Biomass is fuel that is developed from organic materials, a renewable and sustainable source of energy. Harewood House and the Courtyard are heated by a biomass boiler.
We have over 800 acres of woodland on the Harewood Estate. Many areas are Ancient Scheduled Woodland Sites and some sit within our Registered Park and & Gardens. Nearly all areas are viewable from public rights of way and we have a wealth of wildlife that make our forests their home. So our woodland operations need to work sensitively within these constraints and are now geared towards protecting and enhancing the landscape for amenity and biodiversity value.
We conduct necessary thinning of our woodlands on a regular basis to help improve the timber stocks and the values we are trying to protect. Historically we have sent felled timber off to merchants round the country, but we now use it on site within our biomass plants to provide renewable heat for Harewood House and the Courtyard, as well as the Estate’s commercial office spaces, 10 holiday cottages and 15 residential properties. It’s a model of what a renewable energy district heating system of the future might look like.
Once the trees are felled the timber is taken back to the Walled Garden, stacked and left to dry to reduce the moisture content to make it suitable for burning within the biomass plant. Around 8 months later (depending on the weather!) the timber is dry enough to chip and we hire in a Diomante chipper, an amazing piece of kit which picks whole tree stems on the one side, feeds it through a chipper and produces the chip out the other side which is loaded directly into a wagon. The chipper can process up to 50 tonnes per hour!
With the chip created, we take it back to our chip store, where it is unloaded and spread out to aid further drying. We try to keep at least 6 months of chip in stock. Once it’s down to the correct moisture content (30-35%) it can be used in the boilers. We fill up each boilers chip store once a week and it then feeds into the boilers automatically. The feed store has a slowly vibrating floor that moves the chip from front to back to ensure a steady supply of chip to the boiler.
The main boiler at the time of installation was one of the largest in Yorkshire. It burns the chip at temperatures of up to 900°c which then heats the water. It’s incredibly efficient, with hardly any waste material produced, usually just a couple of ash buckets per week. From the storage tanks, which hold around a 24-hour supply, the hot water then goes into the district piping network and out to all the properties that are connected in.
As well as being a reason to reinvigorate our woodland operations, the biomass plants are a great source of renewable energy and have helped us reduce our carbon footprint as well as those of our tenants by association. Compared to an oil system we are saving over 440 tonnes of CO2 each year – if you also factor in the savings by processing the timber on site rather than transporting them to merchants elsewhere the total reaches almost 650 tonnes of CO2 saved each year. That’s roughly equivalent to 1,000 people taking return flights from London to New York or what 25 families would average during a whole year.
We’ve been working with the Leeds Climate Commission, Circular Yorkshire and Sustainable Arts in Leeds to share our story so others can build from our success.
