Wood energy issues
Although there are many benefits associated with the use of wood as energy, there are also some potential issues for users (as there are with other fuel sources).
If the wood fuel used is a by-product of other industries (i.e. forest harvesting and wood processing) it can be difficult to control the quality of the final product. Quality issues can include fuel contamination (e.g. with soil), high moisture levels, partial decomposition and varying particle sizes. However, these issues can be controlled through proper handling and storage techniques on the supplier side or through the use of a fuel source which is more consistent in quality (e.g. wood pellets).
As with quality, the supply of wood fuel can be problematic if the wood fuel used is a by-product of other industries and can not be guaranteed. Although there are significant quantities of wood fuel available throughout New Zealand, the quantities available in regions and the cost of extraction can vary from region to region affecting supply.
If the wood fuel used is not completely combusted it can cause environmental issues such as particle emissions. Particle emissions are one of the causes of smog which can cause respiratory problems. However, wood fuel generally has much lower rates of particle emissions than fossil fuels such as oil.
The National Environmental Standards for Air Quality were introduced in 2004 with the aim of preventing these toxic emissions. The type of wood burner and the quality of the fuel used are two factors which can control emissions. Information on the performance of various wood burner models is available on the Ministry for the Environment’s website.
One of the attractions of using wood energy is the fact that it is carbon neutral (as the carbon created in burning is offset by the carbon absorbed during tree growth) and sustainable (as a new tree is planted for each tree that is cut down). While this is the case for the majority of wood fuel, these factors depend on how the producer manages the environment. For instance, if forestry land is converted to another use for short-term economic gain, the true carbon neutrality and sustainability of the wood fuel previously harvested may be jeopardised.