Farm Diversification

Kaimes is large, seven bedroomed house sited on a 485 hectare farm near the village of West Linton in Peeblesshire. Peter Thomson lives at Kaimes with his wife Kerry and runs Thomson Trees from the site as well as being a partner in running the family farm with his father.

Thomson Trees has several strands of business including tree surgery, tree nursery, tree planting and Peter plans to supply woodchip in the future.
Approximately 10% of the farm is mixed woodland, including large areas of conifers.

Why install renewable energy?

The house, Kaimes, was using a heating system that was installed in the 1920’s.  It originally ran on coal and was then converted to red diesel in 1936, and heated only 10 radiators. This coupled with poor insulation meant the £8k heating cost was actually doing very little to heat the house and needed to be addressed.

Woodland planted by Peter’s father had reached a viable age for harvest; therefore a supply of woodfuel was readily available.

As the heating system for the house needed replacing anyway and there was the opportunity to supply his own fuel, installing a wood-fired heating system appeared to be a logical way forward.

How did you identify the type and scale of renewables project?

Peter did an MSc dissertation on biomass and Short Rotation Coppice as a fuel source nearly 20 years ago and has maintained an interest in this area (short rotation coppice is usually densely planted, high-yielding varieties of poplar or willow grown as an energy crop). The need to manage the trees on the farm, linked to the heating problem at Kaimes made wood-fired heating a logical solution. The cold winter of 2009 motivated the renovation of the heating system which included improving the insulation of the building and the installation of 40 additional radiators, to a total of 50.

The scale of the boiler was dictated by the level of insulation and the size of the house to be heated.

Ground source heat pumps and solar heating were both considered and dismissed as inappropriate: solar due to the location and unreliable nature of the sun for heating and ground source heat pumps due to the difficulty in insulating the building to an appropriate level.
Three installers were approached for a quote.  The installation Peter decided on is a 70kWh Fröling wood chip boiler with an auger feed (with agitator).  

The system is located in a converted workshop. The fuel store is a converted outbuilding of around 25m3 which was formally a small garage used for lawn mowers and other tools, adjacent to the new boiler house.  The roof has a sliding panel door and the store is currently filled through the roof using a tractor and front end loader.  However, this method is time consuming and it is not possible to fill the entire store.  It is Peter’s aim to purchase a truck with chip blower which will be justified once his woodfuel supply business develops.

Researching the idea

Over the period from winter 2009 until early 2010 Peter researched heating solutions for Kaimes and the logistics of each option. A wood boiler fed by logs was considered, but dismissed on the grounds that it was too labour intensive and Peter wanted a system with minimal maintenance that supplied constant heat to the house.

A pellet system would also have been fully automated option but research on the price of pellets indicated that because the farm has its own supply of timber, it made more sense to install an automated woodchip system.
The boiler finally selected was based on research with a number of different installation companies that all provided quotes. 

The economics of the boiler installation were carefully researched.  Although the capital costs of a wood-fired boiler are higher than a fossil fuel boiler, the savings that could be made through self supply of fuel made this a viable business decision.  The proposed Renewable Heat Incentive (RHI) was researched, but Peter decided that it was worth going ahead even without the RHI.  The project was self funded and accessed no grants; however it is likely that it will be eligible for RHI payments although the final details of this scheme for domestic properties are not yet available.  
For more information on the RHI see the  Renewable Heat Incentive information sheet.

Business Establishment

Installation of the boiler and modification heating system were completed by October 2010. In addition, Peter converted part of an existing farm shed (30m x 18m) into a storage shed to enable a year’s supply of dry chip to be stored.
It was important that the timber for the fuel was felled around a year and a half before the boiler was installed to allow time for air drying down to around 30% or below.  The timber is then chipped to the specification required by the boiler, using a contractor with a large Jenz chipper.  This was much more economical than purchasing a chipper.

Approximately 19 hectares of Sitka Spruce (Picea sitchensis) are currently being contracted out to be felled, the poorer quality timber will be air dried over the next year and a half to ensure continuity of supply and create a base for the woodfuel supply business which Peter proposes to develop over the coming years.  The Renewable Heat Incentive is predicted to create a huge demand for wood fuel and Peter has identified an opportunity to expand his woodfuel supply business based on this.
The total project cost £50,000, including the purchase and installation of the boiler and modification of the boiler house and store buildings.
 
Problems encountered

Peter has encountered very few problems with his new wood-fired heating system over the past 5 months.   Minor problems have included:

• Initially there was a problem with pressure in the radiators or wet heating system due to lack of liquid. The accumulator vessel had to be topped up and the heating returned to normal.  
• If a power outage occurs the boiler doesn’t work, but it does re-boot once the power comes back on.  It should be noted that any type of boiler that relies on electricity to drive the pumps would suffer from this problem.  A small generator is being considered by Peter as a solution to prevent these interruptions in heating in the future.
  

Critical Success Factors

Critical success factors for Peter’s project include:

• A good quality boiler reduces maintenance and input required.
• Sizing the boiler correctly
• Improvements to the wet heating system and insulation of the property.
• Ensure the correct feed system is installed for the boiler.
• Appropriately sized fuel store so deliveries are only needed at practical intervals.
• Employing a quality installation company to ensure the system is correctly specified , installed well and good aftercare is provided after the installation is complete.

Finally, but most importantly, a reliable source of the correct specification of chip (in this case G50 chip) with moisture content under 30%, usually closer to 25%.

Contacts
For further information on this project, contact Peter Thomson on 0777 159 3482 or email peter@thomsontrees.com.