Energy recovery strategies in water distribution networks: literature review and future directions in the net-zero transition

Water distribution networks (WDNs) are significant users of energy and contributors to greenhouse gas emissions. Energy recovery strategies (ERSs) have potential for switching WDNs to a renewable energy source, thereby assisting with the transition to net-zero emissions and reducing the dependency of water utilities on power-grids. To address the current lack of understanding of the potential for ERSs to achieve these goals, this work presents a holistic review, which considers all available devices, i.e. turbines, pumps as turbines, and other alternative strategies, such as the GreenValves, as well as all the kinds of application in the literature. Besides describing the latest most significant achievements in the context of ERSs, the review also identifies the most common issues and proposes several future research directions, including the need for a better test and comparison of the various available solutions in field applications, and more thorough analyses of the socio/political problems hampering their diffusion.