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| Fig. 1: Harmful Algal blooms in a pond in Tamil Nadu: Effect of N-rich runoff entering fresh water bodies. (Source: Wikimedia Commons) |
Meeting rising global food needs while mitigating climate impacts requires a careful examination of synthetic nitrogen fertilizers and their associated environmental costs. This report examines India's position within the food security-energy-environment nexus of nitrogen fertilizer production, use, and recovery, and evaluates viable pathways toward a more sustainable and resilient nitrogen economy.
India's food security relies heavily on synthetic nitrogen fertilizers. India consumes approximately 19 Mt of Nitrogen/yr, supporting crop production that feeds around 646 million people. Of these, about 176 million depend directly on imported fertilizers and 379 million indirectly on imported natural gas or feedstocks. [1] The China-to-India N-fertilizer trade flow in 2021 was the largest globally, accounting for USD 1.5 billion. [2] Consequently, global supply shocks or geopolitical disruptions directly threaten domestic food security. [3,4] This highlights an urgent need to improve domestic fertilizer production capabilities.
India's Nitrogen economy has become environmentally unsustainable due to highly polluting manufacturing processes, inefficient fertilizer application, and poor waste-nitrogen recovery. Domestic fertilizer manufacturing alone emits around 45 Mt CO2/yr - excluding fertilizer transport and post-use N2O emissions from soils. [1] Fertlizer runoff containing reactive nitrogen species also ends up polluting freshwater bodies causing eutrophication i.e. the excessive growth of algae due to a high concentration of nitrogen and phosphorus pollutants. Such algal blooms cause large-scale aquatic ecosystem disruption and are extremely toxic if accidentaly connected to drinking water streams. Harmful algal blooms have been largely studied only in the context of the west but their alarming connection to excessive fertilizer use has recently garnered attention in the Indian context. [5]
Excessive fertilizer application - often exceeding the optimal 200 kg N/ha in agrarian states like Punjab - has degraded soil nutrient balance and reduced nitrogen-use efficiency. [6-8] National nitrogen budgets indicate that about 29% of applied fertilizer leaches to groundwater, and of the rest, 33% remains in the environment as reactive nitrogen pollutants. Government efforts, such as mandating neem-coated urea since 2015, intended to improve nitrogen-use efficiency, have not significantly reduced fertilizer application or nitrate losses, suggesting limited practical impact. [9,10] Addressing this inefficiency requires closing the nitrogen loop- recovering reactive nitrogen from agricultural runoff, and reusing it as fertilizer.
India's nitrogen economy relies heavily on fossil-based ammonia production, which is both energy-intensive and a major source of greenhouse gas emissions. Most domestic ammonia synthesis depends on natural gas, making the sector vulnerable to energy price fluctuations and international supply constraints. In 2020, India accounted for 8% of global ammonia production while importing 14% of traded ammonia. Approximately 90% of domestic ammonia capacity relies on natural gas, with imported natural gas costs over twice the U.S. price. [11] Decoupling ammonia production from fossil fuels is therefore critical for domestic energy security and climate mitigation.
Industrial ammonia synthesis is dominated by the Haber-Bosch process, where hydrogen is produced via methane-steam reforming and water-gas shift reactions, then combined with nitrogen over an iron catalyst. Hydrogen production consumes 90-95% of the total plant energy, making it the most polluting stage of fertilizer manufacturing. [11] Overall, producing one kilogram of ammonia requires 7.7-10.1 kWh of energy, primarily for hydrogen generation. [12] Transitioning to lower-emission hydrogen sources, such as electrolytic or biomass-based hydrogen, is essential to reduce both energy demand and CO2 emissions. Detailed strategies are discussed in the subsequent section.
Three strategies can build domestic, sustainable fertilizer production capabilities: (a) carbon capture and storage (CCS) at existing plants, (b) electrolytic hydrogen production using renewable electricity, and (c) biomass-based hydrogen production. [11,13,14] Each approach offers trade-offs between emissions, capital costs, and resource demands.
CCS allows continued use of fossil fuels while capturing CO2 produced during hydrogen and ammonia synthesis. Captured CO2 is transported and permanently stored in underground geological formations. [15] Indian plants already report up to 90% CO2 recovery from flue gas, demonstrating the approach's potential for near-term emission reduction. [16] However, this method does not eliminate fossil fuel dependence.
Biomass-based hydrogen provides a low-carbon alternative, by using CO2 fixed during plant growth, which is later released during ammonia synthesis by burning the biomass, resulting in net-zero emissions. [17] India generates approximately 178 Mt of surplus crop residue annually, which is typically burnt, causing severe air pollution. Using this residue as feedstock for ammonia production could simultaneously reduce emissions and mitigate air quality issues, although large-scale implementation remains limited. [18]
Electrolytic hydrogen production generates H2 from water using renewable electricity, which can also supply energy for the Haber-Bosch process. [13] While this pathway eliminates fossil fuel dependence, it requires 2-3 times higher capital investment and significantly more land or water than conventional production. [2] According to the IEA Sustainable Development Scenario, up to 45% of ammonia could be produced via electrolysis by 2050, provided sufficient investment. [11]
Decentralized electrolytic ammonia plants can reduce natural gas dependence by locating production near agricultural demand centers and using locally available renewable electricity. For example, in Bangalore, solar PV and wind electricity cost roughly USD 35/MWh and 33/MWh in 2020, comparable to the USD 78/MBtu cost of imported natural gas when converted to energy-equivalent units. With projected declines of around 25% in renewable electricity costs, local electricity-based ammonia synthesis could become both low-carbon and economically viable. [11]
Local production also reduces transportation emissions, increases fertilizer availability, stabilizes prices, and buffers farmers from fossil fuel price volatility. While decentralized plants may have higher per-unit costs due to limited economies of scale, they typically require lower upfront capital, lowering investment risk. [12,19] Because renewable electricity output varies, electrolytic processes must operate efficiently across a range of currents, requiring research into electrocatalysts capable of maintaining high ammonia production under fluctuating inputs. [11]
Overall, decentralized, renewable-powered ammonia synthesis offers a feasible pathway toward a more resilient and low-carbon nitrogen economy.
Fertilizer access and pricing strongly influence farmer decisions in India. Farmers rarely view nitrogen fertilizers as an environmental problem; timely, affordable availability during short sowing windows is their dominant concern. Recent supply shortages, resulting in long queues and protests in several states between 2021 and 2025, highlight how disruptions immediately affect agricultural operations. [20,21] In such periods, many farmers resort to advance purchases, warehousing of fertilizers, or informal channels to avoid missing the sowing season. [22,23]
These episodes occur within a broader policy structure that shapes fertilizer use patterns. India's long-standing subsidy policy keeps urea prices far lower than other N-sources, encouraging systematic over-application regardless of crop need. This price distortion has reduced nitrogen-use efficiency, accelerated soil nutrient imbalance, and increased long-term dependence on subsidized N. [6] For small and tenant farmers already facing tight credit and volatile input costs, these incentives reinforce high fertilizer intensity as a risk-minimizing strategy. [24]
Efforts to constrain fertilizer consumption through regulation or supply controls have historically led to diversion, hoarding, and black-market activity. [20,22] These market and policy realities are therefore essential when evaluating low-carbon ammonia pathways. Even if electrolytic or biomass-derived ammonia becomes technically viable, adoption will depend on whether delivered costs are comparable to conventional urea. [6,23] Any new production model must therefore align technical feasibility with the economic and behavioral incentives that govern India's fertilizer market.
India's fertilizer sector requires a low-carbon, resilient nitrogen supply. Decentralized, renewable-powered nitrogen refineries that recover reactive nitrogen from agricultural runoff and convert it into ammonia, urea, or other value-added products can achieve this. Combining local production with nitrogen recovery reduces environmental losses and stabilizes fertilizer availability. This approach of an "Electrocatalytic Nitrogen Refinery" warrants further investigation.
© Devashish Bhave. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute, and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
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