# How much electricity do CNC lathes save over conventional lathes in a machine shop?

Canonical: https://senseible.earth/answers/cnc-lathe-replacing-conventional-lathes-kwh

BEE's Bangalore report claims 105,311 kWh a year, but its baseline is the plain average of two shops using 1,358 and 11,500 kWh a tonne, and the CNC figure is simply 30% below that average. Measure your own kWh per tonne first: the busier shop already beat the CNC figure.

## How the report gets 105,311 kWh

1. Two audited shops with lathes: 1,358.34 kWh a tonne on 50.4 t a year, and 11,500 kWh a tonne on 12 t.
2. Their simple average, 6,429.17 kWh a tonne, becomes the baseline. Weighted by output it would be about 3,309.
3. The CNC lathe is put at 70% of the average: 4,500.4 kWh a tonne.
4. Output is assumed to rise 1.75 times, from 31.2 to 54.6 t.
5. Saving: 1,928.77 kWh a tonne x 54.6 t = 105,311 kWh, Rs 5.27 lakh at Rs 5 a kWh.

## Money: the lathe pays through material and labour

- Benefit claimed: Rs 27,253 a tonne x 54.6 t = Rs 14.88 lakh a year.
- Electricity Rs 9,644 a tonne, material Rs 11,939, labour and utilities Rs 5,670.
- Cost: Rs 40.00 lakh machine, Rs 0.45 lakh civil work, Rs 0.15 lakh consultancy, Rs 0.20 lakh interest during build: Rs 40.80 lakh.
- Payback 2.74 years overall; on electricity alone about 7.7 years.

## Measure before you claim

- Sub-meter the lathe section for a month and log tonnes turned: that is your baseline, not 6,429.
- Ask the supplier for the CNC machine's spindle, drive and coolant loads, and its idle draw between jobs.
- Compare kWh per tonne after a month on the new machine. At 54.6 t and 4,500 kWh a tonne, the shop's bill rises about 45,000 kWh even as each tonne gets cheaper in power.

## Grid CO2 on the report's figures

- Before: 6,429.17 x 31.2 = 200,590 kWh x 0.675 = 135.4 t
- After: 4,500.4 x 54.6 = 245,722 kWh x 0.675 = 165.9 t
- Avoided against old lathes at the new output: 105,311 x 0.675 = 71.1 t
- The report says 79 t, on an older grid factor

Grid at CEA's FY 2025-26 factor, an estimate. The before figure inherits the report's averaged baseline.

## What Senseible does here

Senseible reads your electricity bills into monthly records linked to each bill, with CO2 by the CEA factor for the bill's year, which gives a baseline a lender can check. The green loan check tells you what else a machine loan file needs.

- [Green loan readiness check](https://senseible.earth/green-loan-check)
- [CNC grinding machine: electricity saved?](https://senseible.earth/answers/cnc-grinding-machine-electricity-saving)
- [Bangalore machine tool units: grid power](https://senseible.earth/answers/bangalore-machine-tool-units-grid-power-saving)
- [CNC machined part carbon footprint](https://senseible.earth/answers/cnc-machined-part-carbon-footprint)

Sources: [BEE, Detailed project report: replacement of conventional lathes with CNC lathes, Bangalore machine tools cluster (2010, SAMEEEKSHA)](https://sameeeksha.org/pdf/dpr/Bangalore_machine_tools_cluster/Replacement_of_Conventional_lathes_BNG_MTC.pdf), [CEA CO2 Baseline Database, version 22.0](https://cea.nic.in/cdm-co2-baseline-view?mappingId=234&lang=en)

Last reviewed 2026-11-01. Report figures are from a BEE SME programme project report; costs and paybacks are at 2010 prices. Check a current quote.