How much power does an energy efficient rectifier save in a Jamnagar brass electroplating unit?

The Bureau of Energy Efficiency (BEE) Jamnagar manual prices a new plating rectifier at rupees (Rs) 0.4 lakh. It draws 4.20 kilowatts at full load against 7, saving 2.80 kilowatts. Over 1,500 hours that is 4,200 kilowatt hours (kWh), Rs 0.25 lakh a year at Rs 6 a unit, payback 1.6 years.

What the manual prints

• Old alternating to direct current rectifier at full load: 7 kilowatts. Energy efficient rectifier: 4.20. Saving 2.80 kilowatts, which is 40%.
• Annual hours: 1,500. Saving 2.80 x 1,500 = 4,200 kWh. At Rs 6 a kWh that is Rs 25,200, printed as Rs 0.25 lakh.
• Cost Rs 0.4 lakh, so payback 0.4 / 0.25 = 1.6 years.
• Other benefits it lists: better power factor and a more compact set.
• Barriers it lists: lack of awareness and no suitable local service provider. It was not short-listed for a detailed project report.

How big is 4,200 kWh for a plating unit

The manual's typical plating unit uses 29,973 kWh a year to plate 30 tonnes, which is 0.99 kWh a kilogram. So 4,200 kWh is 14% of the unit's yearly units, or about 0.14 kWh a kilogram. That is a large share for one item, so it is worth checking against your own meter. The manual's 7 kilowatts is a conventional rectifier at full load, not a nameplate rating: 7 kW x 1,500 hours would be 10,500 kWh, 35% of the typical unit's 29,973, which makes the meter check more important.

The saving holds only if the rectifier really runs near full load for those 1,500 hours. A rectifier that spends most of its time at part load will save less than 2.80 kilowatts. The manual states the full load figure and does not give a part load one.

Across the cluster

Table 5.1 counts 200 plating units that could fit one, 840,000 kWh a year in all. At the grid factor for financial year (FY) 2025-26 of 0.675 kilograms of carbon dioxide (CO2) a kWh, that is about 567 tonnes of CO2 a year in Scope 2, or 2.8 tonnes for one unit.

Your own check (example)

• Plating unit with a rectifier drawing 7 kilowatts at full load, running 1,500 hours: 10,500 kWh a year
• Replacement draws 4.20 kilowatts: 6,300 kWh, a saving of 4,200 kWh
• CO2 saved: 4,200 x 0.675 = 2,835 kilograms, about 2.8 tonnes a year
• Money at Rs 6 a kWh: Rs 25,200. Check your own tariff, which will differ

The 7 and 4.20 kilowatts and 1,500 hours are the manual's; the grid factor is the Central Electricity Authority's (CEA) FY 2025-26 figure, an estimate for your bill year.

What Senseible does here

Self-serve, Senseible reads fuel invoices and electricity bills into monthly records; machine meters are custom, on request. Electricity units by month are on file, and the hours of use come from your own log.

• Your carbon number for buyers and banks
• Electroplating carbon footprint per square metre
• Jamnagar brass cluster energy and carbon

Sources: BEE, Manual on energy conservation measures in brass cluster Jamnagar (Winrock International India), CEA, CO2 Baseline Database for the Indian Power Sector, version 22.0

Last reviewed 2026-11-06. Figures are from BEE's Jamnagar manual, which prints no year on the pages used; the Rs 6 a kWh tariff is that report's. Re-check the grid factor for the year of your bill.