Dirty Air and Clean Technology

India has been an agrarian civilization since the dawn of humanity. One of the key reasons for India being a "golden bird" or economically prosperous country in the early millennia--a coveted prize to be won by colonizers--was because India had every type of resource, and enough man-power to utilize the resources.

Dirty Air

In the last few decades, India has seen a huge growth in the agriculture sector, which though useful from production standpoint, carries a heavy, not-so-visible cost with it--that of air pollution. Change of crop rotations and use of high-yield varieties of grains means that the farmers resort to eco-unfriendly means to dispose of the crop residue. This practice is prevalent almost all over India, and in many other Asian countries as well. But it becomes a problem of catastrophic proportions in northwestern India, because of the timing of agricultural fires and geographic patterns of winds and fog in the early winter season in the region. The fumes of agricultural fires travel long distances with the wind and reach the National Capital Region (NCR), where they form a "smog", mixing with the fog, and cause the AQI of the region to spike way beyond 500 for most days. An AQI > 500 is considered a public health emergency. The residents of NCR live with an AQI in the neighbourhood of 500 for almost the entire winter season.

According to the government agency System of Air Quality and Weather Forecasting (SAFAR) [1], the particulate matter (PM 2.5 and PM 10) in the city of New Delhi has been more than 20 times beyond the safe limit during the crop residue burning season. It has been estimated [2] that burning 1 tonne of rice residue yields 13 kgs of particulate matter, 60 kg CO, 1460 kg CO₂, 3.5 kg NO_x, 0.2 kg SO_2. Almost 90% of N and S, and 15–20% of P and K of the soil are lost.

So why do the farmers carry on with this practice? If the farmers can clear the land in a speedy way, they get the opportunity to sow high-yield varieties of wheat, which translates to higher revenue. Burning crop residue has the added advantage of an apparent zero-cost method of waste disposal. They, ofcourse, do not account for the costs associated with land degradation, health costs of respiratory and other health conditions caused by the pollution, and the externalities of the emissions in other places like NCR. Any solution proposed must address these key issues of the farmers.

Clean Technology

There has been growing concern and awareness of the problem of air pollution among the tech community in India and beyond. It would be unfair to say that there is no workable solution for the problem of stubble burning. Research on this topic has been piling up over the last decade, and many technological solutions and interventions have been proposed to resolve the problem amicably. Here is a quick recap of some of these solutions.

Repurposing Crop Residue to Generate Biogas and Biofertilizer

The problem of crop residue disposal was already solved more than a hundred and fifty years ago by Indians themselves: anaerobic digestion in the biogas digester. The world's first biogas digester was built in Bombay in 1859. The technology could not become popular in India, and was imported back into India after its popularization and mass-uptake in other countries like China, Europe and UK.

Biogas plant or "digester" [3] can take multiple types of feedstock: manure, crop residue, municipal wastewater, municipal solid waste etc. Europe is one of the leading producers of biogas and uses crop residue as the feedstock in great part (~50%). "Energy crops" are considered the best for yielding biogas, and can produce up to 300m³/ ton of residue feedstock [1]. It is estimated that India produces almost 620 million tonnes (MT) of crop residue per year. If all of this were repurposed into biogas and biofertilizer, India could produce energy and fertilizer at a very low cost, all over the country. Studies estimate that crop residues have the potential to generate ~17% of the total energy used in India.

As per studies [4], 13,915 kt is estimated to be open-field burning of rice straw in India. If all the surplus and 50% of the rice straw used in other activities is diverted to energy generation, it has the potential of 644.2 Peta Joules (PJ) of energy generation for India.

Where feasible, biogas can also be used to generate electricity, for heating (in cold countries), can be purified and used as cooking gas or as biomethane, used in vehicles.

In China, household biogas production accounts for almost 70% of biogas produced. Favorable policies that endorsed biogas production in rural areas aided the biogas boom in China.

Indian government has a Biogas Programme [5] which gives subsidies to anyone who wishes to install a biogas digester. As per Ministry of New and Renewable Energy (MNRE), there are a total of 4.31 million family-type biogas plants in the country. The focus of the government seems to be towards increasing the small-scale family-type biogas plants. But the technology can also be explored on large-scale, with public-private partnership setup, generating jobs, and giving a boost to the rural economy, reducing air, water and soil pollution.

Happy Seeder

TATA Trusts’ [6] Reviving the Green Revolution (RGR) cell in Punjab, in collaboration with Punjab Agricultural University, developed a seed-sowing machine known as the ‘Happy Seeder’. The machine, which is mounted on a tractor, can 1) cut rice crop residue, 2) sow seeds, and 3) spread the residue on the field for mulching, all at the same time. This is a technological innovation aimed at achieving zero-burn villages in the states of Punjab, Haryana and Uttar Pradesh.

Punjab state government offers a 50% subsidy on the Happy Seeder to farmers and a 75% subsidy to farmers' groups and cooperatives.

To assist farmers to adopt Happy Seeders [7], The Nature Conservancy India (TNC India), Borlaug Institute for South Asia (BISA), International Maize and Wheat Improvement Center (CIMMYT), Precision Agriculture for Development (PAD) and Tata Trusts, have come together under the project "Harnessing the power of Agricultural Residues through Innovative Technologies" (HARIT). Under the RGR and HARIT projects, farmers receive training and demonstrations, enabling the usage of the Happy Seeder in various districts of Punjab.

A survey by RGR shows that farmers report an increase in cost saving, net profit, soil conditions, and a decrease in fertilizer expenditure. A study [8] estimates significant reduction in wheat production costs, amounting to 136 USD ha^–1 owing to the usage of the Happy Seeder.

A lot of the farmers report renting the Happy Seeder, rather than purchasing it. This also contributes to an additional source of income for farmers owning the machine, and lower expenditure for those renting the machine.

Biofuels

"Biofuels" is a generic term given mostly to liquid fuels, as a replacement for petrol, diesel etc. Ethanol and Biodiesel are the main biofuels. Though Biogas is technically also a biofuel--it can be used as a fuel for vehicles like buses--it is not commonly considered in the bracket of "biofuels." Biofuels are used as replacement for diesel and jet fuel, lowering dependency on fossil fuels. Most biofuels are prepared from crops grown for that purpose, especially outside India. Corn, wheat, sorghum and sugarcane are common crops used for generating biofuels.

The transition towards biofuels has been happening at a global scale. USA, Brazil, Indonesia and China have been the leaders in the production of biofuels. India is a growing market for the production of Bioethanol.

In order to increase its production of biofuels, India already has surplus feedstock for biofuel production—agricultural residue from rice crops. Research [12] suggests that as of September 2023, biofuels contributed only 9% of India's renewable energy installed capacity. Based on survey data, India has ∼1313 PJ/year of bioenergy available in crop residue feedstock. This can help India achieve its Net Zero targets and also reduce the menace of air pollution due to crop residue burning.

As per the National Policy on Biofuels [14],

"Few studies undertaken in India have indicated a surplus biomass availability to the tune of 120 -160 MMT annually which, if converted, has the potential to yield 3000 crore litres of ethanol annually. Surplus biomass / agricultural waste which has cellulosic and lignocellulosic content, can be converted to ethanol using second generation (2G) technologies."

As per the latest IEA Renewables report [15], the demand for biofuels is growing in India and other emerging economies. This is a promising trend, and can be an important factor in production of biofuels, paving the way for India to be energy-independent and closer to its decarbonizing goals.

Many other low-tech methods of consumption of agricultural residue also exist, and have been used by farmers for decades, but they are often not chosen due to their costs or low economic profits for the farmers. For any technology to be taken up by the farmers, it should not only be easy to use, readily available, but also economically viable. Effective government policy can make that possible.

References:

1. Satpathy, P., Pradhan, C. Biogas as an alternative to stubble burning in India. Biomass Conv. Bioref. 13, 31–42 (2023). https://doi.org/10.1007/s13399-020-01131-z
2. The National Academy of Agricultural Sciences (NAAS) policy brief, October 2017, "Innovative Viable Solution to Rice Residue Burning in Rice-Wheat Cropping System through Concurrent Use of Super Straw Management System-fitted Combines and Turbo Happy Seeder".
3. IEA (2020), Biogas installed power generation capacity, 2010-2018, IEA, Paris https://www.iea.org/data-and-statistics/charts/biogas-installed-power-generation-capacity-2010-2018, Licence: CC BY 4.0
4. Butchaiah Gadde, Christoph Menke, Reiner Wassmann,
   Rice straw as a renewable energy source in India, Thailand, and the Philippines: Overall potential and limitations for energy contribution and greenhouse gas mitigation, Biomass and Bioenergy, Volume 33, Issue 11,
   2009, Pages 1532-1546, ISSN 0961-9534, https://doi.org/10.1016/j.biombioe.2009.07.018.
5. Biogas Programme (Phase-I) for FY 2021-22 to 2025-26
6. Ending burning of crop stubble through Happy Seeder technology
7. No Burn with More Earn: Critical role of Happy Seeder in ending crop residue burning
8. Keil, A., Krishnapriya, P. P., Mitra, A., Jat, M. L., Sidhu, H. S., Krishna, V. V., & Shyamsundar, P. (2021). Changing agricultural stubble burning practices in the Indo-Gangetic plains: is the Happy Seeder a profitable alternative? International Journal of Agricultural Sustainability, 19(2), 128–151. https://doi.org/10.1080/14735903.2020.1834277
9. Porichha, G.K.; Hu, Y.; Rao, K.T.V.; Xu, C.C. Crop Residue Management in India: Stubble Burning vs. Other Utilizations including Bioenergy. Energies 2021, 14, 4281. https://doi.org/10.3390/en14144281
10. New report estimates district-wise crop residue potential for bioenergy production
11. R. Jain, S. Saboo and A. Techkchandani, "Crop Stubble Burning: Can modern technology trigger a new revolution?," 2021 Innovations in Energy Management and Renewable Resources(52042), Kolkata, India, 2021, pp. 1-4, doi: 10.1109/IEMRE52042.2021.9386730.
12. Taveen S. Kapoor, Chimurkar Navinya, et al, Reassessing the availability of crop residue as a bioenergy resource in India: A field-survey based study, Journal of Environmental Management, Volume 341, 2023, 118055, ISSN 0301-4797, https://doi.org/10.1016/j.jenvman.2023.118055.
13. IEA (2024), Biofuel consumption in the acclerated case in India, 2015 to 2028, IEA, Paris https://www.iea.org/data-and-statistics/charts/biofuel-consumption-in-the-acclerated-case-in-india-2015-to-2028, Licence: CC BY 4.0
14. National Policy on Biofuels, 2018.
15. IEA (2024), Renewables 2023, IEA, Paris https://www.iea.org/reports/renewables-2023, Licence: CC BY 4.0