Methods, devices, and systems of various embodiments are disclosed for exploiting opportunistic energy harvesting conditions for an unmanned autonomous vehicle (UAV). Various embodiments include determining mission power parameters for the UAV and accessing energy-harvesting data. A suitability of an energy-harvesting site for stationary energy harvesting by the UAV may be assessed based on the mission power parameters and the energy-harvesting data. In addition, an initial course of the UAV may be adjusted based on the assessment of the suitability of the energy-harvesting site. Stationary energy harvesting may include a process performed by the UAV that derives energy by conversion from an external power source while in a fixed position and/or in contact with an adjacent object.