Stubble to stove: Turn straw into year-round kitchen fuel

Chandigarh: Why burn paddy stubble when it can provide biogas equivalent to 30-35 cylinders a year to power your kitchen? All it needs is to install batch-fed biogas plants that Ludhiana’s Punjab Agricultural University (PAU) has developed and put straw residue from a 3-acre field into it.
The solution manages problematic paddy straw and generates free kitchen fuel year-round.The batch-fed biogas plant — double the size of a household water tank, roughly — has an initial cost of Rs 3 lakh. Unlike traditional cow-dung-based biogas plants that require daily feeding, these plants need only paddy straw once every three months. That’s why they are called batch-fed plants.


Aimed at the domestic scale, the innovation has the potential to curb the burning of paddy stubble. Developed by PAU’s renewable energy engineering department under the leadership of principal scientist Sarbjit Singh Sooch, the dry fermentation biogas plant has been approved by the Ministry of New and Renewable Energy but its use remains limited to institutional settings until it attracts more farmers.
Sooch said: “The plant uses paddy straw in batches of 15 quintals. Since one acre produces about 20 quintals of straw typically, the plant can handle the stubble from 3 acres and generate 3-4 cubic metres of biogas a day, equivalent to about 3 cylinders a month.” The plant also generates slurry every three months, which is easy to manage. While cow dung is also a raw material, it is required in small quantities, making it unnecessary for the plant to be fed daily. No requirement of daily feeding means that farmers without cattle can also install it.
Despite its efficiency and ease of operation, farmers are reluctant to adopt these plants due to the high initial cost. The govt has received proposals for increased subsidies but is able to offer the farmers only Rs 14,500 for each plant — the same as for cow-dung-based plants. The PAU recommends a 60-70% subsidy to encourage wider adoption. As a result, only 20 units have been installed in the region, so far. Of these, 14 are demonstration units set up in PAU’s Krishi Vigyan Kendras (KVKs) and four are installed in Haryana. Only two farmers in Punjab have installed this plant.