Electrical Distribution System Optimization (EDSO)

Electrical Distribution System Optimization (EDSO) is an energy saving initiative based on adjusting the voltage supplied to building equipment. The voltage level of a facility's electrical distribution system is often higher than required by the equipment in the building. Decreasing the supplied voltage to the actual level required reduces electrical demand and energy use, resulting in cost savings on the electric utility bill. As an additional benefit, the life of lamps, motors, and other electrical equipment is extended.

The most cost-effective method of implementing voltage reduction is to adjust the existing taps on the secondary side of the main transformers, typically allowing for a 2.5% or 5.0% decrease in voltage. Another option is to install additional step-down transformers; although this method is more costly, it may allow for a greater voltage reduction.

Since 2002, Prism has worked closely with BC Hydro in developing an EDSO program for the utility. Prism can perform an EDSO evaluation of a facility's electrical distribution system, recommend measures that would achieve energy savings, and oversee the implementation of these measures. Our experience and expertise has gained Prism a reputation as the consulting firm of choice in British Columbia for EDSO studies. In 18 projects implemented, Prism has helped our customers save over $300,000 annually using this technique with an average payback of less than one year.



Case Studies

The following measured profiles show how voltage reduction will decrease energy consumption. Power demand was reduced by more than 10% with similar conditions:

Vancity Head Office: A pilot EDSO project supported by BC Hydro was implemented in September 2004. Upon analysis of metering results, annual energy savings of 112,000 kWh, or $6,000 per year were projected. The simple payback for this project was projected to be 1.8 years. Additional benefits identified as a result of this project include improved power factor and improved voltage imbalance.

BCIT Burnaby Campus: A pilot EDSO project supported by BC Hydro was implemented in March 2006. Upon analysis of metering results, an annual energy savings of 731,800 kWh, or over $40,000 per year was projected. A total of 19 transformers were monitored and adjusted.




Not all buildings are good candidates for EDSO. Factors such as existing voltage levels, electrical end uses, transformer types, and available tap settings must be examined to determine if there are any potential savings. We would be glad to discuss your building(s) and its suitability for voltage optimization.