Wood pellets can be made from a range of wood biomass materials. Besides wood biomass, other types of pellets (non wood pellets) can be made from paper, cardboard, grain, straw, corn husks, production waste and all manner of things. The process for making biomass wood pellets is principally the same that is used for other materials.
What is a Wood Pellet?
A wood pellet is simply biomass wood materials that have been shredded into sawdust and then highly compressed through a die cast (using hydraulic machines) to create a cylindrical pellet shape (form). The wood pellet is bound together by the naturally occurring lignin in the wood. In the UK, most wood pellets are formed formed in 6mm or 8mm sizes and are generally around a centimeter or two in length.
Wood biomass used in the production of wood pellets can come from virgin or from waste materials used in industry – like sawdust (from processing) or waste off cuts for example in a furniture making factory. Before virgin or waste wood can be made into a wood pellet it is broken down into finer particles. Larger pieces of wood are first run through a chipping machine to break them down into fine particles. The finer the particle the stronger the pellet and the greater the energy it will produce.
Wood pellets are recognised as one of the best sources of sustainable, eco-friendly fuel available. In comparison to the likes of oil and gas, wood pellets are pure, sustainable, and emit considerably less carbon dioxide into the atmosphere.
How are wood pellets better for the environment?
Wood pellet fuel is considered to be carbon neutral. Trees absorb carbon dioxide from the atmosphere during their lifecycle. When the plant is burned, the same amount of carbon dioxide is then released back into the atmosphere. The cycle then begins again when the replacement plants begin to grow.
How much carbon dioxide is produced in comparison with other heating fuels?
Including manufacturing and transportation costs, it is estimated that burning wood pellets produces 34g carbon dioxide per KiloWatt Hour of heat produced (g/kWh).
|Local Wood Pellets||34|
|Imported Wood Pellets||52|
|Local Wood Chip||64|
|Ground Source Heat Pumps||123|
Adapted from “The Carbon Balance of Woodfuel”, Northern Woodheat, 2010.
The process of manufacturing wood pellets is comparatively simple, as it is essentially the compression of sawdust into a pellet. This requires little energy in manufacturing terms and emits minimal carbon dioxide when compared with processes such as oil refining.
With the increase in popularity of wood pellets over recent years it has become necessary to import quantities of wood pellet fuel into the country. Even taking into account the additional transport in this process the amount of embedded carbon dioxide in imported wood pellets is minimal compared to all other popular fuel types – even including locally sourced wood chip.
The newly introduced BSL (Biomass Suppliers List) standards ensure that wood pellets produce two thirds less CO₂ than fossil fuels.
Using wood pellets and biomass as your primary source of fuel has many advantages, from the reduced C02 emissions to the price stability of this type of fuel.
Advantages of using wood pellets
- Reduced carbon emissions – much less than oil, log, coal or gas-fired boilers
- Equivalent heat to traditional fossil fuels
- Wood pellets are much more price stable than many other forms of fuel
- Available on demand and are now extensively produced within the UK
- Wood pellet boilers are now extremely advanced and can operate up to a 95% efficiency rate
- Pellet boilers are widely used across Europe as a favourable alternative to gas or oil
- Wood pellets can be used by those who are not currently on the national grid
- Easy to switch to wood pellets as boilers are similar to oil-fired boilers
- Boilers are low maintenance and easy to control, through automatic settings
- Wood pellets burn cleanly and are more convenient than logs or wood chip
- Wood pellets fall under the Renewable Heating Initiative meaning that users can receive payments for the energy they produce