On-Site Power Generations Options for Water and Wastewater Utilities

Several components within the water and wastewater treatment process are energy intensive to operate. Approximately 2% to 4% of the nation's annual net electricity is used in moving and treating water and wastewater, with the majority of the costs associated with water distribution (85%) and wastewater and sludge processing (82%), respectively. In the event of power outages at treatment plants, whether attributed to a natural disaster or man-made, some source of auxiliary or supplemental power is needed to supply sufficient electrical power to provide reliable treatment. Many facilities utilize outside independent power feeds that may not be available in times of regional grid failure. In such circumstances, use of on-site auxiliary or supplemental power generators can prove beneficial to facilities that want or need the capability to generate their own electricity. Today, there are a variety of cost-effective on-site power generation options available for wastewater and water treatment facilities. This paper discusses several of those options, which include generators powered by diesel, natural gas, and biogas; fueled internal combustion engines; microturbines; fuel cells; solar cells; and wind turbines. The potentials of using other renewable energy sources in the future are also briefly mentioned. Advantages, limitations, and criteria for selecting appropriate auxiliary or supplemental power options are also highlighted.