The most popular form of domestic biomass system uses wood pellets which are formed from highly compressed, uncontaminated sawdust. In order to be regarded as a renewable source of energy it is important that the wood burned comes from a sustainable source and that trees used for fuel are replanted.
Wood pellet systems are available either as stoves for heating a single room or as boilers to provide full central heating and hot water. Pellets can be supplied in 10kg bags but for maximum economy it is better to buy them loose by the tonne. Storage space for pellets therefore is something that needs to be considered.
Wood Pellet boilers can only be used with 6mm approved EN Plus A1 premium pellets with attributes as follows:
• Moisture content below 10%
• Calorific value of 4.8 - 5.2kWh/kg
• Ash content of <1% (Low)
• Bulk density of around 650kg/m3
• Chlorine content of 0.03% or less
• No additives
Using pellets which do not meet the EN Plus A1 specification
from an unapproved supplier will invalidate your boiler warranty.