Plug load controls

Published: February 6, 2014

  • OVERVIEW
  • GUIDELINES
  • BENEFITS & BARRIERS
  • IMPACT
  • CASE STUDIES
  • REFERENCES

Plug load is generated from all the devices that are plugged into electrical sockets in a building. Many of these devices continue to use energy even when they are idle. While they may be designed to use less energy when not in use, they don't turn off completely. Enabling the power management settings on electronic equipment, so they draw less energy when they are idle, and using advanced power strips to turn them off completely when they're not in use for extended periods of time will save energy and reduce costs. In offices, additional savings come from employing strategies to manage server plug load.

Advanced plug load controls

The equipment that we plug into wall sockets in our homes and offices contributes significantly to the amount of energy we use.

Plug load from household electronics can account for as much as 25 percent of a household’s energy use. In office buildings constructed to code (and no more) plug loads typically account for 25 percent of total electricity use while in those buildings that have energy efficient lighting, heating and cooling, plug load can account for as much as 50 percent of electricity use.

Low-cost strategies for managing plug load (enabling power management settings and using advanced power strips) have the potential to save as much as 40 percent of the energy used by this equipment.

Key components

Advanced power strips

Select the power strip that works best for you:

Timer power strip: power strip turns off automatically based on a pre-set schedule.

Activity monitor power strip: power strip has an occupancy sensor and turns off outlets if no activity is detected.

Remote switch power strip: power strip can be turned off using a remote switch.

Master-controlled power strip: power strip automatically turns off peripheral devices (plugged into the controlled outlets) when the primary device is turned off by the user.

Masterless power strip: power strip turns off power to all outlets when all of the controlled devices are turned off.

Power management settings

Enable power management settings on home and office equipment. Newer desktop computers, laptops, monitors, and printers/copiers come with power management features that power down the equipment if it is idle for a period of time.

Set computers and laptops to sleep after 15 – 60 minutes of inactivity.

Set monitors to sleep after 5 – 20 minutes of inactivity.

Set printers/copiers to sleep after 30 – 60 minutes of inactivity.

Sector(s)

commercial
residential

Implementation costs

Advanced power strips: $30 - $70

Potential energy savings

Offices: 20% - 40% of plug load energy use; Homes: 5% - 15% of plug load energy use

Market barrier(s)

lack of technical knowledge
technological barriers

At work:
Use advanced power strips to turn off computers, monitors, imaging equipment and computer peripherals when they are not being used.

Enable power management settings on computers, laptops, monitors, and imaging equipment.

Manage server plug load with simple low-cost to higher cost more complicated strategies. Simple low-cost solutions include:


  • Turning off unused servers
  • Increasing temperature setpoints to the high end of ASHRAE’s recommended limit
  • Managing airflow—installing blanking panels and blocking holes between server racks

Higher cost but still cost effective solutions include:

  • Implementing server power management
  • Consolidating and virtualizing applications

At home:
Use advanced power strips to turn off TVs, computers, computer monitors, printers, DVD players, game consoles, cable boxes and other electronic devices that draw energy even when they are not in use.

Enable power management settings on computers, laptops, monitors and printers.

Benefits

Reduce energy waste

Save money on utility bills

Challenges and market barriers

Choose the right power strip There are a variety of smart power strips on the market. Some are more intuitive than others and it is important to select the appropriate smart power strip for the devices being managed and for how they are used. If the user becomes frustrated because devices are not available when needed, it's more likely that they'll bypass the power strip. Like a programmable thermostat, the smart power strip must be used to save energy.

Lack of knowledge In households, occupants often lack knowledge about which of their electronic devices are good candidates for smart power strips or how to adjust the power management settings on their computers, laptops and printers.

Need a champion In offices, generally a champion is needed to inventory plug-load devices and how they're used and to craft the appropriate strategy for managing those devices. Without a champion, it is more difficult to get buy-in from management for implementing solutions and from office colleagues who might bypass the solutions if they don't work for them.

State impact

We took a high-level look at the potential energy savings in Wisconsin from plug load controls. The estimate is meant to provide a sense of scale showing the impact this technology might have on Wisconsin energy customers.

To estimate statewide impacts, we assumed that plug load controls would be a retrofit opportunity for both residential and commercial applications. The technical savings rate is estimated to be 20% for residential applications and 30% for commercial applications. We assumed that 30% of plug loads would be applicable for controls.

All data used for these estimates are from the Wisconsin Energy Statistics (2012), and Department of Energy's Commercial Energy Consumption Survey data (2003) and Residential Energy Consumption Survey (2009).

Available incentives

Currently there are no direct incentives in Wisconsin for plug load controls.

Electricity Savings Opportunities for Home Electronics and Other Plug-In Devices in Minnesota Homes

Seventhwave (formerly Energy Center of Wisconsin) conducted a field study in Minnesota to determine how much energy is used by plugged-in devices in homes. As a result of metering more than 700 devices in 50 homes, the study concluded that plug-in devices (excluding major appliances and lighting) consume 15% - 30% of a typical home's electricity use. The study also concluded that the single most effective change a homeowner could make to reduce this energy use, was to aggressively enable the power management settings on their computers.
link http://www.seventhwave.org/publications/electricity-savings-opportunitie...

Advanced Power Strips Decrease Energy Consumption
Through its Green Proving Ground program, the General Services Administration assessed the effectiveness of using advanced power strips to manage plug load energy use in offices. They evaluated three types of load reduction strategies: schedule timer control, load-sensing control and a combination of the two. Schedule-based controls reduced plug loads at workstations by 26% even with advanced computer power management in place. This strategy reduced plug load in printer rooms and kitchens by nearly 50%.
link http://www.gsa.gov/graphics/pbs/PlugLoadControl_508c.pdf

"Plug Load Control," GSA - Green Proving Ground, accessed February 12, 2014.
link http://www.gsa.gov/portal/content/121203

"Plugging into savings" Energy Center of Wisconsin, accessed February 18, 2014.
link http://www.seventhwave.org/publications/electricity-savings-opportunitie...

"Plug Load Best Practices Guide: Managing Your Office Equipment Plug Load," New Buildings Institute and Public Interest Energy Research, accessed March 3, 2014.
link http://newbuildings.org/sites/default/files/PlugLoadBestPracticesGuide.pdf

"Reducing Office Plug Loads through Simple and Inexpensive Advanced Power Strips," National Renewable Energy Laboratory, accessed March 3, 2014.
link http://www.nrel.gov/docs/fy13osti/57730.pdf

"Smart Plug Strips: Draft Report," ECOS, accessed April 29, 2014.
link http://efficientproducts.org/reports/smartplugstrip/Ecos-Smart-Plug-Stri...