A Field Test of Direct Load Control of Water Heaters and its Implications for Consumers

Abstract

Utilities and customers are now operating more closely than ever. The prevailing numbers of grid-interactive Distributed Energy Resources are being integrated to provide grid reliability and stability. Different methods of control have been implemented to utilize these Distributed Energy Resources, such as Service-Oriented Load Control and Direct Load Control. This paper investigates the issues associated with the latter. A Direct Load Control method is applied to two Distributed Energy Resources, Electric Water Heater and Heat Pump Water Heater. A load shifting scenario is created where each water heater turns off during water draw events that coincide with peak demand periods. The results of the tests indicated a significant decrease in the temperature of the water in the tank. This implies that using Direct Load Control to control water heaters adversely impacts customer comfort which might lead to unenrollment from Demand Response programs.