Why do the Bureau of Energy Efficiency Surat reports pay back a new 3 or 4 tonne an hour boiler in 5 to 7 months?

The Bureau of Energy Efficiency (BEE) Surat reports price a new 70% efficient boiler at rupees (Rs) 19.93 lakh for 3 tonnes an hour (TPH) and Rs 24.98 lakh for 4 TPH. They save Rs 35.23 and 59.15 lakh a year of coal and lignite, a payback of 7 and 5 months, because old boilers print 33.0 and 38.8%.

The two reports side by side

• 3 TPH: imported coal at 6,000 kilocalories (kcal) a kilogram and Rs 3,800 a tonne. Existing boiler efficiency printed 33.0%, new 70%. Saving 149 kilograms an hour x 6,225 hours = 927 tonnes, Rs 35.23 lakh. Cost Rs 19.93 lakh. Payback 0.57 years, printed as 7 months.
• 4 TPH: lignite at 4,000 kcal a kilogram and Rs 2,830 a tonne. Existing efficiency printed 38.8%, new 70%. Saving 421 kilograms an hour x 4,960 hours = about 2,088 tonnes, printed as 2,089.9, Rs 59.15 lakh. Cost Rs 24.98 lakh. Payback 0.42 years, printed as 5 months.
• Both assume the new boiler turns the same steam at 70%. The sample units made 1,000 kilograms of steam an hour on a 3,000 kilogram boiler, and 2,000 on a 4,000.

Where the printed efficiency comes from

The 33.0% is the average of three units in the 3 TPH report (35.1, 32.7 and 31.3). The 38.8% is the average of three in the 4 TPH report (34.4, 35.3 and 46.8). The savings are not built on those averages. Each is built on one unit's heat figures: 300 kilograms an hour of coal giving 35.1%, and 850 kilograms an hour of lignite giving 35.3%.

The direction matters. A lower old efficiency means more fuel for the same steam, so a larger saving. At 33.0% the 3 TPH saving would be about 169 kilograms an hour, more than the printed 149, so the printed saving is the cautious one. At 38.8% the 4 TPH saving would be about 345 kilograms an hour, less than the printed 421, which is about 1,710 tonnes, Rs 48.4 lakh and a payback of 0.52 years.

Printed figures that do not tie, and carbon dioxide (CO2) with no factor

• The 3 TPH report says in section 1.4.1 that the unit burns 7.85 tonnes of coal a day. Its Table 1.2 and annexure give 7.20, which is 300 kilograms an hour x 24.
• In the 4 TPH report, Table 1.2 heads a column tonnes a year, and shows 20,400 for one unit. That equals 850 kilograms an hour x 24, so it is kilograms a day.
• The CO2 lines are 670 and 1,515 tonnes a year, about 0.72 tonnes for each tonne of fuel saved in both. The reports print no factor for them, so do not copy the lines; work out CO2 from your own coal tonnes with a sourced factor.

Before you order

• Check the baseline on your own coal or lignite invoices: tonnes a day and steam made.
• Ask the maker for the efficiency it will guarantee at your steam load, one third or one half of the rating, not at the design point.
• Re-run the saving at today's fuel price.

The 3 TPH arithmetic from the annexure

• Steam out: 1,000 kilograms an hour x 661.4 kcal = 631,400 kcal an hour
• Old boiler: 300 kilograms of coal x 6,000 kcal = 1,800,000 kcal in, so 35.1%
• New boiler at 70%: 631,400 / 0.70 / 6,000 = about 150 kilograms an hour (151 printed)
• Saving: 149 x 6,225 hours = 927 tonnes x Rs 3,800 = Rs 35.23 lakh. Payback 19.93 / 35.23 = 0.57 years

Figures are the report's own, at the report year's prices.

What Senseible does here

Senseible reads fuel invoices and electricity bills into monthly records, so the coal or lignite bought each month is on file to test a report's baseline against. The green loan check shows what a lender asks for.

• Green loan readiness check
• Online flue gas analyser on a coal boiler
• Surat processing house fuel per metre
• Pali dyeing unit coal boiler CO2

Sources: BEE, Detailed project report: energy efficient boiler, 3 TPH, Surat textile cluster (SAMEEEKSHA), BEE, Detailed project report: energy efficient boiler, 4 TPH, Surat textile cluster (SAMEEEKSHA)

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