Biomass Boilers

About biomass, and how it works

'Biomass' means any fuel which is produced from renewable sources – things like wood, sunflower husks, and other similar materials. Most commonly, a biomass boiler will burn wood in some form, either as logs, wood chips, or pellets.

Pellets can be delivered either in 15kg bags, or bulk delivered by tanker to a purpose built hopper. 


Log boilers are like log burning stoves in that they are hand filled, and need to be refilled regularly with fuel. The difference is that they are connected to the central heating system and heat the water for the central heating. Once the log boiler is filled and lit it will burn for several hours and heat up a large tank of water (a buffer tank) which stores enough heat to keep the heating running for the rest of the day.

Eco Angus Log boiler.

 Okofen handfill pellet boiler shown below. 


Biomass pellet boilers work very much like an oil or gas boiler. They burn wood pellets, which can be delivered in bulk, straight to the fuel store, and these are drawn as needed by the boiler. They are clean, efficient, and fully automated. Needing no regular attention other than normal boiler servicing. They have a fuel store which is filled from time to time in the same way that an oil or LPG tank is refilled. If there is nowhere to locate a large fuel store, the boiler can use a smaller fuel hopper which is filled by hand every few days, or perhaps once a week – this only takes a few minutes.

 External 5 Ton hopper fitted at an installation in Kirkbymoorside

Fuel is widely available from a well established network of suppliers, it is produced in the UK and is FSC certified. The price of wood pellets has remained relatively stable over the years, and does not suffer the same fluctuations seen with fuel oil prices. The pellets are manufactured using waste material from the timber industry – sawdust, and the unused offcuts from timber mills. The timber is cropped from managed forests, and is a viable, renewable source of heating. The UK currently exports around 80% of its pellet production to places like Scandinavia and Germany, where Biomass is a well established and popular form of heating.

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