Trees for industrial energy studied

Ruapehu Bulletin, Volume 10, Issue 470, 26 January 1993, Page 7

Trees for industrial energy studied

Using trees to turn effluent into energy is being investigated by Massey University and meat packers and exporters, Richmond Limited. The project has the potential to lessen reliance on fossil fuels. However the immediate aim is to substitute some, or all, of the 4000 tonnes of coal used annually in the boiler of Richmond's Oringi meat works using wood from an adjacent 'coppice' stand of eucalyptus trees. Coppice planting produces a dense growth of small trees which are cut back every three or five years to produce a continual supply of wood. Richmond has already decided to plant 90 hectares in this way over a three year period. The eucalypts are cur-

rently being used to purify freezing works wastes irrigated onto them. An earlier five year trial at Oringi established that the rapidly growing coppice trees purified waste water by removing nitrogen and other potentially polluting chemicals from the soil. To utilise the potential energy source within the trees, Massey University postgraduate student Hamish Lowe, has been appointed to investigate the necessary wood harvesting, handling and storage systems. He has already begun looking into the effects of tree spacing and drying rates at different times of the year. Mr Lowe's supervisor, Massey University agri-

cultural engineer Ralph Sims, said wood as an Industrial fuel has important implications for global warming. "Wood is a 'carbonneutral' fuel. That is, trees give off carbon dioxide when burnt but it is also re-absorbed when they grow." However Mr Sims said developing an efficient system would not be easy. "The trees will be all shapes and sizes as after the first harvest they may generate four or five stems. We want them to re-grow so we don't want to damage the stUmps." Mr Sims said Richmond is leading the way in an area that is likely to have widespread practical application.