India relies heavily on imports of liquefied natural gas (LNG) and fertilizers to meet domestic demand. Over the past three years (2022-2024), the country has imported 22 million tonnes of LNG and eight million tonnes of fertilizers in nutrient equivalents (nitrogen, phosphorus, and potash) per annum, accounting for approximately 46 per cent and 31 per cent of its domestic demand, respectively.
Excessive dependence on foreign sources not only strains the country’s foreign exchange reserves, but also renders the country vulnerable to disruptions in global supply chains and fluctuating global prices affecting food production, agricultural profitability, and food prices. Furthermore, the increasing use of fossil fuels and chemical fertilizers has led to degradation of natural resources and the environment, ultimately affecting human health.
Interestingly, although agriculture contributes to these problems, it also offers unique solutions. India has a huge livestock population, including 303 million cattle and buffaloes, that produce over 1,271 million tonnes of dung per annum. This abundant resource can be converted from what is often considered a waste and environmental contaminant into a valuable source of renewable energy and natural fertilizers.
Technological advancements in waste management have facilitated the conversion of dung into clean fuel for domestic and commercial applications without compromising its nutritional contribution to agriculture.
Dung economics
In India, approximately 35 per cent of the total dung is utilised as traditional domestic fuel by rural households, while the remaining 65 per cent is available for manuring.
Given this usage pattern, dung adds 2.64 million tonnes of nitrogen, 1.16 million tonnes of phosphorus, and 2.48 million tonnes of potassium to the soil. Nevertheless, the potential of dung as a commercial source of renewable energy remains largely unexploited.
Given the prevalent utilisation pattern, processing dung currently used as manure for energy production without compromising its nutrient contribution to agriculture could generate an estimated 13.4 million tonnes of bio-compressed natural gas (CNG). If the entire 1,270 million tonnes of dung were to be processed, it could yield 21.8 million tonnes of bio-CNG, which is nearly equivalent to the country’s LNG imports. Moreover, this process generates an additional 3.4 million tonnes of organic fertilizer, potentially reducing fertilizer imports by approximately 43 per cent.
The processing of dung manure can significantly reduce the methane emissions that would otherwise be released from unmanaged waste into the environment. Furthermore, the resultant slurry utilized as a biofertilizer enriches the soil with essential nutrients and beneficial microorganisms, enhancing its structure, water retention capacity, and long-term fertility. Notably, with the government’s emphasis on natural and organic farming, the demand for dung-based organic fertilizers is expected to expand.
The potential bio-CNG produced from dung equals 31.9 billion litres of petrol, which can reduce carbon emissions by up to 60 per cent when utilised as a fuel alternative.
Feedstock issues
The governments’ schemes to promote biogas production from dung to provide clean cooking fuel and reduce fossil fuel dependence have met with limited success due to inadequate feedstock availability at the household level.
However, the policy emphasis is now shifting towards using dung for the production of biogas and bio-CNG on a commercial scale.
To support this transition, it is necessary to develop efficient dung collection models and incentives for farmers; offer financial assistance, particularly for new bioenergy facilities; and implement carbon credit trading schemes as an additional incentive for investing in biogas and bio-CNG projects.
Kumar is Principal Scientist and Pratap S Birthal is Director, ICAR-National Institute of Agricultural Economics and Policy Research, New Delhi. Views are personal