Which Biomass Type Has the Highest Heating Value?
On a dry basis, nutshells and olive pits top the list at about 19–20 MJ/kg, with woody biomass close behind at 17.5–19 MJ/kg. On a delivered, as-received basis, wood pellets and olive pits deliver the most usable energy at roughly 16–17.5 MJ/kg (4.4–4.9 kWh/kg). Dry-basis values mislead, because moisture decides: food waste has a respectable dry value yet only about 2 MJ/kg as received.
Dry Value Versus Delivered Value
These are two different questions. Dry-basis heating value tells you how good the material would be with all water removed; as-received tells you what your boiler actually receives. Every kilogram of water costs about 2.44 MJ to evaporate, so the conversion is straightforward: subtract that penalty from the dry value multiplied by the dry fraction. Rankings change completely once you do—straw looks competitive dry and poor delivered at high moisture.
Comparative Data Table: Heating Value by Fuel
| Fuel | Moisture | LHV dry (MJ/kg) | LHV as received (MJ/kg) | kWh/kg as received |
| Olive pits | 10% | 19.5 | 17.3 | 4.8 |
| Coconut shell, nutshell | 10% | 19.0 | 16.9 | 4.7 |
| Wood pellets | 8% | 18.0 | 16.4 | 4.6 |
| Wood chips | 35% | 18.0 | 10.8 | 3.0 |
| Wheat straw | 15% | 17.0 | 14.1 | 3.9 |
| Sugarcane bagasse | 50% | 18.0 | 7.8 | 2.2 |
| Bedded cattle manure | 30% | 15.0 | 9.8 | 2.7 |
| Food waste | 80% | 21.0 | 2.3 | 0.6 |
What This Means for Plant Design
Boiler sizing, storage volume, and fuel contracts should all be written against as-received values, not brochure dry figures. A plant that buys wood chips at 45% instead of 35% moisture receives roughly 20% less energy per tonne and will need proportionally more trucks, more storage, and more grate area. Conversely, high-moisture streams with good dry values such as food waste are best processed by anaerobic digestion, which does not have to evaporate the water first.
Frequently Asked Questions (FAQ)
Q1: Which biomass type has the highest heating value?
A: Dry basis, nutshells and olive pits lead at about 19–20 MJ/kg. Delivered basis, wood pellets and olive pits give the most usable energy, roughly 16–17.5 MJ/kg or 4.4–4.9 kWh/kg as received.
Q2: What is the LHV of wood pellets?
A: About 16–17 MJ/kg as received at 8–10% moisture, equal to roughly 4.4–4.8 kWh/kg. The dry-matter value is around 18 MJ/kg; the small gap is the moisture penalty.
Q3: Why does moisture matter more than dry calorific value?
A: Because every kilogram of water costs about 2.44 MJ to evaporate before any heat is released. A fuel with excellent dry value but 60% moisture can deliver less usable heat than a poorer fuel that arrives dry.
Q4: Which delivered fuel gives the most energy per tonne?
A: Pellets, olive pits, and nutshells at roughly 4.4–4.9 kWh per kilogram delivered — about 4.4–4.9 MWh per tonne. By comparison, food waste delivers only around 0.6 kWh per kilogram and belongs in anaerobic digestion.