Prepared for the General Services Administration and Department of Energy

By the National Renewable Energy Laboratory

FEBRUARY 2019

Plug Load Management 

System Field Study

ALICEN KANDT AND ROIS LANGNER
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY i

Disclaimer

This document was prepared as an account of work sponsored by the United States Government. While this 

document is believed to contain correct information, neither the United States Government nor any agency 

thereof, nor the National Renewable Energy Laboratory, nor any of their employees, makes any warranty, 

express or implied, or assumes any legal responsibility for the accuracy, completeness, or usefulness of any 

information, apparatus, product, or process disclosed, or represents that its use would not infringe privately 

owned rights. Reference herein to any specific commercial product, process, or service by its trade name, 

trademark, manufacturer, or otherwise, does not constitute or imply its endorsement, recommendation, or 

favoring by the United States Government or any agency thereof, or the National Renewable Energy 

Laboratory. The views and opinions of authors expressed herein do not necessarily state or reflect those of 

the United States Government or any agency thereof or the National Renewable Energy Laboratory.

This work was authored by the National Renewable Energy Laboratory, operated by Alliance for Sustainable 

Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-08GO28308. Funding 

provided by U.S. Department of Energy Office of Energy Efficiency and Renewable Energy Building 

Technologies Office. 

Acknowledgements

The authors would like to thank the following people for the contributions to the pilot project and/or their 

review of this report.

U.S. Department of Energy: Amy Jiron, Cedar Blazek, Jordan Hibbs

Test Location A: Rachael Ruelas, Kevin Chihak, Rich Coombe (no longer with company)

Test Location B: Bill Balsamo, Heather Miram

Ibis Networks: Christy Matsushige, Kevin Hause (no longer with Ibis)

National Renewable Energy Laboratory: Anya Peterson, Kim Trenbath, Jesse Dean, Bethany Sparn 

McIntyre Communications Inc.: Maureen McIntyre

For more information contact:

Rois Langner

National Renewable Energy Laboratory

Email: Rois.Langner@nrel.gov

GSA’s GPG program and DOE’s High Impact Technology (HIT) Catalyst program enable federal and 

commercial building owners and operators to make sound investment decisions in next generation 

building technologies based on their real-world performance.
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY ii

Executive Summary

As commercial buildings become more efficient and HVAC electrical loads go down, plug load efficiency 

becomes more relevant to achieving aggressive energy reduction targets.1 Plug loads consume at least 

30% of whole-building energy use,

2 and include all plug-in and hardwired electric loads in a building that 

are not associated with major heating, ventilating, or air-conditioning equipment; lighting; water 

heating; or any other major building equipment needed for basic building operation.3

This field study assessed a plug load management (PLM) system in two commercial building applications. 

The Ibis InteliNetworkTM PLM system includes: intelligent socket devices, which plug into existing 

electrical outlets, collect energy usage information, and provide on-off, schedule-based control of 

connected devices; a gateway, which manages communication between the intelligent sockets and the 

PLM cloud service; and a PLM network, which is a cloud-based measurement and control network for 

the entire system. The PLM enables users to measure and analyze device energy use and identify 

opportunities for reduction of plug load energy use. A scheduling function can be used to save plug load 

energy by setting times for individual devices (or groups of devices) to turn off when not in use, rather 

than left on and in an idle states. The vendor estimates that the PLM solution that was demonstrated

could help customers cut energy consumption for individual plug loads by 20%–50%, resulting in an 

overall energy savings of up to 10% for commercial buildings.

Two stores were selected as field study sites for this PLM solution. Test location A is a pet-oriented retail 

store located in Chandler, Arizona, and Test Location B is an eyewear manufacturer and retail store in 

Honolulu, Hawaii. Following site visits to assess each location, 46 devices in Test Location A and 130 

devices in Test Location B were identified for monitoring, control, or other efficiency strategies via the 

PLM system. Plug load equipment at the two sites was comprised of a wide range of devices, including:

checkout counter devices, pet grooming equipment, medical equipment, office equipment, and break 

room devices. Devices that consume low levels of energy or that are not present in large numbers 

throughout the store, such as pencil sharpeners or clocks, were generally not included in this pilot. Also 

not included were devices that are required to stay on, such as refrigerators or life safety equipment for 

maintaining appropriate environmental conditions for animals.

Quantitative and qualitative performance objectives for the PLM field study were developed with input 

from the vendor and the retailers. The quantitative and qualitative performance objectives for the PLM 

field study, as well as indicators of whether the success criteria were met, are provided in Table 1.

Energy and energy cost savings were calculated by taking the difference between overall plug load 

energy consumption during a baseline period, and the plug load energy consumption after schedulebased controls were applied. This simple approach was used because that is how building owners 

typically calculate energy savings.

1 “Annual Energy Outlook 2018,” U.S. Energy Information Administration, accessed December 20, 2018, 

https://www.eia.gov/outlooks/archive/aeo18/.

2 Ibid.

3 “Navigating Cybersecurity Implications of Smart Outlets,” ACEEE, 2018 ACEEE Summer Study on Energy Efficiency in Buildings, accessed December 

20, 2018, https://aceee.org/files/proceedings/2018/#/paper/event-data/p373. 
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY iii

Table 1: PLM Quantitative and Qualitative Performance Objectives

Metrics & Data Test Location A Test Location B Success 

Criterion Met

Quantitative Performance Outcomes

Electricity 

Savings

Metered electric 

consumption

1,040 kWh/year 

$124.80/year4

11% savings5

2,730 kWh/year

$819/year6

18% savings7

CostEffectiveness

Simple payback 59 years 24 years

Savings to investment 

ratio (SIR) 0.17 0.41

Deployability

PLM solution has broad 

applications across the 

retailer’s portfolio of 

buildings (for a large 

quantity of devices 

within each store)

Unfavorable payback and 

SIR; however, complications 

during pilot negatively 

affected outcomes and 

savings potential

Unfavorable payback and 

SIR; however, 

complications during pilot 

negatively affected 

outcomes and savings 

potential

Qualitative Performance Outcomes

Ease of 

Installation

Time required to install 

system at test site Less than a day to install 9 hours to install

Time required by vendor 

to configure and provide 

online data interface 

access

2–3 days 2–3 days

Impact of install on 

operations None None

Operability

Usability of intelligent 

sockets Easy and intuitive

Easy and intuitive, but 

problems encountered 

with devices not 

functioning as intended 

after controls deployed 

and with staff unplugging 

sockets

(Location A)

(Location B)

Usability of online data 

interface

Did not use enough to 

provide feedback

Did not utilize online data 

interface

4 Assuming a blended electric rate of $0.12/kWh.

5 Percent savings in measured plug loads.

6 Assuming a blended electric rate of $0.30/kWh.

7 Percent savings in measured plug loads.
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY iv

Time commitment 

required for monitoring 

and management of plug 

loads

Staff did not have the 1–2 

hours needed per week

Staff did not have the 1–2 

hours needed per week

Nonenergy 

Benefits

PLM solution results in 

increased equipment 

life, early detection of 

device failure, awareness 

of energy use trends 

resulting in savings not 

attributed to controls, 

staff become educated 

about and engaged in 

energy management, 

and other related 

benefits

None

This pilot was a good way 

to engage staff about plug 

load energy use.

(Location A)

(Location B)

The PLM system was found to be effective at reducing plug load energy use, with a projected annual 

plug load reduction of 11% and 18% in Test Locations A and B, respectively.8 However, the economics 

are not favorable at either test site. Test Location A has a simple payback period of 59 years and a SIR of 

0.17 (assuming a project lifetime of 10 years9

). Test Location B has a simple payback period of 24 years 

and a savings-to-investment ratio (SIR) of 0.41 (assuming a project lifetime of 10 years).

Staff interviewed for this report stated that the PLM hardware was easy to use and intuitive, though 

there were reports of store employees becoming frustrated with devices being off when they 

anticipated them being on, and simply unplugging the devices to override controls. In one of the field 

studies, store employees unplugged more than half of the intellisockets. The online data management 

system (dashboard), however, was not used by staff at either test location, which was one large 

limitation of the success of this study. Personnel familiar with the test site need to be engaged in the 

study and frequently monitor the dashboard to identify potential issues and capitalize on savings 

opportunities. For example, there were instances at both test locations of intelligent sockets going 

offline because staff had unplugged devices from the sockets. The dashboard can also be used to 

capitalize on nonenergy benefits such as monitoring device health over time, which could be indicated 

by changes or drifts in the energy consumption that are trended and displayed in the dashboard. 

Minute-level submetered data are available for download via the dashboard. These nonenergy benefits 

were not realized in this study.

Another limitation of the study (involving educational awareness and how users engaged with the 

product) was ensuring that staff, including workers from all shifts as well as janitorial and other service 

providers, were made aware of the installation of the PLM technology and understood what the 

technology was, the intent of using it, how it worked, and who to contact with questions or issues. 

This PLM solution shows promise as an effective means to monitor, control, and reduce plug load energy 

use. The system is not currently cost effective; however, deployment at a site with a staff member who 

is able to actively manage the data (to continually find new opportunities for energy savings), monitor 

the sockets (to ensure they are not being removed), and confirm that the control schedules are being 

8 Percent savings in measured plug loads.

9 Project lifetime of 10 years accounts for equipment lifetime and SaaS fee structure.
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY v

implemented as intended (and not overridden), at regular time intervals, may result in improved 

economics over those realized at these two test sites.

In addition, these two test sites experienced complications. At one site, a flood forced the remapping of 

devices and required a second (shorter) baseline and controls period. At the second, staff continually 

unplugged devices from the intelligent sockets, yielding a much smaller data set than anticipated. 
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY vi

Table of Contents

EXECUTIVE SUMMARY II

I. INTRODUCTION 1

A. WHAT WE STUDIED................................................................................................................... 1

B. WHY WE STUDIED IT ................................................................................................................. 2

II. EVALUATION PLAN 4

A. EVALUATION DESIGN ................................................................................................................ 4

B. TEST BED SITES .......................................................................................................................... 4

C. METHODOLOGY ...................................................................................................................... 10

III. RESULTS 14

A. QUANTITATIVE RESULTS ......................................................................................................... 15

B. QUALITATIVE RESULTS ............................................................................................................ 23

C. COST-EFFECTIVENESS.............................................................................................................. 26

IV. SUMMARY FINDINGS AND CONCLUSIONS 27

A. OVERALL TECHNOLOGY ASSESSMENT BASED ON FIELD STUDY ............................................. 27

B. LESSONS LEARNED AND BEST PRACTICES ............................................................................... 27

C. FIELD STUDY RECOMMENDATION.......................................................................................... 28

V. APPENDICES 29

A. MANUFACTURER CUT SHEETS ................................................................................................ 29

B. TEST LOCATION A DATA .......................................................................................................... 40

C. TEST LOCATION B DATA .......................................................................................................... 45
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY vii

List of Figures

Figure 1: Intelligent Sockets.................................................................................................................................1

Figure 2: Screenshot of the PLM network dashboard .........................................................................................2

Figure 3: Miscellaneous Electric Loads in Buildings (2016 – 2030)......................................................................3

Figure 4: Device Category Counts for Test Location A.........................................................................................6

Figure 5: Device Category Counts for Test Location B...................................................................................... 10

Figure 6: Energy Use by Device Category ......................................................................................................... 17

Figure 7: Energy Use by Device Category for Site B.......................................................................................... 21

Figure 8: Additional Store Equipment - Total Energy: 510.56 kWh ($61.27) / Year......................................... 40

Figure 9: Kitchen Equipment - Total Energy: 3,516.16 kWh ($421.94) / Year.................................................. 40

Figure 10: Office Equipment - Total Energy: 344.98 kWh ($41.40) / Year........................................................ 41

Figure 11: Pet Equipment - Total Energy: 5,300.99 kWh ($636.12) / Year....................................................... 41

Figure 12: Additional Store Equipment - Realized Savings: 318.81 kWh ($38.26) / Year................................. 42

Figure 13: Kitchen Equipment - Realized Savings: 93.25 kWh ($11.19) / Year................................................. 42

Figure 14: Office Equipment - Realized Savings: 14.61 kWh ($1.75) / Year ..................................................... 42

Figure 15: Pet Equipment - Realized Savings: 2.77 kWh ($0.33) / Year............................................................ 43

Figure 16: Additional Store Equipment - Potential Savings Projected from Baseline: 73.41 kWh 

($8.81) / Year .................................................................................................................................................... 43

Figure 17: Kitchen Equipment - Potential Savings Projected from Baseline: 949.43 kWh ($113.93) / Year.... 43

Figure 18: Office Equipment - Potential Savings Projected from Baseline: 15.05 kWh ($1.81) / Year............. 44

Figure 19: Pet Equipment - Potential Savings Projected from Baseline: 2.53 kWh ($0.30) / Year................... 44

Figure 20: Kitchen Equipment - Total Energy: 3,827.35 ($1,148.21) / Year..................................................... 45

Figure 21: Office/Retail Equipment - Total Energy 8,941.23 kWh ($2,682.37) / Year...................................... 45

Figure 22: Optometry Equipment - Total Energy 13,677.5 kWh ($4,103.25) / Year ........................................ 48

Figure 23: Security Equipment - Total Energy: 11.56 kWh ($3.47) / Year........................................................ 55

Figure 24: Kitchen Equipment - Realized Savings: 904.14 kWh ($271.24) / Year............................................. 56

Figure 25: Office/Retail Equipment - Realized Savings: 107.59 kWh ($32.27) / Year....................................... 56

Figure 26: Optometry Equipment - Realized Savings: 139.27 kWh ($41.78) / Year......................................... 57

Figure 27: Security Equipment - Realized Savings: 2.56 kWh ($0.77) / Year.................................................... 58

Figure 28: Kitchen Equipment - Potential Savings from Baseline: 1,194.6 kWh ($358.38) / Year ................... 58

Figure 29: Office/Retail Equipment - Potential Savings Projected from Baseline: 325 kWh ($97.5) / Year..... 59

Figure 30: Optometry Equipment - Potential Savings Projected from Baseline: 816.16 kWh 

($244.85) / Year ................................................................................................................................................ 60

Figure 31: Security Equipment - Potential Savings Projected from Baseline: 5.36 kWh ($1.61) / Year........... 63
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY viii

List of Tables

Table 1: PLM Quantitative and Qualitative Performance Objectives.................................................................iii

Table 2: Test Location A—Device Counts by Type and Category ........................................................................5

Table 3: Test Location B—Device Counts by Category ........................................................................................7

Table 4: PLM Quantitative and Qualitative Performance Objectives............................................................... 11

Table 5: Baseline and Control Period Lengths.................................................................................................. 12

Table 6: Average Power per Device and Percent Difference from Lab Meter ................................................. 13

Table 7: Plug Load Management Quantitative and Qualitative Performance at Two Pilot Sites..................... 14

Table 8: Quantitative Results............................................................................................................................ 15

Table 9: Annual Energy Use by Device Type for Test Location A...................................................................... 16

Table 10: Realized and Projected Energy Savings for Controlled Devices for Test Location A......................... 18

Table 11: Annual Energy Use by Device for Test Location B............................................................................. 19

Table 12: Realized and Projected Energy Savings for Controlled Devices for Test Location B......................... 22
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 1

I. Introduction

A. WHAT WE STUDIED

This field study assessed the Ibis InteliNetworkTM plug load management (PLM) system in two commercial 

building applications. The system comprises:

• Intelligent sockets, which capture and control device energy 

• A gateway, which communicates energy data from the intelligent sockets to a cloud network

• A PLM network, which is a cloud-based measurement and control network for the entire system.

The intelligent socket plugs into a wall electrical outlet, and the metered device plugs into the intelligent 

socket. The intelligent sockets are available in single or dual socket models, with the dual socket having one 

controllable socket and one “always-on” socket. The intelligent sockets come in a range of models

appropriate for both 120V/15A devices and 240V/20A devices. Two intelligent socket models are shown in 

Figure 1. Manager cut sheets for all system components are in Appendix A. 

Figure 1: Intelligent Sockets 

Image: Ibis Networks

The Gateway manages communication between the intelligent sockets and the PLM network. The Gateway 

collects energy usage data from up to 120 intelligent sockets and conveys the data to the cloud-based PLM 

network in real time. The Gateway also receives information from the network related to powering devices 

on or off. 
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 2

The PLM network is the interface and tool for viewing, analyzing, reporting, and managing plug load data. 

This cloud-based service utilizes a dashboard that provides reporting, scheduling, data analytics, and system 

management tools.10 A screenshot of the PLM network dashboard is in Figure 2. 

Figure 2: Screenshot of the PLM network dashboard

The vendor estimates that this PLM solution could help customers cut energy consumption for individual 

plug loads by 20%–50%, resulting in an overall energy savings of up to 10% for commercial buildings.

Two stores—a pet-oriented retail store located in Chandler, Arizona (Test Location A), and an eyewear 

manufacturer and retail store in Honolulu, Hawaii (Test Location B)—were selected as host sites for the 

technology. Forty-six devices in Test Location A and 130 devices in Test Location B were identified for 

monitoring, control, or other efficiency strategies via the PLM system. The two sites included a range of 

equipment, comprising checkout counter devices, grooming equipment, medical equipment, office 

equipment, and break room devices. The equipment tested generally did not include devices that consume 

low levels of energy and are not present in large numbers throughout the store, such as pencil sharpeners or 

clocks. It also did not include certain devices that the retailer deemed disallowable, such as refrigerators or 

life safety equipment for maintaining appropriate environmental conditions for animals.

B. WHY WE STUDIED IT

Miscellaneous electric loads (MELs) are electric loads used by appliances and devices outside a building’s 

core functions of heating, ventilation, air conditioning, lighting, water heating, and refrigeration. MELs 

represent 82% of all miscellaneous electric and gas energy loads for commercial buildings. MELs include plug 

and process loads (PPLs)—loads plugged into electrical outlets in a building such as computers, coffee 

makers, etc.—and hard-wired loads, such as fire detectors, escalators, etc.11 PPLs consume over one third of 

primary energy in U.S. commercial buildings.12 As buildings become more efficient, PPL efficiency becomes 

more relevant to achieving aggressive energy targets.13 At the building level, MELs account for 

10 “InteliNetwork,” Ibis Networks, accessed December 20, 2018, http://ibisnetworks.com/ibissystem/intelinetwork/. 

11 “Miscellaneous Electric Loads: What Are They and Why Should You Care?” U.S. Department of Energy Building Technologies Office article, 

September 15, 2016, https://www.energy.gov/eere/buildings/articles/miscellaneous-electric-loads-what-are-they-and-why-should-you-care.

12 “Plug & Process Loads,” U.S. Department of Energy Better Buildings, accessed December 20, 2018, 

https://betterbuildingsinitiative.energy.gov/alliance/technology-solution/plug-process-loads.

13 Ibid.
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 3

approximately 25% of the total electrical load in a minimally code-compliant commercial building and can 

exceed 50% in an ultra-high efficiency building.14 Figure 3 demonstrates the increasing percentage of energy 

use attributed to MELs as buildings become more efficient, projected from 2016 to 2030.

This PLM system is purported to have positive attributes that make it a potentially useful PLM and electricity 

reduction solution. The system is said to be highly secure, scalable, and affordable. The vendor estimated a 

reduction up to 10% (based on previous projects they had implemented), in total electricity consumption at 

both test locations.

Figure 3: Miscellaneous Electric Loads in Buildings (2016 – 2030) 

Data From: EIA Annual Energy Outlook 2015 http://www.eia.gov/forecasts/archive/aeo15/; 

EIA Residential Energy Consumption Survey https://www.eia.gov/consumption/residential/; 

Commercial Buildings Energy Consumption Survey https://www.eia.gov/consumption/commercial/.

14 Lobato, Chad, Shanti Pless, Michael Sheppy, and Paul Torcellini. 2011. Reducing Plug and Process Loads for a Large Scale, Low Energy Office 

Building: NREL's Research Support Facility. Golden, CO: National Renewable Energy Laboratory. NREL/CP-5500-49002. 

https://www.nrel.gov/docs/fy11osti/49002.pdf. 
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 4

II. Evaluation Plan

A. EVALUATION DESIGN 

The vendor worked with the two test locations to first identify plug loads to monitor and/or control, and 

then to install the PLM system, which consisted of intelligent sockets that plugged directly into existing 

electrical outlets; one or more gateway(s) to manage communication between the intelligent sockets and 

the PLM cloud service; and the cloud-based PLM network, which is the measurement and control network 

for the entire system.

An initial baseline period utilizing the intelligent sockets captures data from all monitored devices in each 

location, facilitating the continual collection of data over that period. The baseline period was 4 weeks and 1 

day for Test Location A, and 3 weeks and 6 days for Test Location B. This allowed for measurement and 

documentation of a wide variety of operational situations (weekday versus weekend operations, business 

and nonbusiness hour operations, transition times [businesses closed but staff or cleaning crews present]) 

over several weeks. 

After the baseline period, National Renewable Energy Laboratory (NREL) researchers and the vendor jointly 

studied and analyzed the baseline data to determine an initial energy usage profile by device and device 

type, the devices with the most potential for savings associated with schedule controls, and potential socket 

changes (moving a socket from one device to another). These findings were presented to the retail store’s 

energy manager for each test location, and policies for deploying control strategies and communicating 

them with staff at each test location, control strategies (time on and off per day for each controlled device), 

and socket changes were then approved by the test locations. 

During the control phase, control strategies were applied to approved devices, and data were collected on 

energy use at the socket level. At the end of the control phase, all data were collected and analyzed, and 

that analysis is presented here. 

B. TEST BED SITES

The vendor and NREL jointly selected two locations for the technology field study: a pet-oriented retail store 

located in Chandler, Arizona (Test Location A), and an eyewear manufacturer and retail store in Honolulu, 

Hawaii (Test Location B). The following characteristics were used in the site selection process:

• Required characteristics

 Commercial building types such as office, multi-tenant office, retail, higher education, 

hospitality, or other building type with documentation of significant plug loads

 A building owner open to introducing a wireless network and connectivity through Ethernet 

cable or access to cell service for data transmission

 Building owner and occupants willing to participate in a receptacle control field study and 

provide feedback

 Building owner and occupants open to a multi-month (3–6 months) field study time

 Access to an on-site building manager and a staff representative who can act as a liaison 

between the field study leads and building occupants or tenants.
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 5

• Desired characteristics

 Presence of a building automation system with BACNet IP communication protocols that the 

vendor technology is allowed to communicate with

 If a building automation system is not present, access to logs or other measurement 

and verification records for building systems 

 High-level documentation of general building characteristics

 High-level approximation of existing plug load types within the building.

TEST LOCATION A

Test Location A is a pet-oriented retail store located in Chandler, Arizona. The store is open from 9:00 a.m. 

to 9:00 p.m. every day except Sunday, when it is open 9:00 a.m. to 7:00 p.m. In addition to the retail store, 

there are other services provided such as grooming and veterinary care, which have different operating 

hours and days. This study used the average annual (blended) electricity rate for this location, which is 

$0.12/kWh. Note that time-of-use and peak demand charges were not accounted for in this study, but 

should be accounted for by entities considering this technology, as these charges may impact expected and 

realized energy savings. 

Initially, 46 devices were identified for inclusion in the baseline period. A breakout by device type and a 

mapping to device category is provided in Table 2.

Table 2: Test Location A—Device Counts by Type and Category

Device Type Device Count Device Category

Aquarium 7 Pet Care Equipment

Charger 2 Additional Store Equipment

Computer 1 Office Equipment

Driers 9 Pet Care Equipment

Fan 1 Office Equipment

Floor Scrubber 1 Additional Store Equipment

Pet Food Freezer 2 Pet Care Equipment

Grooming Tables 12 Pet Care Equipment

Microwave 2 Kitchen Equipment
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 6

Monitor 3 Office Equipment

Printer 1 Office Equipment

Refrigerator 2 Kitchen Equipment

Vending 3 Kitchen Equipment

A breakout of device counts by device category is provided in Figure 4.

Figure 4: Device Category Counts for Test Location A

TEST LOCATION B

Test Location B is a vision retail store in Honolulu, Hawaii. The store is open from 9:30 a.m. to 9:00 p.m.

every day except Sundays, when it is open 10:00 a.m. to 7:00 p.m. The facility also includes optometry 

services and on-site production of eyewear. The average annual (blended) electricity cost is $0.30/kWh.15

Initially, 130 devices were identified for inclusion in the baseline period. A breakout by device and a mapping 

to the device category are provided in Table 3.

15 Time-of-use and peak demand charges were not accounted for in this study.

6

3

7

30

Device Category

Office Equipment Additional Store Equipment

Kitchen Equipment Pet Care Equipment
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 7

Table 3: Test Location B—Device Counts by Category

Device Device Count Device Category

Bicrome Red 4 Optometry Equipment

Cable Box 1 Office/Retail Equipment

Calculator 1 Office/Retail Equipment

Camera 4 Security Equipment

Cash Box 1 Office/Retail Equipment

CD MP3 1 Office/Retail Equipment

Charging Station 1 Office/Retail Equipment

Chiller 1 Optometry Equipment

Chiller Flush Refill 1 Optometry Equipment

Clarifye 1 Optometry Equipment

Clean-n-Coat 4 Optometry Equipment

Computer 17 Office/Retail Equipment

Credit Card Machine 7 Office/Retail Equipment

Equipment Center 1 Optometry Equipment

Exam Machine 5 Optometry Equipment

Exam Table 2 Optometry Equipment

Fan 2 Office/Retail Equipment

Finish Blocker 1 Optometry Equipment

Frame Buffer 1 Optometry Equipment

Gerber Turbo 1 Optometry Equipment
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 8

Hilco TempMaster 1 Optometry Equipment

Hilco Ultrasonic Cleaner 1 Optometry Equipment

Hilco TempMaster 1 Optometry Equipment

Hilco Ultrasonic Cleaner 1 Optometry Equipment

Hotfigure 1 Optometry Equipment

Imaging System 1 Optometry Equipment

Ionizing Gun 1 Optometry Equipment

Keeler 1 Optometry Equipment

Lamp 6 Optometry Equipment

Lens Tinting 1 Optometry Equipment

Monitor 13 Office/Retail Equipment

Network Switch 7 Office/Retail Equipment

Optometry Chair 3 Optometry Equipment

Pal ID 1 Optometry Equipment

Phantom Research Lab 1 Optometry Equipment

Phone 2 Office/Retail Equipment

Printer 7 Office/Retail Equipment

Ptronics 3 Optometry Equipment

RayBan Inker 1 Optometry Equipment

Refrigerator 2 Kitchen Equipment

Scan Gun 1 Optometry Equipment

Server 1 Office/Retail Equipment
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 9

Shredder 1 Office/Retail Equipment

Stapler 1 Office/Retail Equipment

Surface DeBlock 1 Optometry Equipment

Systech Switch 1 Optometry Equipment

TempMaster 1 Optometry Equipment

TimeClock 1 Office/Retail Equipment

Trans Lenses 1 Optometry Equipment

TV 1 Office/Retail Equipment

UV Trans Meter 1 Optometry Equipment

Vacuum 2 Office/Retail Equipment

Vending Machine 1 Kitchen Equipment

Water Cooler 2 Kitchen Equipment

WECO Finish 1 Optometry Equipment

WelchAllyn 1 Optometry Equipment

Zeiss Machine 2 Optometry Equipment

A breakout of device counts by device category is provided in Figure 5.
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 10

Figure 5: Device Category Counts for Test Location B

C. METHODOLOGY

Quantitative and qualitative performance objectives for the PLM study were developed with input from the 

vendor and the retailers. The primary objectives of the measurement and verification study are to:

• Verify plug load electricity savings 

• Verify cost-effectiveness (payback and savings-to-investment ratio [SIR]) 

• Evaluate suitability of technology deployment across different building and equipment types 

• Evaluate ease of installation, operability, data access, and ability to implement control strategies

• Evaluate nonenergy benefits.

The quantitative and qualitative performance objectives for the PLM study are provided in Table 4.

5

67

54

4

Device Category

Kitchen Equipment Office/Retail Equipment

Optometry Equipment Security Equipment
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 11

Table 4: PLM Quantitative and Qualitative Performance Objectives

Objective Metrics & Data Success Criterion

Quantitative Objectives

Electricity 

Savings Electricity savings

Electricity savings compared to a baseline 

period:

• At least 10% electricity reduction in 

measured plug loads

CostEffectiveness Simple payback and SIR

• Simple payback < 10 years

• SIR > 1

Deployability

PLM solution has broad applications 

across the retailer’s portfolio of 

buildings (for a large quantity of 

devices within each store)

Favorable payback and SIR are achieved in 

most building and equipment types

Qualitative Objectives

Ease of 

Installation

Interview with vendor and retailer 

representative(s):

• Time required to install and 

configure

• Labor associated with install 

• Impact of install on operations 

• < 1 day to install

• < 1 week to provide online data access

Operability

Interview with retailer 

representative(s):

• Usability of intelligent sockets

• Usability of PLM network

• Time commitment required for 

continual management of plug 

loads

• No impact to operation and 

maintenance effort

• < 4 hours to understand online data 

interface

Nonenergy 

Benefits

At least one non-energy benefit is realized
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 12

QUANTITATIVE STUDY DESIGN

The testing protocol for each of the two locations began with an equipment inventory and PLM installation 

period followed by a baseline period and a controls period. For both locations, the baseline and control 

periods analyzed were the same length, although they varied between the sites, as shown in Table 5.

Table 5: Baseline and Control Period Lengths

Test Site Baseline Period Controls Period

Test Location A 4 weeks 1 day* 4 weeks 1 day*

Test Location B 3 weeks 6 days 3 weeks 6 days

*Note that the baseline and controls period for Test Location A did not occur during the store’s flood incident.

After the baseline period, device energy use was analyzed at the device-type and device-category level to 

identify opportunities for energy reduction via the deployment of control strategies (shutting devices off 

when not in use). Following this analysis and dialogue with each test site, a subset of devices was selected 

for control strategies. 

At Test Location A, 12 devices were identified for control strategies, and at Test Location B, 63 devices were 

identified for control strategies. After the control period concluded, data were analyzed to determine 

realized savings and to quantify projected savings potential (over a longer time period and using a larger 

data set of devices/sockets). Data for the baseline and control period for Test Location A can be found in 

Appendix B, and data for the baseline and control period for Test Location B can be found in Appendix C. 

QUALITATIVE STUDY DESIGN

The qualitative analysis was based on user input gathered via post-study feedback. It included telephone 

interviews with the main contacts at each test location, input from the vendor, and firsthand knowledge of 

the PLM solution gained by the authors of this report. 

DATA ANALYSIS

For this analysis, a subset of minute-level data for a given period (baseline or control) was used to calculate 

an “average week” (average consumption for given device or device category for each hour of the week). 

The socket sampling interval is every 15 seconds and data was summed to provide minute-level data. 

Averages were calculated by first summing minute-level data to create hourly data for each week, then 

averaging weekly data by the hour. Annual numbers were calculated using simple multiplication by 52 

weeks; no seasonal variation or holidays were taken into account. 

Potential savings were calculated by applying a proposed schedule to baseline data; that is, zeroing out 

consumption for times when the controls would have turned the device off. Potential savings are calculated 

by taking the difference between the measured baseline and baseline with the control schedule applied. 

This does not consider changes in consumption for particular devices when powering up or down, since 

none of the devices in this study had significant “recovery energy” when turned back on. However, if a study 

has equipment with significant recovery energy, it should be considered to avoid an overprediction of 
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 13

energy savings. This method was used to calculate savings potential due to large documented 

inconsistencies between performance and energy use in the baseline versus control periods, the general loss 

of data sources between baseline and control periods (attributed to staff unplugging the device from the 

intelligent socket), and the small number of devices that were actually controlled. 

The highest confidence in savings potential occurs when the measured savings from the controlled devices 

are well matched when compared with the potential savings calculated by zeroing out the consumption 

from the baseline period. 

DATA ANALYSIS LABORATORY TEST RESULTS OF INTELLIGENT SOCKETS FOR ACCURACY

The vendor’s intelligent sockets were installed in NREL’s Energy Systems Integration Facility (ESIF) Systems 

Performance Laboratory (SPL) to test for metering accuracy. The sockets were tested on the following 

equipment to get a broad range of power consumers:

• Dishwasher

• Efficient refrigerator

• TV and DVD player

• Small space heater.

Laboratory meters collected data at 1-second intervals and averaged up to 1 minute for the accuracy 

calculation. To determine the percent difference between the laboratory meters and intelligent sockets, the 

power was averaged over each “cycle” or appliance test. Table 6 shows the average power values (in watts) 

for each device and the percent difference. The intelligent meters tend to measure slightly lower than the 

laboratory power meters, so the percent difference is negative. The results show that the percent difference 

is small and not of concern, especially for this type of sensor. Additionally, the error does not seem 

dependent on the size of the load.

Table 6: Average Power per Device and Percent Difference from Lab Meter

Equipment

Average Power–

Laboratory 

Meters (W)

Average Power–

Intelligent 

Sockets (W)

Percent 

Difference

Dishwasher Cycle 795.5 778.8 -2.1

Refrigerator 33.7 33.1 -2.0

TV/DVD 109.7 105.4 -3.9

Heater 966.5 931.3 -3.6
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 14

III. Results

Quantitative and qualitative findings from the pilots at each of the two test sites are provided below. The 

findings are summarized in Table 7. 

Table 7: Plug Load Management Quantitative and Qualitative Performance at Two Pilot Sites

Metrics & Data Test Location A Test Location B Success 

Criterion Met

Quantitative Performance Outcomes

Electricity 

Savings

Metered electric 

consumption

1,040 kWh/year

$124.80/year16

11% savings17

2,730 kWh/year

$819/year18

18% savings19

CostEffectiveness

Simple payback 59 years 24 years

Savings to investment 

ratio (SIR) 0.17 0.41

Deployability

PLM solution has broad 

applications across the 

retailer’s portfolio of 

buildings (for a large 

quantity of devices 

within each store)

Unfavorable payback and 

SIR; however, complications 

during pilot negatively 

affected outcomes and 

savings potential

Unfavorable payback and 

SIR; however, 

complications during pilot 

negatively affected 

outcomes and savings 

potential

Qualitative Performance Outcomes

Ease of 

Installation

Time required to install 

system at test site Less than a day to install More than a day to install (Location A)

(Location B)

Time required by vendor 

to configure and provide 

online data interface 

access

2–3 days 2–3 days

Impact of install on 

operations None None

16 Assuming a blended electric rate of $0.12/kWh.

17 Percent savings in measured plug loads.

18 Assuming a blended electric rate of $0.30/kWh.

19 Percent savings in measured plug loads.
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 15

Operability

Usability of intelligent 

sockets Easy and intuitive

Easy and intuitive, but 

problems encountered 

with devices not 

functioning as intended 

after controls deployed 

and with staff unplugging 

sockets

(Location A)

(Location B)

Usability of online data 

interface

Did not use enough to 

provide feedback

Did not utilize online data 

interface

Time commitment 

required for monitoring 

and management of plug 

loads

Staff did not have the 1–2 

hours needed per week

Staff did not have the 1–2 

hours needed per week

Nonenergy 

Benefits

PLM solution results in 

increased equipment 

life, early detection of 

device failure, awareness 

of energy use trends 

resulting in savings not 

attributed to controls, 

staff become educated 

about and engaged in 

energy management, 

and other related 

benefits

None

This pilot was a good way 

to engage staff about plug 

load energy use.

(Location A)

(Location B)

A. QUANTITATIVE RESULTS

The quantitative findings for both of the test locations are summarized in Table 8. 

Table 8: Quantitative Results

Site

Baseline Performance 

(annual energy use, all 

monitored devices)

Technology Performance 

(potential annual energy 

savings)

% Savings 

Compared to 

Baseline

Test Location A 9,673 kWh/year 1,040 kWh/year 11%

Test Location B 15,215 kWh/year 2,730 kWh/year 18%

Average 12,444 kWh/year 1,885 kWh/year 15%

Not all devices with potential for savings via control strategies were included in the control period due to a 

number of factors—the test site opted a particular device type or device category out of control for 

functional purposes or operational considerations (they were concerned about not having reliable access to 

that device or about the impact of having to restart a device); staff at the test site unplugged the device 

from the intelligent socket, thus disabling the ability to control that device; the device was no longer in use 

in the store after the baseline period (and therefore could not be controlled); and, in the case of Test 
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 16

Location A, a flood after the baseline period impacted which sockets and devices were functional and 

capable of being controlled. 

The subsections below discuss the quantitative results in more detail. 

TEST LOCATION A

Test Location A experienced a flood that affected the store following the initial baseline period, 

necessitating a second baseline period (all data in this report are from the second baseline period). As a 

result of the flood, store operations as well as electrical sockets and devices were impacted. Some intelligent 

sockets and equipment were destroyed, and some intelligent sockets had to be moved to other devices and 

the data management system remapped to account for these socket moves. After the remapping, a second 

baseline period was necessary to accurately capture device energy use and savings potential based on a 

smaller subset of devices that were included in the second baseline period. Therefore, the opportunities for 

savings associated with control strategies were also reduced.

After the second baseline period, the collected data were analyzed and control opportunities identified for a 

subset of devices. Out of the 46 devices included in the baseline period, 11 were identified as being 

intended for control (see “Devices Intended for Control” in Table 9), and only five devices of those 11

devices yielded a full data set for the entire control period (see “Controlled Device Count” in Table 9). The 

other six were either unplugged by staff and/or suffered large losses of data and could not be included in 

this analysis.

Annual energy use, based on summing energy use for all device counts in the baseline period, as well as 

device counts, controlled device counts, and devices intended for control are provided in Table 9. 

Table 9: Annual Energy Use by Device Type for Test Location A

Device

Baseline

Device 

Count

Baseline 

Electricity 

Use20,21

(kWh/year)

Controlled 

Device 

Count

Devices 

Intended for 

Control

Aquarium 7 1,280 0 0

Charger 2 184 0 0

Computer 1 46 0 0

Driers 9 3,335 0 0

Fan 1 14 1 1

20 Summing measured electricity use for all monitored devices for each device type (aquarium, charger, computer, etc.).

21 A subset of data from the baseline period was used to calculate an “average week,” which was multiplied by 52 to attain annual energy use by 

device, as further described in Section II-Data Analysis.
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 17

Floor Scrubber 1 327 1 1

Grooming Table 12 89 1 6

Microwave 2 64 0 0

Monitor 3 208 0 0

Pet Food Freezer 2 597 0 0

Printer 1 77 1 1

Refrigerator 2 957 0 0

Vending Machine 3 2,495 1 2

TOTAL 46 9,673 5 11

A breakout of device energy use by device category, as measured by the intelligent sockets during the 

baseline period, is provided in Figure 6.

Figure 6: Energy Use by Device Category

Realized and projected energy savings data for the five controlled devices are provided in Table 10. The 

measured energy use for all 46 devices during the baseline period, averaged and projected for a full year, 

was 9,673 kWh/year.22 When testing the five controlled devices by applying schedules during the controls 

22 Method further explained in Section II-Data Analysis.

345 511 

3,516 5,301 

Energy Use by Device Category (kWh/year)

Office Equipment Additional Store Equipment

Kitchen Equipment Pet Care Equipment
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 18

period, the realized savings were 429 kWh/year. Applying controls to the baseline data by zeroing out that 

data during the control periods for all of the devices that were intended to be controlled is estimated to 

have potential savings of about 1,040 kWh/year—approximately 11% savings over the baseline data. Some 

external variables could not be controlled between the baseline and control periods, so the higher-thanprojected savings may be attributed to varying consumption patterns (less use of a device during the control 

period than the baseline period).

As previously mentioned, potential savings were calculated by applying a proposed schedule to baseline 

data; that is, zeroing out consumption for times when the controls would have turned the device off. 

Potential savings are calculated by taking the difference between the measured baseline and baseline with 

the control schedule applied. This method was used to calculate savings potential due to large documented 

inconsistencies between performance and energy use in the baseline versus control periods, the general loss 

of data sources between baseline and control periods (attributed to staff unplugging the device from the 

intelligent socket), and the small number of devices that were actually controlled.

Table 10: Realized and Projected Energy Savings for Controlled Devices for Test Location A

Device

Control 

Period

Device 

Count

Control Period 

Realized 

Savings 

(kWh/year)

Devices 

Intended for 

Control Count

Potential Savings, 

Estimated from 

Baseline for all 

Devices Intended for 

Control (kWh/year)

Fan 1 7.43 1 4.82

Floor Scrubber 1 318.81 1 73.41

Grooming Table 1 2.77 6 2.53

Printer 1 7.18 1 10.23

Vending Machine 1 93.25 2 949.43

TOTAL 5 429.44 11 1,040.42

Devices with control period realized savings (during the control period) larger than potential savings 

calculated from baseline (such as the fan and the floor scrubber) or smaller (vending machine) show very 

different consumption patterns from the baseline period to the control period. The usage patterns of these 

devices were unpredictable.

TEST LOCATION B

Out of the 130 devices included in the baseline period for Test Location B, 54 were identified as being 

intended for control (see “Devices Intended for Control” in Table 11), and only 19 devices of those 54

devices yielded a full data set for the entire control period (see “Controlled Device Count” in Table 11). At 

the initiation of the control period, all identified devices (54) were controlled, but during the several weeks 
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 19

that controls were activated, staff unplugged many of the intelligent sockets, thus yielding an incomplete 

data set. Only devices that were controlled for the full control period (3 weeks and 6 days for Test Location 

B) are included in this analysis. 

Annual energy use, based on summing energy use for all device counts in the baseline period, as well as 

monitored device counts, controlled device counts, and devices intended for control, are provided in 

Table 11.

Table 11: Annual Energy Use by Device for Test Location B

Device

Baseline

Device 

Count

Baseline 

Electricity 

Use23, 24

(kWh/year)

Controlled 

Device 

Count

Devices 

Intended for 

Control

Bicrome Red 4 218 1 4

Calculator 1 9 0 1

Camera 4 12 1 4

Cash Box 1 5 0 1

CD MP3 1 13 0 0

Chiller 1 3,275 0 1

Chiller Flush Refill 1 16 0 0

Credit Card Machine 7 87 0 6

Finish Blocker 1 19 1 1

Frame Buffer 1 4 0 0

Gerber Turbo 1 422 0 1

Hilco TempMaster 1 20 0 0

Hilco Ultrasonic Cleaner 1 0 0 0

23 Summing measured electricity use for all monitored devices for each device type (aquarium, charger, computer, etc.).

24 A subset of data from the baseline period was used to calculate an “average week,” which was multiplied by 52 to attain annual energy use by 

device, as further described in Section II-Data Analysis.
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 20

Hotfigure 1 0 0 0

Ionizing Gun 1 12 0 1

Lamp 6 16 5 6

Lens Tinting 1 16 1 1

Monitor 13 4,212 2 8

Pal ID 1 16 0 0

Phantom Research Lab 1 630 1 1

Printer 7 479 1 4

Ptronics 3 928 0 3

Refrigerator 2 967 0 1

Scan Gun 1 16 1 1

Stapler 1 8 0 1

Surface DeBlock 1 0 0 0

TempMaster 1 306 0 0

Trans Lenses 1 19 1 1

TV 1 5 1 1

UV Trans Meter 1 21 0 1

Vacuum 2 562 1 2

Vending Machine 1 2,083 1 1

Water Cooler 2 777 1 1

WECO Finish 1 42 0 1

TOTAL 74 15,215 19 54
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 21

A breakout of device energy use by device category, as measured by the intelligent sockets during the 

baseline period, is provided in Figure 7.

Figure 7: Energy Use by Device Category for Site B

Actual and projected energy savings data for the 19 controlled devices are provided in Table 12. The 

measured energy use for all 130 devices during the baseline period, averaged and projected for a full year, 

was 15,215 kWh/year.25 Application of controls to the 19 controlled devices resulted in realized savings of 

1,088 kWh/year. Applying controls to the baseline data by zeroing out that data during the control periods 

for all of the devices that were intended to be controlled is estimated to have resulted in potential savings of 

about 2,730 kWh/year—approximately 18% savings over the baseline data. 

Some external variables could not be controlled between the baseline and control periods, so the higherthan-projected savings may be attributed to varying consumption patterns (less use of a device during the 

control period than the baseline period). Conversely, lower-than-projected savings may be attributed to an 

increase in use of a device during the control period versus the baseline period. 

25 Method further explained in Section II-Data Analysis.

3,827 

13,678 8,941 

12 

Energy Use by Device Category 

(kWh/year)

Kitchen Equipment Office/Retail Equipment

Optometry Equipment Security Equipment
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 22

Table 12: Realized and Projected Energy Savings for Controlled Devices for Test Location B

Device

Control 

Period

Device 

Count

Control Period 

Realized 

Savings 

(kWh/year)

Devices 

Intended for 

Control 

Potential Savings, 

Estimated from 

Baseline for All

Devices Intended for

Control (kWh/year)

Bicrome Red 1 16.25 4 29.47

Calculator 0 0 1 4.59

Camera 1 2.56 4 5.36

Cash Box 0 0 1 2.63

Chiller 0 0 1 650.20

Credit Card Machine 0 0 6 30.47

Finish Blocker 1 (0.83) 1 0.06

Gerber Turbo 0 0 1 4.35

Ionizing Gun 0 0 1 5.38

Lamp 5 (36.34) 6 0.09

Lens Tinting 1 15.61 1 7.07

Monitor 2 79.68 8 187.88

Phantom Research Lab 1 132.46 1 30.83

Printer 1 63.24 4 76.95

Ptronics 0 0 3 36.30

Refrigerator 0 0 1 388.81

Scan Gun 1 3.56 1 7.52

Stapler 0 0 1 3.77

Trans Lenses 1 8.57 1 9.22
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 23

TV 1 (37.08) 1 2.38

UVTrans Meter 0 0 1 0.13

Vacuum 1 1.75 2 16.33

Vending Machine 1 762.12 1 1,001.80

Water Cooler 1 142.02 1 192.80

WECO Finish 0 0 1 35.54

TOTAL 19 1,087.73 54 2,729.93

B. QUALITATIVE RESULTS

Qualitative results, including feedback from staff associated with both of the test locations and the NREL 

authors of this study, are provided below.

TEST LOCATION A

Data were collected from the company’s lead contact for this pilot project via email. She indicated that she 

was not present for the installation—the person who was present has since left the company—but she 

indicated that it took less than a full day. She’s not aware of any impacts associated with the installation.

She indicated that the intelligent sockets are very intuitive and easy to use, and the label on them is very 

clear. She did use the online dashboard a few times, but not frequently. She indicated that if she had more 

time to dedicate to the project, she would’ve used it more often, but with her limited use, she isn’t able to 

speak to its usability. 

She identified the biggest issue associated with this pilot as a lack of dedicated staff time to manage plug 

loads based on feedback from the energy usage data measured by the intelligent sockets. She indicated that 

they ended up just measuring plug load energy use, rather than proactively using the data to effectively 

manage the loads. 

Additional feedback indicated that this pilot project experienced many issues, some of which were selfimposed and others pure bad luck. A monsoon storm caused a roof leak, which flooded portions of the 

store, damaging the building, sockets, and some equipment. One socket went missing during the project, 

presumably removed by an associate. And the highest energy-using device—a piece of equipment used to 

make tags for dogs and cats—is poorly designed, and any interruption of power damages the internal 

central processing unit (CPU). 

She felt this system required a lot of effort and oversight to keep it running and to monitor it frequently, and 

that this system is likely not a good fit for broader deployment at other stores. She indicated that associates 

tampered with the system, and that, combined with varying operational schedules and usage patterns, 

made it difficult to effectively manage the system. She felt that without adequate time to monitor the data 
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 24

and make changes in schedules, the benefits of the system are not realized. She said that for their specific 

store, plug loads are very small compared to heating, ventilating, air-conditioning, and lighting loads, and 

she felt that focusing on reducing those loads would be a better use of time and resources. 

TEST LOCATION B

A phone interview was conducted with staff familiar with the project at Test Location B—a store manager 

and the company’s lead contact for this pilot project. They indicated that the system took approximately 

three hours to install at the Honolulu store, and the impact of the installation on operations was minimal; 

vendor staff began the installation before operating hours and finished it approximately one hour after the 

store had opened. 

The staff interviewed stated that the intelligent sockets were easy to use, and that instructional material 

provided with the system very clearly explained how to reset the sockets, if needed. However, there were 

significant issues at this store associated with staff unplugging devices from the intelligent sockets and 

removing the sockets. This was in response to a couple pieces of equipment that froze or did not work as 

expected or when expected. Staff stated that they tried to reset the devices but that was ineffective at 

solving some of the problems. They did not look at the online dashboard or consult with NREL or Ibis 

Networks to further troubleshoot the problem, and eventually resorted to unplugging a large number of the 

sockets. 

Neither of the two people interviewed used the online dashboard. They didn’t see a need to monitor the 

performance of the measured devices as they believed that was happening through the vendor and NREL.

Both staff members interviewed were open to continued or expanded use of the technology in the future. 

However, additional methods to reach all store staff would need to be identified. In a retail setting with two 

to three or even more shifts, it is difficult to inform everyone of a pilot like this, including what the 

technology is, what the intent of using the technology is, how it works, and who to contact with questions or 

issues. All of this information was communicated to the store manager directly, and signage was placed 

throughout the store. However, it seems to have been insufficient. 

NREL STAFF EVALUATION

PLM System Ease of Use: 

At both test sites, the PLM system was installed and configured by vendor staff. However, the PLM system is 

simple to install and set up. Each socket needs to be configured and labeled with the individual device that is 

plugged into it. This is done via the online dashboard, using a ZigBee-based dongle to communicate with the 

gateway (via ZigBee wireless communication protocols) to recognize each socket. The gateway can be 

preconfigured by the vendor offsite or configured on site by anyone with an installation kit (a vendor is not 

required to be on site). The gateways require a wired Ethernet connection, which can be achieved with a 

mobile hotspot and WiFi-to-Ethernet adapter. The intelligent sockets are available in the following 

configurations:

1. Dual socket model with one controllable socket and one always-on socket. Both sockets have 

metering capabilities, for 120V/15A devices

2. Single socket model with meter and control capabilities, for 120V/15A devices

3. Power socket model with meter and control capabilities, for 240V/20A devices.
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 25

The PLM online dashboard has a number of useful features, as well as some that could be improved upon: 

• Data are easy to read and device energy is easily comparable.

• Schedule-based controls are moderately easy to set up and activate, although the controls must be 

activated manually through the online dashboard (i.e., if you want the controls to start at 2am on a 

specific day, then the user must activate the controls via the online dashboard at 2am on that 

specific day).

• Online dashboard features could be improved through:

o Graphing capabilities that are more intuitive

o Interval data that are easier to download. One-minute data is available, but the user must 

request one-minute data from Ibis Networks directly for time periods greater than 12 hours. 

o Control activation start times that could be set up ahead of the actual activation time, so 

controls would automatically be implemented at the specified time and date.

The PLM system triggers alerts—sent via email or SMS to a defined user—when an intelligent socket goes 

offline, and again when it comes back online. The sockets often go offline for short periods of time

(sometimes one second), but then come back online. Data are not lost during these short interruptions due 

to the socket and gateway’s ability to hold data for short periods of time and push them to the cloud after 

reconnecting. (For example, in a system of 50 sockets, a gateway can cache data for up to 8 hours.26) 

However, these short interruptions trigger alerts—sometimes many alerts—and it can be challenging to 

identify critical alerts among so many noncritical alerts.

Education and Communication:

It is very important that all occupants interacting with the PLM system:

1. Are aware of why the intelligent sockets have been installed

2. Understand how they work, the on/off equipment schedules, and how to override controls if need 

be (otherwise, personnel are likely to unplug the sockets)

3. Have a point of contact to call if any issues arise or changes to the system need to be made

4. Know to contact the point of contact if equipment is moved from one socket to another.

26 “Hardware FAQ.” Ibis Networks, accessed December 20, 2018, http://docs.ibis.io/HardwareFAQ.pdf.
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 26

C. COST-EFFECTIVENESS

The vendor provided cost estimates for the systems as deployed in each of the two test locations. The 

vendor also charges a software-as-a-service (SaaS) fee of $6 per intelligent socket per year deployed. The 

SaaS fee was applied to all sockets that were identified for control during the baseline period (for the 

assumed 10-year project lifetime).

TEST LOCATION A

Test Location A had 46 intelligent sockets and one gateway deployed. The vendor provided an estimated 

cost for this hardware of $4,545, which included labor associated with site walkthrough, device inventory 

creation, installation, and as-needed support and may also have been discounted by the vendor.27

The SaaS fee is assumed to be:

SaaS fee = 10 years * 46 sockets * $6/socket/year = $2,760

Annual electricity savings at Test Location A were estimated to be 1,040 kWh/year. Using the site’s annual 

average electricity rate of $0.12/kWh, the annual cost savings would be $124.80/year. 

The simple payback period and the SIR over the assumed project lifetime of 10 years are 58.53 years and 

0.17, respectively. 

TEST LOCATION B

Test Location B had 130 intelligent sockets and one gateway deployed. The vendor provided an estimated 

cost for this hardware of $12,063, which included labor associated with site walkthrough, device inventory 

creation, installation, and as-needed support and may also have been discounted by the vendor.

The SaaS fee is assumed to be:

SaaS fee = 10 years * 130 sockets * $6/socket/year = $7,800

Annual electricity savings at Test Location B were estimated to be 2,730 kWh/year. Using the site’s annual 

average electricity rate of $0.30/kWh, the annual cost savings would be $819/year. 

The simple payback period and the SIR over the assumed project lifetime of 10 years are 24.25 years and 

0.41, respectively. 

27 Hardware costs broken down by component can be provided by the vendor.
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 27

IV. Summary Findings and Conclusions

A. OVERALL TECHNOLOGY ASSESSMENT BASED ON FIELD STUDY

A PLM system was tested in two stores—a pet-oriented retail store located in Chandler, Arizona (Test 

Location A), and an eyewear manufacturer and retail store in Honolulu, Hawaii (Test Location B). The PLM 

system was found to be effective at reducing plug load energy use, with a projected annual plug load 

reduction of 11% and 18% in Test Locations A and B, respectively. However, the economics were not 

favorable at either test site, with Test Location A having a simple payback period of 59 years and a SIR of 

0.17 (assuming a project lifetime of 10 years). Test Location B had a simple payback period of 24 years and a 

SIR of 0.41 (assuming a project lifetime of 10 years).

However, both test sites experienced complications that negatively affected outcomes and savings 

potential. Staff at both locations unplugged devices from intelligent sockets, causing a disruption in data 

collection and limiting realized savings. One site experienced a flood, and the baseline and controls periods

were shortened. Lastly, neither site closely monitored energy data on the dashboard, which is important for 

continually finding opportunities for energy savings and for identifying issues soon after they arise (such as 

unplugged sockets). 

This PLM solution shows promise as an effective means to monitor, control, and reduce plug load energy 

use. The economics of the system are not currently cost effective; however, deployment at a site with a staff 

member who is able to actively manage the data, the sockets, and the control schedules by dedicating at 

least one to two hours per week to this effort may result in improved economics over those realized at these 

two test sites.

B. LESSONS LEARNED AND BEST PRACTICES

This PLM solution, although easy to use and seemingly low maintenance, requires regular interaction with 

both the online data management system and with building occupants to bring awareness on how to use 

the system effectively, for successful PLM and savings achievement. Personnel familiar with the test site, the 

operations at the site, and the devices being monitored need to be engaged in the study and regularly 

monitor the dashboard to assess alerts, identify potential issues, and capitalize on savings opportunities. 

They also must regularly engage with and remind building occupants of how the system works and its 

importance, and of protocols for moving devices and overriding controls if necessary. For example, there 

were instances at both test locations of staff unplugging devices from the sockets that could have been 

avoided or remedied quickly with more diligent monitoring of the system and better communication with 

staff about operational protocols. The dashboard can also be used to capitalize on nonenergy benefits, such 

as monitoring device health, which could be indicated by declining performance as measured and displayed 

in the dashboard. For example, researchers were able to identify an old refrigerator at one of the sites, due 

to the fact that the energy usage was very high, and the usage pattern did not show regular compressor 

cycles that are typically seen in newer, efficient models. However, these nonenergy benefits were not 

realized in this study.

Another important takeaway from this pilot is the importance of communicating well and often with all staff 

at the site where the PLM solution is installed. All staff, including workers from all shifts as well as janitorial 

and other service providers, must be made aware of the installation of the PLM technology, understand 
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 28

what the technology is, be clear about the intent of using the technology, know how it works, and know who 

to contact with questions or issues. Depending on the type of building the PLM technology is deployed in 

(retailer, office, etc.), staff may be limited in their time and motivation to learn about and interact with the 

system.

C. FIELD STUDY RECOMMENDATION

This PLM solution will be most cost effective when used in areas with high utility rates and/or in applications 

with a large percentage of plug loads. An organization with many facilities might find success in investing in 

this PLM solution for one site, using it to monitor and control loads, and then moving some of the sockets 

(perhaps from devices deemed not appropriate for controls) to another site for monitoring and control 

strategies. Additionally, buildings that have multiple high-energy loads—such as hotels with minirefrigerators and ice machines, or schools with window-box air conditioners—can leverage this technology 

to monitor the health of these devices and remotely turn off the devices when they are not in use. 
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 29

V. Appendices

A. MANUFACTURER CUT SHEETS
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 30
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B. TEST LOCATION A DATA

BASELINE DATA

Figure 8: Additional Store Equipment - Total Energy: 510.56 kWh ($61.27) / Year

Figure 9: Kitchen Equipment - Total Energy: 3,516.16 kWh ($421.94) / Year
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 41

Figure 10: Office Equipment - Total Energy: 344.98 kWh ($41.40) / Year

Figure 11: Pet Equipment - Total Energy: 5,300.99 kWh ($636.12) / Year
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 42

CONTROL DATA

Figure 12: Additional Store Equipment - Realized Savings: 318.81 kWh ($38.26) / Year

Figure 13: Kitchen Equipment - Realized Savings: 93.25 kWh ($11.19) / Year

Figure 14: Office Equipment - Realized Savings: 14.61 kWh ($1.75) / Year
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 43

Figure 15: Pet Equipment - Realized Savings: 2.77 kWh ($0.33) / Year

PROJECTED SAVINGS FOR ALL INTENDED TO BE CONTROLLED DEVICES

Figure 16: Additional Store Equipment - Potential Savings Projected from Baseline: 73.41 kWh

($8.81) / Year

Figure 17: Kitchen Equipment - Potential Savings Projected from Baseline: 949.43 kWh 

($113.93) / Year
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 44

Figure 18: Office Equipment - Potential Savings Projected from Baseline: 15.05 kWh ($1.81) / Year

Figure 19: Pet Equipment - Potential Savings Projected from Baseline: 2.53 kWh ($0.30) / Year
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C. TEST LOCATION B DATA

BASELINE DATA

Figure 20: Kitchen Equipment - Total Energy: 3,827.35 ($1,148.21) / Year

Figure 21: Office/Retail Equipment - Total Energy 8,941.23 kWh ($2,682.37) / Year
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Figure 21 (continued): Office/Retail Equipment - Total Energy 8,941.23 kWh ($2,682.37) / Year

Figure 21 (continued): Office/Retail Equipment - Total Energy 8,941.23 kWh ($2,682.37) / Year
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 47

Figure 21 (continued): Office/Retail Equipment - Total Energy 8,941.23 kWh ($2,682.37) / Year

Figure 21 (continued): Office/Retail Equipment - Total Energy 8,941.23 kWh ($2,682.37) / Year
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 48

Figure 21 (continued): Office/Retail Equipment - Total Energy 8,941.23 kWh ($2,682.37) / Year

Figure 22: Optometry Equipment - Total Energy 13,677.5 kWh ($4,103.25) / Year
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Figure 22 (continued): Optometry Equipment - Total Energy 13,677.5 kWh ($4,103.25) / Year
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Figure 22 (continued): Optometry Equipment - Total Energy 13,677.5 kWh ($4,103.25) / Year
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Figure 22 (continued): Optometry Equipment - Total Energy 13,677.5 kWh ($4,103.25) / Year
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Figure 22 (continued): Optometry Equipment - Total Energy 13,677.5 kWh ($4,103.25) / Year
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Figure 22 (continued): Optometry Equipment - Total Energy 13,677.5 kWh ($4,103.25) / Year
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 54

Figure 22 (continued): Optometry Equipment - Total Energy 13,677.5 kWh ($4,103.25) / Year
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 55

Figure 22 (continued): Optometry Equipment - Total Energy 13,677.5 kWh ($4,103.25) / Year

Figure 22 (continued): Optometry Equipment - Total Energy 13,677.5 kWh ($4,103.25) / Year

Figure 23: Security Equipment - Total Energy: 11.56 kWh ($3.47) / Year
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CONTROL DATA

Figure 24: Kitchen Equipment - Realized Savings: 904.14 kWh ($271.24) / Year

Figure 25: Office/Retail Equipment - Realized Savings: 107.59 kWh ($32.27) / Year
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Figure 26: Optometry Equipment - Realized Savings: 139.27 kWh ($41.78) / Year

Figure 26 (continued): Optometry Equipment - Realized Savings: 139.27 kWh ($41.78) / Year
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Figure 26 (continued): Optometry Equipment - Realized Savings: 139.27 kWh ($41.78) / Year

Figure 27: Security Equipment - Realized Savings: 2.56 kWh ($0.77) / Year

PROJECTED SAVINGS FOR ALL INTENDED TO BE CONTROLLED DEVICES

Figure 28: Kitchen Equipment - Potential Savings from Baseline: 1,194.6 kWh ($358.38) / Year
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Figure 29: Office/Retail Equipment - Potential Savings Projected from Baseline: 325 kWh ($97.5) / 

Year

Figure 29 (continued): Office/Retail Equipment - Potential Savings Projected from Baseline: 325 

kWh ($97.5) / Year
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 60

Figure 29 (continued): Office/Retail Equipment - Potential Savings Projected from Baseline: 325 

kWh ($97.5) / Year

Figure 30: Optometry Equipment - Potential Savings Projected from Baseline: 816.16 kWh 

($244.85) / Year
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Figure 30 (continued): Optometry Equipment - Potential Savings Projected from Baseline: 816.16

kWh ($244.85) / Year
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 62

Figure 30 (continued): Optometry Equipment - Potential Savings Projected from Baseline: 816.16

kWh ($244.85) / Year

Figure 30 (continued): Optometry Equipment - Potential Savings Projected from Baseline: 816.16

kWh ($244.85) / Year
PLUG LOAD MANAGEMENT SYSTEM FIELD STUDY 63

Figure 31: Security Equipment - Potential Savings Projected from Baseline: 5.36 kWh ($1.61) / 

Year