Home Energy Management System (HEMS): Coupled Flexible Load Management in Homes

Abstract

Electricity suppliers have introduced time-of-use (TOU) metering and pricing in residential buildings in recent years. By increasing the price of electricity during on-peak hours (e.g., 2 pm to 7 pm in summer months), suppliers expect to regulate the energy usage from homeowners when the grid is near capacity. Therefore, homeowners are motivated to shift the load by moving their home electricity use from on-peak hours to off-peak hours for utility cost savings. However, peak load management is another factor that needs to be considered, since a higher peak load might cause other penalties, such as making suppliers change their current tariff policy in the next paying period since the grid needs to fulfill a higher demand. In this paper we explore the Home Energy Management System (HEMS) Strategy for homeowners who are considering saving money by reducing/avoiding the on-peak hour electricity usage while reducing peak load. A multi-goal scheduling problem is solved by constructing a coupled compromise decision support problem in which a water heater is coupled with flexible, non-thermal appliances such as a washing machine. To address these multiple goals, we use Decision Support Problem (DSP) construct. A use case simulation shows that our scheduler can make a reasonable tradeoff between two conflicting goals, helping the homeowner save money while maintaining low peak demand.