Product Abstract

As the smart grid evolves through advances in technology, the benefits of deploying and leveraging "smart" systems are becoming more and more significant relative to the costs. EPRI's Smart Grid Demonstration project is conducting research focused on integration of distributed energy resources to help advance widespread deployment of these systems. This report provides a technical description of the hardware, software, and communication infrastructure in one such system. Specifically, it documents an ongoing two-way electric water heater direct load control project pilot, including lessons learned in the installation process. Future reports will provide analytical results based on the performance of the project.

Objective

The main objective of the project is to shift peak electric load using an existing conventional electric water heater, with little modification required and with no resulting discomfort to the customer. To accomplish this objective requires overcoming several technical challenges, including real-time monitoring and control of the water heater; application of ZigBee wireless communications for a home area network (two-way communication in the home); and implementation of a Fiber to the Home (FTTH) IP based wide area network for two-way communication and energy management between the distribution utility and the customer.

Approach

The project team prepared this report through direct evaluation and participation in the deployment of the smart water heater control system for BTES.

Results

The subject of the report is a two-way water heater direct load control project being carried out by Bristol Tennessee Essential Services (BTES) and its electricity supplier, Tennessee Valley Authority (TVA). This project will help contribute to an understanding of how electric water heaters can be used to effectively shift peak electric load on a daily basis. The report discusses the project's technical objectives, provides a functional description of the infrastructure involved, and presents results from Phase 1 of the project, which demonstrates and validates the proof-of-concept and hardware of the system. These results include the following:

Temperatures can be measured accurately.

Wireless communications can be successfully accomplished between the Carina-designed switch retrofitted at the water heater and the Carina AMI revenue meter collar using ZigBee wireless communications.

Installation of the entire system is not overly complicated.

Water heater function can be controlled and monitored remotely.

Electric water heating load can be moved out of peak periods.

Consumer comfort and hot water availability expectations are not affected.

The WISE unit can turn the water heater on and off in a matter of seconds based on minimum and maximum temperature settings as established in the firmware and software.

Parameters can be remotely changed individually or in groups in a matter of seconds.

Application, Value and Use

This report will be of value to electric utilities involved in or otherwise interested in the following:

Permanent peak shifting applications

Demonstrating residential electric water heater control with existing electric water heaters

Wireless performance of ZigBee (Note: Smart Energy Profile is not being evaluated.)

Capabilities of emerging smart technologies and communication infrastructures

Demonstrating potential smart grid benefits of two-way communications

Leveraging existing broadband communications for demand response applications

EPRI Perspective

This project is a "first of its kind" evaluation of a combination of emerging hardware, software, and communication technologies that are making the smart grid a reality. It is important for the electricity industry to understand the technology capabilities and benefits of two-way communications that can enable daily control of customer-owned resources with no customer discomfort. This report is one of several involving the BTES/TVA water heater project and complementary research activities that are supporting widespread deployment of distributed energy resources as part of the 5-year smart grid demonstration project.