India's state-owned generator NTPC has demonstrated 20pc torrefied biomass-coal co-firing at a 110MW unit at its Tanda power plant in the northern state of Uttar Pradesh.
The test was part of NTPC's efforts to expand biomass co-firing across its coal-fired fleet as it aims to lower emissions. Each percentage point of biomass co-firing has the potential to reduce carbon emissions by approximately the same percentage, while also helping in mitigating air pollution caused by direct burning of agricultural waste in farmlands, NTPC said. The generator currently conducts 7-10pc non-torrefied biomass co-firing at NTPC's Dadri power plant, near Delhi.
Torrefied biomass was found suitable for higher co-firing percentages without significant system modifications, NTPC said. The torrefied biomass was produced by heating biomass in the absence of oxygen to exhibit characteristics akin to high-quality coal. The gross calorific value and cost of torrefied biomass pellets were currently equivalent to imported coal, it added. Costs could be reduced with the maturity of technology and market in the long run, NTPC said.
India's push to cut coal reliance
NTPC's efforts are part of India's broader goal of cutting emissions as the country aims to trim reliance on coal in the coming years and attain net zero by 2070.
Delhi had initially asked Indian utilities to adopt co-firing of at least 5pc biomass pellets by October 2022. But only a fraction of utilities followed the directives, which eventually prompted the federal power ministry to review the biomass co-firing policy.
The ministry amended the policy in June last year and delayed the start date of co-firing, asking all coal-based thermal power plants with bowl mills to use a minimum 5pc blend of biomass pellets made primarily from agricultural residue, with effect from the start of India's 2024-25 fiscal year on 1 April. The threshold would increase to 7pc from the start of 2025-26, the ministry said. Plants with ball and race mills should co-fire the same percentages of torrefied biomass pellets made from agricultural residue during the same time frame, it said.
India has surplus biomass supplies of about 230mn t/yr, largely from agricultural residue, the power ministry previously said.
NTPC tenders
NTPC has awarded biomass supply contracts totalling about 5.2mn t for 20 power plants operated by NTPC, and a joint venture plant. Out of which, it has so far co-fired 316,657t of biomass pellets at 13 NTPC power plants and at the joint venture plant.
The generator is setting up biomass pellet plants at various locations to ensure a steady supply of pellets for co-firing. It has set up a 22 t/d non torrefied pellet plant at Lehra Mohabbat, Bhatinda in Punjab state. It is building a 100 t/d torrefied and 100 t/d non-torrefied pellet plant at joint ventureAravali Power's Jhajjar plant. It is also building a 50 t/d non-torrefied pellet plant at the Dadri plant.
