Intervention concepts for energy saving, recovery and generation from the urban water system

There are numerous options for energy measures in the water sector ranging from water conservation and process efficiency improvements to new technologies and redesigning water systems. Next to energy efficiency improvements, there is a need for new concepts in which water is viewed as a carrier of energy. Municipal wastewater is a potential source of chemical energy, i.e. organic carbon that can be recovered as biogas in sludge digestion. Even more so, domestic (waste)water is a source of thermal energy. And in areas with altitude differences, installing micro-hydro technologies in water distribution systems can convert energy from the pressure and flow into electricity. This report presents intervention concepts for energy saving, recovery and generation from the urban water system. Summarised, the main outcomes of research undertaken at 9 case studies are: i) Algarve and Alcoy water supply system: by performing an energy audit, the most energy efficient operating scheme can be determined. ii) Oslo and Amsterdam water cycle: the thermal energy recovery potential from wastewater is large, and it is in particular feasible if coupled to aquifer thermal energy storage systems. iii) Schiphol and Athens wastewater treatment: the energy generation at wastewater treatment plants through biogas can be enhanced by co-digestion and thermophilic digestion. iv) Lanhirano, Athens and Algare water supply system: in a water distribution system, water and energy can be saved by integrating pressure and energy management., i.e. by installing micro-turbines.