# Life Cycle Assessment on a Biorefinery Approach to Pyrosis Oil for Wood Modification Treatment
## 5 Conclusions  
This study shows that there was currently sufficient data available to complete an LCA on pyrolysis oil applications, and that in this particular case uncertainties could be limited to such an extent that meaningful conclusions could be drawn. The results show that, when forestry residues and maize digestate were compared as feedstock for pyrolysis oil production, the use of maize digestate had significantly higher environmental impact for two of the three determined impact categories. These were damage to human health (10 times higher) and resource scarcity (2.6 times higher). This increased impact was attributed to the lower energetic yield and higher ash production from the pyrolysis process on maize digestate. When pyrolytic sugars were compared to fossil-based creosote for wood modification, pyrolytic sugars showed significantly lower impacts for two of the three determined impact categories, i.e., damage to human health (7.4 times lower) and damage to resource scarcity (1.7 times lower). This lower impact was attributed to lower greenhouse gas emissions (reduction of 82%) and the avoidance of the use of toxic creosotes. The impact on ecosystems did not change significantly because the largest impact originates from the use of the wooden pole itself. In a sensitivity analysis the selection of the choice in end of life was shown to have no influence on the conclusions. Thus, the use of forestry residues for pyrolysis oil production had a lower environmental impact than the use of maize digestate, and the use of pyrolytic sugars as wood modification treatment had a lower environmental impact than the use of fossil creosotes. This study had shown that pyrolysis oil was a sustainable alternative to the currently used creosotes for modified wooden poles using an LCA methodology. Moreover, the current study presented the first full LCA on pyrolysis oil using real data on a demo plant scale. This opened the pathway to develop a pyrolysis oil platform of biobased products that could replace fossil-based products in a sustainable matter and provided information on how to assess the sustainability of these new biobased products. Future work is directed at determining the environmental impact of these systems and the environmental benefits of replacing current fossil-based systems with a sustainable pyrolysis oil platform.  
The following are available online at [[http://www.mdpi.com/2076-3417/9/20/4233/s1](http://www.mdpi.com/2076-3417/9/20/4233/s1)]([http://www.mdpi.com/2076-3417/9/20/4233/s1](http://www.mdpi.com/2076-3417/9/20/4233/s1)), Table S1: Midpoint scores for 1 GJ of pyrolysis oil. Table S2: Midpoint scores for 1 m\({}^{3}\)a treated wood pole. Document S3: LCA review statement by Blonk Consultants.  
Conceptualization, P.R., C.W. and E.B.; Methodology, J.S., P.R. and M.V.; Investigation, J.S. and M.V.; Resources, T.W., S.P.W.H. and M.V.; Writing - Original Draft Preparation, J.S. and T.W.; Writing--Review & Editing, S.P.W.H.; Visualization, S.P.W.H.; Supervision, C.W., E.B. and P.R.; Project Administration, P.R.; Funding Acquisition, P.R., C.W., E.B. and S.P.W.H.  
The project 'Groen Goud' was executed as part of the INTERREG-program Deutschland-Nederland and financially supported by the European Union, the Dutch ministry of Economic Affairs, the MWEIMH NRW and the province Cverissel. The project 'Bio4 Products' has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 723070.  
Data visualization was aided by [PERSON]'s XL Toolbox addin for Excel, version 7.3.2, by [PERSON], Wurzburg, Germany (www.xltoolbox.net).  
BTG Biomass Technology Group has a commercial interest in pyrolysis oil, which is covered by submitting the LCA to an external review before submitting the article to the peer review of this journal. The other authors declare no conflict of interest.