Coal and Thermal Power Plants in India | 15 Jun 2024

Source: IE

Why in News?

Recently, According to the data on NITI Aayog’s energy dashboard, India’s coal-fired thermal capacity grew to 218 GW in FY24 from 205 GW in FY20, a 6% growth.

• A recent report alleges that in 2014, the a company misrepresented low-grade Indonesian coal as high-quality, and sold it to a public power generation company in Tamil Nadu.

What is the Current Status of India's Power Sector?

• Background: The power market is experiencing a growing demand-supply mismatch due to a slowdown in new coal-fired power plant capacity and a lack of effective storage options for renewable energy. 
  • This has put pressure on the country's grid managers, especially with increasing power demand during soaring temperatures. 
• Thermal Power Plants: The share of coal-fired power generation has risen to 75% in FY2023-24 from 71% in FY2019-20.
  • Generation by coal-fired thermal plants also increased by 34% from 960 billion units (BU) to 1,290 BU, and the average plant load factor (PLF) rose from 53% to 68%.
  • In the past five years, thermal capacity addition has fallen short of the government’s targets by an average of 54% annually with the private sector only contributing 7% of new capacity. 
    • The private sector has contributed only 1.7 GW, or 7% of the total thermal capacity added in the last five years. 
  • There has been a push for investments in new thermal power projects, including from the private sector, with a target of adding 80 GW of new thermal power capacity by 2032.

• Renewable Energy: India's solar capacity has seen a significant surge, doubling to 81 GW. Wind power capacity has also witnessed impressive growth, increasing by 22% to reach 46 GW.

  • Setting up a new coal plant (Rs 8.34 crore per MW) is considerably more expensive compared to setting up a solar power plant (per MW cost much lower).

What Grade of Coal does India Produce?

• High Grade’ vs ‘Low Grade’ Coal: The Gross Calorific Value (GCV) determines the gradation of coal based on the amount of heat or energy that can be generated from burning it. 
  • Coal is a mixture of carbon, ash, moisture, and other impurities. The higher the available carbon in a unit of coal, the better its quality or 'grade.'
  • The most important uses of coal are in thermal power plants and in powering blast furnaces for steel production, each requiring different kinds of coal.
    • Coking coal is needed for producing coke, an essential component of steel making, and requires minimal ash content. 
    • Non-coking coal can still be used to generate useful heat for running boilers and turbines despite its ash content.
• Characteristics of Indian coal: Indian coal historically has high ash content and low calorific value compared to imported coal. 
  • Domestic thermal coal has an average GCV of 3,500-4,000 kcal/kg, while imported thermal coals have over 6,000 kcal/kg. 
  • Also, Indian coals also have over 40% ash content, while imported coal has less than 10%. 
    • Burning high-ash coal results in higher particulate matter, nitrogen, and sulphur dioxide.
    • The Central Electricity Authority (CEA) recommended in 2012 that about 10-15% blending of imported coal can be safely used in Indian power boilers designed for low-quality Indian coal.
• Clean Coal: Clean coal is achieved by increasing the carbon content and reducing ash content. 
  • This can be done through washing plants on coal plant sites, which use blowers or a 'bath' to remove ash. 
  • Another method is coal gasification, which converts coal into gas using steam and hot pressurised air or oxygen. 
    • The resulting syngas are then cleaned and burned in a gas turbine to generate electricity, increasing the efficiency of coal used.
• Future of Coal in India: In 2023-24, India produced 997 million tonnes of coal, showing an 11% increase from the previous year. Most of the production came from the state-owned Coal India Ltd and its subsidiaries.
  • Despite commitments to move away from fossil fuels, coal remains the main source of energy in India. 

What are the Technologies to Reduce Emissions from Thermal Power Plants?

• Flue Gas Desulfurization (FGD): FGD systems scrub flue gas (exhaust gas) with methods like wet or dry scrubbing process that absorbs SO₂, removing it from the emissions before they are released into the atmosphere. 
  • This technology targets sulfur dioxide (SO₂), a major air pollutant linked to respiratory problems.
• Selective Catalytic Reduction (SCR): SCR systems tackle nitrogen oxides (NOx), another group of pollutants contributing to smog and acid rain.
  • During the SCR process, hot flue gas passes through a catalyst coated with precious metals like platinum. This triggers a chemical reaction that converts harmful NOx into harmless nitrogen gas and water vapor.
• Electrostatic Precipitators (ESPs): It targets particulate matter (PM), tiny particles linked to respiratory illnesses.
  • ESPs use high voltage electricity to charge particles in the flue gas. These charged particles then stick to collector plates, which are periodically cleaned.
• Fabric Filters (Baghouses): Similar to ESPs, baghouses capture particulate matter. They may be used in conjunction with ESPs or as a standalone technology.
  • Flue gas passes through a fabric filter bag, trapping PM on the fabric's surface. The bags are periodically shaken to release the collected particles.
• Coal Washing: This pre-combustion technology aims to reduce emissions by improving coal quality.

  • Coal is washed with water to remove impurities like ash and sulfur, which can contribute to air pollution when burned.

• Co-firing with Biomass: This approach involves co-burning biomass (organic matter) along with coal.

  • The revised Biomass Policy of 2023, mandates 5% biomass co-firing in thermal power plants from FY 2024-25. 

What are the Existing Challenges and Government Initiatives in Thermal Power Sector?

• Challenges:
  • Demand-Supply Mismatch: Rising electricity demand is outpacing the addition of new capacity of thermal power plant, particularly from renewable sources due to their unreliable nature.
  • Reliance on Coal: Coal remains the dominant source of power generation, despite its environmental impact and rising costs.
  • Limited Private Sector Participation: The private sector is hesitant to invest in new coal plants due to financial and environmental concerns.
  • High-Ash Indian Coal: Domestic coal has lower calorific value and higher ash content compared to imported coal, leading to higher emissions.
  • Technological Limitations: Large-scale battery storage solutions are still under developed which are crucial for integrating renewables into the grid.
• Government Initiatives:

  • UDAY (Ujwal Discom Assurance Yojana)

  • PM-KUSUM 

  • Green Energy Corridor (GEC)

  • National Smart Grid Mission (NSGM) and Smart Meter National Programme

  • International Solar Alliance (ISA)

  • Sovereign Green Bonds for Solar Sector

Way Forward

• Accelerating the growth of solar and wind power, with a focus on grid integration solutions like large-scale battery storage.
• Implementation of technologies like Flue Gas Desulfurization (FGD) and Selective Catalytic Reduction (SCR) to reduce emissions from existing coal plants.
• Offering financial and regulatory incentives for private companies to invest in cleaner and more efficient power generation technologies.
• Promoting energy efficiency measures to reduce overall demand and lessen the pressure on the grid.
• Modernising the grid infrastructure to handle the integration of variable renewable energy sources and improve overall efficiency.
• Exploring alternative sources like clean coal gasification, gravity battery, harnessing ocean energy and nuclear power (with strict safety protocols) to meet energy needs.

Conclusion

India's power sector transformation requires a well-defined roadmap that balances immediate energy needs with long-term sustainability goals. By focusing on renewables, clean coal technologies, and energy efficiency, India can ensure a reliable and sustainable power supply for its growing economy.