Public administrative action is crucial in facilitating sustainability transitions. Although organizational structures, cultures and established practices have been shown to lead to differing innovation results and technological diffusion at various levels of governance, little attention has been paid to the role of local government and administration in sustainable energy transitions. This study analyses renewable energy innovation at the local level of public administration in Norway. Drawing on the institutional and entrepreneurial literature, we examine the key formal decisions and organizational culture development that, combined with policy entrepreneurship, ultimately led to an unlikely and risky decision: to include a costly and unusual local energy system in the construction of a new secondary school. Tracing the administrative processes over 20 years, and drawing on document data supported by 14 interviews, we find that the strong and politically shielded administrative section, backed by a firm mandate and an established internal culture of innovation anchored in historic and local identity among the population and local industry, led to this decision. These factors were further facilitated by acts of policy entrepreneurship at crucial moments, shaping the underlying structures and institutional culture. The independence and strong direction of the administrative section can be emulated in other contexts in order to facilitate innovation. With suitable adaptations to other contexts, our findings may help to accelerate energy transitions through system innovations elsewhere.