As a potential solution to better use water-embedded resources, the transition to circular water systems and services requires technology-focused approaches that can enhance a positive reception by organizations in the public, business and government sectors. NextGen focuses on water, energy and nutrients/material cycles in the water and wastewater sector to make them economically and environmentally attractive. This report addresses new approaches and best practices for closing the energy cycle in the water sector. Five NextGen case studies developed and demonstrated a wide range of innovative energy recovery technologies/approaches: Athens (EL), Filton Airfield (UK), Braunschweig (DE), Spernal (UK) and Westland (NL).