Biomass is a biological material that comes from a living or recently living organism such as a tree. It is a renewable fuel source that is widely available throughout the UK. It is the most common form of fuel for renewable heating in the UK. There are heating and hot water systems that can be used in domestic homes as well as commercial businesses, schools and factories.
Whilst burning wood does release carbon dioxide into the atmosphere, it is equal to the same amount that was absorbed by the tree when it was growing thus making it ‘carbon neutral’. Biomass wood fuel however is not completely carbon neutral as there are some emissions associated with production and transport. There are many sustainable forests being managed specifically to provide wood for biomass boilers.
There are 3 types of wood fuel available...
Logs are used in basic boilers, these boilers are the cheapest option. However they do need to be filled up manually once a day.
Logs need to be well seasoned to be energy efficient and keep your boiler running smoothly. Unseasoned logs contain a lot of moisture meaning they do not produce as much heat. In addition to being less efficient, unseasoned wood releases a lot of condensates which can damage the flue system.
Almost any tree can be used for fuel, however there is a major difference in the energy output between different types of wood. Softwoods do not produce as much energy as hardwoods, meaning that larger quantities of softwood are needed to produce the equivalent amount of energy provided by hard woods.
When considering a log boiler you need to consider the source of your logs and where you will store them. You will need enough space for this heating season and the next one, to enable the logs to be well seasoned.
Wood pellets are relatively new to the UK but have been in Europe and America for some time. They can be produced from wood by-products such as saw dust and waste but may also be produced directly from the tree.
Pellets are the most convenient type of wood fuel as pellet boilers are automated. There is also a large range of pellet boilers available to suit individual requirements.
As pellets are manufactured, they have a very low moisture content, are very efficient, produce less ash and condensates and require a smaller storage space due to their high bulk density. Good quality pellets will provide greater heat.
Storage does need to be considered as the pellets must be kept dry. Depending on the type of storage option you choose you can feed the boiler either by gravity, an auger (screw mechanism) or via a vacuum system.
Wood chip can be made from almost any kind of wood including whole trees. Wood chip systems are usually automated making them more convenient than logs.
Wood chip has a low bulk density meaning that wood chip requires a bigger storage space. Moisture content should also be considered when using wood chip. A higher moisture content will not be efficient as some of the heat will be used when the moisture is vaporised. It may produce a lot of condensates which will damage your boiler and flue system.
The only form of automated delivery for wood chip is an auger (screw mechanism) meaning that the fuel store and the boiler must be close together.
We supply pellets made from virgin timber. There is no waste or recycled wood used in the manufacture of these products. We use 2 production plants – Andover, Hampshire and Grangemouth, Scotland. Each plant has an annual production capacity of 55,000 tonnes of wood pellets.
Each boiler will have a fuel specification that should be met. Specifications include moisture content, impurities and size. Using fuel that does not meet the required specification will result in poor efficiency and damage to your boiler and flue system. It may also invalidate your warranties.