What Are Wood Pellets? A Guide to Wood Pellet Fuel

Wood pellets are a renewable heating fuel made from compressed sawdust and wood shavings. Each pellet is a small, dense cylinder, a few millimetres across, that burns cleanly and evenly in a pellet stove or biomass boiler. Because they are dry, uniform and easy to feed automatically, wood pellets are the most convenient form of wood fuel for heating homes and businesses.

This guide explains how wood pellets are made, what the quality grades mean, how to buy and store them, and what to look for in a supplier. It is written by Balcas Energy, which has made wood pellets in the UK and Ireland since 2004.

How are wood pellets made?

Wood pellets start as sawdust, a co-product of sawmilling. The sawdust is dried, then forced through a die under high pressure. The heat and pressure bind the wood fibres together using the wood’s own natural resin, so no glue or additives are needed. The pellets are then cooled, screened to remove dust, and bagged or stored for bulk delivery.

At Balcas Energy we make our pellets at two mills, in Enniskillen, Northern Ireland, and Invergordon, Scotland, from the sawdust of our own sawmills. The timber is spruce or pine from sustainably managed forests, and the energy that runs the mills comes from our own combined heat and power plants, fuelled by sawmill co-products. See how we make our wood pellets.

What are wood pellets used for?

• Pellet stoves - room heaters that burn pellets from a small built-in hopper, usually filled by hand from 10kg bags.
• Biomass boilers - central heating and hot water for homes, farms and businesses, fed automatically from a pellet store.
• Larger heating systems - schools, hotels, care homes and industrial sites, often supplied in bulk on contract. See commercial wood pellet supply.

Wood pellet quality: what ENplus A1 means

ENplus is the international certification scheme for wood pellet quality. It sets limits for moisture, ash, durability, fines and chemical content, and it covers the whole supply chain - production, storage and delivery - with regular independent audits. A1 is the highest ENplus grade and the one recommended for residential stoves and boilers.

Pellets that are not certified can look identical but behave very differently. They can carry up to 10 times more ash, melt at a lower temperature and form clinker on the grate, contain more chlorine that corrodes the heat exchanger, and break down into dust that upsets the fuel feed.

Balcas was the first producer in the UK and Ireland to be audited for ENplus, gaining accreditation in April 2011. All our bulk and bagged pellets are ENplus A1. See our specifications and certificates.

What is the Biomass Suppliers List (BSL)?

The Biomass Suppliers List is the UK government’s register of wood fuel suppliers whose fuel meets its sustainability criteria. Participants in the UK’s Renewable Heat Incentive must buy their fuel from a BSL-authorised supplier to keep receiving their payments. Balcas is on the list, trading as Balcas Timber Ltd. Your BSL number is shown on your invoices and in your online account.

Are wood pellets a low-carbon fuel?

Wood pellets are made from wood, a renewable resource: the carbon released when they burn is carbon the trees absorbed as they grew, and managed forests are replanted. How low the footprint really is depends on where the pellets come from and how they are made. Pellets made locally, from sawmill co-products, with renewable energy, travel a short distance to reach you and avoid the emissions of shipping imported fuel. Read our sustainability story.

Bulk or bagged wood pellets?

Wood pellets are sold in two ways. Bulk pellets are delivered by lorry and blown straight into a boiler’s store, usually from a minimum of 3 tonnes. Bagged pellets come in 10kg bags on a pallet and suit stoves and smaller systems. If you have a pellet boiler with a store, bulk is usually the better choice; if you fill your appliance by hand, bags are easier.

• Bulk wood pellets - how blown delivery works
• Bagged wood pellets - pallet sizes compared

How to store wood pellets

Keep wood pellets dry: wet pellets swell, break down and burn poorly. Bags are best kept indoors, in a garage or shed. A bulk store must be waterproof, sealed and ventilated, with no electrical fittings inside, and should be ventilated before anyone enters, because stored pellets can give off carbon monoxide. Our pellet storage guide has the full checklist.

How much wood pellet fuel will I use?

It depends on your appliance, the size and insulation of your building and how much heat you need. As a guide, a 10kg bag in a pellet stove lasts between 1 and 3 days. Your installer’s figures for your boiler are the best starting point for planning bulk deliveries.

Where to buy wood pellets

Balcas Energy delivers ENplus A1 wood pellets across the UK and Ireland, in bulk and in bags, and you can get a live price for your postcode, with delivery and VAT included, in our online quote. Find wood pellets near you, or buy wood pellets in the UK or wood pellets in Ireland.