Rice straw: Transforming a residue into a valuable resource in Punjab, India
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Agricultural waste burning is one of the world's largest sources of seasonal air pollution. In India’s Punjab province, 15.4 million tonnes of rice straw are burnt after each crop harvest. Globally, around 450 million tonnes of crop residues are burnt each year, resulting in 1.2 million tonnes of methane emissions.
Burning crop residues not only harms human health and the climate but also deprives the soil of essential nutrients and affects its pH levels, moisture, available phosphorus, and organic matter. For each tonne of rice straw burnt, 5.5 kg of nitrogen, 2.3 kg of phosphorous, 25 kg of potassium and about 1.2 kg of sulfur are lost. Like other types of agricultural residues, however, rice straw can be used for multiple purposes to further climate, health and broader sustainability goals.
Rice straw has proven viable for water purification, electricity production, and biofuels, as well as ground cover, compost, and animal feeds. However, its potential has been limited by value chain gaps, which prevent private sector actors from capitalizing on the resource. To help the government of India achieve its policy objectives and contribute to its Nationally Determined Contribution (NDC) targets, the Climate and Clean Air Coalition (CCAC) and the Food and Agriculture Organization of the United Nations (FAO) jointly supported a project to identify how this crop residue can be used in environmentally sustainable and economically viable ways by both farmers and entrepreneurs.
Due to the pressure to plant wheat within three weeks of harvesting rice, farmers need to dispose of the straw quickly. Without the established infrastructure to collect and deliver the rice straw to the market for private sector actors, burning is often the only option for farmers. Attaching an economic value to this residue, usually considered waste by many, is the most effective way to incentivize farmers and entrepreneurs to utilize rice straw for more effective and sustainable means.
FAO developed a study to assess the requirements for mobilizing rice straw as a valuable resource and examined its potential to be an energy source to replace coal and traditional transport fuels in India.
The analysis found that making rice straw-derived biofuels profitable requires large-scale production, and India has the potential to be one of the first countries where a viable value chain could be established. As crop residues are important for maintaining soil quality as mulch and compost, the study based its modeling on using only 30 percent of available crop residues.
The study concluded that an investment of US$309 million would be needed to collect, transport and store this amount of rice straw within a 20-day period. This would be a major step in enabling the function of a market for rice straw and its downstream products.
Successful development of this value chain would reduce greenhouse gas (GHG) emissions by about 9.7 million tonnes of CO2 equivalent and around 66,000 tonnes of particulate matter (PM2.5). Using 30 percent of the rice straw to replace coal-fired power would achieve 143 percent of the National Thermal Power Corporation's initial target of procuring 5mn tonnes/year of pellets per year to cofire in its thermal power plants.
Economically viable uses for rice straw, in both second-generation ethanol and burnable pellets, require facilities operating at large scale. The Government of India has set a target of 20 percent ethanol in all petrol by 2025, and there is a projected increase in demand for high-quality ethanol. However, second-generation ethanol may still require government subsidies or pricing mechanisms until the full demand for ethanol enters the market. For their part in the value chain, farmers would earn between INR 550 and 1 500 ($6.66-$18.16) per tonne of rice straw.
The Government of India is actively supporting the development of these value chains and is exploring measures to subsidize critical gaps in the value chain. It aims to reduce its dependence on energy imports and improve livelihoods and value chains in the agricultural sector. Public transport fleets in India are already largely run on compressed biogas, one of the economically viable products which can be produced from rice straw.
"We need to identify rural, agricultural raw materials which have the potential to bring about a revolution. It will bring about a lot of development and create employment opportunities," said Indian Minister for Road Transport and Highways, Shipping and Water Resources, River Development and Ganga Rejuvenation. “This will lead to a decrease in imports, an increase in exports and making our economy stronger," he added.
Watch the project video here.
Read the publication here.