Optimization of Enhanced Weathering Networks with Alternative Transportation Modes

Enhanced weathering of alkaline rocks and minerals is a negative emissions technology (NET) that is potentially scalable to deliver gigaton-level carbon dioxide removal (CDR) for climate change mitigation. This technique relies on the acceleration of naturally occurring weathering reactions with water and carbon dioxide by reducing these substances into a fine powder with high specific surface area. The ex situ enhanced weathering process chain consists of the acquisition of suitable natural or synthetic materials, grinding to a fine particle size, transportation, and application on suitable sites. Future enhanced weathering systems can be envisioned as supply chain-like networks which have to be optimized to deliver maximum CDR given physical constraints. There is a notable research gap in the literature on decision support for such systems. To address this gap, a mixed integer linear programming (MILP) model is developed in this work to optimize enhanced weathering networks for CDR. The model also incorporates the availability of multiple transportation options and constraints on network topology. Two test cases are used to demonstrate the model capability to determine optimal and near-optimal networks. The top ten solutions in these two scenarios yield total CDR levels of 3.4316–3.4363 Mt and 15.27017–15.27960 Mt.