03 July, 2006

ARTICLE: Seeing the wood waste from the trees

Andrew Lang

The Age, July 3, 2006

Australia should be paying closer attention to Europe on biofuels, writes Andrew Lang.

AUSTRALIA could within 15 years be producing up to 20 per cent of its energy needs from oody waste, but this has thus far been almost totally ignored.The media is informative about nuclear and fossil fuels energy, with the occasional mention of renewable sources of electricity production only touching on wind and solar energy.

The potential for woody biomass as fuel for off-the-shelf cost-effective energy plants for some reason is being overlooked. Government pronouncements and speakers rarely mention bioenergy, except in the odd comment about biodiesel, or ethanol in petrol.

Yet, in central Finland, up to 45 per cent of industrial and household energy consumption is produced by power plants burning woody waste. This is mainly sourced from thinning or harvesting of private forest, or timber processing waste. Overall in Finland, the world leader in industrial bioenergy production, it is more than 22 per cent.

The European Union has a short-term goal of 12 per cent of energy to be produced from renewable sources by 2010. Austria already produces about 18 per cent from wood, with central heating or power plants in many towns. The smaller plants are often supplied with their wood chip fuel by farmer syndicates. In Sweden, the figure is almost 20 per cent. The Swedes have recently decommissioned two nuclear plants, and are decommissioning their remaining seven nuclear plants as soon as they can replace them with renewable energy sources, mainly with wood-fuelled plants. The Germans are aiming to similarly decommission all their nuclear power plants. In Bavaria, taxes on fossil fuels are used to generate subsidies for municipalities to develop co-generation plants fired by a mix of municipal waste and woody waste.

Denmark and the other Scandinavian countries use the same general principle. There, heating oil and vehicle fuels are taxed on the basis of their energy value, and part of the revenue raised is used to lift the price paid for chipped forest thinnings and harvest waste delivered to the power plants. In Finland some incentive subsidy is paid for the thinning process and to offset transport and chipping costs.

Last September there was an international conference in Finland about the latest available technology on woodchip-fired power generators. These come in all sizes, from about two megawatts — enough for a small rural community — to over 200MW, enough for a city of 100,000 residents. An equally informative conference was held some months later in Norway.

The Finnish website www.finbio.fi shows the great potential for this energy source. The Swedes have a similar website at www.svebio.se. The Danes, leaders in using straw as a biofuel, are at www.danbio.dk. A web search using "bioenergy" plus the country name will bring up similar sites for Germany and Austria.

The British are building a power plant near Lockerbie in southern Scotland that will be fuelled by woody biomass.

This will use about 200,000 tonnes a year of thinnings and harvest waste from plantation forestry management in the area (Victoria exports five times that amount, mostly from chipped eucalypt logs).

In the US, despite a primary renewable energy focus on wind, solar and hydro-electricity, there are many websites detailing the growth in the bioenergy sector. A general site is www.bioenergy.ornl.gov.

Woody waste comes from several main sources. In practice, for a 10MW or larger plant, it would come from an extensive, sustainably managed, private forestry industry. Sawlog-producing plantations are normally thinned twice as part of good management. Five thousand hectares of managed sawlog plantings progressively established — whether as scattered farm sawlog woodlots across 500 farms, or as several large industrial plantations — will annually produce enough chipped thinnings and harvest waste to fuel a significant bioenergy plant.

Waste wood from building demolition or renovation is another significant source, largely going to waste in Australia. In some countries, including Denmark, householders must by law separate all flammable municipal waste for energy generation or recycling.

A key issue in favour of bioenergy as a by-product of a sustainably managed plantation timber industry is that it is almost carbon neutral. For each tree cut down, at least one more is planted, or the coppice regrowth is managed.

In addition, appropriately sited trees are playing a role in salinity mitigation, improving water quality, or providing habitat. The logs from harvested trees are milled, with up to 50 per cent of the volume going into durable products. These may keep the carbon component sequestered for 100 years or more.

Crucial for reduction of greenhouse gas emissions, the use of woody biomass for generating energy means that it reduces the fossil fuel used by that amount of energy. And the ash from the clean wood combustion process is a useful product as a potential component of agricultural fertiliser.

Off-the-shelf power plants fuelled by woody biomass are relatively cheap, have low visual impact, and come in all sizes. They can be fuelled by alternative solid flammable wastes, such as straw, nut husks or olive pits, and can be the source of heat and steam for adjacent industry.

Andrew Lang is a farmer, farm forester, and chairman of the innovative SMARTimbers marketing co-operative.

Original article