With the growing demand of ubiquitous and reliable wireless connectivity, as well as the imperative for future communication networks that are environmentally sustainable, the option of non-terrestrial networks (NTNs) that are energy neutral seems as an attractive solution. NTNs embrace several tiers of off-the-ground serving nodes, mounted on devices that fly at heights as low as a few meters and up to no more than 100s of meters from the ground (such as unmanned aerial vehicles – UAVs) and moving up to high altitude platforms (HAPs) in the troposphere and the stratosphere (up to and over 20 km above the ground, respectively) to low earth orbit (LEO) and medium earth orbit (MEO), satellites, which fly at 160-2000 km and above 2000km heights, respectively. While these “flying” serving nodes can provide improved coverage compared to terrestrial layouts, their operation in the net-zero energy regime requires the combination of a number of relevant energy technologies (e.g. solar and radio harvesting, efficient energy storage and balancing, etc.), which should be optimized jointly with the communication system design (in terms of energy efficiency, including the RF, baseband and antenna units and within the link requirements and quality of service constraints).This proposed technical panel at ICC 2023 aims to showcase both the opportunity and the associated challenges of net-zero energy NTNs. The key technical areas that will be addressed are: Design of NTNs and their incorporation with the ground segment Net-zero energy technologies suited for non-terrestrial networks Energy consumption/generation/storage modelling and balancing Joint optimization of communication and energy resources UAV-based portable access Intelligent and energy-aware satellite communications