Although 5G networks can play a key role in supporting the net zero transition enabling decarbonisation across the economy, they also use energy and produce emissions. It’s necessary to measure and manage these environmental impacts, particularly the carbon emissions of 5G networks, to ensure that the overall effect is beneficial.  NetZeroNet (NZN) will focus on modelling ‘use-phase carbon emissions’ for a well-defined network configuration, providing a foundation for activities aimed at minimising the carbon footprint of telecommunications infrastructure. As data handling networks and IT systems grow, so will energy consumption and associated emissions. However, innovation within the network or at its edge has the potential to reduce these impacts. NZN will address the increasing need to profile both the energy costs and related carbon emissions of 5G networks, ensuring a focus on 5G sustainability.