In the Bureau of Energy Efficiency Vapi chemical cluster reports, is wood counted as a carbon saving or as zero, and which upgrade pays back fastest?

In five Bureau of Energy Efficiency (BEE) Vapi reports, a wood gasifier replacing furnace oil pays back in 1.03 years at one unit and 2.90 at another, while two wood boilers take 2.96 and 2.76. The boiler reports count wood saved at 1.4 tonnes of carbon dioxide a tonne. The gasifier reports count wood as renewable.

The five reports side by side

• Boiler, 400 kilograms of steam an hour: cost rupees (Rs) 5.10 lakh, wood saved 49 tonnes a year (135 down to 86, boiler efficiency 41.4 up to 65 percent), benefit Rs 1.72 lakh, payback 2.96 years, internal rate of return 18.53 percent, printed carbon dioxide (CO2) cut 68 tonnes.
• Boiler, 600 kilograms an hour: Rs 6.13 lakh, wood saved 63 tonnes (200 down to 137, efficiency 44.41 up to 65 percent), Rs 2.22 lakh, 2.76 years, 21.17 percent, CO2 88 tonnes.
• Hot air generator: Rs 6.78 lakh, wood saved 150 tonnes while using 14,000 kilowatt hours (kWh) of power a year, Rs 4.45 lakh, 1.52 years, 46.64 percent, CO2 198 tonnes.
• Wood gasifier, 400,000 kilocalories (kcal) an hour: Rs 9.50 lakh, furnace oil replaced 56.70 tonnes by 216 tonnes of wood and 4,700 kWh, Rs 9.18 lakh, 1.03 years, 78.25 percent, CO2 180 tonnes.
• Wood gasifier, 500,000 kcal an hour: Rs 15.60 lakh, furnace oil replaced 34.44 tonnes by 131.2 tonnes of wood and 6,266 kWh, Rs 5.38 lakh, 2.90 years, 19.50 percent, CO2 105 tonnes.
• Prices are Rs 3,500 a tonne for wood in the boiler and gasifier reports, and Rs 30,000 a tonne for furnace oil in the gasifier reports.

Two treatments of wood

The 400 kilogram boiler report says its CO2 figure takes an emission factor of 1.4 tonnes of CO2 for each tonne of wood. 49 x 1.4 is 68.6 and 63 x 1.4 is 88.2, which the reports print as 68 and 88. For the hot air generator, 150 x 1.4 is 210, and the printed 198 is 12 tonnes lower, about what 14,000 kWh of power would add at 0.86 kilograms a kWh (our arithmetic; the report prints no power factor).

Both gasifier reports instead say CO2 reduced comes from the furnace oil saved, considering wood as a renewable source of energy. Our check, with the Intergovernmental Panel on Climate Change (IPCC) residual fuel oil default of 77.4 tonnes of CO2 per terajoule (TJ) and 40.4 gigajoules a tonne, which is 3.13 tonnes for each tonne: 56.70 tonnes of oil is 177 and 34.44 tonnes is 108, against the 180 and 105 printed. The printed 105 implies about 3.05 a tonne.

So the boiler and generator CO2 lines count wood saved as a cut, and the gasifier lines count wood burnt as zero. Our reading: CO2 from burning wood is biogenic and sits outside Scope 1, so only the gasifier figures, which replace a fossil fuel, are a Scope 1 cut. The Vellore husk boiler reports print no CO2 cut for biomass saved.

Why the same gasifier pays back so differently

The gasifier reports are for two units. The first burns 35 kilograms of furnace oil an hour for 6 hours a day on 270 days, 1,620 hours. The second burns 41 kilograms an hour for 3 hours a day on 280 days, 840 hours. The larger gasifier is sized for the second unit's higher hourly heat, 410,000 kcal against 350,000, but that unit runs about half the hours, so it saves 34.44 tonnes of oil against 56.70. Hours of use drive the payback more than the size. Check your own burner hours before you read either figure as yours.

The 600 kilogram boiler and the first gasifier, rebuilt

• Boiler wood: 200 minus 137 = 63 tonnes. 63 x Rs 3,500 = Rs 2.205 lakh (printed Rs 2.22 lakh). Payback 6.13 / 2.22 = 2.76 years
• Boiler CO2: 63 x 1.4 = 88.2 tonnes
• Gasifier oil: 35 kilograms x 6 hours x 270 days = 56,700 kilograms, 56.70 tonnes. Heat 35 x 10,000 = 350,000 kcal an hour; wood at 3,500 kcal a kilogram and 75 percent efficiency is 350,000 / (3,500 x 0.75) = 133.3 kilograms an hour
• Gasifier money: oil 56.70 x 30,000 = Rs 17.01 lakh, less wood 216 x 3,500 = Rs 7.56 lakh, less power 4,700 x Rs 5.7 = Rs 0.27 lakh = Rs 9.18 lakh
• Payback: 9.50 / 9.18 = 1.03 years

All inputs are the reports' own figures. The CO2 treatments are as the reports state them; the Scope 1 reading is ours.

What Senseible does here

Senseible reads fuel invoices and electricity bills into monthly records, so the fuel invoices you upload give a year of use before a change to compare against. Burner hours and the stock of wood on hand come from your own logs, which you add.

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Sources: BEE, Detailed project report: energy efficient boiler 400 kilograms an hour, Vapi dyes and chemicals cluster (SAMEEEKSHA), BEE, Detailed project report: energy efficient boiler 600 kilograms an hour, Vapi dyes and chemicals cluster (SAMEEEKSHA), BEE, Detailed project report: hot air generator, Vapi dyes and chemicals cluster (SAMEEEKSHA), BEE, Detailed project report: wood gasifier 400,000 kcal an hour, Vapi dyes and chemicals cluster (SAMEEEKSHA), BEE, Detailed project report: wood gasifier 500,000 kcal an hour, Vapi dyes and chemicals cluster (SAMEEEKSHA)

Last reviewed 2026-11-05. Report figures are from BEE's Small and Medium Enterprises (SME) programme project reports, at the report year's prices. Check today's wood and oil prices, your burner hours and a current quote before you rely on the payback.