Underground Coal Gasification (UCG)

Underground Coal Gasification (UCG) is in the news because the Ministry of Coal has recently launched a significant pilot project in Jharkhand’s Jamtara District. This initiative aims to harness UCG technology, which converts unmineable coal into valuable gas for energy production.

More context:

1. Policy Background: In 2015, the Indian Ministry of Coal approved a dedicated policy framework to develop UCG in coal and lignite-rich areas. This policy was designed to address challenges related to mining difficult or inaccessible coal deposits.
2. Project Details: Coal India has selected the Kasta coal block in Jamtara District for this pilot project. The choice of this location aligns with the policy's objectives, and the project will test UCG technology adapted to India’s specific geological conditions.
3. Why It Matters:
   • Energy Production: UCG can convert coal that is not viable for traditional mining into synthetic gas, which can then be used for power generation or as a chemical feedstock.
   • Environmental Benefits: UCG can potentially reduce the environmental impact compared to conventional mining and coal usage by minimizing surface disturbance and improving efficiency.
   • Resource Utilization: It helps in tapping into coal reserves that are otherwise difficult to access, contributing to energy security.

The pilot project’s success could pave the way for broader adoption of UCG technology in India, contributing to more sustainable and efficient use of coal resources.

Underground Coal Gasification (UCG) is a process that allows for the extraction of energy from coal deposits that are otherwise difficult or impossible to mine using traditional methods.

How UCG Works

1. Gasification Process: UCG involves converting coal into synthesis gas (syngas) while it is still in the coal seam. This is achieved through in-situ combustion.
2. Initiation: The process starts by injecting steam and air or oxygen into the coal seam and igniting the mixture. The temperatures required are typically above 1000°C.
3. Reaction: The coal is gasified to produce syngas, which primarily consists of methane (CH4), carbon dioxide (CO2), hydrogen (H2), and carbon monoxide (CO). The exact composition of the syngas can vary based on factors such as coal type, temperature, and the type of oxidant used.

Products of UCG

1. Electricity: The syngas produced can be used to generate electricity. It can be combusted to produce steam, which drives a turbine, or the hot syngas can be used directly to drive a steam turbine.
2. Chemical Feedstock: Syngas can be used as a raw material to produce various chemicals, including methanol, hydrogen, and ammonia. Adjusting the hydrogen to carbon monoxide ratio allows for the production of different chemical products.
3. Hydrogen Production: UCG can also be used as a method for producing hydrogen, a potentially significant near-zero carbon energy carrier. Studies have explored combining UCG with solid oxide fuel cells (SOFCs) to generate electricity directly from hydrogen.

Benefits of UCG

1. Access to Unmineable Coal: UCG enables the extraction of energy from coal deposits that are otherwise too deep or otherwise inaccessible for conventional mining.
2. Reduced Capital Expenditure: UCG reduces the need for infrastructure associated with traditional coal mining, such as mining equipment, transportation, and storage facilities. This lowers the overall capital and operational costs.
3. Energy Density and Land Use: UCG requires significantly less land compared to traditional coal bed methane extraction methods. For the same amount of energy produced, UCG uses less than 3% of the land area required for coal bed methane.

Applications

• Energy Production: UCG can be integrated into energy production systems to supply electricity and heat.
• Chemical Manufacturing: The syngas can be converted into various chemicals and fuels, making it valuable for industrial applications.
• Hydrogen Generation: As a source of hydrogen, UCG could play a role in future energy systems focusing on low-carbon technologies.

Concerns

1. Induced Subsidence

Concern: The creation of voids in the coal seam during UCG can lead to subsidence, causing deformation in both the remaining coal and surrounding rocks.

Solutions:

• Monitoring and Modeling: Implement advanced monitoring techniques (e.g., satellite-based remote sensing, ground-penetrating radar) to track subsidence and deformation in real-time. Accurate geological modeling can predict potential subsidence and guide operational adjustments.
• Support Systems: Design and implement support systems to stabilize the surrounding rock mass, such as controlled mining techniques and reinforcement methods.
• Pre-emptive Measures: Conduct thorough pre-gasification site assessments to identify areas at higher risk of subsidence and develop contingency plans.

2. Contamination of Groundwater

Concern: Chemicals produced during UCG, such as phenols, benzene, and carbon dioxide, may migrate and contaminate groundwater sources.

Solutions:

• Containment Systems: Design robust containment systems, such as impermeable barriers and monitoring wells, to prevent the migration of contaminants.
• Water Management: Implement effective water management strategies to control the flow of water around the gasification area and prevent contamination. Regularly test groundwater quality to detect any potential contamination early.
• Cleanup Technologies: Develop and apply remediation technologies to address any contamination that does occur, such as advanced filtration and chemical treatment methods.

3. Lack of Proven Technology

Concern: The technology for converting India’s coal to syngas is not well-established, which affects the cost and viability of UCG projects.

Solutions:

• Research and Development: Invest in research and development to advance UCG technologies and reduce conversion costs. Collaboration with international experts and institutions can help accelerate technological advancements.
• Pilot Projects: Start with pilot projects to test and refine technology on a smaller scale before full-scale deployment. This approach can help identify and address technological challenges early.
• Cost-Benefit Analysis: Conduct thorough cost-benefit analyses to evaluate the economic feasibility of UCG projects, considering both direct and indirect costs. Explore funding options, such as government grants or public-private partnerships, to support technology development.

4. Unsteady-State Process

Concern: UCG processes are inherently unsteady due to variables like cavity growth, coal properties, water influx, and ash buildup, which affect reaction rates.

 Solutions:

• Process Control: Develop advanced process control systems to monitor and adjust operational parameters in real-time. Implement adaptive management strategies to respond to the dynamic nature of UCG.
• Simulation and Modeling: Use sophisticated simulation and modeling tools to predict and manage the unsteady behavior of the gasification process. This can help optimize process conditions and improve efficiency.
• Data Collection: Gather extensive data during gasification operations to better understand the unsteady aspects of the process and refine operational strategies based on empirical evidence.

Indian government has introduced several initiatives to advance coal gasification

1.National Coal Gasification Mission:

1. • Objective: This mission aims to achieve coal gasification and liquefaction of 100 million tonnes (MT) of coal by 2030.
   • Significance: It represents a strategic effort to transition from conventional coal usage to more efficient and environmentally friendly coal gasification processes, which can produce cleaner fuels and chemicals.
2. Scheme for Promotion of Coal/Lignite Gasification:
   • Details: This scheme provides financial assistance to support coal and lignite gasification projects undertaken by both public sector undertakings (PSUs) and private sector companies.
   • Allocation: The government has earmarked ₹8,500 crores for incentives under this scheme, aimed at encouraging investment and innovation in coal gasification technologies.
3. Joint Venture Agreement (JVA):
   • Collaborative Projects: The government is fostering partnerships through joint ventures to advance coal gasification projects. For example, the collaboration between Coal India Limited (CIL) and Bharat Heavy Electricals Limited (BHEL) is focused on setting up an ammonium nitrate plant using coal gasification technology.
   • Purpose: Such joint ventures are intended to leverage the strengths of both public and private sector players to achieve technological advancements and scale up the application of coal gasification.

Way Ahead

Attract Investment: Financial incentives, tax breaks, and subsidies can help make UCG projects more appealing to investors and companies, facilitating the development of new technologies and infrastructure.

1. Foster Innovation: By supporting research and development, the government hopes to advance UCG technologies, making them more efficient and cost-effective.
2. Promote Sustainability: UCG can potentially reduce the environmental footprint of coal utilization by lowering surface mining impacts and capturing more pollutants during the gasification process.
3. Enhance Energy Security: By diversifying the methods of coal utilization, India can improve its energy security and reduce dependence on imported fuels.
4. Create Jobs: The development and operational phases of UCG projects can create new job opportunities and stimulate local economies.