---
title: "Wood pellet"
description: "Wood pellets are densified biomass-fuel pellets, typically 6–10 mm in diameter and 10–40 mm long, manufactured by milling and pressing wood residues without binder. Industrial wood pellets are the dominant biomass fuel for utility-scale co-firing and for dedicated biomass conversions of former coal-fired power stations (Drax Power Station in the UK is the largest example)."
canonical_url: "https://sylio.co/glossary/wood-pellet"
last_updated: "2026-06-28T02:29:42.161Z"
---

**Wood pellets** are densified biomass-fuel pellets, typically 6–10 mm in diameter and 10–40 mm long, manufactured by milling and pressing wood residues without binder. Industrial wood pellets are the dominant biomass fuel for utility-scale co-firing and for dedicated biomass conversions of former coal-fired power stations (Drax Power Station in the UK is the largest example).

## Pellet-silo bridging

Wood-pellet storage silos at biomass power plants are notoriously prone to [bridging](/glossary/bridging) and [rat-holing](/glossary/rat-holing):

- Pellets self-heat in storage, releasing volatile organics that bind adjacent pellets
- Mechanical compression in tall silos breaks pellets into fines that consolidate
- Moisture absorption from atmospheric humidity worsens cohesion
- Self-ignition is a documented fire hazard requiring inertisation

[Sonic horns](/glossary/sonic-horn) at silo discharge points provide continuous flow promotion without the mechanical impact of [air cannons](/glossary/air-cannon-air-blaster), which is particularly valuable on tall silos where structural stress matters.

## Fouling

Wood-pellet combustion produces moderate alkali ash typical of [biomass](/glossary/waste-to-energy) operation — slagging on the radiant section, fouling on the convective pass. Less chlorinated than waste-derived fuels.

## Related terms

- [Silo](/glossary/silo)
- [Bridging](/glossary/bridging)
- [Alkali metals in ash](/glossary/alkali-metals-in-ash)
- [Boiler](/glossary/boiler)