Unmanned aerial vehicle (UAV)-femtocell systems have been a paragon solution to the challenge of geolocating missing persons in civil protection (e.g., post-earthquake) scenarios. Bearing in mind the limited energy capacity on board a drone, it is extremely critical to provide advanced green UAV communication solutions in this particular application context. This article proposes a game theory-based energy efficiency approach to geolocation of mobile terminals via UAV-femtocell systems. In particular, this study introduces a statistical analysis of Nash equilibria by providing a simplified version of utility function and extending it to application scenarios characterized by nonisotropic propagation of radio-frequency signals. According to research findings, when considering the number of mobile devices in use, drones can save time and energy anywhere from 25% to 66%, if compared to alternative methods introduced in the literature.