         
Based on an article by Asher Minns.
Find out more about wood fuel, its environmental credentials, and its potential in Oxfordshire.
Tags: oxfordshire, wood fuel IntroductionWould you like a log fire in the living room? Contrary to popular belief, wood burning can be environmentally friendly. The Forestry Commission, Renewable Energy Association, and the National Energy Foundation are promoting the use of sustainable wood fuel over fossil fuels as a way of reducing carbon dioxide emissions. Asher Minns writes about how a wood fuel renaissance could breathe life into abandoned woodlands and reduce household carbon dioxide. Editor's notes...Since this article was first written, a new Biomass Energy Centre has been formed, funded by Defra and operating through the Forestry Commission. This came into being as a result of the Biomass Task Force report which was published in April 2006. The centre aims to be a one-stop shop providing the public and suppliers with information and sign posting on all types of biomass energy. Find out more in ‘Where next'. Sections in this article
Wood Fuel benefits for Oxfordshire's economyWood is a very versatile fuel. It can be used for space heating, electricity generation and for a combination of both. The main difficulty is that it is bulky, but this is perhaps an environmental advantage, making it best suited to local economies and local use. For example, if Oxfordshire's small woods were managed to produce fuel wood, they could produce 40,000 tonnes or so per year, and the income has the potential to pay for their management. Oxfordshire's tree surgeons produce up to another 40,000 tonnes of wood waste each year. Some is already recycled, but a great deal of it goes into landfill at a cost of £45 per tonne. The wood rots and produces methane, a greenhouse gas 21 times more powerful over 100 years than carbon dioxide. Wood Fuel Home heating near carbon neutral Provided that some basic rules are followed, the burning of wood for the production of energy can be described as carbon neutral, unlike the burning of fossil fuels such as coal. In general terms this means that the amount of carbon dioxide released when wood is burned is no greater than the carbon dioxide absorbed by the tree when it is growing. Young trees absorb carbon dioxide as they grow but as they mature they are no longer net absorbers of carbon dioxide. Growing and burning wood can recycle carbon, and compared to fossil fuels it adds only a small amount of carbon dioxide to the atmosphere. To get the maximum benefit from a tree's ability to absorb carbon dioxide, it is necessary to harvest and recycle the carbon from young trees or from regenerated trees, called coppice.
Today's existing woodlands survived clearance for agriculture because they had fuel and other important uses of value to their owners. They were managed to provide fuel and other materials, mostly using coppice systems. Coppice management benefits wildlife and has been shown to be a very efficient way of recycling atmospheric carbon. Breathing life into woodlandsCoppicing is the traditional woodland management of repeatedly cutting deciduous trees to ground height every three to five years (called short rotation coppice), or longer. The tree regenerates into multiple stems that are then periodically harvested for generations. Trees such as willow and poplar are particularly suitable for short rotation coppice because of their rapid regrowth. Most native trees, such as ash, oak and beech can also be coppiced, as well as other broadleaf trees. Another clear advantage of well-managed trees and woodlands is that they give us attractive towns and countryside - new coppice could be planted on surplus agricultural land. Many types of woodland are no longer managed because they do not provide any economic benefit to their owners, yet they are highly valued as an amenity and for their biodiversity. Many old coppices that have had no proper management for 60-80 years are in serious decline and almost everything that lives within them depends upon intervention for their continued survival. There is a realisation that this needs to change, and action is being taken to begin regeneration. Continued neglect or no intervention is not a sustainable option for the future of smaller woodlands and their flora and fauna. Only big woods of about 100,000 hectares or more are sustainable without human management. For an example of scale, Oxfordshire has 3200 woodlands of which only 200 or so are bigger than 10 hectares in size. There are also up to 4.4 million non-woodland trees in the County, and an average of 10,000 non-woodland trees die each year and must be removed for safety. Much of it ends up as 'green waste' in landfill sites that rots to produce methane. This wood could potentially be managed and used as fuel, for both economic and ecological benefit. How is Britain creating a thriving wood fuel energy supply?A government funded scheme of the National Energy Foundation in the early ‘00s aimed to set up Fuel Wood Buyer's Clubs, joining people join together so that they have a greater influence over the price, sustainability and quality of fuel wood. This scheme was replaced by the ‘Logpile project' which provides information and guidance on wood fuel, and a means of connecting suppliers and users. The recently launched Biomass Energy Centre of the Forestry Commission now acts as a hub of information sharing and guidance around wood fuel supply and use in the UK. Groups with lobbying functions such as the Renewable Energy Association are active in aiming to establish the best policy framework to support wood and other renewable energy suppliers and their users.
The picture of coppice regrowth is with the permission of Ambleside Primary School in Cumbria Fuel wood facts and figuresWhat is sustainable wood?Many different sources of fuel wood can be sustainable; wood from commercial plantations after the timber has been felled and processed; waste wood from tree surgery; and wood from trees that have been grown in a coppice rotation. Woodland that has been managed in accordance with a Woodland Grant Scheme, or is certified by The Forest Stewardship Council (FSC) is also guaranteed sustainable. This picture of a log pile is with kind permission of Dr Howard Grubb at Reading University. Drying woodGreen wood is difficult to burn; it clogs the chimney, and produces unnece ssary emissions, and it contains between 35% and 65% of water by weight. For proper drying, or ‘seasoning', it should be felled during one winter and stored undercover until the next before it is burnt. A second winter of seasoning is even more preferable. How much is wood?
Costs vary with the type of wood that is being supplied, with hard woods being more expensive than soft woods and whether they are properly seasoned or not. Split logs by the load - usually delivered as the contents of a 'pick-up truck' - vary between £35 and £65. Split logs by the tonne are £60-£80, and by the cubic metre are around £40 to £80. Unless you know the wood is properly seasoned, it is better to buy by volume rather than by weight. How much do I need?Clearly the amount of wood you use depends on the size of your home or building, how warm you want to keep it, and how many hours a day. According to British Biogen (now part of the Renewable Energy Association), typical consumption is 7 tonnes per year for a 3-bed house, 15 tonnes per year for a farmhouse, 150 tonnes for a Secondary school, and 600 tonnes for a Residential College. How to burn itOpen fires look nice but they tend to have low efficiencies with all but 10 to 15% of the heat going up the chimney. In a wood-burning stove, efficiencies increase to about 70-80%. Some types of stove (burning well-seasoned wood) can even be used in smoke control zones where open fires are not permitted. Ranges are also very efficient burners, and the wood fuel can be used for hot water and central heating as well as cooking. The cost of a domestic wood-burning stove starts at around £300, though smaller 'pot-belly' stoves are considerably cheaper. Using wood to heat commercial and public buildings is very common in countries such as Austria and Sweden. More information about wood fuel stoves and supplier lists is held by the logpile project of the National Energy Foundation (see ‘Where next'). AcknowledgementsSome of the information given above is based upon the minutes of the Oxfordshire Fuel Wood Buyer's Club at Oxford County Hall on 11th February 2002, based upon the talks given by Eric Dougliss and Sandra Hayes. Sandra Hayes is Renewable Energy Research Officer at the National Energy Foundation, email Sandra@greenenergy.org.uk, and Eric Dougliss is the Oxfordshire County Forester email, forestry@oxfordshire.gov.uk. [Ed. This group is no longer in existence, and those interested are recommended to visit the Biomass Energy Centre website (see below).] Where next- including Find a Local SupplierOn ClimateX.orgArticles on this site that discuss some of the theoretical background to the concept of wood fuel carbon as a ‘carbon neutral fuel' are ‘Carbon sequestration' and ‘The carbon cycle and climate'. Finding a wood fuel and equipment supplier, getting more information and guidanceFind a wood supplier near you! National Energy Foundation, Logpile project Searchable directory of local wood fuel suppliers, and lots more information about wood fuel, suitable stoves and equipment, contacts and FAQs http://www.nef.org.uk/logpile/ Information about wood fuel, referred to as ‘Energy Crops from Biomass', with archive of searchable articles relating to biomass energy policy, and a map of UK Bioenergy projects, can be found at the Renewable Energy Association. http://www.r-p-a.org.uk/portal_group_view.fcm?groupid=1 The Forest Research and Forestry Commission now host a one stop website providing advice, guidance and signposting for users and suppliers of wood fuel and other forms of biomass energy. http://www.biomassenergycentre.org.uk/ Article by
Asher Minns
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