The transition from nearly zero-emission building (NZEB) to positive energy building (PEB) models is a new trend, justified by the need to increase the efforts to address the climate change targets and the ambition for a clean energy transition in the construction sector. In line with this scenario, this study assumes that PEB may be applied to meet climate change targets and promote new approaches to urban regeneration plans. It focuses on the functional and energy regeneration of abandoned buildings, considering that many abandoned European buildings are often located in a strategic part of the city. Therefore, the research question is as follows: to what extent can abandoned buildings be converted into a PEB? What would be the meaning of this new association? In order to answer this question, this study developed a procedure to transform an abandoned building into a PEB, implemented through a case study of a former Italian industrial site. Findings pointed out the variables impacting PEB configuration and were used to support a discussion, stressing how rethinking abandoned buildings as PEB may drive new trends to synchronise the socio-technical evolution of energy infrastructure and urban regeneration plans.