WSU Energy Program Logo
Bonneville Power Administration Logo
  • Home
  • About
  • Database
      • Browse
      • Energy Systems
        • Building Envelope
        • Electronics
        • HVAC
        • Irrigation
        • Lighting
        • Motors & Drives
        • Multiple Energy Systems
        • Power Systems
        • Process Loads & Appliances
        • Refrigeration
        • Transportation
        • Water Heating
      • Sector
        • Agricultural
        • Commercial
        • Industrial
        • Residential
        • Utility
  • TAG Portal
      • 2017 Residential Lighting TAG (#14)
      • 2016 Multifamily Building TAG (#13)
      • 2015-1 Commercial HVAC TAG (#11)
      • 2014 Residential Building TAG (#10)
      • 2014 Commercial Building TAG (#9)
      • 2013 Information Technology TAG (#8)
      • 2013 ALCS TAG (#7)
      • 2012 Smart Thermostat TAG (#6)
      • 2012 LED Lighting TAG (#5)
      • 2011 Energy Management TAG (#4)
      • 2010 HVAC TAG (#3)
      • 2009 HVAC TAG (#2)
      • 2009 Lighting TAG (#1)
  • Webinars
    • Webinar Archives
  • Glossary
>

Summary

Intelligent Power Strip

Power Strip: Intelligent vs. Always On

Automation is used to control a power strip that turns off power to unused equipment using control strategies including master switching of related peripherals, sensing equipment in standby mode and occupant sensing.

Synopsis:

Devices that draw energy even when they are not being used can account for a substantial portion of the electricity used in homes and commercial buildings. Between 9% and 15% of residential electricity use and 30% of commercial electricity use may be due to these “plug loads,” and these numbers are increasing.
Even though some devices are becoming more efficient, the extra economy of plugging them into a power strip that shuts them off after they have not been in use for a specified period of time is predicted to save 25 to 180 kWh in offices and 25 to over 100 kWh in homes annually.

A strip from Enmetric offers multiple control strategies for each plug and allows scheduled and load-sensing options.  Multiple power strips can be controlled from a website and are openADR-compliant for use with demand response.  The National Renewable Energy Laboratory studied it and found scheduling devices saved the most energy—22-48% depending on the type of device.  Cost is about $100 per strip but payback varies widely—from 1-50 years.  Note that this is not an endorsement for Enmetric, but rather an example of a more advanced product that has had studied by a reputable research organization recently.  
As the smart grid is further developed, such strips can respond to price signals from utilities and decide when it is most economical to operate, in addition to responding to on-site needs.  

Energy Savings: 28%
Energy Savings Rating: Approved Measure  What's this?
LevelStatusDescription
1Concept not validatedClaims of energy savings may not be credible due to lack of documentation or validation by unbiased experts.
2Concept validated:An unbiased expert has validated efficiency concepts through technical review and calculations based on engineering principles.
3Limited assessmentAn unbiased expert has measured technology characteristics and factors of energy use through one or more tests in typical applications with a clear baseline.
4Extensive assessmentAdditional testing in relevant applications and environments has increased knowledge of performance across a broad range of products, applications, and system conditions.
5Comprehensive analysisResults of lab and field tests have been used to develop methods for reliable prediction of performance across the range of intended applications.
6Approved measureProtocols for technology application are established and approved.
Simple Payback, New Construction (years): 3.0   What's this?
Simple Payback, Retrofit (years): 3.0   What's this?

Simple Payback is one tool used to estimate the cost-effectiveness of a proposed investment, such as the investment in an energy efficient technology. Simple payback indicates how many years it will take for the initial investment to "pay itself back." The basic formula for calculating a simple payback is:

Simple Payback = Incremental First Cost / Annual Savings

The Incremental Cost is determined by subtracting the Baseline First Cost from the Measure First Cost.

For New Construction, the Baseline First Cost is the cost to purchase the standard practice technology. The Measure First Cost is the cost of the alternative, more energy efficienct technology. Installation costs are not included, as it is assumed that installation costs are approximately the same for the Baseline and the Emerging Technology.

For Retrofit scenarios, the Baseline First Cost is $0, since the baseline scenario is to leave the existing equipment in place. The Emerging Technology First Cost is the Measure First Cost plus Installation Cost (the cost of the replacement technology, plus the labor cost to install it). Retrofit scenarios generally have a higher First Cost and longer Simple Paybacks than New Construction scenarios.

Simple Paybacks are called "simple" because they do not include details such as the time value of money or inflation, and often do not include operations and maintenance (O&M) costs or end-of-life disposal costs. However, they can still provide a powerful tool for a quick assessment of a proposed measure. These paybacks are rough estimates based upon best available data, and should be treated with caution. For major financial decisions, it is suggested that a full Lifecycle Cost Analysis be performed which includes the unique details of your situation.

The energy savings estimates are based upon an electric rate of $.09/kWh, and are calculated by comparing the range of estimated energy savings to the baseline energy use. For most technologies, this results in "Typical," "Fast" and "Slow" payback estimates, corresponding with the "Typical," "High" and "Low" estimates of energy savings, respectively.

Status:

Details

Intelligent Power Strip

Power Strip: Intelligent vs. Always On

Automation is used to control a power strip that turns off power to unused equipment using control strategies including master switching of related peripherals, sensing equipment in standby mode and occupant sensing.
Item ID: 27
Sector: Residential, Commercial
Energy System: Multiple Energy Systems--Energy Management
Technical Advisory Group: 2011 Energy Management TAG (#4)

Synopsis:

Devices that draw energy even when they are not being used can account for a substantial portion of the electricity used in homes and commercial buildings. Between 9% and 15% of residential electricity use and 30% of commercial electricity use may be due to these “plug loads,” and these numbers are increasing.
Even though some devices are becoming more efficient, the extra economy of plugging them into a power strip that shuts them off after they have not been in use for a specified period of time is predicted to save 25 to 180 kWh in offices and 25 to over 100 kWh in homes annually.

A strip from Enmetric offers multiple control strategies for each plug and allows scheduled and load-sensing options.  Multiple power strips can be controlled from a website and are openADR-compliant for use with demand response.  The National Renewable Energy Laboratory studied it and found scheduling devices saved the most energy—22-48% depending on the type of device.  Cost is about $100 per strip but payback varies widely—from 1-50 years.  Note that this is not an endorsement for Enmetric, but rather an example of a more advanced product that has had studied by a reputable research organization recently.  
As the smart grid is further developed, such strips can respond to price signals from utilities and decide when it is most economical to operate, in addition to responding to on-site needs.  

Baseline Example:

Baseline Description: Home theater and computer equipment with manual switching
Baseline Energy Use: 0.4 kWh per year per square foot

Comments:

The Northeast Energy Efficiency Partnership study found that residences averaged 603 kWh/year of entertainment equipment energy use and 198 kWh/year of computer equipment energy use (Northeast Energy Efficiency Partnership, 2012 Pg 6).  The average square footage of homes, including single-family and manufacturers, is 1920 square feet (David Baylon, 9/1/2012).  So the average plug load energy use per square foot is 0.42 W/sf. 

Manufacturer's Energy Savings Claims: Currently no data available.
Best Estimate of Energy Savings:

"Typical" Savings: 28%
Energy Savings Reliability: 6 - Approved Measure

Comments:

The Northwest Power and Conservation Council, in 2013, approved a deemed savings for residential advanced power strips of 100 kWh/year, to expire in August, 2015.  (NWPCC Regional Technical Forum, 2013).  

The US Navy studies the impact of advanced power strips in 30 homes and one office for 100 people.  In the office, they found plug load energy use dropped by 28% due to reduced operation evenings and weekends.  (Hardesty, 2014)

The Pennsylvania Public Utility Commission "Technical Reference Manual" (June 2014) provides formulas for determining energy savings from a wide range of efficiency measures.  For Smart Power Strips, they assume an annual electrical energy savings 62.1 kWh/year for a 5-plug unit connected with an entertainment center and 74.5 kWh/year for a 7-plug unit used with an entertainment center.  Many homes have a computer workstation (computer, monitor, printer) plus one or more entertainment centers that can be controlled with smart strips or smart plugs.

Note: This is a deemed commercial measure under the October 1, 2014 BPA "Energy Efficiency Implementation Manual".  The deemed amount is $15 per strip. 

Energy Use of Emerging Technology:
.3 kWh per square foot per year What's this?

Energy Use of an Emerging Technology is based upon the following algorithm.

Baseline Energy Use - (Baseline Energy Use * Best Estimate of Energy Savings (either Typical savings OR the high range of savings.))

Technical Potential:
Units: square foot
Currently no data available.
First Cost:

Installed first cost per: square foot
Emerging Technology Unit Cost (Equipment Only): $0.03
Emerging Technology Installation Cost (Labor, Disposal, Etc.): $0.00
Baseline Technology Unit Cost (Equipment Only): $0.00

Comments:

The National Renewable Energy Laboratory's testing found the cost ranged from $19 to $70, with a median of $30.  (Earle, 2012 Pg 4)

Assume the use of two power strips for entertainment centers for each 1,920 sf home.  Cost is then $0.03 per square foot.

Cost Effectiveness:

Simple payback, new construction (years): 3.0

Simple payback, retrofit (years): 3.0

What's this?

Cost Effectiveness is calculated using baseline energy use, best estimate of typical energy savings, and first cost. It does not account for factors such as impacts on O&M costs (which could be significant if product life is greatly extended) or savings of non-electric fuels such as natural gas. Actual overall cost effectiveness could be significantly different based on these other factors.

Reference and Citations:

LBNL, 2013. Standby Power - LBNL
Lawrence Berkeley National Laboratory

Scott Kessler, 06/14/2012. Advanced Power Strip Research Report
New York State Energy Research and Development Authority

Catherine Mercier, 11/15/2010. Tapping into Commercial Office Plug Load Savings: How Can We Reduce Energy Consumption of Plug Load Devices Through Changes to Hardware, Software & Occupant Behavior?
Ecos Consulting

Ecova, 2013. Survey of Plug Loads
EfficientProducts.org

David Baylon, et. al., 2012. Residential Building Stock Assessment Reports
Northwest Energy Efficiency Alliance & Ecotope

NWPCC Regional Technical Forum, 08/20/2013. RTF Unit Energy Savings (UES) Measures
Northwest Power and Conservation Council

National Renewable Energy Laboratory, 09/25/2014. Saving Energy Through Advanced Power Strips
National Renewable Energy Laboratory

L. Earle, 08/12/2012. Results of Laboratory Testing of Advanced Power Strips
National Renewable Energy Laboratory
Special Notes: Delivered at the ACEEE Summer Study. Co-author is B. Sparn.

Linda Hardesty, 04/27/2014. NREL, US Navy Reduce Plug Loads
Energy Manager Today

Northeast Energy Efficiency Partnership, 01/01/2012. Advanced Power Strips Deemed Savings Methodology
Northeast Energy Efficiency Partnership

Rank & Scores

Intelligent Power Strip

2011 Energy Management TAG (#4)


Technical Advisory Group: 2011 Energy Management TAG (#4)
TAG Ranking:
Average TAG Rating:
TAG Ranking Date:
TAG Rating Commentary:

Contact
Copyright 2023 Washington State University
disclaimer and privacy policies

Bonneville Power Administration Logo