The Virudhachalam profile prints rubber process oil at rupees (Rs) 3940,000 a kilolitre: what does its own bill table imply, and which fuel cost least for each unit of heat?

The profile's bill table implies about Rs 39,000 a kilolitre for rubber process oil, not the printed Rs 3940,000. On that table imported coal cost about Rs 1,429 for each million kilocalories of heat, firewood Rs 1,304, petcoke Rs 1,815 and oil Rs 4,236, so oil cost about three times coal.

What the profile prints

• Prices: rubber process oil (RPO) Rs 3940,000 a kilolitre, imported coal Rs 10,000 a tonne, petcoke Rs 16,000, firewood Rs 3,000, electricity Rs 6.75 a kilowatt hour (kWh).
• Cluster energy for 2015, with the annual bill in million rupees: RPO 1,316 kilolitres, 1,211 tonnes of oil equivalent (toe), 51.3; imported coal 4,800 tonnes, 3,360 toe, 48.0; petcoke 1,440 tonnes, 1,267 toe, 23.0; firewood 18,000 tonnes, 4,140 toe, 54.0; electricity 1.18 million kWh, 102 toe, 8.0.
• Totals 10,079 toe and Rs 184.3 million. The rows add: 1,211 + 3,360 + 1,267 + 4,140 + 102 = 10,080, one off from rounding; 51.3 + 48.0 + 23.0 + 54.0 + 8.0 = 184.3.

The oil price, checked

Divide the bill by the quantity. Coal: 48.0 million / 4,800 tonnes = Rs 10,000, as printed. Petcoke: 23.0 million / 1,440 = Rs 15,972, near the printed 16,000. Firewood: 54.0 million / 18,000 = Rs 3,000, as printed. Electricity: 8.0 million / 1.18 million kWh = Rs 6.78, near Rs 6.75. Oil: 51.3 million / 1,316 kilolitres = Rs 38,982 a kilolitre.

So every row of the bill table ties to its price, and the oil row points to about Rs 39,000 a kilolitre. The printed Rs 3940,000 is about a hundred times that and looks like a misprint. I cannot tell what was meant, so use your own invoice for oil. The Khurja profile from the same team prints rubber process oil at Rs 32,000 a kilolitre.

Cost of a million kilocalories

A kilocalorie (kcal) is a small unit of heat. The profile's tables count 10 million kcal to a toe, which its electricity row supports: 1.18 million kWh at 860 kcal each is 101.5 toe. Dividing each bill by its toe, then by 10, gives the cost of a million kcal:

• Firewood: Rs 13,043 a toe, Rs 1,304 a million kcal.
• Imported coal: Rs 14,286 a toe, Rs 1,429.
• Petcoke: Rs 18,153 a toe, Rs 1,815.
• Rubber process oil: Rs 42,362 a toe, Rs 4,236.
• Electricity: Rs 78,431 a toe, Rs 7,843. It is not burnt for heat, so it is listed only for scale.

What it shows, and what it does not

• Oil cost 2.96 times imported coal and 3.2 times firewood for the same heat.
• Coal and firewood are close, within about 10%. Firewood burns in downdraft kilns, which the profile shows using the most heat for each kilogram of ware, 4,200 kcal.
• These are bills for the cluster's mix of kilns. A fuel cost less per heat does not mean it fires better, because kilns waste different shares of the heat.
• Heat per kilolitre is not the same in both profiles: 1,211 toe over 1,316 kilolitres is 0.92 toe in Virudhachalam, while Khurja's oil row is 14,602 over 19,032, or 0.77. I cannot tell why, so use the heat value on your own supplier's sheet.

Your own cost of a million kcal, example numbers

• Oil at Rs 39,000 a kilolitre with 9,200 kcal a litre (example heat value): 39,000 / 1,000 litres = Rs 39 a litre; 39 / 9,200 x 1,000,000 = Rs 4,239 a million kcal
• Coal at Rs 10,000 a tonne with 7,000 kcal a kilogram (example): 10 / 7,000 x 1,000,000 = Rs 1,429 a million kcal

The 9,200 kcal a litre is what the profile's own toe and kilolitre rows imply (1,211 toe over 1,316 kilolitres), not a printed heat value. Heat values here are examples. Use the values on your own invoices and the same month for both fuels.

What Senseible does here

Senseible reads fuel invoices and electricity bills into monthly records, so a unit's own gas, oil and power lines are on file to set beside the report's figures. It does not measure a kiln or replace an audit.

• Virudhachalam kiln fuels and carbon
• Tunnel kiln heat per kilogram in Khurja and Virudhachalam
• Morbi fuels by cost per heat, 2009
• Green loan readiness check

Sources: TERI, Cluster profile: Vriddhachalam ceramics and refractory industries (SAMEEEKSHA), TERI, Cluster profile report: Khurja potteries (SAMEEEKSHA)

Last reviewed 2026-11-07. Prices and the 2015 energy table are from the profile of The Energy and Resources Institute (TERI); its spelling of the town is Vriddhachalam. The checks are my arithmetic. Use your own invoice prices.