New energy vehicle innovation network, innovation resources agglomeration externalities and energy efficiency: Navigating industry chain innovation

Energy efficiency is critical in managing the economy, resources, and environment. Existing research primarily focuses on the effect of the internal urban innovation resources and their agglomeration externalities on energy efficiency. Importantly, it overlooks the effect of external resources acquired through urban innovation networks, referred to as the 'borrowing size effect'. This effect becomes particularly pronounced in the innovation-driven energy transformation of the new energy vehicle industry chain. Therefore, drawing on the spatial Durbin and Super-SBM models, this study examined the effects of three representative types of new energy vehicle innovation networks on energy efficiency, and investigated the borrowing size effect of urban innovation networks on innovation resources agglomeration externalities. The research findings revealed that: (1) The entirety and collaboration innovation networks had promising results on energy efficiency; (2) The structure innovation network demonstrated an insignificant impact, but the innovation of upstream, midstream, and downstream in the industry chain individually exhibited a promoting effect; (3) The externalities of the collaboration innovation network demonstrated a positive spatial effect, and a borrowing size effect.