Mull Woodchip Group

To assist those looking at our woodfuel ideas, I have constructed this page to view our current position and resources.

Background

Over the last couple of years, various members of the Mull Community have been looking at the possibility of constructing a woodfuel group. The project is expensive to develop and requires help from funding agencies to initiate. I, for my part (Alan Parker) have applied for, and received, funding through the A.B.D.s scheme to construct a self catering unit. This has given me the chance to use this funding to proceed with woodchip for water and central heating.

Robin sedgewick of Crannich Farm has brought forward a plan to construct a combined domestic and commercial heating plant for his own development and also to be the woodchip producer. Both parties have combined resources to drive the woodchip group forward. Behind these individuals is a group of about 8 others who have committed to seriously considering woodchip if a supply chain can be firmly established.

Why timber fuel is important

The rationale for woodchip on Mull is unquestioned because of our huge biomass supply in the forests. The economics of taking the timber 'off island' are very 'shaky' as it involves an expensive ferry crossing and large distances on single track roads. If the cost of road repair and a true cost of forestation was considered, the result would be a massive loss!

However, forestry is vital to the eco system of the world and Mull. Trees filter out and use CO2, not to mention create habitat and stop erosion. How can we economically use this resource to reduce Carbon emissions and manage the forest?

Low value timber products may easily be converted into the valuable heating product of wood chip fuel. This requires the low tech. processes of air drying (leaving the timber stacked for a number of months in the open air) to a suitable moisture content and there-after chipping to a suitable particle size.

Carbon Neutral Woodfuel

Woodfuel is said to be 'Carbon Neutral' as even though burning wood produces CO2, creating the forest and managing the forest, soaks it back up again. However, in burning wood fuel, you are only using minimal electricity for control systems and diesel in transport.

How does it work on Mull? (Click all images to enlarge) (mouse over them for a description)

Timber is harvested by conventional means in the local forest and transported to a seasoning area to dry.

When seasoned (dried out a bit) it is taken to the chipping and storage area

Timber being delivered to the seasoning area at Crannich Quarry

Chipping is done on and industrial scale to keep costs low. The chipper is owned and operated by a local forestry operator. Site location Crannich Farm

Chipping operation in progress at Crannich Farm. Chips being blown ito the drying barn.

The woodchip is blown by the chipper into the storage and quality control shed, where it is inspected for consistent size and moisture content

Examination of the chips by the contractor and establishment of the moisture content.

For efficiency, the woodchip needs to be between 25 and 30% moisture content

The fuel is then delivered o the customer either in bulk, or, by 1 cubic metre bags on a vehicle with a crane unit.

Gus White, our local coalman, delivering chips from Crannich to the hopper at Sealladh Carrachan

Once inside the storage hopper or silo, the chip is gathered together by 'collectors' and fed automatically into the auger and carried into the boiler where it is very efficiently burned. The boiler responds automatically to the returning water temperature. In my case, the boiler services three properties separated by about 50metres.

A view looking vertically inside the hopper at Sealladh Carrachan. The screw thread in the centre winds the woodchip into the boiler, located in the barn.

Delivery of hot water is by highly insulated twin pipe tubing. This tubing is one of the more expensive elements of the whole operation when a delivery network is constructed.

Thermoflex piping ready for installation into the second of three propeties at Sealladh Carrachan

Security of supply is one of the issues that is brought up when woodfuel is discussed. We have had meetings with both Forestry Scotland and the contractors, Iggersons about the subject and clear arrangements have been made to address the issue. It has to be said that woodfuel is a major potential outlet for timber products, and could, turn Mulls' fragile forest economy around. Not to mention keep down the timber miles on our roads.

Robin and Alan meeeting with senior officials from Forestry and Iggersaons

Costs

The cost of installing any of the 'alternative energy' heating options such as heat pumps, ground absorbsion or solar panels is not cheap. Woodchip is no exception. The burden of costs of installation is normally cushioned by grants. In our case, we have received a 50% grant towards the total cost. Without the grant, 'payback time' is probably beyond most people's expectations, however, in Scotland the signs are that support is liable to get better, and the Scottish Executive have 'ring fenced' several million pounds towards bio fuel. THE TIME IS RIGHT TO INVEST. calculations are that in larger units, woodchip is about half the cost of oil. These calculations are now two years old. I am keeping records of my own fuel consumption and will give my costings public viewing after one year.

Even if the cost was the same as oil I firmly believe that woodchip is worth doing on the grounds of global warming and positive effects on the local economy. Also, living on an island, I am a little more in control of my own energy consumption and not dependent on expensive delivery systems.

Appropriate installation

Woodchip boilers are not suited to small buildings with limited access to delivery vehicles. Also, the basic rule is: The bigger the usage of hot water for heating and domestic use, the bigger the saving. Ideal installations to get the most benefit are: Swimming pools, facilities with public showers etc like campsites, distilleries, large houses, particularly those that are older and difficult to heat, housing schemes served by a common boiler, etc etc. Bigger the better!

For smaller buildings like modern homes, wood pellet would be more appropriate. This should only be contemplated when a good deliver service is available. Wood pellets are often produced from by-products of saw mills. (compressed sawdust)

Examples

Local examples to look at are : Mid Argyll Swimming Pool click to link

ALIenergy owns and operates a 200kW VITO woodchip boiler at Mid Sargyll Swimming Pool, Lochgilphead. Visits can be arranged

ALIenergy can also arrange visits to the 50 home district heating scheme at Whitegates, Lochgilphead. ALIenergy also has expertise in woodfuel supply chain development

New schemes at Aqualibrium in Campbeltown and Glenshellach, Oban will see biomass plant assisted by ALIenergy exceed two megawatts of installed capacity

Help.

In my own county, Argyll, expert and independent help can be gained from :Alienergy

A fact sheet in PDF about small scale biomass can be gained by clicking here