What does a 50 kW biomass gasifier power plant do for a tea factory's CO2?

About 121 t of CO2 a year at today's grid factor, not the 185.4 t in BEE's Jorhat report, for 180,000 kWh made from garden wood. It is more if the plant replaces diesel generator hours. Cost Rs 22 lakh, saving Rs 10.26 lakh, payback 2.14 years at 2010 prices.

Why Jorhat factories look at this

• Grid supply is available about 70% of the time; diesel generators cover the rest.
• The report blends grid power at Rs 5.50 and generator power at Rs 12 into Rs 7.45 a kWh.
• Woody biomass from the gardens is otherwise left to rot.

The plant and the money

• A downdraft gasifier feeding a 50 kW engine that runs on producer gas alone, 12 hours a day for 300 days: 180,000 kWh.
• Power valued at 180,000 x Rs 7.45 = Rs 13.41 lakh a year.
• Wood at 50 kg an hour: 180 t at Rs 1.75 a kg = Rs 3.15 lakh.
• Net Rs 10.26 lakh against Rs 22 lakh (gasifier and engine Rs 17 lakh, civil work Rs 2.50 lakh, commissioning Rs 0.50 lakh, contingency Rs 2 lakh): 2.14 years.
• The report's table labels wood power at Rs 1.25 a kWh; its own sum gives Rs 1.75.

Two numbers to pin down before you buy

• Wood per kWh: the report assumes 1 kg and gives no engine efficiency. Ask for a guaranteed figure at 50 kW; every extra 0.25 kg a kWh costs about Rs 0.79 lakh a year at the report's wood price.
• Running cost: the saving counts wood only. Add an operator and engine upkeep from the supplier's quote.

CO2 counted properly

The report applies 1.03 kg a kWh to every unit. On today's grid factor, 180,000 kWh is 121.5 t. Units that replace generator power save more: 2.645 kg for every litre of diesel the generator no longer burns, which the report could not estimate, so take it from your generator log. CO2 from the wood is biogenic and reported separately; its methane and nitrous oxide, about 5 t CO2e, stay in Scope 1.

One season of 3,600 hours

• All 180,000 kWh replacing grid power: x 0.675 = 121.5 t CO2
• If 30% replaces generator power: 126,000 kWh x 0.675 = 85 t, plus 2.645 kg per litre of diesel saved
• Wood methane and nitrous oxide: 180 t x 0.030 = 5.3 t CO2e
• Biogenic CO2 from the wood, reported separately: about 314 t

Grid at CEA's FY 2025-26 factor; diesel at 2.645 kg CO2 a litre. Wood at IPCC 2006 defaults (15.6 GJ a tonne; 112,000 kg CO2, 30 kg methane and 4 kg nitrous oxide per TJ) with AR6 warming potentials. Estimates.

What Senseible does here

Senseible reads electricity bills and diesel invoices into monthly kWh, litres and CO2, with diesel at 2.645 kg a litre, so both the grid units and the generator diesel the gasifier replaces show up. It has no wood factor; add the wood lines above. For a Rs 22 lakh project, the green loan check lists what a lender asks for.

• Green loan readiness check
• Tea dryer: 250 kW gasifier on coal
• Diesel generator CO2 per kWh against the grid
• Biomass boilers: methane stays in Scope 1
• Jorhat tea factories: coal, gas and CO2

Sources: BEE, Detailed project report: biomass gasifier of 50 kW for electrical application, Jorhat tea cluster (2010, SAMEEEKSHA), IPCC 2006 Guidelines, Volume 2 Energy, Tables 1.2 and 2.3, IPCC AR6 Working Group I, Chapter 7, global warming potentials (methane 27.0 non fossil; nitrous oxide 273), GHG Protocol Corporate Standard (biogenic CO2 reported separately from the scopes), CEA, CO2 Baseline Database for the Indian Power Sector, version 22.0 (FY 2025-26 grid factor)

Last reviewed 2026-11-01. Report figures are from a BEE SME programme project report; costs and paybacks are at the report year's prices. Check today's fuel and power prices and a current quote before you rely on the payback.