Reclimatize.in  ·  27 April 2026  ·  Fertilisers  ·  CCTS Offset Mechanism  ·  Low-Cost Abatement

N₂O Abatement at Nitric Acid Plants: India’s Highest-Leverage CCTS Opportunity in the Fertiliser Sector

At current CCC prices and abatement costs, N₂O catalytic reduction at nitric acid plants delivers a 4-to-8 times financial return on every rupee of abatement investment. No process change is required. The technology is mature. And the CCTS offset mechanism is specifically designed to credit exactly this type of project. This is the fastest-payback decarbonisation opportunity available to Indian fertiliser companies in 2026.

The fertiliser sector’s decarbonisation challenge is typically framed around its largest emission source: the natural gas used as feedstock and fuel in ammonia synthesis, which accounts for the majority of total Scope 1 and Scope 2 emissions at an integrated ammonia-urea complex. The transition pathway for that dominant emission source — green hydrogen replacing natural gas under the Hydrogen Purchase Obligation — is clear in regulatory intent but expensive in execution, with green hydrogen currently costing approximately Rs 400 to 500 per kg against natural gas-based hydrogen at Rs 60 to 120 per kg equivalent.

But within the fertiliser sector there exists a second emission category — N₂O from nitric acid production — that receives far less analytical attention and far less management focus, despite being an extraordinarily high-leverage abatement opportunity. Nitric acid is produced at fertiliser complexes primarily as an intermediate for ammonium nitrate and calcium ammonium nitrate fertilisers. The Ostwald process that converts ammonia to nitric acid uses platinum-rhodium catalysts to oxidise ammonia at 800 to 950°C, producing nitric oxide (NO) as the primary product and releasing nitrous oxide (N₂O) as an unavoidable process by-product. N₂O is not destroyed in the absorption column — it passes through as a tail gas emission unless specifically captured and destroyed by a downstream abatement system.

The reason N₂O abatement deserves its own dedicated analytical treatment is the combination of three factors that makes it unique in India’s industrial decarbonisation landscape: the enormous GWP of N₂O (273 times CO₂ on a 100-year basis under IPCC AR6), the low cost of the abatement technology relative to the CO₂e value of the emission avoided, and the availability of the CCTS offset mechanism to monetise the abatement through Carbon Credit Certificates tradeable on IEX and PXIL. No other single-technology intervention in Indian industry offers the combination of scale, speed, cost efficiency, and established carbon market monetisation pathway that N₂O abatement at nitric acid plants provides.

The N₂O emission: understanding the scale of the opportunity

Understanding why N₂O abatement represents such a large CO₂e opportunity requires working through the numbers at a plant level. A typical integrated fertiliser complex in India producing 300,000 tonnes of nitric acid per year — which would support approximately 200,000 to 250,000 tonnes per year of ammonium nitrate or calcium ammonium nitrate production — emits N₂O at concentrations of approximately 700 to 2,000 parts per million in the tail gas stream, at total N₂O emission rates of 700 to 2,000 tonnes of N₂O per year depending on the catalyst type, plant age, and production conditions.

The numbers in the formula above are not illustrative of a future scenario — they are an approximation of the current financial opportunity at a single mid-size nitric acid plant at current CCC prices. Rs 42.5 crore of net annual return from an investment of approximately Rs 8 to 15 crore in catalytic abatement equipment — before any government subsidy, before any SIGHT-type incentive, before any procurement preference — represents one of the highest-return industrial investments available in India today, across any sector, not just within the fertiliser sector.

The technology: tertiary catalytic reduction and its alternatives

Three technical approaches to N₂O abatement at nitric acid plants have been deployed commercially. Tertiary catalytic reduction — installation of a dedicated N₂O decomposition catalyst in the tail gas stream after the absorption column — is the most widely adopted approach globally because it is retrofittable to existing plants without modification to the ammonia oxidation reactor, operates independently of the primary Ostwald process catalyst, and is effective across the full range of N₂O concentrations found in industrial tail gas streams.

Secondary catalyst approaches — which modify the platinum-rhodium primary catalyst or add a secondary catalyst within the ammonia oxidation reactor to simultaneously reduce N₂O formation at source — are technically effective but require more complex integration with the primary process and have longer installation timelines because they involve the ammonia burner assembly. Secondary approaches are typically more appropriate for new plant construction than for retrofits to existing plants.

Extended absorption approaches — which prolong the absorption process to decompose N₂O into nitrogen and oxygen within the absorption column — are less capital-intensive than catalyst-based approaches but also less effective, typically achieving 30 to 60 percent N₂O reduction rather than the 80 to 95 percent achievable with tertiary catalytic reduction.

For India’s existing fleet of 30 to 35 nitric acid plants — most of which were built between the 1970s and 2000s using Uhde, Espindesa, or Chemico technology — tertiary catalytic reduction is the appropriate starting point for almost all operators. It minimises disruption to ongoing production, can be installed during scheduled plant shutdowns of 7 to 14 days, and does not require any modification to the ammonia oxidation section that would require a fresh environmental clearance or statutory approval.

The CCTS offset pathway: how to register and what to expect

The CCTS offset mechanism, which BEE opened for non-obligated entities in June 2025, includes N₂O abatement at nitric acid plants as one of the eight approved project categories eligible for CCC issuance. The registration and verification pathway follows the framework established in BEE’s Detailed Procedure for the Offset Mechanism (Version 1.0, March 2025).

Project registration begins with the preparation of a Project Design Document using the BEE-approved N₂O abatement methodology — which draws on the UNFCCC CDM AMS-III.I methodology for N₂O destruction at nitric acid plants, adapted for the CCTS framework. The PDD must document the project scope, the baseline N₂O emission rate (established through continuous N₂O monitoring for a minimum of 60 days pre-abatement), the abatement technology selected, the monitoring and reporting plan, and the third-party validation approach. For companies that completed CDM N₂O abatement projects before 2012, much of this documentation will already exist and can be adapted rather than prepared from scratch.

The verification cycle under the CCTS offset mechanism requires continuous electronic N₂O monitoring with data logging for the duration of the crediting period, annual report submission to a BEE-accredited Carbon Verification Agency, and BEE review before CCC issuance. The monitoring requirement is more demanding than the manual sampling approaches used in some CDM projects — continuous electronic monitoring is required — which adds approximately Rs 30 to 80 lakh in monitoring equipment capital cost per plant for new installations. For CDM veterans with continuous monitoring systems already installed, this is a zero-incremental-cost requirement.

The project economics: building the financial case

The financial case for N₂O abatement at nitric acid plants has never been stronger than it is in April 2026, for three reasons. First, the CCTS offset CCC price of Rs 1,740/tCO₂e — the current IEX CCC price — is significantly above the expected Phase 1 compliance market launch price of Rs 600 to 900/tCO₂e. Offset CCCs from non-obligated entities will need to be priced at a discount to compliance market CCCs to attract buyers, but even at a 30 to 40 percent discount — Rs 1,000 to 1,200/tCO₂e — the financial return on N₂O abatement investment remains 2.5 to 4 times the abatement cost. Second, FY2026-27 CCTS targets are more stringent than FY2025-26 across all seven notified sectors, which means compliance market demand for CCCs — and therefore the price that obligated entities will pay for offset credits — will be higher in 2027 than in 2026. Third, the CCTS offset mechanism explicitly permits project crediting for a period of 10 years from project start date, providing long-term revenue visibility that supports project financing at lower cost of capital than point-in-time investment analysis would suggest.