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Environment Working Group.
Heating with Chips – a renewable way of producing energy.
On 11th June, members of the Lynsted’s EWG were shown around the Renewable Energy project at Great Higham Farm, Milstead. The visit was arranged by EWG member Neil Anderson. The guide was owner John Leigh-Pemberton. Some of the main points to come out of this fascinating visit included:
- Burning wood is a ‘renewable’ way of providing heat. The carbon dioxide locked into trees during their growth is released into the atmosphere during combustion – where it is available to be absorbed by trees again. It is thus a cyclic process, in contrast to the use of oil, or gas, which is a ‘one-way ticket’ contributing to carbon dioxide build-up in the atmosphere.
- The Great Higham unit, established in 2006, provides all the heating needed for seven habitations and a swimming pool.
- The heart of the system is an Austrian-made boiler (the UK is far behind other countries in this technology) that uses wood in the form of ‘chips’. These are small (3cm) fragments of timber produced by a form of shredder. The boiler needs no other fuel input and is fully automated.
- The boiler is continuously supplied, by a simple Archimedes screw mechanism, from a 30-tonne capacity chip store that is topped up every three months.
- The process is robust and will work on wood of any quality. Seasoned timber is preferable, as there is less moisture to drive off. ‘Green’, or partly seasoned, timber can contain 50% water or more. This drops to 25% after a year in the open, giving a more efficient burn. But this implies the need for a store area in which to do the seasoning.
- Capital costs are high for the boiler and shredder (indicating a need for financial aid for ‘start-up’ if this technology is to catch on). Running costs, however, are very low. Labour needs are only ten man days per year at Great Higham.
- There is plenty of timber ‘just waiting’ in the neglected coppiced chestnut woodland with which much of Kent is clothed. Very few of these woodlands have been managed for coppicing since the demand for the product disappeared with the closing the paper mills that took timber, twenty years ago. There is an enormous, virtually endless, supply of appropriate woodland timber.
- Provision of heat accounts for perhaps 30% of the nation’s energy needs. Using wood as a fuel would lessen the need for nuclear power, or reliance on imports of oil and natural gas.
- Revitalising the woodland industry would bring great benefits in terms of land use, increasing employment, landscape quality and enhanced wildlife.
- The technology, although well-tried (in other countries), relatively trouble-free, and ‘local’, is at a very early stage of development in this country. The nearest equivalent unit, for example, is in Ashford. A ‘supply chain’ needs to be established. There are plenty of opportunities for entrepreneurs, institutions and local authorities.
- The system can be operated on almost any scale, but it is preferable to install the facility at the start of a building development, or at the design stage. Housing estates, schools, public buildings could all benefit. Houses can readily be fitted with ‘heat meters’ – equivalent to those for gas, water and electricity, allowing owners to pay for the heat they use.
- There are some limitations. Proper grant-aid, designs, and supply-and-demand systems are not yet in place in the UK. The process does not yet lend itself to efficient electricity production, and this is a challenge for the future.
Anyone who has in mind a development that could use this technology in our parish area should contact Cllr.John Disney (01795 521 518) in the first instance.
The Parish Council, through the Environment Working Group, is keen to help promote Renewable Energy. Please contact John or myself if you have any comments or input.
Bob Baxter,
Coordinator, Environment Working Group.
Phone 512 515.
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