Beyond pipelines: Multi-modal CO2 transport enables timely CO2 capture, transport, and storage deployment

CO 2 capture, transport, and storage (CCTS) is essential to meet climate targets, but its success is threatened by the slow expansion of pipelines, due to regulatory hurdles and public opposition. The resulting deployment limits are insufficiently accounted for in current infrastructure optimization models, which therefore overestimate the speed of expanding CCTS value chains. Here, we expand the energy system optimization model ZEN-garden to consider temporal diffusion limits for pipelines and analyze the consequences of constrained deployment for a case study of Switzerland. First, we assess the risk of missing climate targets due to the constrained deployment of CO 2 pipelines, and second, we evaluate strategies to mitigate this risk. We find that realistic pipeline diffusion speeds lead to a 9 % deficit in CO 2 sequestration compared to climate targets. The additional deployment of non-pipeline transport modes circumvents these limits and enables compliance with policy goals at a cost increase of 5 %. Such a multi-modal transport system proves substantially more cost-effective than compensating the CO 2 sequestration gap via carbon removal. Based on our findings, multi-modal transport should play an integral role in the design of CO 2 transport infrastructure to mitigate the risk posed by delays and slow pipeline deployment. The results suggest that an exclusive focus on pipelines for CO 2 transport may jeopardize the success of the entire CO 2 value chain.