The Power and Energy (P&E) sector needs to respond to several challenges fostering investments in research and development. According to the Open Innovation (OI) paradigm, key stakeholders like utilities, vendors, laboratories, universities etc. should take advantage of external knowledge to improve their innovation performance. Several studies have demonstrated that firms adopting the OI paradigm are more likely to innovate. Despite the interest of P&E firms in enhancing their innovation capabilities, surprisingly few articles (usually case studies) described the implementation of the OI paradigm in P&E firms. This article fills the gap by identifying the key drivers that encourage a firm in the P&E sector to embrace the OI paradigm. The authors adopt a hybrid research approach collecting evidence from the literature and through a multiple case-study analysis involving seven British firms and universities operating in the P&E industry. As the drivers of OI have mutual influence, this article describes them with a fuzzy cognitive map. Finally, the authors identify appropriated policies to enhance the OI adoption and, consequently, the sustainability of innovation in the P&E sector. A salient research agenda closes the paper.