Towards circularity in the wind industry: Optimal reverse supply network design under various policy scenarios

Abstract

Wind energy is key to supply renewable energy. However, the increasing number of end-of-life wind turbines is still predominantly landfilled, while regulatory aspects such as waste shipment and landfilling rules hinder the development and scalable implementation of reverse supply networks.

This work aims to understand how EU directives impact the structure and viability of circularity-enabling networks by investigating the optimal reverse supply network design for end-of-life wind turbine blades under different policy scenarios. Three policy scenarios were explored through a Mixed-Integer-Linear-Programming model: (i) ‘as-is’; (ii) ‘EU Proposal 2021/0367′, removing transboundary restrictions on waste shipments; (iii) ‘Landfilling Ban’ enforcing an EU-wide ban on landfilling composites. The optimal reverse supply networks with minimum costs were identified for each scenario, contextually determining location and sizing of recycling facilities and calculating landfilling quota and GHG emissions. The costs and emissions were minimum for the EU Proposal scenario, at 15,706,041€ and 2,081 tCO2e respectively. A sensitivity analysis on landfilling gate fees highlighted that they should be significantly increased to incentivise higher recycling rates and close material loops.

This research is the first to evaluate the effects of policy initiatives on the shaping of optimised reverse supply chains through mathematical programming methods. The work contributes to the waste management literature by designing optimal circular supply chain networks for the management of waste from wind turbines decommissioning at the EU-level to improve sustainability of renewable energy installations.