactor core and reserve fuel under a 2024 contract.
Fuel Supply Contract: Guarantees lifetime fuel supply for both the Third and Fourth VVER-1000 reactors.
🏭 Kudankulam Project Scale:
Tarapur Atomic Power Station (TAPS)
Maharashtra
Rajasthan Atomic Power Station (RAPS)
Rajasthan
Madras Atomic Power Station (MAPS)
Tamil Nadu
Narora Atomic Power Station (NAPS)
Uttar Pradesh
Kakrapar Atomic Power Station (KAPS)
Gujarat
Kaiga Generating Station (KGS)
Karnataka
Kudankulam Nuclear Power Plant (KKNPP)
Tamil Nadu
📝 India-Russia Cooperation (Dec 2025):
Rosatom delivered first fuel for Unit-3. Six reactors planned, 6,000 MW total capacity. India's largest nuclear project.
Prototype Fast Breeder Reactor (PFBR)
Tamil Nadu
Gorakhpur Haryana Anu Vidyut Pariyojana (GHAVP)
Haryana
Jaitapur Nuclear Power Project
Maharashtra
As of 2022: Global nuclear capacity was 390 GW
Supplying about 10% of global electricity
As of August 2023: 410 civilian reactors worldwide
With more under construction and planned
Largest fleet in the world
Generating nearly 800 TWh/year
Operating with a 92% capacity factor
Energy forestry involves growing fast-growing tree or woody shrub species specifically for biomass or biofuel used in heating or power generation.
Species: Poplar, Willow, Eucalyptus
Growth Cycle: 2 to 5 years before harvest
Species: Alder, Ash, Birch, Eucalyptus, Poplar, Sycamore
Growth Cycle: 8 to 20 years before harvest
Wood is a highly efficient source of bioenergy in terms of energy released per unit of carbon emitted.
Wood products have multiple end-uses.
Helps prevent soil erosion.
Cleans and improves soil quality.
Experiments in Sweden show willow plantations improve soil and water quality compared to conventional crops.
Can meet bioenergy demands while providing multiple benefits:
Potential Yields: Can reach up to 11 oven dry tonnes per hectare annually
Commercial Reality: Actual yields in commercial plantations, such as in Scandinavia, may be lower
Energy forestry offers a sustainable and flexible alternative to fossil fuels, with significant environmental benefits and the ability to adapt to market and ecological conditions.
✓ Largest contributor to India's electricity generation.
✓ Coal-based power dominates the thermal sector.
✓ Accounts for ~75% of total power production.
✓ Gas-based plants supplement power supply.
✓ Diesel-based plants have minimal contribution.
Madhya Pradesh
Gujarat
Odisha
Chhattisgarh
Chhattisgarh
⚡ EXAM IMPORTANT: Thermal Energy contributes maximum to India's total electricity production (~75%)
Coal (~55%) – The largest contributor to electricity generation.
Gas (~7%) – Used for peaking power supply.
Diesel (<1%) – Minimal contribution.
Solar & Wind (~15%) – Rapidly growing.
Hydropower (~12%) – Major source of renewable energy.
Plays a small but stable role in energy production.