- Location: Jedburgh, Scottish Borders
- Wood fuel usage: district heating scheme for a development of eleven (will eventually be twelve) domestic properties (a mix of steading conversion and new build)
- Installation date: November 2009
Reasons for choosing woodfuel
Gilbert Properties wanted to use a renewable, carbon-lean fuel to reduce the carbon footprint of their new development.
The site is in an area with no main gas network but situated just six miles from a source of woodfuel. Alternative fuels (oil or LPG) would have been more costly to operate as well as less environmentally friendly.
Having a secure local sustainable source of energy, not subject to the price fluctuations of fossil fuels, means that annual energy costs are predictable.
System features and benefits
The nine properties are connected by a heating pipe network which distributes heat generated from a central wood fuel boiler.
Known as a district heating scheme, this system is cost effective since a single boiler, boiler house and fuel store supply all nine properties, reducing installation and maintenance costs.
In addition, each property saves space with only a heat exchanger and small heat meter needed inside the house.
The heat meters allow accurate fuel bills to be produced for each customer based on delivered heat.
Each house is also fitted with solar panels that connect to an independent hot water cylinder. This heats water in the summer, further reducing energy bills.
A solar programmer automatically activates the biomass boiler if the water temperature is not high enough.
Wood fuel supply
Woodfuel is supplied by Border Ecosystems, an energy services company (ESCo), who also maintain the system and read meters.
Wood chips are delivered from a source six miles away, every three weeks in winter and every six weeks in summer.
To maintain this supply, the ESCo is working alongside local wood suppliers to guarantee a continuous cycle of replanting following harvesting.
- Work with local timber suppliers to source supply of fuel prior to installation design in order to ensure compatibility
- The district heating pipework insulation works very well, with minimal thermal losses
- Installation personnel with a depth of experience are recommended
- Seek multiple sources of advice to compare opinions
- Investing in independent advice to ensure the correct system and design to suit your needs at the beginning might save you money in the long term
- Information on how to meter and charge customers can be difficult to locate, so seek information from your experienced installer
- Get a qualified heating engineer to guarantee the system so that you have some come back if it does not deliver what is promised
- Gilbert Properties have found the woodfuel experience, on the whole, very positive. Now they have had the system for a while and fully understand it, they definitely consider it superior to a fossil fuel system. They find that woodfuel boilers produce more heat than equivalent sized oil boilers
- Running the boiler at optimum capacity and efficiency maximises the economic benefit of a woodfuel system.
Facts and figures
Note: figures are approximate
|Fabric||Timber frame kits with stone skin and 150mm of insulation|
|Boiler system||ETA boiler with accumulator vessels and underground delivery pipework, plus integrated solar panel programmer|
|Maximum boiler output||130 kW|
|Fuel type||Wood chip|
|Fuel specification||Moisture content: 30% (M30)|
|Back-up/top-up system||Each house has solar panels linked to wet system|
|Wood fuel store and handling||A purpose-built wood chip blower trailer provides the delivery service to an above ground storage hopper|
|Wood fuel store capacity||48m3|
|Fuel Supply Contract||ESCo Service – supply and deliver chip, read meters and maintain boiler|
|Fuel consumption, costs and savings|
|Annual wood fuel use||60-70 tonnes- this figure will rise with the recent addition of new properties to the system|
|Annual energy consumption||260,000 kWh|
|Annual CO2 savings||62 tonnes|
|Wood fuel cost||£100 per tonne for supply, delivery, system maintenance and meter reading|
|Annual fuel cost saving||£5,080 (this figure will likely change with the addition of thenew properties)|
|Installation cost and funding|
|Boiler system||£110,000 overall project cost|
|Funding source||Scottish Biomass Heat Scheme (see note below)|
|Funding support rate||50% of additional costs over fossil fuel equivalent|
- Environmentally friendly heating solution
- Lower energy bills for householders
- Local employment created through wood fuel harvesting and processing
- Short distance to secure fuel supply reduces energy costs