# How much power does a CNC gear hobbing machine save over a conventional one?

Canonical: https://senseible.earth/answers/cnc-gear-hobbing-machine-replaces-conventional-kwh-per-tonne

The BEE and SAMEEEKSHA report for the Bangalore machine tools cluster shows specific energy falling from 3,126 to 2,344.5 kWh per tonne, a saving of 68,928 kWh a year, shown as 51.7 tonnes CO2. That annual figure assumes output rises 1.75 times.

## The per-tonne saving

3,126 minus 2,344.5 is 781.5 kWh per tonne, or 25%. The report credits this to hob speed: carbide-tipped hobs run at about 160 metres a minute against 16 for the HSS cutters of conventional machines, so each part takes 5 to 10 times less time.

## The annual saving rests on an assumption

The report takes output from 50.4 to 88.2 tonnes a year, 1.75 times more, on the same machine. 781.5 x 88.2 is the 68,928 kWh. If your output does not rise, the saving is smaller.

## Other facts in the report

- Cluster: 100 units in Bangalore; 30 studied and 10 audited in detail.
- Installation: 4 to 5 days, with no effect on production.
- Life: up to 20 years with proper maintenance.

## Worked CO2, with and without the output assumption

- With the report's output rise: 68,928 kWh x 0.675 kg per kWh (FY 2025-26) = 46,526 kg, or 46.5 t. The report shows 51.7 t, about 0.75 t per MWh.
- Output unchanged at 50.4 tonnes: 781.5 x 50.4 = 39,388 kWh.
- At 0.675: 39,388 x 0.675 = 26,587 kg, or 26.6 t.

The report dates from 2010; check the current grid factor for your bill year.

## What Senseible does here

Senseible reads electricity bills into a monthly kWh record, so output and energy per tonne can be compared before and after a machine change.

- [CNC lathes replacing conventional lathes](https://senseible.earth/answers/cnc-lathe-replacing-conventional-lathes-kwh)
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- [Carbon calculators](https://senseible.earth/calculators)

Sources: [SAMEEEKSHA and BEE, DPR: replacement of conventional gear hobbing machine with CNC gear hobbing machine, Bangalore machine tools cluster](https://sameeeksha.org/pdf/dpr/Bangalore_machine_tools_cluster/Replacement_of_conventional_gear_hobbing_machine_to_CNC_gear_hobbing_machine_BNG_MTC.pdf)

Last reviewed 2026-11-03.