© 2020 The Author(s) Dealing with composite waste from decommissioned wind turbine blades will become a major issue in the coming years. This study aims to determine the most sustainable disposal method for Irish blade waste in the next ten years by using life cycle assessment to compare three scenarios: Co-processing in cement kilns in Germany, co-processing in Ireland, and landfill in Ireland. The results of this study establish a baseline impact scenario with which to compare future repurposing solutions, which are higher on the European Waste Hierarchy. Co-processing is not carried out in Ireland at the moment, but as blade waste increases, there is a strong likelihood of it becoming viable. Co-processing utilizes shredded blade waste to replace fuel and raw materials in the production of clinker, whereby environmental gains are made through material substitution. Comparative Life Cycle Assessment is used to determine which scenario is the least environmentally impactful, and which of the variables has the strongest impact. Co-processing in Ireland is determined to be the least impactful, due to the material substitution and the reduced transport. Material substitution is found to have a stronger impact than increased transport between Ireland and Germany. There is, however, a concern with co-processing as a preferred method to dispose of Irish blade waste in that the ease of disposal in this fashion might de-incentivize repurposing. Future research is needed to compare the costs of co-processing to other repurposing ideas, and to develop policy that requires farm owners to set aside bonds to pay for more sustainable second life options for blade waste. This will ensure that the option of co-processing in Ireland is passed over for a more sustainable Irish alternative.