Why does the Bureau of Energy Efficiency 800 kilogram aluminium wood gasifier report pay back in 0.94 years when the 400 and 600 kilogram ones take about 1.7?

In three Bureau of Energy Efficiency (BEE) Jagadhri reports, a wood gasifier on a 400, 600 or 800 kilogram aluminium pit furnace pays back in 1.69, 1.68 and 0.94 years. The gasifier costs almost the same in each. The melts a day and working days differ.

What each report assumes

• 400 kilogram melts: 64 litres of furnace oil a melt at rupees (Rs) 25 a litre, Rs 1,600. Wood 224 kilograms at Rs 3, Rs 672, plus Rs 121 of power and labour: Rs 793. Saving Rs 807 a melt. 5 melts a day, 240 days: 1,200 melts, 76.8 kilolitres of oil, Rs 9.69 lakh. Cost Rs 16.38 lakh.
• 600 kilogram melts: 75 litres, Rs 1,875. Wood 260 kilograms, Rs 780, total Rs 901. Saving Rs 974. 4 melts a day, 250 days: 1,000 melts, 75 kilolitres, Rs 9.74 lakh. Cost Rs 16.38 lakh.
• 800 kilogram melts: 110 litres, Rs 2,750. Wood 385 kilograms, Rs 1,155, total Rs 1,276. Saving Rs 1,474. 4 melts a day, 300 days: 1,200 melts, 132 kilolitres, Rs 17.69 lakh. Cost Rs 16.70 lakh.
• The gasifier itself is the same Rs 14.38 lakh unit in the 400 and 600 kilogram reports and Rs 14.70 lakh in the 800 kilogram one.

Why the 800 kilogram report pays back first

Oil per kilogram melted is 0.16, 0.125 and 0.1375 litres. Yearly metal melted is 480, 600 and 960 tonnes. Saving per tonne melted is about Rs 2,020, Rs 1,620 and Rs 1,840. So the 800 kilogram report does not save more per tonne than the 400 kilogram one. It melts twice the metal a year, 960 tonnes against 480, over a gasifier that costs the same. Payback is a statement about how hard the furnace works, not about the gasifier.

Check your own furnace the same way: litres of oil a melt, melts a day and days a year give your saving before any report does.

The carbon dioxide (CO2) line

Each report lists the estimated CO2 reduction as Nil. Furnace oil is a fossil fuel, so the oil you stop burning is a real cut in Scope 1, while the wood's CO2 is biogenic and reported separately. At about 2.97 kilograms of CO2 a litre of furnace oil, an estimate, 76.8, 75 and 132 kilolitres are about 228, 223 and 392 tonnes a year, before a few tonnes for the gasifier's electricity.

Before you switch

• Log oil per melt for a month; the reports' 64, 75 and 110 litres are not your furnace.
• Chip supply of 260 to 460 tonnes a year, dried and weighed with invoices.
• Space for the chipper, dryer and ash handling.
• If the aluminium goes to the European Union, the wood only counts as zero if it meets the sustainability criteria and you can prove it.

Rechecking the 800 kilogram report

• Per melt: Rs 2,750 of oil less Rs 1,276 of wood, power and labour = Rs 1,474
• Year: 4 melts x 300 days = 1,200 melts x Rs 1,474 = Rs 17.69 lakh
• Payback: Rs 16.70 lakh / Rs 17.69 lakh = 0.94 years
• Same 1,200 melts as the 400 kilogram report: the saving per melt is Rs 1,474 against Rs 807

All inputs from the reports, which price oil at Rs 25 a litre and wood at Rs 3 a kilogram.

What Senseible does here

Senseible reads fuel invoices and electricity bills into monthly records, so oil bought before the switch and wood bought after sit on file. Melts a day and kilograms a melt come from your own log.

• Green loan readiness check
• Aluminium melting: oil to wood gasifier, 400 kilogram
• Brass melting: coke to wood gasifier

Sources: BEE, Detailed project report: wood gasifier for aluminium melting, 400 kilogram, Jagadhri (SAMEEEKSHA), BEE, Detailed project report: wood gasifier for aluminium melting, 600 kilogram, Jagadhri (SAMEEEKSHA), BEE, Detailed project report: wood gasifier for aluminium melting, 800 kilogram, Jagadhri (SAMEEEKSHA)

Last reviewed 2026-11-04. Report figures are from BEE's Small and Medium Enterprises (SME) programme project reports; costs, tariffs and paybacks are at the report year's prices. Check today's prices and a current quote before you rely on the payback.