# Can a voltage stabiliser cut a rice mill's electricity use?

Canonical: https://senseible.earth/answers/rice-mill-voltage-stabiliser-kwh-saving

It protects motors on a weak supply, but do not bank on the kWh. BEE's Ganjam report claims 9,503 kWh a year from a 75 kVA stabiliser on a 2 TPH mill, Rs 0.40 lakh, payback 2.63 years. That figure treats the whole load as a loss. Meter the mill with and without it before you count any saving.

## The problem is real

Ganjam mills draw power through shared distribution transformers that are smaller than the load. BEE measured 270 to 350 volts against 415 needed, and about 30% of mills face acute low voltage. Motors pull more current, windings overheat and burn, and owners run only part of the line, so motors sit lightly loaded. A stabiliser holds the output at 415 volts within 1%.

## What the report claims

- Mill: 2 TPH, 14 hours a day for 340 days, 95,000 kWh a year, 14.1 kWh a tonne.
- Measured: 360 volts, 22.4 amps, power factor 0.67.
- Claim: raising the voltage to 415 cuts current to 19.43 amps and saves 2 kW, so 2 x 14 x 340 = about 9,503 kWh a year, 10% of the mill's power.
- Cost: stabiliser Rs 1.00 lakh after discount, plus Rs 0.05 lakh fitting. Saving Rs 0.40 lakh at Rs 4.20 a kWh. Payback 1.05 / 0.40 = 2.63 years.

## Why the kWh figure does not hold

- The report's 'loss' of 8.06 kW is 360 volts x 22.4 amps: the circuit's whole draw, not a loss.
- It then assumes the same power at higher voltage and the same resistance. Both cannot be true, so the 2 kW cut is an artefact of the sum.
- Higher voltage does cut current and the heat lost in cables and windings, but that is a small share of the power, and a stabiliser has losses of its own.
- The report also gives two CO2 figures, 7 t and 9 t, for the same saving.

## When it is still worth buying

1. Count the motors rewound in the last two years and their cost. Fewer burnouts is the solid return.
2. Ask the discom about a dedicated or larger transformer; it fixes the cause.
3. If you fit a stabiliser, log kWh per tonne for a month with it bypassed and a month in service, at similar output.

## What the claim would be worth if it held

- 9,503 kWh x 0.675 = 6.4 t CO2 a year
- Share of the mill's power: 9,503 / 95,000 = 10%
- The report says 7 t in its summary and 9 t in the body

CO2 at CEA's FY 2025-26 grid factor of 0.675 kg per kWh. Shown only to correct the report's figure, not as an expected saving.

## What Senseible does here

Senseible's calculators turn measured kWh into CO2 on the current grid factor, and it reads monthly electricity bills into records, so a month bypassed and a month in service can be compared bill against bill.

- [Carbon calculators](https://senseible.earth/calculators)
- [Voltage optimisers and servo stabilisers](https://senseible.earth/answers/voltage-optimiser-servo-stabiliser-savings)
- [Ganjam rice mills: power records that pay](https://senseible.earth/answers/ganjam-rice-mills-electricity-saving)
- [Rice mill improved paddy cleaner](https://senseible.earth/answers/rice-mill-improved-paddy-cleaner-saving)

Sources: [BEE, Detailed project report: voltage stabiliser 75 kVA, Ganjam rice mill cluster (SAMEEEKSHA)](https://sameeeksha.org/pdf/dpr/Ganjam_rice_mill_cluster/14_Voltage_stablizer75KVA_Ganjam_Rice_mill.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 the report year's prices. Check today's tariff and a current quote.