The Electrical Load Duration Curve is an excellent graphical representation of the amount of time the facility is above a given electrical demand level. The electric demand, or electric load, is plotted on the vertical axis, and the percent of occurances, throughout the year, is plotted on the horizontal axis.
In the above example of the electrical load duration chart, the facility is only above 150 Kw for 1% of the time, 88 hours a year. For this customer they are paying $2000 per month in additional demand charges, for the 1% of the time that their electrical demand is above 150 KW. This electric customer is an excellent candidate for an Electrical Peak Demand Control System, or a Battery Energy Storage System. The electrical demand controller will be programmed to automatically shed loads when the demand curve approaches 150 KW.