Gross calorific value (GCV) is the total heat released when a fuel burns completely, measured in kcal/kg. It is the single most useful number for comparing fuel quotes.
How GCV is tested
A small sample is burnt in a bomb calorimeter, which measures the heat released. Labs usually report GCV along with moisture, ash and volatile matter in a proximate analysis.
Why moisture matters
Water in the fuel does not burn — it absorbs heat as it evaporates. Two loads of the same material can have very different usable heat if one is wetter. Always check whether GCV is reported on an “as received” or “dry” basis.
Comparing quotes on cost per heat
Formula: Cost per 1,000 kcal = Delivered price per kg ÷ (GCV in kcal/kg ÷ 1,000)
A cheaper fuel with low GCV can cost more per unit of heat than a slightly more expensive fuel with high GCV. Use delivered prices, including freight, for a fair comparison.
What to ask your supplier
- A recent test report for the material you will receive
- Whether GCV is on an as-received or dry basis
- Typical moisture and ash ranges across the year
Want a test report with your quote?
Every batch we supply can come with a GCV, moisture and ash report.
