Governments use artificial intelligence (AI) to support policy decisions, yet its democratic legitimacy remains contested. We examine public legitimacy perceptions of hybrid human-AI decision-making (HyDM) versus traditional human decision-making (HDM) in the siting of onshore wind power stations, a task made critical by Russia’s full-scale invasion of Ukraine, which heightened the urgency of renewable deployment. In a preregistered online experiment with n = 1205 German citizens, we further investigate whether framing the energy transition as a security issue moderates the effect of decision-making type on legitimacy perceptions. While HDM was seen as slightly more legitimate in input aspects, there was no detectable difference in throughput or output legitimacy between HDM and HyDM. Framing the energy issue as a security threat showed no statistically significant moderation of these relationships. These findings provide arrangement-specific evidence on legitimacy perceptions of AI-supported decision-making in an energy-infrastructure context and highlight the role of public evaluations for the design of such decision-making processes.