Case Studies in Energy Management: Experience From Germany

The estimated potential for long-term energy-efficiency improvement of water/wastewater utilities (WWUs) ranges from 10 to 30%. Energy efficiency measures generally have short payback periods and are more economical than adding renewable energy generation. This article presents experience gained from working with German WWUs on energy efficiency since 2013, focusing on six case studies: (1) making full use of available energy use data, (2) reducing costs by avoiding demand spikes and optimizing electricity contracts, (3) improving the efficiency of over-dimensioned booster station pumps, (4) reducing energy use for space heating at a water treatment plant, (5) replacing pressure-reducing valves with turbines to make use of excess hydraulic capacity, and (6) avoiding energy waste of wastewater treatment plant blowers by keeping oxygen sensors properly calibrated. The main partner WWU achieved a 13% improvement in energy efficiency after less than two years of focused energy management, with an average payback period per measure of 1.2 years. © 2017 American Water Works Association