Energy and environmental profile comparison of TMT production from two different companies - a Spanish/Portuguese case study

Abstract

Life Cycle Assessment (LCA) is a technique for assessing the environmental aspects and potential impacts associated with a product and has been increasingly used to identify processes or stages in the wood chain with a high environmental impact or to highlight areas where environmental information is unknown. The main aim of this study was to quantify and compare the environmental impacts and the energy used for the production of one cubic meter of Thermally Modified Timber (TMT) by two different companies, one in Spain and the other in Portugal, using the LCA methodology. The LCA study was developed based on ISO 14040/44 standards. The inventory analysis and, subsequently, the impact analysis were performed using the LCA software SimaPro8.1.0.60. The method chosen for the environmental impact assessment was ReCiPe, and for energy use the Cumulative Energy Demand method was chosen. The results show that to produce 1 m3 of thermally modified pine timber the Portuguese company used 14.38 GJ of cumulative energy demand, of which 1.92 GJ was nonrenewable and 12.46 GJ renewable, and the Spanish company used a total of 17.55 GJ, of which 2.52 GJ was nonrenewable and 15.03 GJ renewable. The thermally modified pine timber produced by the Spanish company presented the best environmental results for 13 impact categories in comparison to the 5 best environmental results presented by the Portuguese company. From the weighting triangle, we can conclude that the Portuguese pine boards have a lower environmental impact than Spanish pine boards if a high weight (> 40%) is given to resources, while a weight of <80% is given to human health; otherwise the opposite is true. Regardless of the company, the energy used in the thermal treatment process was identified as the main factor responsible for climate change, acidification, eutrophication, photochemical oxidant formation, metal depletion and fossil depletion. This has to be expected as the treatment is based on heat production and no chemicals are added during the heat treatment process. The round wood production was identified as the leading process responsible for ozone depletion and also presented remarkable contributions to eutrophication and photochemical oxidant formation.