BIOMASS BOILERS
What is Biomass?
Biomass is a generic term that includes all plant material that can be burn. So it includes wood but also things like straw, rape seed pellet, grain and flax. Usually it means wood as either log, chip or pellet.
Logs are precisely that but modern log burners often need logs cut to specific size. Chip is often the waste from forestry work, that is chipped to a specific size to enable better drying and easier handling. Pellet is wood dust - also often waste wood, forestry waste, sawdust from joinery works, old pallets and the like – formed under pressure to 6mm or 8mm diameter pellets. 
Wood pellet is by far the most common biomass fuel as it offers the best calorific value (the amount of heat for each unit of fuel), is lightest by volume (because it is the driest) and is the easiest to handle.
Cost of Biomass Fuel
The cost of biomass fuel varies with the type and quantity purchased – 
from £35 per tonne for logs bought locally to £210 per tonne for good quality pellets bought in small quantities in 10kg bags.
The table below sets out typical cost as a comparison to traditional fuels.
Fuel | Unit price | Boiler efficiency | Price per kWh heat output | CO2 per kWh |
Electricity | 12p / kWh | 100% | 12p | 0.43kg |
Natural Gas | 4.5p / kWh | 85% | 5.3p | 0.19kg |
Fuel Oil | 55p / litre | 85% | 6.1p | 0.26kg |
LPG | 57p / litre | 93% | 8.3p | 0.21kg |
Logs | 1.2p / kWh | 80% | 1.5p | 0 |
Wood Chip | 1.9p / kWh | 90% | 2.1p | 0 |
Wood Pellet (bulk) | 3.7p / kWh | 93% | 4.0p | 0 |
Wood Pellet (bagged) | 4.5p / kWh | 93% | 4.8p | 0 |
It is worth noting that the price of bulk wood pellet in 2005 was 2.7p per kWh. a rise of just 27% in 3 years, compared to over 80% rise in the price of heating oil. And the rise in wood pellet prices is slowing (even reversing in some areas) as more manufacturers enter the market. Similarly, the price of wood chip is tending to fall as the market for it expands and more producers enter the market.
Boiler Types & Costs
The range of types of burners is huge; from simple log-burning stoves to fully automated, industrial size wood chip or pellet boilers. To decide on which boiler is right for you there are 2 issues to consider; the type or fuel you want to use and the level of automation you want. A largely manually operated log-fired stove/boiler will cost around £2000 plus installation cost, while a fully auomated wood pellet boiler with fuel storage and delivery system could cost £15000.
Grants
The Low Carbon Build Program is still offering grants to support the installation of biomass heating systems. A wood stove will attract a grant of £600 or 20%, whichever is less and a boiler £1500 or 30%. In Scotland the grants rises to 30% of the cost. And they all attract VAT at 5%.
This page was last modified on 05 May 2009 15:05