Environment & Ecology
Context: The beginnings of a renewable energy revolution rooted in agriculture are taking shape in India with the first bio-energy plant of a private company in Sangrur district of Punjab having commenced commercial operations recently. It will produce Compressed Bio Gas (CBG) from paddy straw, thus converting agricultural waste into wealth.
About Bioenergy:
- Bioenergy is renewable energy made available from organic materials derived from biological sources. It is the energy derived from biomass such as bagasse, cotton stalk, coconut shell and wood, plants, etc.
Compressed Bio Gas (CBG):
- Bio-gas is produced naturally through process of anaerobic decomposition from waste and bio-mass sources like agriculture residue, cattle dung, municipal solid waste, sugarcane press mud, sewage treatment plant (STP) waste, etc.
- It is called CBG after biogas is purified and compressed, which has pure methane content of over 95%. CBG is exactly similar to commercially available natural gas in its composition and energy potential. Its calorific value and other properties are similar to CNG.
The need for CBG:
- It has become common practice among farmers in Punjab, Haryana and western Uttar Pradesh to dispose of paddy stubble and the biomass by setting it on fire to prepare fields for the next crop, which has to be sown in a window of three to four weeks. The resultant clouds of smoke engulf the entire National Capital Territory (NCT) of Delhi and neighbouring States for several weeks between October to December. This plays havoc with the environment and affects human and livestock health.
- The Capital’s air quality index (AQI) deteriorated slightly and continued to be in the “poor” category on Tuesday, according to the Central Pollution Control Board (CPCB) data of October 2022.
- Meanwhile, recently the Delhi government started spraying Pusa bio-decomposer solution in paddy fields in the city to reduce stubble burning. Commission for Air Quality Management in NCR and Adjoining Areas (CAQM) recently announced an immediate ban on all construction and demolition activity unregistered with the authority.
Some measures:
- The Government of India has put in place several measures and spent a lot of money in tackling the problem. The Commission for Air Quality Management in National Capital Region and Adjoining Areas (CAQM) had developed a framework and action plan for the effective prevention and control of stubble burning. The framework/action plan includes:
- in-situ management: incorporation of paddy straw and stubble in the soil using heavily subsidised machinery (supported by crop residue management (CRM) Scheme of the Ministry of Agriculture and Farmers Welfare).
- Ex-situ management, i.e., CRM efforts include the use of paddy straw for biomass power projects and co-firing in thermal power plants, and as feedstock for 2G ethanol plants, feed stock in CBG plants, fuel in industrial boilers, waste-to-energy (WTE) plants, and in packaging materials, etc.
- Additionally, measures are in place to ban stubble burning, to monitor and enforce this, and initiating awareness generation. Despite these efforts, farm fires continued unabated.
A project in place
Ex-situ uses of rice straw:
- In its search for a workable solution, NITI Aayog approached FAO India in 2019 to explore converting paddy straw and stubble into energy and identify possible ex-situ uses of rice straw to complement the in-situ programme.
- The results suggest that to mobilise 30% of the rice straw produced in Punjab, an investment of around ₹2,201 crore would be needed to collect, transport and store it within a 20-day period. This would reduce greenhouse gas (GHG) emissions by about 9.7 million tonnes of CO 2 equivalent and around 66,000 tonnes of PM 2.5.
Pellets:
- A techno-economic assessment of energy technologies suggested that rice straw can be cost-effective for producing CBG and pellets. Pellets can be used in thermal power plants as a substitute of coal and CBG as a transport fuel.
- Union Environment Ministry recently announced a ₹50 crore scheme to incentivise industrialists and entrepreneurs to set up paddy straw palletisation and torrefaction plants.
- Paddy straw made into pellets or torrefied can be mixed along with coal in thermal power plants.
- This saves coal as well as reduces carbon emissions that would otherwise have been emitted were the straw burnt in the fields, as is the regular practice of most farmers in Punjab and Haryana.
SATAT Scheme:
- With 30% of the rice straw produced in Punjab, a 5% CBG production target set by the Government of India scheme, “Sustainable Alternative Towards Affordable Transportation (SATAT)” can be met.
SATAT has following four objectives:
- Utilising more than 62 million metric tonnes of waste generated every year in India,
- Cutting down import dependence,
- Supplementing job creation in the country
- Reducing vehicular emissions and pollution from burning of agricultural / organic waste.
- From paddy stubble, CBG valued at ₹46 per kg as per the SATAT scheme will be produced. Paddy straw from one acre of crop can yield energy output (CBG) worth more than ₹17,000 — an addition of more than 30% to the main output of grain. This initiative is an ideal example of a ‘wealth from waste’ approach and circular economy.
Way forward:
- There are several other benefits of adopting CBG for a renewable energy revolution:
- the slurry or fermented organic manure from the plant (CBG) will be useful as compost to replenish soils heavily depleted of organic matter, and reduce dependence on chemical fertilizers.
- The plant will also provide employment opportunities to rural youth in the large value chain, from paddy harvest, collection, baling, transport and handling of biomass and in the CBG plant.
- Every year, about 27 million tonne of paddy straw is generated in Punjab and Haryana. About a third of this straw is from non-basmati rice, which cannot be fed to cattle as fodder because of its high silica content. This is usually burnt which adds to the air pollution crisis in Delhi NCR and adjoining areas. So, converting it into CBG is the last resort.
From the point of view of environmental benefits, renewable energy, value addition to the economy, farmers’ income and sustainability, this initiative is a win-win situation. It is replicable and scalable across the country and can boost the rural economy.
Source: The Hindu
