Authorities need to move now to expand straw gasification and combat the next airpocalypse that is worsened by farm residue burning every spring and autumn
The masks are back in north India. Air quality in the region that includes national capital Delhi plummeted to the lower end of the “Very Poor” category in 2019 autumn and 2019-20 winter. Unsurprisingly, the dip was accompanied by a small jump in the share of pollution from biomass burning.
This pattern is now well established and was particularly stark last autumn during the end October-early November ‘airpocalypse’ that paralysed north India, and especially the national capital region (NCR).
During the worst phase, schools were closed, flights diverted, trains cancelled and several offices in the NCR asked employees to work from home as air quality remained stuck at extremely hazardous levels for several days running.
According to the attribution modelling carried out by the government, the contribution of crop burning in neighbouring states where paddy stubble was being cleared by fire hovered around 40% for PM2.5 levels in Delhi.
As satellite images of the burning farms in India’s northwest went viral, monitoring by the System of Air Quality and Weather Forecasting And Research (SAFAR) revealed around 23,000 farm fires between October 28 and November 8 in Punjab, Haryana and Uttar Pradesh.
Burning of crop residue
Criminal charges were filed en masse against farmers. A carrot was in the offing too, as governments rushed to procure paddy stubble and announced financial incentives to farmers towards the end of November under pressure from the Supreme Court.
There were already subsidies on the purchase price of deep tilling machines popularly known as Happy Seeders, towards which the central government earmarks millions of rupees each year. In 2019, the scheme had an allocation of INR 11.5 billion (USD 160 million).
Government intervention thus far though has been akin to applying duct tape on a cracked dam wall, says agriculture and trade policy analyst Devinder Sharma. “Efforts from the government are nowhere near as sustained or as widespread as is required. The last minute efforts to procure paddy stubble, for example, has amounted to the collection of just 1-2% of the total residue. With the manpower and capacity that the government currently deploys, it is impossible to procure the massive amounts of residue. Just Punjab generates around 20 million tonnes, which is way beyond the government’s procurement capacity unless proper working channels are established that reach all paddy growing areas.”
While farmers are given a lot of stick for their seasonal role in Delhi’s air woes, there is no sign of the concerted effort required to comprehensively tackle the issue. “Paddy stubble burning, at the heart of the matter, is an economic decision taken by farmers. There is absolutely no reason for farmers to hold out if they can earn anything from the procurement of the stubble,” Sharma said.
“Instead, the government has been pushing heavy machinery down their throats through subsidies, which just does not work out given their high costs and low efficiencies. The fact that air pollution is not solely the result of seasonal stubble burning, and rather a symptom of overall failures in controlling industrial, vehicular and construction emissions is not lost on the farmer,” Sharma said. “The problem is one of priority. It is well known that if the administration earmarks and disburses adequate funds, which incidentally are a fraction of the bonuses it announces for government employees every year, this issue would have been resolved by now.”
Biomass resource atlas
According to the biomass resource atlas published by the Ministry of New and Renewable Energy (MNRE) and the Indian Institute of Science (IISc), India produces 495.85 million tonnes (MT) of crop every year, which results in the generation of 511.04 MT of biomass. Of this, about 145 MT is deemed to be surplus.
Residue from paddy holds the largest share by far in this biomass generation, amounting to around a third of both the total biomass generated and the surplus biomass. Strikingly, over 33% of this surplus crop residue, or around 50 MT, comes from the three states of Punjab, Haryana and Uttar Pradesh.
According to experts, handling such quantities of crop residue requires not only reactive measures but the setting up of well-planned infrastructure that go beyond viewing paddy stubble, and crop residue in general, as a seasonal scourge.
“The significance placed on Happy Seeders as a solution to crop stubble management is a testament to the short-sightedness of government policies, especially in light of seasonal changes due to climate change which has reduced the turnaround period between the kharif (autumn) harvest of paddy and rabi (winter) sowing of wheat to just around 15 days,” said Yogender Yadav, a post-doctoral fellow at the Sardar Swaran Singh National Institute of Bio-Energy in Punjab. “This turnaround period is too short for effective clearance by expensive Happy Seeder machines which cost up to INR 400,000 and can clear just 4-5 acres a day. A long-term approach would require setting up of strong procurement channels and establishment of infrastructure close to sites of procurement, which can enable a circular economy with regards to the stubble.”
Crop stubble as resource
Despite the momentum in exploring alternative fuel sources over the past decade or so, the transformational change of viewing crop stubble as resource rather than residue has not yet come to fruition in any discernible way. Prominent among the proposals to manage crop stubble has been the possibility of gasification which entails the conversion of crop stubble into natural gas through so-called digesters.
Gasification is basically the process of converting the heterogenous organic mixture of crop residues into natural gas through a series of processes involving heating and drying, pyrolysis, oxidation, and reduction heating — all in a specially designed digestion tank. The efficiency of the process depends on a variety of factors including biomass composition, moisture content, ash content, heating value, size, bulk density, char reactivity, gasiﬁcation temperature and equivalence ratios.
While currently, India’s bioenergy capacity is around 9.5 GW, some 14% of the total renewable potential, a 2016 evaluation published in the journal Energy Policy pegs the total potential to be between 23-35 GW, of which cereals alone account for anywhere between 19-28 GW, depending on the thermal efficiency. Incidentally, paddy residue accounts for almost 40% of all residue generated from cereals.
Not a silver bullet
The gasification option is no silver bullet, and requires careful planning to be viable. “Compared to waste such as sugarcane bagasse, rice straw energy yields are seen to be poor. Added to this are the high capital investments and technological bottlenecks which have together limited investments in bioenergy alternatives for paddy stubble and other cereal residues,” said S. Bhuvaneshwari, an assistant professor at SRM University who has been working on effective methods of crop residue management. “So far, scalable, large-scale projects have failed to yield dividends and this is evident in the stunted growth of the sector.”
The gulf in viability is clearly visible when one compares the proliferation of processing units turning sugarcane bagasse into ethanol with those for other crops such as paddy which are still few and far between despite the significant quantities of residue generated. Over 60% of the total bioenergy capacity of 9.4 GW comes from just three states — Uttar Pradesh, Maharashtra and Karnataka —ostensibly due to the large-scale sugarcane farming and refining in these states.
Bioenergy utilisation from non-bagasse agricultural residues by comparison has been paltry at under 700 MW, just about 7.5% of the total. For Uttar Pradesh, the state with the highest installed non-bagasse bioenergy capacity, the installed capacity amounts to 170 MW, just 8% of its total.
Put together, Punjab, Haryana and Uttar Pradesh utilise less than 400 MW of their non-bagasse bioenergy potential despite generating a third of the total biomass surplus.
Economic viability of such units may also depend on how they are planned and set up rather than solely on potential for conversion to gas. Take, for example, the case of the 1 MW capacity gasification plant set up by Sampurn Agri Ventures Pvt. Ltd. In Fazilka, Punjab.
The plant, in operation since 2006, works 350 days a year, digesting 25 tonnes of paddy straw a day and producing 1.247 MWh per year, which is sold to the government. Apart from generating energy and employment for locals, the project had a payback period of just over five years.
But efforts to scale such experiences have failed so far, mainly due to the cookie-cutter, one-size-fits-all approach that central and state governments have been pursuing, said Yadav. “The current shoot-and-scoot approach that governments undertake each year around this (stubble burning) time is not only short-sighted but also betrays poor understanding of the issue.”
“The only way in which the entire process can be viable and ensure a good pay-back period for investments is if small units are set up close to sites of procurement with good facilities for storage of raw material and energy produced. This is the only way this process becomes profitable and viable,” said Yadav.
Achieving this requires continued government support which has been near-absent so far. “So far governments have been chasing numbers with planned plants of several MW capacities, which is why each year several plans are announced for bioenergy investments and yet nothing takes off. Government support and long-term planning is imperative to ease requirements of capital investments,” Yadav said. “With good support such projects established through cooperatives could yield great results. Unfortunately, there seems to be little sign of such movement.”
Transformational change seldom grows from stop-gap, reactive measures. As the issue of crop burning recedes from the front pages of newspapers, one can only hope that the next harvesting season brings with it sustained action and policy initiatives that look at stubble burning as more than just a month of inconvenience, pressure and passing the buck. Going by experience, the odds that the authorities will do some long-term planning remain discouraging.
To put it in perspective, stubble burning leads to air pollution peaks every spring and autumn, while the bulk of air pollution from coal-fired power plants, oil burning vehicles and dust-spewing construction activities remain mostly unaddressed. So, even large-scale gasification of rice and wheat straw will save only a bit of your lungs. Under pressure, the Indian government produced a National Clean Air Plan, but that remains a record of pious intentions, almost none of which has been implemented yet.