# 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?

Canonical: https://senseible.earth/answers/surat-3-and-4-tph-boiler-reports-compared

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](https://senseible.earth/green-loan-check)
- [Online flue gas analyser on a coal boiler](https://senseible.earth/answers/coal-boiler-online-flue-gas-analyser-saving)
- [Surat processing house fuel per metre](https://senseible.earth/answers/surat-processing-house-fuel-per-metre)
- [Pali dyeing unit coal boiler CO2](https://senseible.earth/answers/pali-textile-dyeing-unit-coal-boiler-co2)

Sources: [BEE, Detailed project report: energy efficient boiler, 3 TPH, Surat textile cluster (SAMEEEKSHA)](https://sameeeksha.org/pdf/dpr/surat_3TPH.pdf), [BEE, Detailed project report: energy efficient boiler, 4 TPH, Surat textile cluster (SAMEEEKSHA)](https://sameeeksha.org/pdf/dpr/surat_4TPH.pdf)

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.