How different is the energy use of a parboiled rice mill and a hulling-only mill?

Roughly 25 times. In Red Hills, a medium parboiled mill uses 384 toe a year, mostly husk or wood for steam, plus 545,460 kWh. A hulling unit that only removes husk and polishes uses 180,000 kWh, 15 toe, about 40 kWh per tonne of rice. Soaking, steaming and drying make the gap.

What each mill does

A Red Hills parboiled mill cleans paddy, soaks it about 4 hours in pits holding about 8 t each, steams it in 600 to 700 kg batches, then dries it from about 32% moisture to 22% and on to 13 to 14% over about 30 hours, before milling. A hulling unit skips soaking, steaming and drying and sends cleaned paddy straight to milling. Hulling units run round the clock for about three months, making raw rice for government programmes.

The three typical units

• Medium parboiled, 4 tph, 40 units: 545,460 kWh and 384 toe a year; electricity is about 12% of its energy.
• Small parboiled, 3 tph, 30 units: 109,092 kWh and 110 toe a year.
• Hulling, 3 tph, 30 units: 180,000 kWh and 15 toe a year, all electricity; about 40 kWh per tonne of rice, 0.003 toe.
• Parboiled units overall: 0.061 to 0.064 toe per tonne. Milling alone draws 6.5 to 7 kWh per 75 kg bag of paddy.

The dryer is the big steam user

About 80% of a parboiled mill's steam goes to the dryer, where steam heats air through a heat exchanger. TERI costed a husk fired hot air generator for a medium mill burning 1,120 t of husk, 900 t of it for drying: 28% saved, about 250 t of husk, Rs 5 lakh a year for Rs 5.5 lakh, payback about a year. The boiler can then shrink to about 1 tph, for parboiling only.

Two cheaper fixes

• Economiser and condensate return: 112 t of husk a year for Rs 1 lakh, payback about 5 months.
• Combustion air control, against the unburnt husk and black smoke many boilers show: 60 t a year for Rs 0.7 lakh, payback about 7 months.

Which figure your buyer sees

A parboiled mill's fossil CO2 is its power bill; the husk is biogenic and reported apart, though its methane and nitrous oxide count. A hulling unit's footprint is almost all grid power, so kWh per tonne is the whole story.

Per mill, per year (estimate)

• Medium parboiled: 545,460 kWh x 0.675 kg = 368 t fossil CO2
• Medium parboiled husk: (384 toe minus 47 toe of power) x 41.868 GJ x 100 kg = about 1,410 t biogenic
• Small parboiled: 109,092 kWh x 0.675 = 74 t fossil
• Hulling: 180,000 kWh x 0.675 = 122 t fossil; 40 kWh x 0.675 = 27 kg per tonne of rice

Unit figures from TERI's Red Hills profile (2014-15). Biogenic CO2 uses the IPCC 2006 default for solid biomass; grid factor from CEA for FY 2025-26.

What Senseible does here

Senseible reads your electricity bills into monthly kWh and CO2 at the CEA factor, which for a hulling unit is nearly the whole footprint and for a parboiled mill is its fossil line.

• Your carbon number for buyers and banks
• Red Hills vs Villupuram energy
• Bargarh mills by size
• Rice mill energy benchmark

Sources: TERI, Energy profile: Red Hills rice mill cluster (SAMEEEKSHA, 2014-15 data), CEA, CO2 Baseline Database for the Indian Power Sector, version 22.0, IPCC 2006 Guidelines, Volume 2 Energy

Last reviewed 2026-10-31.