Is the Vapi 4 lakh kilocalorie wood gasifier in the Bureau of Energy Efficiency report big enough for the oil burner it replaces?

Not clearly. The Bureau of Energy Efficiency (BEE) Vapi report names a 400,000 kilocalorie (kcal) an hour wood gasifier for a burner that needs 350,000. Its spec table gives two answers, about 309,600 kcal and about 459,000, so it cannot settle it. Ask the maker for output at your own wood and hours.

What a gasifier does, in plain words

A wood gasifier heats wood with very little air, so the wood gives off a burnable gas instead of burning outright. The gas is piped to the same burner that used furnace oil, a thick fuel oil. Think of a wood stove that makes its own cooking gas.

The report is a detailed project report (DPR), a costed plan for one upgrade, by the Bureau of Energy Efficiency (BEE) for Vapi dye and chemical units.

What the burner needs

• Oil burnt: 35 kilograms an hour at 10,000 kcal a kilogram = 350,000 kcal an hour.
• Hours: 6 hours a day x 270 days = 1,620 hours. 35 x 1,620 = 56,700 kilograms, the 56.70 tonnes the report prints.
• Wood to match, at 3,500 kcal a kilogram and a gasifier efficiency of 75%: 350,000 / (3,500 x 0.75) = 133.3 kilograms an hour. 133.3 x 1,620 = 216 tonnes, as printed.

What the spec table says

• Model RG-200, rated output 360 kilowatts of heat, able to replace up to 30 litres an hour of high speed diesel. It burns 175 kilograms of wood chips an hour at full output, holds about 800 kilograms in its hopper, takes wood at 15% moisture and is charged by hand once an hour. Auxiliary power is 7.5 horsepower.
• Our conversion: 360 kilowatts x about 860 kcal for each kilowatt hour = about 309,600 kcal an hour. On that line alone it is below the 350,000 the burner is said to need and the 400,000 in the report's title. 400,000 kcal an hour is about 465 kilowatts.
• The same table burns 175 kilograms of wood an hour at full output. At 3,500 kcal a kilogram and the report's 75% that would be about 459,000 kcal an hour. So the table gives two answers, 309,600 or about 459,000, and the maker must say which.
• The sentence above the table calls it a gasifier of 5,00,000 kcal, which looks carried over from the sister 500,000 kcal report. That report's model RG-300 is rated 600 kilowatts and also burns 175 kilograms an hour.
• Wood: 175 x 1,620 hours = 283.5 tonnes if run flat out. The saving counts 216, which is 76% of that (our arithmetic).

The old boiler test has mixed units

The text says the existing boiler runs at 68.01% and the annexure prints 68.1%. In the annexure, steam is given as 400 kilograms a day over 24 operating hours, while heat input is given as 350,000 kcal a day. 350,000 is 35 kilograms x 10,000, which is an hourly figure. Also 400 x 622 = 248,800, not the 238,400 printed. So we cannot tell which basis the 68% rests on.

The annexure gives the fuel as 10,000 kcal a kilogram, the value the report uses for furnace oil, while the typical unit above it is described as using wood. Our reading: treat the 0.05 and 0.10 kilograms per kilogram of product in this report as fuel, not as proof of wood use.

The money

• Net saving Rs 9.18 lakh a year in rupees (Rs): oil saved less wood bought and extra power. A lakh is 100,000. The line-by-line sum is on the Vapi reports page linked below.
• Cost Rs 9.50 lakh = 8.30 equipment + 0.20 civil work + 0.50 miscellaneous + 0.50 fitting. Payback 9.50 / 9.18 = 1.03 years. Own money Rs 2.38 lakh, loan Rs 7.13 lakh.

Does 360 kilowatts cover the burner?

• Burner heat need: 350,000 kcal an hour
• Gasifier rating: 360 kW x 860 = 309,600 kcal an hour
• Wood burn at full output: 175 x 3,500 x 0.75 = 459,375 kcal an hour
• Shortfall at the rating: 350,000 minus 309,600 = 40,400 kcal an hour, 11.5% of the need
• Rating the report's title implies: 400,000 kcal an hour = about 465 kW

Burner need and rating are the report's own. The 860 kcal for each kilowatt hour is a standard unit conversion, and the shortfall and the 459,375 line are our arithmetic.

What Senseible does here

Senseible reads fuel invoices and electricity bills into monthly records, so the oil bought each month is on file. Divide by your burner hours for the hourly burn. Gasifier output is the maker's figure to give; meters can be set up with the Senseible team on request.

• Green loan readiness check
• Vapi reports: wood counted as a cut or zero
• Biomass gasifier or LPG furnace
• Coal to biomass boiler: loan readiness

Sources: BEE, Detailed project report: bio mass gasifier 4,00,000 kCal/hr, Vapi chemicals and dyes cluster (SAMEEEKSHA), BEE, Detailed project report: bio mass gasifier 5,00,000 kCal/hr, Vapi chemicals and dyes cluster (SAMEEEKSHA)

Last reviewed 2026-11-07. Figures are from the report named above, written in 2010; costs, fuel prices and paybacks are at that year's prices. Check today's prices and a current maker's quote before you rely on the payback.