Pellets or wood chip

[edit] Heating with Pellets

Domestic pellet heating systems typically cost between £80 and £100 per kW installed. Commercial systems are a little more expensive, costing between £100 and £120 per kW. Pellets have to be purchased from a retailer, and are available for approximately £150 per tonne. Buying small quantities of pellets could be more expensive.

Pellets are essentially biomass materials (wood, leaves etc) squashed together into small pellet shapes. Resins and binders (lignin) occurring naturally in the biomass hold wood pellets together, so they usually contain no additives. Pellet fuelled heaters can be appropriate for houses and industrial premises. A pellet heating system can provide space heating and hot water. The technology offers property owners the opportunity to heat buildings in a sustainable and economical manner.

[edit] Heating with Wood Chips

A wood-chip fuelled heating system typically costs around £200 per kW installed. Fuel can effectively be free for owners of woodland, although the running costs of the wood chipping process have to be taken into account. If there are no on-site fuel resources, wood-chips can be purchased from retailers at a price of £20 to £40 per tonne, depending on the quality.

Wood-chip boilers can be used to meet the heating and hot water demand for various types of buildings. The heat may also be used in industrial processes (kiln drying, for example).

Wood-chips are produced from various types of wood residue, manufacturing waste, and energy crops. For efficient handling and combustion, wood-chips should be sized between 2 and 25mm in their largest dimension. However, wood-chips up to 200mm can be used in more tolerant systems. The moisture content of wood-chips is important; maximum moisture content is dictated by the requirements of the boiler. As a rule of thumb, no more than 10% of a load should have a moisture content greater than 35%.