In November 2014 the wood fuel boilers for the biomass project for the National Trust for Scotland at Mar Lodge Estate were fired up for the first time. The biomass system provides heat to a house, the stable block (containing offices and staff accommodation), Mar Lodge itself and the famous Stag Ballroom, saving an estimated £120,000 per year and reducing CO2 emissions by 450 tons per year on heating alone.
As part of their forest management plan NTS have been carrying out conservation thinning on their plantations in order to create a more natural forest structure. Creating gaps in the forest allows the trees left behind to grow more naturally than the regimented rows they were planted in.
Thinning is achieved using a mixture of horse logging, low impact mechanical harvesting and traditional chainsaw felling, depending on the sensitivity of each site, its location and weather conditions. The by-product of this thinning is obviously timber and this provides an opportunity to fuel the biomass boilers.
Installation of 2 x 333kw Fröling biomass boilers, 600 m pipe and drying floor in customer-built shed
This biomass project for the National Trust for Scotland was a large scale initiative with multiple facets involving complex design and technical challenges.
The shed which houses the biomass boilers measures 20m x 48m. Situated in the heart of a National Park it was important that the impact of this building did not detract from the landscape quality of the area. We installed two 333kw Fröling biomass boilers along with 600m of piping required to pipe the heat. The size of the shed means there is the capacity to store enough fuel to power the boilers through an entire winter, a necessity due to the harsh winters the Cairngorms are famous for.
To power the heating network 1000 tons per year of green round wood is required to be turned into woodchip. The wood will be chipped directly into the shed and onto the drying floor where it will be dried to provide the 600 tons of dried wood chip required per year to keep the boilers working.
As far as possible wood from Mar Lodge Estates own forests will be used but wood will also be purchased from neighbouring estates, as in some cases their forests are closer to the biomass shed, thus reducing the need to transport large volumes of timber over longer distances.
The reduction in CO2 will contribute to the Trust's green targets as well as national targets to reduce the effects associated with climate change.
The £120,000 saving that the biomass scheme will allow comes from savings made on purchases of LPG and oil combined with renewable heating incentives provided by the Government. This will help to ensure the financial stability of the estate and help us to continue to care for this unique and very special place.