Quantitative relationship between low-carbon pathways and system transition costs based on a multi-period and multi-regional energy infrastructure planning approach: A case study of China

Low-carbon transition would trigger huge costs from reshaping complex energy systems due to large-scale renewable energy investment and early retirement of fossil-energy infrastructure. Reducing costs is challenging, because multiple transition pathways, comprised of massive transition policies and their schedule and pace, would lead to variation on system transition costs, despite achieving the same transition degree. In this paper, we aim to explore a proper pathway with lower costs towards the same transition degree, whilst previous studies focus on impacts of achieving different transition targets. A multi-regional, multi-period, infrastructure-based model is applied to quantify system transition costs, and China is taken as a case study. Scenarios, describing representative pathways to the same transition degree, are designed to establish quantitative relationship between pathways and costs. Results show that, for coal-dominated countries, approaching marginal cost balance of deep electrification and intensive non-fossil power penetration would lead to lower costs. An improper pathway would raise system transition costs up by 17% than a proper pathway we present, whilst this proper pathway would still lead to 35% more costs than the reference scenario. Furthermore, specific infrastructure deployment recommendations are discussed to make the pathway feasible and executive.