In the Howrah galvanizing manual, why is the cluster's total coal use of 680,833 kg lower than the galvanizing column's 1,161,000 kg?

It does not add as printed, and the manual gives no reason. Neither total can be confirmed: 1,161 tonnes reproduces the carbon dioxide (CO2) table's 1,358 tonnes at 1.17 kg a kg, 680.8 tonnes gives 1.99, and one typical unit in a Bureau of Energy Efficiency (BEE) gasifier report uses 840 tonnes. That is my reading.

Table 2.6 as printed

• Electricity: 867,325 + 2,243,290 = 3,110,615 kilowatt hours (kWh). It adds.
• Diesel oil: 19,200 + 12,000 = 31,200 litres. It adds.
• Furnace oil: 731,695 litres, galvanizing only. Wood: 600,000 + 300,000 = 900,000 kg. Liquefied petroleum gas (LPG): 135,000 kg, wire drawing only. These agree.
• Coal: galvanizing 1,161,000 kg, wire drawing blank, total 680,833 kg. A total cannot be smaller than its only entry. The gap is 480,167 kg.

What the carbon table and the gasifier report say

• Table 4.1 gives CO2 emitted a year for the 15 audited units: coal 1,358 tonnes, wood 1,728, diesel 85 (under the light diesel oil column), furnace oil 2,205, LPG 404.
• Divide each by the Table 2.6 total: wood 1.92 kg of CO2 a kg, furnace oil 3.01 a litre, diesel 2.72 a litre, LPG 2.99 a kg. Each is a plausible factor, which suggests Table 4.1 may use Table 2.6's totals for those fuels; I have not confirmed it.
• Coal: 1,358 tonnes over 680.8 tonnes is 1.99 kg a kg. Over 1,161 tonnes it is exactly 1.17, the figure of CO2 per tonne of coal that the BEE detailed project report on biomass gasifiers for coal based furnaces gives. At the 1.76 kg a kg used for Indian coal on this site, 680.8 tonnes gives 1,198 tonnes and 1,161 tonnes gives 2,043.
• The same gasifier report says a typical galvanizing unit burns 840 tonnes of semi hard coke coal a year, more than the 680.8 tonne cluster total. So neither total can be confirmed from the manual, and 680,833 may be the misprint. The manual's note under Table 4.1 names the U.S. Department of Energy Information Administration and the Central Electricity Authority's CO2 Baseline Database, version 2.0. It does not say that Table 2.6 and Table 4.1 cover the same units; I assume so because four of five fuels line up.

What to do

1. Do not cite either coal total from the manual.
2. Take coal from your own weighbridge slips or purchase invoices, in tonnes.
3. Multiply by a sourced factor. The manual's wood CO2 is counted in its 9,597 tonne total; check how your buyer treats wood before copying that.

A galvanizer's coal, with your own numbers

• Coal bought in a year: 60 tonnes on invoices
• 60,000 kg x 1.76 kg CO2 a kg = 105,600 kg, or 105.6 tonnes of CO2
• Per tonne galvanized, if you dipped 1,500 tonnes: 105.6 / 1,500 = 0.07 tonnes

The 60 tonnes and 1,500 tonnes are examples, not the manual's. 1.76 is the Indian coal factor used on this site.

What Senseible does here

Senseible reads fuel invoices and electricity bills into monthly records, so the coal bought each month is on file instead of inferred from a table.

• Howrah galvanizing and wire: fuel and Carbon Border Adjustment Mechanism (CBAM)
• Howrah savings: 11.3 crore or 11.9 crore
• Galvanizing coal furnace to biomass gasifier (the BEE report's 840 tonnes and 1.17)
• Galvanizing plant energy per tonne

Sources: Bureau of Energy Efficiency (BEE), Manual on energy conservation measures in the galvanizing and wire drawing sector, Howrah cluster (SAMEEEKSHA)

Last reviewed 2026-11-05. Figures are the manual's. It is undated; about 2010 to 2011, as its references were read in 2010. The manual does not say which coal total is intended; which one is right is my reading from the gasifier report, not a correction.