Biomass fuels are renewable and also considered carbon-neutral. This is because, when they are burned, they release the same amount of carbon they absorbed during their time growing as plants and trees.
Fuels can be seen as wet or dry and high or low density. The wetter fuels are lower in calorific value (meaning less energy per kilo) and are therefore cheaper. But some moisture is desirable as the extremely dry fuels are not ideal for most biomass boilers.
Density is down to the space they take up. The denser they are the smaller they are, whilst still containing the same amount of energy. Most fuels are measured by “Energy Density by Volume” also stated as kWh/m3.
The most popular biomass fuels
1 – Biomass Wood Pellets
Usually around 10x33mm in size and manufactured from waste wood products, these pellets are compacted from the offcuts of saw milling, wood product manufacture and waste wood found after logging. Typically, a binding agent is used to hold their shape, this is most commonly flour or corn starch.
Pellets can be sold in bags ranging between 10kg and 1000kg or they can be delivered in larger quantities in a lorry. They are a high-density, low-moisture biomass fuel which makes them easy to transport and store with 1 tonne only accounting for approximately 1.5 cubic meters of storage space.
Being of uniform shape and size they are easy to use and add to boilers. The larger of which often come attached with timed hoppers, adding more fuel at specific intervals to ensure constant energy production. This means reliable, constant heat for home or business.
2 – Wood Chips
These are a cheaper alternative to wood pellets since there are less processes involved in their production. Wood chipping machines are simply fed the de-barked logs and produce ready wood chips for transport and burning.
They are not as efficient as wood pellets since they are both higher in moisture content as well as larger and taking up more storage space. They are commonly used in larger boilers, which are incredibly efficient, but often come at minimum sizes.
3 – Wood Logs
Very readily available and requiring the least processes to produce, wood logs have been used as heating fuel for thousands of years. Their main disadvantages is that, as large logs, they have a smaller surface area than chips or pellets and, as such, have a much lower calorific value. In short, they are less energy efficient.
Typically, logs come from freshly felled trees and therefore need to be dried for a significant period of time before they are suitable for burning. They also take up far more room than chips or pellets and double the amount will have to be stored to produce the same energy output.
They also can’t be loaded automatically, meaning boilers fuelled with them need to be hand-fed, increasing the maintenance required for their use.
What do we recommend?
The ETA biomass boilers cater to all three fuel types so depending on your requirements and preference we have a heating system suitable for you!
To arrange your free no-obligation biomass boiler consultation, please complete the form below and a member of our team will be in touch.