Coal Trading: Thermal vs Metallurgical Coal Explained

Coal is not a single commodity but rather a family of carbon-based materials with vastly different properties and uses. Thermal coal (steam coal) is used primarily for electricity generation, accounting for roughly 85% of global coal trade. Metallurgical coal (coking coal) is used in blast furnaces for steelmaking and commands significantly higher prices due to stricter quality requirements and fewer substitutes.

Global coal trade exceeds 1.3 billion tonnes annually. Despite the energy transition, coal demand remains robust in Asia, particularly in China, India, and Southeast Asia. Metallurgical coal faces less substitution risk than thermal coal, as viable alternatives for blast furnace steelmaking remain limited.

Thermal coal quality is measured primarily by calorific value (energy content), typically quoted in kilocalories per kilogram (kcal/kg) on a GAR (gross as received) or NAR (net as received) basis. Standard grades include 6,000 kcal NAR (premium), 5,500 kcal NAR (standard), and 4,200 kcal NAR (lower grade). Ash content, sulfur content, and moisture are other key specifications.

Metallurgical coal quality depends on coking properties measured by CSR (Coke Strength after Reaction), CRI (Coke Reactivity Index), fluidity, and volatile matter. Premium hard coking coal (CSR >65) commands the highest prices. Semi-hard, semi-soft, and PCI (pulverized coal injection) coals are lower-quality metallurgical grades used to optimize blast furnace economics.

Thermal coal benchmarks include the Newcastle 6,000 kcal NAR index (Asia-Pacific) and the Richards Bay/API2 index (Atlantic). Metallurgical coal references the Platts PLV HCC (Premium Low Volatile Hard Coking Coal) FOB Australia index. SGX and ICE host coal futures contracts for hedging.

Physical coal trades at benchmark prices adjusted for quality (kcal/kg for thermal, CSR for met coal), quantity, and delivery terms. Most Asian thermal coal trades on a CIF basis, while FOB pricing is common for Australian and Indonesian exports. Quarterly or monthly pricing has replaced annual benchmarks in most met coal contracts.

Indonesia is the world's largest thermal coal exporter, shipping primarily to China, India, Japan, and Southeast Asia. Australia is the dominant met coal exporter, with Queensland mines supplying steel mills in Japan, South Korea, India, and China. Russia, South Africa, Colombia, and the US are other significant exporters.

Coal is shipped in Capesize (met coal, large thermal shipments) and Panamax/Supramax (thermal coal) bulk carriers. Loading rates and vessel turnaround times vary significantly between ports. Stockpile management at both loading and discharge ports is important due to coal's susceptibility to spontaneous combustion when stored improperly.