No EU carbon charge on your tiles or glass. Your kiln still sets your number.

For tile, pottery, sanitaryware and glass exporters

Ceramics and glass are not on the list of goods the European Union charges a carbon cost on at the border. Buyers still ask how much carbon went into each tile or piece. Most of the answer is in how you fire.

Which goods are on that list?

The border carbon charge is called CBAM, short for Carbon Border Adjustment Mechanism. Think of it as a toll that only a few heavy goods pay when they cross into Europe.

Only iron and steel, aluminium, cement, fertilisers, hydrogen and electricity are on the European Union list. Ceramic tiles (code 6907), sanitaryware (6910) and glassware (chapter 70, including bottles, jars, bangles and beads) are not. Finished tiles and sanitaryware made from clay are not covered.

• One edge case: if you sell clay itself, check code 2507 00 80 with your buyer.
• A lantern with a metal frame and a glass part can be classed by its metal. Agree the code with your buyer.
• The United Kingdom said in October 2024 that neither ceramics nor glass would be in scope from 2027. Check the current UK goods list on gov.uk.
• Both lists can be widened later, so a footprint you already hold stays useful.

Turn up the kiln

Drag the slider to push a load of tiles through. Watch the heat build, then tap a stage to see what a buyer asks about it.

Drying

Wet clay powder and pressed tiles are dried before they meet the kiln. Think of washing drying on a line, with hot air from burning gas or coal gas instead of sun.

Spray dryers turn clay slip into press powder. Other dryers work after pressing. The CO2 here is fuel only.

In Morbi, spray dryers mostly ran on coal gasifiers or lignite hot gas units. Moving that dryer to gas cuts its CO2 by about 45 percent, if it stays as efficient.

What the buyer asks: How much of your fuel goes to drying, and how much to firing? Keep the dryer on its own gas meter if you can.

Firing

A slow climb, then a hold. In a Khurja shuttle kiln the load heats to about 1,240 °C in about 36 hours, then soaks for about 2 hours so the glaze fires. Think of baking bread: a steady rise, then time at full heat.

This is the biggest fuel use, and the clay lets out its locked CO2 here too.

Bad tiles carry their gas into the good ones, so how many tiles come out good moves your number as much as the kiln does.

What the buyer asks: Fuel per square metre of good tiles, from the gas bill and meter, not the contracted quantity. Log start, peak, soak, fuel and good ware for each firing.

Cooling

The burners are cut off. Only blowers push air through until the kiln is at about 200 °C, then the doors open and the ware cools by itself.

No new fuel is burnt now, but the hot air leaving the kiln still holds heat. Sending kiln exhaust heat to the dryer cuts gas.

The profile prints no cooling time, so the curve above is not to scale on this side.

What the buyer asks: Is any kiln heat reused? Show the firing log and how many pieces came out good.

Curve as The Energy and Resources Institute printed it for a Khurja shuttle kiln in its 2015 profile. The start at 30 °C is our assumption, and the profile prints no cooling time.

Switch the fuel

Same kiln. Same tiles. Only the fuel changes. The number below is carbon dioxide (CO2) per tonne of fired ware, from the fuel plus the CO2 locked in the clay.

A gigajoule (GJ) is a measure of heat, the way a litre measures milk. Coal gas is gas made by heating coal in a gasifier, then burnt in the kiln like natural gas.

Natural gas is the lowest of the three: 290 kg per tonne in this tunnel kiln.

• Heat needed: 4.3 GJ per tonne of ware in a tunnel kiln.
• Fuel CO2: 4.3 x 56.1 = 241 kg (56.1 kg of CO2 per GJ).
• Clay CO2: 1.1 x 0.10 x 0.4453 = 0.049 tonnes = 49 kg. The fuel switch does not change it.
• Total: 241 + 49 = 290 kg of CO2 per tonne of ware.

Where do these example numbers come from?

Heat needed: a tunnel kiln uses about 4.3 megajoules (MJ) of fuel per kg of ware, a shuttle kiln about 15.7. That is 4.3 and 15.7 gigajoules (GJ) per tonne. A joule is a unit of heat, the way a litre is a unit of milk. Khurja measured these on oil-fired kilns (The Energy and Resources Institute profile, 2015). We reuse the heat need with other fuels so you can see the fuel effect alone.

CO2 per GJ of heat, from the Intergovernmental Panel on Climate Change (IPCC) 2006 defaults: natural gas 56.1 kg, liquefied petroleum gas such as propane 63.1 kg, bituminous coal 94.6 kg.

Coal is burnt in a gasifier first, which turns it into gas for the kiln and loses part of its energy on the way. At 70 percent efficiency, 94.6 divided by 0.70 is 135.14 kg per GJ of gas reaching the kiln. At 75 percent it is 126.13. We use 70 percent. Older gasifiers do worse.

Clay slice: 1 tonne of product uses 1.1 tonnes of clay. The default is 10 percent carbonate in the clay, split 85 percent limestone and 15 percent dolomite. The blend is 0.85 x 0.4397 + 0.15 x 0.4773 = 0.4453 tonnes of CO2 per tonne of carbonate. So 1.1 x 0.10 x 0.4453 = 0.049 tonnes, so 49 kg. Real clays run from 0 to over 30 percent carbonate, so an assay of your own clay replaces this.

The CO2 that the fuel switch cannot touch

Clay and glass mix hold carbon dioxide inside, the way a fizzy drink holds its gas. Heat lets it out. This is called process CO2. It happens even if the kiln runs on clean fuel, so a buyer will want it listed apart from fuel.

Glass: soda ash, limestone and dolomite

The glass mix, called the batch, holds carbonates that give off CO2 as they melt. By the IPCC 2006 factors, each tonne gives off about:

• 0.415 tonnes of CO2 for soda ash
• 0.440 for limestone
• 0.477 for dolomite

Multiply the tonnes of each you bought by its factor and add the results to the gas burnt in the furnace. Recycled glass, called cullet, has no carbonates left to give off, so more cullet means less process CO2 per tonne melted.

Firozabad fuel as an example: melting takes 0.20 to 0.35 standard cubic metres (scm) of gas per kg of glass. At 2.05 kg CO2 per scm, 0.20 x 2.05 = 0.41 and 0.35 x 2.05 = 0.72 kg CO2 per kg of glass, from fuel alone (The Energy and Resources Institute profile, 2015).

Tiles and pottery: carbonates in the clay

Same idea, smaller. Without a lab test of your clay, the IPCC default works out to about 0.049 tonnes of CO2 per tonne of fired product. That is the grey slice in the bar above.

Fuel is a separate line. Coal, wood, gas or oil burnt in the kiln is worked out from your invoices.

Four places, four fires

Tap a cluster to see what it burns. Each figure shows its year, because fuel mixes have moved since.

Morbi tiles: Study of 2009 to 2010

• About 479 units made over 70 percent of India's ceramic tiles, with about 67,750 jobs.
• In a year they burnt 66 crore scm of natural gas, 13.2 lakh tonnes of lignite (a soft brown coal) and 120 crore kWh of power.
• Bureau of Energy Efficiency (BEE) put it at about 41 lakh tonnes of CO2, an estimate, about 0.87 tonnes per tonne of product. Lignite was the biggest line, bigger than gas.
• After a 2019 National Green Tribunal order against coal gasifiers, units were pushed onto piped gas. Use these numbers as a baseline, not as Morbi today.

Firozabad glass: Profile of 2015

• A tank furnace burns about 52,000 scm of gas a day. 52,000 x 2.05 kg = 1,06,600 kg, about 107 tonnes of CO2 a day.
• A pot furnace burns about 3,500 scm. 3,500 x 2.05 kg = 7,175 kg, about 7 tonnes a day.
• Across the cluster: 8,79,280 scm a day, about 32.1 crore scm a year, about 6,58,000 tonnes of CO2 a year from gas.
• About 400 muffle furnaces, which anneal bangles, mostly burn coal and firewood. For those, every coal invoice is your record.

Khurja pottery: Profile of 2015

• About 400 units run 156 kilns: 91 tunnel, 60 shuttle and 5 old downdraft kilns. Most burn light diesel oil or rubber process oil, and about 10 units use piped gas.
• A tunnel kiln uses about 4.3 MJ per kg of ware. A shuttle kiln uses about 15.7, about 3.6 times as much, because it heats and cools the whole load and kiln each batch.
• On oil at 74.1 kg CO2 per GJ: 4.3 x 74.1 = 319 kg, about 0.32 kg per kg of ware in a tunnel kiln. 15.7 x 74.1 = 1,163 kg, about 1.16 kg in a shuttle kiln.
• Natural gas gives about 40 percent less CO2 than bituminous coal per unit of heat: 1 minus 56.1 / 94.6.

Thangadh sanitaryware: Profile of 2009, power at the FY 2025-26 grid factor

• About 225 ceramic units, 161 of them sanitaryware. Kilns fire ware at about 1,200 °C.
• A year of fuel, 83 percent of it natural gas: 33 million scm of gas, 18 million kWh of power, 360,000 litres of diesel. Charcoal CO2 is counted separately as biogenic.
• Gas: 33 million x 2.05 kg = 67,650 tonnes. Power: 18 million kWh x 0.675 kg per kWh (grid factor for FY 2025-26) = 12,150 tonnes. Diesel: 360,000 litres x 2.645 kg = about 950 tonnes.
• Sum: 67,650 + 12,150 + 950 = 80,750 tonnes of fossil CO2, on about 3,70,000 tonnes of product. That is about 0.22 tonnes per tonne.

Bring your own bills

The kiln above is an example. Your number comes from your gas, coal and power bills and your good tiles or pieces packed. Senseible reads the bills and builds the figure. It does not verify the figure. A buyer who wants a checked number uses an independent verifier.

Work out the carbon from my kiln fuel

All figures on this page are examples from published cluster profiles and standard factors, with their years shown. They are not your plant's numbers.