Energy management opportunities
Abstract
Energy costs are a major part of total operation and maintenance expenses for a water utility. An energy survey of the American Water System (AWS) water companies was conducted, and energy audits were conducted at three representative AWS water supply systems. The audits identified energy savings ranging from 10 to 32 percent compared with 1993 electrical costs. Cost-effective energy conservation measures consisted of base loading the most efficient plant in a multiplant water system, implementing strategies to reduce demand charges, modifying pumps, and installing energy-efficient lighting. Installation of variable-frequency drives, standby generators, and energy-efficient motors was recommended, but these devices were not cost-effective. Energy savings and the corresponding implementation costs were extrapolated for the entire AWS on the basis of the surveys and results of the three audits. Identified energy conservation measures may save AWS $3.4 million annually (12.3 percent of existing energy costs) at an implementation cost of $6.1 million, with a payback period of 1.8 years.