Which is better for a biomass boiler: wood chips vs wood pellets?

There are several considerations to keep in mind when choosing the fuel for your biomass boiler heating system.

There are two main fuel types; wood chip and wood pellets.

The choice of fuel type is commonly a decision that is made during the planning stages of the heating design. The logistics and storage of your fuel required can often predict which fuel type is chosen.

What is wood chip biomass fuel?

Wood chips are small pieces of wood that have been cut to sizes between 5mm and 50mm.

To produce wood chip fuel, trees are coppiced and the offcuts are chipped and then dried until the chip moisture meets the desired requirements.

What is wood pellet biomass fuel

Wood pellets are comprised of sawdust or fine shavings of wood made into pellets by pressure. This binds the material into cylindrical shapes between 6mm and 10mm in width and 10mm to 30mm long.

No artificial chemicals are added to wood pellets but starch or corn flour is sometimes used to improve stability: the result is a high density fuel with low moisture contents, which is less bulky to transport and store.

Benefits of wood chip

• Cheaper energy per kWh
• Easier to get hold of in the local area
• You can chip your own wood from managed woodland after preparation
• Can benefit businesses in the local economy

Benefits of wood pellets?

• Less storage space is required
• Less variation in moisture content resulting in more reliable performance
• Can also be delivered and stored in bags for hand-feeding options

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