This project aimed to demonstrate and evaluate a novel technology that non-intrusively monitors the electricity consumption of individual devices inside a building. Energy consumption in U.S. Department of Defense (DoD) buildings represents a major cost and has both security and environmental impacts. For these reasons, the DoD continuously seeks to reduce energy consumption in its building stock. The starting point must be a good understanding of how much energy is consumed and which devices are consuming it. The Belkin Echo is a novel technology that enables non-intrusive electricity monitoring of individual devices inside a building. Non-intrusive monitoring is attractive because it can substantially decrease the cost of acquiring detailed energy consumption data and permit rapid identification of energy waste or mechanical breakdown. One approach to non-intrusive load identification is to install a single, highly sensitive meter and apply cloud-based algorithms to identify unique high-frequency signatures of each energy-using device in the building.
The project’s primary goal was to demonstrate the technology and its ability to guide retrofits in DoD buildings. Success would be demonstrated by meeting four quantitative objectives:
- Low-cost installation
- Accurate measurement of energy consumption
- Identification of energy consumption by individual devices
- Identification of energy-saving measures and their impact
Belkin’s Echo technology consists of a sensor and disaggregation algorithms. The sensor collects real-time voltage and current measurements at one sampling rate, and broadband high frequency (HF) noise measurements at a second, much higher, sampling rate. The combination of power characteristics and the HF noise from each type of device has a unique signature that results from the device’s internal electrical circuit design. Echo captures this “signature,” which enables it to “itemize” electricity use of devices in the building.
The performance objectives were only partially achieved. The Echo was not able to generate an accurate itemization of electricity consumption, but it was able to identify some major loads and estimate their energy consumption. Echo’s most novel feature, extracting performance behavior from high-frequency power data, had difficulty identifying device signatures because: non-specific high frequency noise obscured many device signatures; the high number of simultaneous device signatures greatly complicated identification; and many devices had power consumption (or changes in power) around 100 watts, which was below the measurement threshold. More than 30 percent of all electricity consumption in the buildings was continuous, and that consumption was invisible to the Echo technology. An Echo deployment in a single building costs about $19,000 more than a circuit-level monitoring technology. The higher costs of Echo data analysis are largely responsible for the difference, though they are offset by the lower costs of installation and removal. The Echo metering system would most likely be cheaper than circuit-level monitoring for basewide deployment because Echo’s costs decline sharply with scale, while circuit-level metering costs decline less so.
Belkin’s Echo was designed for residential applications and required extensive modification to accommodate three-phase service at Joint Base Lewis-McChord (JBLM) buildings. It also required time-consuming post-processing. The most important institutional barrier was restrictions on communications inside the military bases. Security regulations prevented the use of base communications networks and forced development of a unique communications strategy for each building.