Opposition to the Mogo/Broulee charcoal plant proposed by Australian Silicon Limited has been described as blinkered and irresponsible (CT, March 7, p.20). This is not the view of many of Australia's most eminent scientists who have examined and understand the issues. No-one opposes an industry that produces high-quality silicon. But let's get the perspective right about charcoal, silicon, and its means of production.

The Lithgow silicon smelter needs low-ash carbon to produce a high quality grade of silicon metal. At present, the most convenient source for this carbon is from wood charcoal, derived by roasting 200 000 tonnes per annum of 'residual waste' from forests on the South Coast. The whole project is likely to get financial backing only if this supply of carbon is assured. In recent weeks, State Forests have agreed to supply this wood to ASL for 20 years, so construction of the charcoal plant at Mogo/Broulee would make the project 'bankable'.

However, we need to ask whether the centuries-old method of producing suitable carbon is still appropriate today, and what effects it will have on our forests.

Australian science has a better answer.

There is an alternative for a source of low-ash carbon that's also 'bankable'. This is an Australian invention that's now coming on line, that bypasses the third-world technology for making charcoal.

Over the past decade, CSIRO, government and industry have invested about $30 million in the development of Ultra Clean Coal (UCC). This is a recognised competitor for wood charcoal in silicon smelting. This is Australian owned, with a pilot plant at Cessnock ready to produce its first batches. The UCC process results in a low-ash carbon product ideally suited to the requirements of the silicon smelter. On current timelines, full commercial quantities of UCC should be available during 2004. This corresponds to the earliest startup time of the proposed Lithgow smelter.

The UCC project has been developed mainly to supply fuel for gas turbines in electric power plants. By replacing normal coal, it reduces greenhouse gas emissions by 24 percent. A commercialised plant for UCC would easily supply the needs of the Lithgow smelter as a sideline. The developer of the Cessnock plant has stated that "they would love to be a supplier to the Lithgow smelter".

More importantly, the use of ultra-clean coal would eliminate the need for intensified forest harvesting, and the proposed charcoal plant near Mogo. It would capitalise on CSIRO science, a new Australian-owned industry with potentially massive export earnings, and contribute in no small measure to ecologic sustainability in the South Coast forests.

"We need to put the charcoal plant in context", states Vicki Dunne (CT, March 7, p.20). Ms Dunne claims that the silicon project will solve the energy needs of Australia and resource-starved countries of the world. This is wishful thinking, and certainly not correct. Silicon metal has almost no connection with sustainable energy production.

The biggest market for silicon metal is for non-ferrous alloys and several chemicals based on silicones. Only two percent is used for solar cells or computer chips. The ASL project has nothing to do with that technology. In fact, just about any quality of silicon from any source can serve as a feedstock for these uses. High-purity silicon for these uses does not require the ASL project, so any arguments based on sustainable energy are specious.

Anyway, solar cells remain a prohibitively expensive way of generating electricity. They would certainly never be used to pump water or operate sewerage plants. Far from being energy efficient, the Mogo/Broulee charcoal plant will simply waste the equivalent energy of a 50 megawatt power station.

The major issue must be whether the charcoal plant is required at all. If the silicon project is to be "bankable", then a secure source of low-ash carbon is needed. NSW State Forests calculates that it can supply 200,000 tonnes of residual waste from the harvesting of 48 500 cubic metres of sawlogs. This 4:1 ratio appears to be excessive, unless another source of 'waste' is included. As well, NSW Forests assure ASL that the waste timber has low ash content. This will be true only if the main timber species are 'red woods'. Till now, most of these trees remained in the forest after harvesting, because they were not desired for sawlogs or for woodchipping. Now, it looks as though they will be reclassified as 'waste', and used for charcoal manufacture.

This means that forest harvesting will be far more intensive than at present, and impacts on other forest values (water, habitat, biodiversity) will be greater. These impacts are irreversible, and have not been evaluated.

Bankability for one company's interests is one thing. Sustainability of the environment is another. Companies come and go, often for a quickly realised profit to their principals. But the southern forests are at risk of irreversible damage if the charcoal plant proposal goes ahead. If it does, then this will surely be a blinkered view of the big picture.

Dr Emmett O'Loughlin is a hydrologist and a resident of Rosedale. He was a Chief Research Scientist in CSIRO, and the Founding Director of the Cooperative Research Centre for Catchment Hydrology. His main work dealt with the effects of forest management on water. More recently, he has worked with the Eurobodalla Shire Council on its Coastal Environment Capacity Planning Project. He is a consultant who has frequently appeared as an expert witness in the Land and Environment Court.