Now, scientists turning paddy straw into ‘pellets’

Gurvinder Singh

Tribune News Service

Ludhiana, December 22

In an initiative that will give farmers an incentive and avenue to sell paddy straw instead of burning it, scientists at the Punjab Agricultural University (PAU) are turning paddy straw into ‘pellets’.

After treatment, these are not only put back in the soil to maintain its fertility, but also for the generation of hot water and cold water. The ‘zero-emission’ pilot project is not only meant to deal with the menace of stubble burning, but also reducing carbon footprint to reduce global warming.

Under this project named Energy Harvest, stubble is compressed to turn into small pellets. These pellets can be directly used in power-generation plants, but for putting these for even better use, these pellets are heated under controlled conditions to leave 40 per cent solid residue of ‘biochar’. During the heating process, vapour from pellets goes into ‘hot water generator’ to generate hot water and later are then put into ‘vapour absorption machine’ to generate cold water, thus producing several useful products.

“The biochar still retains nutrients, which can be put back into the soil not only to maintain its fertility, but some portion of it becomes carbon, which goes into the soil,” says Dr Manpreet Singh Mawi, a senior scientist at the varsity working on this project.

“The temperature of hot water goes up to 85° C, whereas that of cold water generated through the process goes down to 5° C, which can be utilised for different heating and cooling applications, including air conditioning and in cold stores,” says Dr Sudhakar Saji, a senior scientist at Aston University, UK, who is collaborating for this project.

The advantage of turning straw into pellets is that these not only save space, but are easy to store as well. “We have already saved 600 tonnes of straw from burning in around 300 acre of farmland,” says Dr Saji. As part of the project, Dr OP Choudhary, head, department of soil science at the varsity said while the project was still in the pilot stage, the prospects look good in terms of reduction of carbon footprint, retaining soil fertility as well as preventing emission of gases. He said the department is also studying the use of the ‘biochar’, which is used as a byproduct to make water less saline for irrigation purposes.

NTPC mulls use of agri residue for power generation

It is learnt that the National Thermal Power Corporation (NTPC) will also float tenders for procuring such pellets soon. During visit to the varsity, an official from the corporation said the corporation was considering replacing 10 per cent of the fuel for power generation from coal to agricultural residue. He said the corporation was taking this step to reduce carbon footprint. So, different varieties of such pellets are being explored. This will give farmers a reason and a channel to sell the residue instead of burning it in the fields.