Why in the news?

  • The Ministry of Coal launched the 14th Round of Commercial Coal Mine Auction, introducing Underground Coal Gasification.

Underground Coal Gasification (UCG)

  • What is it?:  Underground Coal Gasification (UCG) is an in-situ (on-site) process that converts coal in the ground into combustible gas by injecting controlled amounts of oxidants (air, oxygen, or steam) through boreholes and extracting the product gas through production wells.
  • Process:
    • Drilling Wells: Two wells are drilled: one for injection and one for production.
    • Injection of Oxidants: Air, oxygen, and steam are injected to partially oxidize the coal underground.
    • Gasification Reaction: The reaction produces syngas (a mixture of CO, H₂, CH₄, CO₂, and small hydrocarbons).
    • Gas Extraction: The syngas is brought to the surface through the production well for power generation or as a chemical feedstock.
  • Uses of Syngas:
    • Power generation (gas turbines)
    • Production of methanol, ammonia, and synthetic fuels
    • Hydrogen generation
  • Advantages:
    • No need for surface mining: Avoids land disturbance and large-scale waste handling.
    • Economic utilization of deep/unmineable coal seams: Exploits coal that cannot be mined economically or safely.
    • Cleaner than direct coal combustion: Allows pre-combustion carbon capture and easier emission control.
    • Energy security: Expands domestic resource utilization, supporting Atmanirbhar Bharat in energy.
    • Potential for hydrogen economy: Syngas can be a source of clean hydrogen for industrial and mobility sectors.
  • Environmental Considerations:
    • Benefits:
      • Reduced surface disturbance compared to open-cast mining.
      • CO₂ management possible through capture and underground sequestration.
    • Concerns:
      • Groundwater contamination due to leakage of gases or chemicals.
      • Subsidence (collapse of underground cavities).
      • Monitoring challenges for deep subsurface reactions.
  • Indian Initiatives:
    • Policy Support: The Ministry of Coal has included UCG under its energy diversification and clean coal initiatives.
    • Technology Partnerships: Collaboration with global technology providers (e.g., Linc Energy, Ergo Exergy) and R&D with CSIR-CIMFR and IITs.
    • Pilot Projects: 
      • ONGC Energy Centre (OEC) – pilot in Gujarat (Vastan Lignite Block).
      • CMPDI and Singareni Collieries Company Ltd (SCCL) – project proposals in Telangana and Odisha.
  • Challenges:
    • Subsurface complexity: Geological heterogeneity makes process control difficult.
    • Environmental regulation: Need for robust groundwater protection standards.
    • Technology costs: Initial setup and monitoring systems are capital-intensive.
    • Public acceptance: Environmental and safety concerns hinder rapid deployment.