Material Insights · Understanding the Material World

Bagasse and black-liquor cogeneration: Impact and additionality

Renewable power that strengthens a renewable host

What this tab covers The impact and additionality lens: direct emission cuts, side benefits for water and air, and the risk of prolonging the life of a polluting host plant.

Residue-fired cogeneration is among the largest renewable CHP sources and displaces fossil steam and grid power. Its climate value depends on residues being genuinely surplus and on efficient, low-particulate boilers.

Direct Scope 1 and Scope 2 abatement

Favourable

India had 9,821 MW of bagasse cogeneration plus 936 MW of non-bagasse biomass cogeneration in October 2025 (MNRE data), up slightly from 9,806 MW in December 2024. In the US, renewable fuels fire nearly 8 GW, close to 40%, of boiler and steam turbine CHP, and AF&PA members drew 63% of their energy from biomass, much of it black liquor and residues, in 2022. Because the fuel is biogenic, each MWh exported displaces grid emissions while the mill's own steam carries little fossil CO2. Using CEA's weighted average grid factor of 0.727 t CO2 per MWh (FY2023-24), 1 MW running at 60% load factor would avoid about 3,500 t CO2 a year on its net output (calculated); this is an upper bound, since only power that truly displaces grid or captive fossil supply counts.1109161125

India bagasse cogeneration (Oct 2025) 9,821.32 MW10 India non-bagasse cogeneration 935.99 MW10 Renewable-fuelled US boiler/steam turbine CHP nearly 8 GW, close to 40%1 AF&PA member energy from biomass (2022) 63%16 CO2 avoided per MW at 60% load factor about 3,500 t/yr at 0.727 t/MWh (calculated)1125

Water and air synergy

Mixed

Older bagasse boilers emit particulates and need electrostatic precipitators or bag filters. DOE's 1999 assessment of black liquor steam reforming projected cuts of about 50% in SO2 and over 65% in NOx compared with recovery boilers, plus removal of the smelt-water explosion risk. Mills also reuse condensate, reducing fresh water demand. Trade press reports that Indian mill upgrades also cut process steam use from about 40% to 32% of cane weight or less.69

Projected SO2 cut, black liquor reforming about 50%6 Projected NOx cut over 65%6 Steam use, before and after upgrade about 40% to 32% of cane9

Avoided lock-in

Favourable

This tile helps a renewable host rather than prolonging a fossil one. The upgrade path is clear: black liquor gasification could lift electrical efficiency above 40% and raise mill power output by at least 50%, according to a 1999 DOE projection (dated), though the technology has not been widely commercialised. The main risks are using bagasse that could feed higher-value products, and coal co-firing in the off-season.6

Projected black liquor gasification efficiency above 40% electrical6 Projected mill power increase at least 50%6

Sources

  1. Steam Turbines, CHP Technology Fact Sheet Series (DOE/EE-2976) US Department of Energy, 2025
  2. New process will recover more energy from black liquor and improve environmental performance and safety of paper making (1999, dated) US DOE Office of Industrial Technologies, 1999
  3. High efficiency levels: tapping bagasse-based cogeneration plants to add to India's renewable power (MNRE data) (trade press) Power Line, 2025
  4. Green frontiers: increasing scope of bioenergy in the energy transition (MNRE data, October 2025) (trade press) Renewable Watch, 2025
  5. Order No. 02 of 2025: determination of tariff for procurement of power from biomass and bagasse based cogeneration projects (control period 2023-27) Gujarat Electricity Regulatory Commission, 2025
  6. Facts about energy use and the paper industry American Forest and Paper Association, 2024
  7. CO2 Baseline Database for the Indian Power Sector, User Guide Version 20.0 (FY 2023-24) Central Electricity Authority, Government of India, 2024