E H C Brun
Fring Hall
King's Lynn
PE31 6SF

T : 01485 518229
E : ebrun@fringhall.co.uk

© Copyright 2007 E.H.C.Brun

Wood Chips :

Wood is emerging as an important fuel as part of the Government's drive for increasing the proportion of our energy produced from sustainable biofuels.

Trees grow every summer using the energy of the sun to fix carbon from the atmosphere. Every woodland has a sustainable yield of timber, which can be harvested indefinitely without depleting the resource in any way. Wood is carbon neutral and does not contribute to greenhouse gasses. Burning wood gives off carbon dioxide just like fossil fuels, but this is balanced by the carbon absorbed by the growing trees. Un-harvested wood will give off the same amount of carbon dioxide when it eventually decomposes as it would have done if burnt in a boiler.

Wood is an age old fuel which fell out of use in Britain with the industrial revolution and advent of cheap fossil fuels. However, wood is still the primary fuel for people in many countries around the world, both developing and developed. In Britain, with increasing concern about climate change, wood is now an increasingly attractive energy source along with other forms of biomass.

Wood chip is widely use in other European countries as a fuel for heating and in combined heat and power systems, particularly in countries with a strong forestry tradition such as Scandinavia and Austria. Wood chip boilers are available for all scales of operation.
As with wood pellets modern wood chip boilers can provide a high level of automation and convenience for wood fuelled space heating. Wood chip systems generally have an output of greater than 20 kW and are not currently cost effective or appropriate for typical domestic scale applications. Extensive fuel handling systems and fuel storage facilities are required for automated operation.

Due to oil and gas price rises over the last three years, wood chip is a very cost-competitive fuel with the less processed forms such as logs and chips typically undercutting all other domestic fuels. The downside is that the equipment to burn them is usually considerably more expensive than that for fossil fuels. However, with the recent introduction of various grant schemes to help with these capital costs the scales are more balanced, particularly as the variable costs are lower and more predictable. Oil prices, in particular, are very volatile whereas woodfuel costs are stable and may be fixed in long-term contracts.

Wood chips present no risk if accidentally released into the environment, unlike oil which is a serious pollutant and gas which can explode. There are no harmful by-products. The flue gas is smoke-free and the ash content of between 0.5% and 3% by volume (depending on material), is minimal. Unlike coal ash, wood ash is an excellent fertiliser and can be used in the garden or returned to the forest. Modern appliances burn very cleanly with minimal smoke.

The majority of woodchip boilers currently being installed in the UK require fuel to comply with the Austrian ONORM M 7133 specification.

Our woodchips meet this specification to the following standard:

G30 Woodchip Size
<1 mm
1-3 mm
3-16 mm
>16 mm
Maximum Extremes
3 sq.cms
8.5 cms

W35 Moisture Class
30 - 34% Moisture Content