Summary & Outcomes
The original proposal was to purchase a wood compressor to make firewood briquettes from the woody arisings resulting from heathland management which are generally left on site. This can delay high quality heathland restoration for example through nutrient build up.
However, when the project started it became apparent that there were difficulties transforming the arisings into a workable product for example through removal of moisture. The emphasis changed, and an initial report “Making saleable wood fuel from heathland restoration arisings” was produced.
This estimated that around 600 tonnes of chipped material would be produces each year through on-going heathland maintenance management, with an additional 2,000 tonnes per annum produced between 2013 and 2020 resulting from heathland restoration. If converted to wood chip, this could potentially provide enough energy to heat around 630 houses.
The next stage was to draw up a costed bid for installing a combined heat and power woodchip boiler. This would enable wood chip from heathland arisings to produce electricity locally and gain feed in tariff. A further report was produced “Developing a cost-effective use for heathland management arisings in Purbeck and the New Forest”. This assessed the amount of heat or electricity that could be produced, and identified the associated costs. The report concluded that to be viable, a small sized electricity generating plant would be required.
Highlights and challenges
It is perhaps no surprise that finding an energy-generating solution for woody biomass has been hard work, and that there is no small-scale power plant available now; and had something been available, the project would have used it. The investigation has, however, got the partnership to a position where the minimum quantities of woody biomass that can be generated from the heaths are known, together with the likely electrical / thermal output that could be expected. As soon as small-scale plant is commercially viable, the partnership will be in a good position to install.
An outline bid has been submitted to the Local Enterprise Partnership for funding a small-scale generating plant on expectation that market-ready technology will be available soon.
There is an alternative under consideration by the Forestry Commission in partnership with Ecotricity, examining the potential for converting woody biomass mixed with green grass into biogas in an Anaerobic Digester. In Dorset, where there is insufficient green grass along forestry tracks to fuel AD plants, arisings from cutting road verges are being considered as a substitute, involving discussions with Dorset County Council and Alaska Environmental Contracting.