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

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
• CNC grinding machine: electricity saved?
• Bangalore machine tool units: grid power
• CNC machined part carbon footprint

Sources: BEE, Detailed project report: replacement of conventional lathes with CNC lathes, Bangalore machine tools cluster (2010, SAMEEEKSHA), CEA CO2 Baseline Database, version 22.0

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.