Biomass systems fall into 2 main categories: - commercial and domestic
Commercial biomass systems
An installation is considered “commercial” if it is an obvious commercial operation such as a factory or a residential property where there is more than one rateable dwelling.
Biomass boilers burn wood in one of several forms:
Logs. Burning of logs can be very cost effective if labour and a ready supply of suitable timber is available. Hover the process is labour intensive and not normally automated. The logs need to be split and dried to a moisture content of less than 30%.
Chips. Chipped wood biomass systems can be automated and the fuel fed with an auger system. The economic viability of a chip system depends on the availability of the timber and the chipper. Moisture levels are of paramount importance in chipped fuelled systems.
Pellets. Pellet biomass systems burn wood that has been reconstituted and extruded to form pellets. The quality of the pellets is vital and is governed by a European standard. Pellet driven systems are fully automated and can be driven by either a vacuum blower or an auger.
Combination biomass systems.
Commercial biomass systems range from 20kW upwards. There is a tier 1 tariff cut off point at 199kW which currently stands at 8.6p per kW hour for 20 years.
Domestic biomass systems
The domestic tariff for biomass is less than the commercial systems and will be paid over 7 years. The domestic tariff will not be introduced until April 2014.