How Many Calories Should Coal Have? Lignite, Imported and Soma Coal

Short answer: under Turkey's solid fuel regulation of 16 September 2026, imported heating coal must have a net calorific value of at least 6,400 kcal/kg on a dry basis. For domestic coal the minimum is 4,800, 4,200 or 3,400 kcal/kg by province group, each with 200 kcal/kg tolerance. Lignite runs about 2,500–4,700 kcal/kg in the US classification.

Current prices and types: Coal prices →

How many calories must coal have by law?

The limits for heating coal now sit in Annex 1, Table 2 of the Regulation on the Control of Solid Fuels for the Protection of Air Quality (Official Gazette, 16.09.2026, no. 33372). On that date, Articles 22–25, 27 and 28 and the first paragraph of Article 26 of the older Regulation on the Control of Air Pollution from Heating were repealed; solid fuels now fall under the new regulation. The 6,400 kcal/kg limit for imported coal matches the old regulation's 2010 Table 10.

The footnotes allow ±10% by weight outside the size range and sizes down to 10 mm for mechanically fed boilers. Domestic coal with at least 5,000 kcal/kg on a dry basis (−500) and combustible sulphur of at most 1.5% may also be used in group 2. The ministry sets and publishes province groups; governorships may require better fuel by local environment board decision (Article 15). The ministry's April 2026 presentation gives the same figures.

Dry basis or as received: why do bag figures differ?

Dry basis is the value of coal with its moisture removed; as received is the value of coal as it is in the bag, moisture included. The regulation sets net calorific value on a dry basis and moisture as received. The laboratory conversion (ASTM D5865 / ISO 1928 formulas, as summarised by SGS) is: as received ≈ dry × (100 − moisture) ÷ 100 − heat to evaporate the moisture. That heat is about 24.4 J/g, or 5.8 kcal/kg, per percentage point of moisture.

Example: coal at 7,000 kcal/kg on a dry basis, with 10% moisture (the highest the regulation allows imported coal), gives 7,000 × 0.90 − 10 × 5.8 ≈ 6,240 kcal/kg; for 7,800 the result is ≈ 6,960. This is an assumed calculation. A real declaration: our boiler coal bag states 7,800–8,200 kcal/kg on a dry basis and 7,400 kcal/kg as received.

What is the difference between net and gross calorific value?

Gross calorific value includes the condensation heat of the water formed during combustion; net value does not, because in a stove that water leaves the flue as vapour. UN and IEA energy statistics training notes that for solid fuels the net value is typically 5–6% below the gross value. It is measured in a laboratory calorimeter or estimated from elemental analysis (carbon, hydrogen, oxygen, sulphur) with empirical formulas, not at home.

How many calories do lignite, hard coal and anthracite have?

The US Energy Information Administration (EIA) gives values in million Btu per short ton. Since 1 million Btu per short ton = 500 Btu/lb and kcal/kg = Btu/lb ÷ 1.8, 1 million Btu per short ton ≈ 277.8 kcal/kg. They are on a moist, mineral-matter-free basis, not directly comparable with Turkish dry-basis net values. For the differences, see anthracite, lignite and coke.

What do our coal bags declare?

Nut size is meant for mechanically fed boilers, which the regulation allows down to 10 mm; for stove use, see which coal burns in a stove. On Siberian coal, see what Siberian coal is; for domestic versus imported, imported or domestic coal; for bag lines, the figures on a coal bag; for choosing, how to tell quality coal.

What does it depend on?

• Coal type and rank (from lignite to anthracite)
• Whether the value is on a dry or as-received basis
• Whether it is the net or gross value
• Total moisture and ash
• Your province's fuel group and local environment board decision

Season quantity: use our fuel calculator.

Safety note

No coal is smokeless, whatever its calories. Carbon monoxide is colourless and odourless; with symptoms, air the room, call 112 and use a carbon monoxide detector.

Frequently asked questions

How many calories does Siberian coal have?

According to the bag declaration, the Siberian coal we sell is 7,000–7,800 kcal/kg on a dry basis; the legal minimum for imported coal is 6,400.

How many calories does Soma coal have?

Our TKİ Soma Kısrakdere coal declares a net calorific value of 4,800–5,200 kcal/kg. Bag and tonne price and availability: TKİ Soma coal price and specifications.

How many calories does nut coal have?

Nut-size boiler coal declares 7,800–8,200 kcal/kg on a dry basis and 7,400 kcal/kg as received.

Can the calorific value of coal be increased?

No, heating value belongs to the coal itself. Keeping it dry does avoid losing heat to evaporating moisture.

Why do coal calorie tables differ between sellers?

Mostly because of the basis: a dry-basis value is higher than the same coal's as-received value. Compare like with like, including net or gross.

Sources: Ministry of Environment, Regulation on the Control of Solid Fuels, Annex 1 Table 2 and amending regulation (Official Gazette, 16.09.2026); the ministry, heating fuel presentation (28.04.2026); EIA glossary: lignite, subbituminous, bituminous, anthracite; UN/IEA, energy statistics training; SGS, Coal calculations; Ministry of Health, Carbon Monoxide Poisoning.