Contributors: M. Srinivas, DGM; R.V. Kiran, Senior Supervisor; Rohan Sabat, Supervisor; and P. Krishna Kishore, Supervisor, NTPC Restricted
The escalating consequences of climate change prompt a shift from carbon-heavy energy sources to cleaner alternatives. As a participant in the Paris Agreement, India has committed to lowering its carbon intensity by 45% by 2030 and achieving net-zero emissions by 2070. The energy sector is the largest emitter of carbon dioxide (CO2) in India, making its transition to renewable energy essential. Green ammonia, produced with renewable energy, offers a feasible path for decarbonization when co-fired in coal-based thermal power plants (TPPs), utilizing existing infrastructures while substantially reducing carbon emissions.
This article examines the feasibility of green ammonia co-firing in TPPs, addressing its practicality, advantages, and a strategy for implementation. Green ammonia represents an innovative method for decarbonizing TPPs by reducing greenhouse gas (GHG) emissions and improving renewable energy integration. The authors also propose commencing a pilot project in this arena.
Technical Viability of Green Ammonia Co-Firing
The technical viability of utilizing green ammonia as a co-firing fuel in TPPs is determined by its physical properties, integration hurdles, and potential for emission reductions. Key factors affecting technical viability include:
Combustion Compatibility: Studies suggest that co-firing up to 20% ammonia with coal is technically feasible without necessitating major alterations to the boiler systems. Experimental findings show stable combustion even at higher ammonia co-firing ratios, potentially reaching up to 80%. Necessary modifications may include advanced ammonia injection techniques, optimized nozzle designs, adjustments at the burner front, and selective catalytic reduction (SCR) systems to address nitrogen oxide (NOX) emissions.
Emission Characteristics: Co-firing with ammonia can significantly reduce CO2 emissions but poses challenges in managing NOX emissions. The use of enhanced SCR technologies or staged combustion methods is essential for minimizing NOX. Life cycle assessments indicate that green ammonia has the lowest GHG emissions, estimated at 1,062 kg CO2e per MWh, compared to blue and gray ammonia.
Energy Efficiency: Co-firing may reduce boiler efficiency by about 1% compared to conventional coal plants, while carbon capture and storage (CCS) integration often leads to an 8% efficiency drop due to the energy-intensive nature of CO2 capture technologies.
Infrastructure Requirements: Existing coal-fired plants will require modifications for the safe storage, transport, and injection of ammonia. Ammonia storage facilities must ensure temperatures below -33°C to maintain safety and operational effectiveness.
NOX Emission Control: Studies indicate that employing staged combustion along with SCR technologies can effectively limit NOX emissions to acceptable levels, even with higher ammonia co-firing ratios. Ongoing research into optimal injection technologies and SCR designs is crucial for meeting emission regulations.
Scalability and Integration: While infrastructure for ammonia has primarily been developed for fertilizer production, adaptation for energy applications is feasible. The incorporation of green ammonia into existing power plants is quicker and less complicated than implementing CCS, providing a strategic advantage for rapid decarbonization initiatives.
Technical Hurdles of Co-Firing Ammonia in Existing Coal-Based TPPs:
Ammonia Slip and Toxicity: Unburned ammonia, or ammonia slip, poses safety and environmental risks. Enhanced combustion technologies and SCR systems are vital to effectively mitigate these concerns.
Storage and Transportation: The safe handling of ammonia is crucial due to its toxic and flammable characteristics. Expanding infrastructure to accommodate large-scale ammonia use in power generation would require significant investment.
Cost of Green Ammonia: The current production cost of green ammonia stands at approximately $666 per tonne, primarily due to renewable electricity expenses. Advancements in production scale and reductions in renewable energy prices are necessary to make green ammonia a more feasible option.
Recent studies and pilot projects affirm the technical feasibility of green ammonia for co-firing in TPPs, suggesting it could serve as an effective decarbonization strategy when combined with efficient emission control technologies and cost-reduction measures. Although challenges related to NOX emissions, storage, and production costs persist, technological improvements in ammonia combustion and production show promise for its scalability as a solution in the energy sector.
Proposed Pilot Project: Community Green Fusion
We propose a pilot initiative aimed at implementing green ammonia co-firing as a sustainable energy project, employing advanced technologies to enhance decarbonization efforts. Renewable energy sources, such as solar and wind, will power an electrolyzer for green hydrogen generation, while an air separation unit will extract nitrogen from the atmosphere. These elements will converge in an eco-friendly ammonia synthesis facility to produce green ammonia.
The synthesized green ammonia will be stored and utilized for co-firing in boilers, replacing conventional fuels. This plan is designed to reduce GHG emissions and facilitate the integration of renewable energy into existing infrastructure. The project’s goal is to validate the practicality, cost-effectiveness, and environmental advantages of green ammonia co-firing, positioning it as a scalable solution for sustainable energy supply.
Project Planning
The project will span an area of 125 acres and include:
- A green hydrogen production facility (350 TPD) – occupying 30-35 acres.
- An ammonia synthesis unit (1,900 TPD) – covering 50-60 acres.
- An air separation unit – utilizing 10-15 acres.
- Electrical switchyards and substations (10-15 acres) along with a green belt area (30 acres).
- An industrial support area (20 acres).
Phased Implementation
The rollout of the green ammonia production facility will occur in stages:
Phase I: Preparatory activities including tendering, engineering, and initial civil infrastructure development.
Phase II: Scaling up production to 150 TPD of green hydrogen and 850 TPD of green ammonia, alongside infrastructure upgrades, including a central business district and utilities for water and electricity supply.
Phase III: Completing final civil works such as water treatment systems and infrastructure.
Funding sources for the project will comprise equity capital, government grants, loans, carbon tax savings, carbon credits, and improvements in environmental, social, and governance (ESG) practices. This structured approach ensures sustainable growth while securing financial and operational viability.
The
projected valuation for the suggested inexperienced ammonia production initiative is pegged at Rs 124.0336 billion. Primary expenditures are expected to be allocated for land procurement, infrastructure enhancement (including roads, drainage, and industrial amenities), energy framework, and initial operational expenses. The stepwise approach guarantees an organized allocation of resources for long-lasting development.
Capital investments for the pilot project will encompass expenses related to electrolysis, air separation units, and ammonia production and storage facilities. A well-structured financing strategy will support gradual growth of the initiative. Significant fiscal forecasts comprise:
- Expected reductions in green ammonia prices, decreasing from Rs 85 per kg in 2024 to Rs 70 per kg by 2035.
- Initial investments will likely be balanced by savings derived from decreased coal consumption and carbon levies.
- Revenue generation opportunities through carbon credits and enhanced ESG performance.
Key obstacles that may arise during project implementation include high initial capital needs, readiness of current infrastructure, and market acceptance. Ongoing governmental support through incentives, subsidies, and favorable policy frameworks will be crucial in ensuring the project’s financial feasibility.
Group Green Fusion’s Business Model: Evaluating Operational and Financial Dimensions
Our team has crafted a business model to assess the impact of various operational and financial aspects connected with establishing a green ammonia production unit and its subsequent application in co-firing scenarios.
By varying the co-firing ratio, our model is able to compute the levelized cost of green ammonia, capital expenditure needs for the project, anticipated carbon tax savings, capital expenditure distribution throughout the project’s lifespan, electrolysis costs, and variable costs associated with the co-fired plant. Below are insights derived from our model:
Capital Expenditure: The outline of capital investment for setting up a green ammonia facility indicates that expenses related to hydrogen production make up 48%, while nitrogen and ammonia costs account for 24%, collectively comprising over 70% of total project expenditure. This highlights that in the forthcoming decade, reducing electrolysis costs through technological advancements and shifts in supply-demand dynamics is essential for rendering green ammonia production economically viable.
Impact of Co-Firing Ratio on Variable Costs: As the co-firing ratio increases, the variable costs for coal-fired plants also escalate. Identifying an optimal point for the pilot project to balance cost implications against current market rates will be crucial.
Decrease in Electrolysis Costs: Over the coming decades, a decline in the cost of electrolysis is anticipated, attributed to technological maturation, shifts in market dynamics, and the scalability of projects, leading to reduced variable costs for co-fired units.
Carbon Tax Savings: An increase in the co-firing ratio is associated with heightened carbon tax savings. For instance, with a co-firing rate of 20%, savings surpass Rs 5 million daily.
Conclusion and Future Outlook
Green ammonia co-firing represents a crucial advancement in India’s shift toward sustainable energy. Despite the challenges, the long-term benefits—lowered emissions, economic savings, and alignment with national climate objectives—outweigh the hurdles. By capitalizing on technological advancements and forming strategic partnerships, TPPs can successfully integrate green ammonia into India’s energy ecosystem. Future research should prioritize scaling technology, enhancing cost efficiency, and ensuring active stakeholder involvement.
