Life cycle assessment of creosote treated wood and tall oil treated wood with focus on end-of-life
L G F Tellnes, U Hundhausen
The use of creosote for protecting wood products in heavy-duty application outdoors has been common for many years, but stricter regulations have limited creosote’s use. Life cycle assessments (LCA) have shown that in some applications alternatives to creosote treated products do not have less environmental impacts. Searching for alternatives to creosote, tall-oil-based preservatives have been of interest; in this regard, a LCA study has therefore been performed to compare the creosote and tall oil treated products according to their impacts on global warming potential (GWP). There are several approaches to include the removal and release of biogenic carbon in LCA. Under current end-of-life scenarios for treated wood, the different approaches give the same total impact on GWP when the whole life cycle is included. However, if carbon capture and storage is implemented at end-of-life of treated wood, the different approaches have large differences in the results. Tall oil treated wood has been shown in this study to have a relatively large contribution to GWP compared to creosote treated wood from a cradle-to-gate perspective. When the whole life cycle is included, the tall oil has a relatively lower contribution to GWP. This is because tall oil is from a renewable resource and that the combustion at end-of-life thus has a significantly lower impact than fossil-based creosote.
Keywords: life cycle assessment, creosote, tall oil, end-of-life, carbon capture and storage