Willow Coppice
This is the start of my series on the production of Willow (Salix viminalis) as a Biomass fuel for my own use on the Scottish Island of Westray, Orkney. This series of articles was started on 25 September 2009 and will include my findings and guidance on the setting up, using and management of a ‘Short Rotation Coppice’ of willow.
The idea is to supplement the reduction of my heating costs by using renewable and sustainable energy. Orkney has no gas supplies (other than propane/butane bottles), so other than oil (expensive and dwindling) or electricity (intermittent and getting expensive), there is nothing else available in the traditional energy sources.
Hence the use of alternative energy sources. Scotland has a good supply of wind energy, in fact I seem to remember reading somewhere that Scotland gets 80% of Europe’s wind energy. To this end, wind turbines are pretty common in these sorts of remote communities. But electricity is not the solution for everything.
Most people who can in these remote areas are using as many energy sources as possible to supply their needs, and I’m no exception. The property is currently heated with a traditional oil fired heating system. However, with thick stone walls and exceptional quantities of wind, if the walls are wet, then there is no way the oil heating would be able to keep the building warm. So additional sources are required.
First choice would be wind power. Orkney typically only gets around 10 days of still air every year, meaning the other 355 days there must be wind and hence free power. Solar power is also possible, but due to the fact that Orkney lays between 59°41’N and 59°24’N, the suns rays have to travel through a lot of atmosphere before striking the panels (water or electric). Winter use would be almost non-existent and summer (with 24hr daylight) would be good for hours of light, but not quality. Water is a possibility, but rivers are not very common on Orkney and sea power requires serious investment to avoid damage due to the sea conditions available.
Then you move onto other technologies, such as heat pumps and bio systems. Orkney is primarily an agricultural area, so slurry (animal waste, normally cattle) is in good supply. This can be used for the production of fuel systems, such as methane to run a turbine, or a rich NPK source for crop production (but the wind prevents many crops from growing). Both air and ground source heat pumps have proved reliable in Orkney. The ground pumps because the soil temperature remains high all year round, thus producing lots of energy. Air source are not so good, due to the wind chill effects during winter, when it is needed the most.
Orkney has little in the way of forestation to use as a fuel source, primarily due to the effects of wind and the change of climate over the last few thousand years. Originally Orkney was forested, the same as northern Scotland, but this has since changed to a treeless landscape more similar to Arctic tundra, of thick heathers and coarse grass (if left alone). Any limited numbers of trees that do grow, are either stunted, sheltered in urban areas or within walled gardens.
The Orkney’s are an a archipelago of 70 low lying islands located 10 kilometres from the north east coast of Scotland and are at the same latitude as the south of Greenland and southern Norway. This profile leaves the landscape open to be ravaged by the oceanic weather and the only really successful crop is grass, which is used to feed beef cattle and other farm animals. Hay production is almost impossible and generally excess grass is converted to silage.
The production of a biomass crop, such as willow or poplar, two common biomass sources would be a challenge. However, with more hybrid versions of these plants becoming available, this is really becoming a viable and possible fuel source. The challenge is to grow these crops in an area that normally does not support cropping.
The islands offer little protection from the elements for the growing of wooded crops and establishing these is the primary challenge. High winds and high salt content cause the plants to ‘age’ early and this causes a die back in the growing tips of the plants, thus stunting their growth. Other factors include uprooting and tear-offs by the wind, making plants with a heavy leafing prone to damage. Tress also suffer from water logged conditions caused by the oceanic aspect of islands, prevalent throughout winter.
Early experiments with willow and poplar, have indicated that poplar does not like the conditions in Orkney, but willow, although not thriving, does grow pretty well. General production of willow appears to favour air-dried poles/batons, rather than chipping. Due to the remoteness of Orkney, power machines for planting and harvesting make these sorts of machines expensive to obtain and maintain.
Baton fuel from the air-dried rods can easily be produced with standard agricultural machinery, and gives a good source of replacement plants. Choosing boilers that take this type of fuel is required (rather than pellets/chips). This format of boiler also supports burning of many other fuel types, making it ideal choice for this type of remote area. Allowing the burning of most combustible items, such as wood, straw, cardboard, etc.
I have been wading through many articles on the Internet, particularly the UK Forestry Commission sites. I have even purchased various information packs, rather than books for the moment. But by a quirk of fate, a very helpful person in the Forestry Commission pointed me in the direction of Orkney College which have been doing studies into biomass fuels based on willow in the Orkneys, around Kirkwall. I now have a couple of their reports which I am reading through. I hope to be able to visit the plantations that they have established for a group of 44 houses near Kirkwall.
The results of these reports are very interesting and encouraging, I hope to get permission to publish a copy here soon, or at least provide a link to them.
So this is the end of the first article on my endeavours to grow willow as a sustainable fuel on Orkney. I need to finish reading the reports and write up some more on the subject here. So stay posted and make this page in your favourites as I will past links to all future articles from here.
Related posts:
- News: Short Rotation Williow Coppicing for Fuel Willow Coppice I have now been focusing my attentions on...
- Series: SRC: Planning the field Last Updated: 28 September 2009 This is the second of...
- Series: Movement on Coppicing Last week on Westray there was a public visit by...
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