Wood Fired Heating System
All of the heating and hot water needs of West Dean College (and parts of the village) are met entirely, and on a sustained basis, by using wood fuel grown on the West Dean Estate. The biomass district heating scheme was one of the first, and remains one of the largest of its kind, in the UK.
West Dean College and its five annex buildings accommodate up to 140 residential students. The House is also the administrative hub of the Foundation, occupied by over 70 staff involved in the many diverse areas of the Foundation‘s activities from fine arts through to farming, pottery and ceramics to property management.
Courses take place every day of the week with only a short break between Christmas and New Year. There is also a small but thriving conference business. Most of the 120 bedrooms have en-suite bathrooms. The entire operation can therefore be likened to a large country house hotel with a significant office complex and consequently the demand for heating and domestic hot water is high, around 2.5 million kilowatt hours per year.
In the early 1970s, when the College was being developed, the heating came from 50 year old coke-fired boilers which had been converted to oil in the late l950's. These were extremely wasteful, operating at about 40-45% efficiency. Periodic flooding in the boiler house from ground water was also potentially hazardous, the boiler being located within the house complex. By the late 1970s electric night storage heaters had to make up the heating deficit and it soon became clear that this highly inefficient system would not cope with the increasing demands of student accommodation and the growth of the College.
The Trustees therefore commissioned a survey into new heating systems and all forms of fuel were considered; Natural Gas was not available in the village, with little prospect of connection in the foreseeable future. Solid fuels were considered but not favoured because of pollution, the uncertainty of the mining industry at the time with its poor industrial relations, and the unavoidable dust problem. Oil was a serious contender except that in the late 1970s political uncertainties due to the Middle East oil crisis led to highly volatile prices and the possibility of supply difficulties in the future.
The Estate‘s own sustainable resources were then considered, the most obviously renewable resources being straw and wood. Straw as a fuel had the enormous problem of storage due to its bulk, and the proximity of a very large store to the College was impossible to contemplate with the major environmental constraints of the area. Furthermore, the demand for straw for the Estate‘s own livestock enterprises was likely to result in a fluctuating supply being available for fuel purposes, and straw could only provide part of the fuel requirement.
Wood fuel, on the other hand, appeared to be a possible alternative. It was estimated that to heat and provide domestic hot water for West Dean College would need approximately 1,000 tonnes of wood fuel per annum, and a study confirmed that this annual yield could be sustained. The Estate has 2,000 acres of woodland.
There were other important, if less tangible, advantages in using wood as a fuel source:
Wood is a renewable and sustainable source of energy. Trees grow using the energy of the sun to fix carbon from the atmosphere. The woods have a sustainable yield of timber which can be harvested indefinitely without depleting the resource in any way.
It is virtually carbon neutral and does not contribute to greenhouse gasses. Burning wood gives off carbon dioxide, just like fossil fuels, but this is balanced by the carbon absorbed by the growing trees. (Unharvested wood will give off the same amount of carbon dioxide when it eventually decomposes as it would have done if burnt in a boiler.)
It is a clean and safe fuel. Wood chips present no risk if accidentally released into the environment, unlike oil and gas. There are no harmful by products. The flue gas is virtually smoke-free and the ash content at less than 1% by volume is minimal; wood ash is simply returned to the forest.
It benefits woodland management in creating a guaranteed outlet for timber which would otherwise have no market and allows thinning operations to be silviculturally rather than market influenced. Typically wood fuel supplies at West Dean are derived from coppicing and thinning, which in turn lets in more light creating more diversity in the woodlands for wildlife.
It benefits the local economy. Labour comprises the biggest element of the cost of wood chips; the main cost in fuel supply goes to local people rather than to remote multinational companies.
The system was designed to burn chips with moisture content of up to 60% on a dry basis (37.5% on a wet basis) since it was realised that the moisture content of a stack of wood would be extremely variable. Chip size is uniform, typically 25mm nominal to meet the requirements of the feed augers in an automated system.
The plant today processes 1,200 tonnes of chips per year. The chipyard can be used to store nearly two months supply of fuel wood should this be required, although the current practice is to have a year's supply stacked, drying naturally, in strategic locations throughout the Estate.
The underground mains feed not only the College, five large student residences, 6,000 square feet of new teaching and exhibition space, but also the glasshouses in the walled Kitchen Garden, nine Estate houses, the Gardens Visitor Centre, an outdoor swimming pool, and even the village church, said to be the warmest church in the south of England!
After 27 years of successful operation, the Foundation has replaced one of the two biomass boilers with a modern state-of-the-art boiler having an output capacity of 1,200 kilowatts and an efficiency rating of 92%. The Department of Energy and Climate Change provided a valuable grant towards the capital works.
Edward James died only three years after the wood-fuelled district heating scheme was commissioned, but the project echoes the spirit of the man and his far-sighted vision; an ecologically sound and sustainable concept, contributing to the caring stewardship of his beloved woods and trees, and a thoughtful use of the Estate's natural resources.