What is it?
Plug loads are pieces of equipment, usually found in office spaces, that are plugged into a standard 120V outlet. As lighting and HVAC equipment become more efficient, plug loads are consuming a greater share of office energy consumption. Computers, monitors, printers, copiers, task lighting, and water coolers are the most common plug loads. Many plug loads are uncontrolled, meaning they consume power whether someone is using the equipment or not. Instead of allowing plug loads to draw power at all times, plug load management, such as advanced power strips, computer power management software, and timers can be used to power down equipment when no one is using it.
How does it work?
These technologies use foot pedals, occupancy sensors, current sensors, and timers (physical and software-based) to determine if a person is using a computer, copier, workstation, etc. If no one activates the sensor/pedal/software after a set period of time, the outlet/strip/computer is turned off. Current sensors determine if a “master” outlet serving a computer, for example, is drawing power and if not, will shut down power to all other outlets on the strip.
What are the most appropriate applications?
Plug load management makes the most sense in office environments with multiple computers/work stations and copiers. The benefits are even greater in spaces that have desktop computers instead of laptops, and where desks have plug-in task lighting.
What are the savings?
According to a study in Minnesota, advanced power strips that use occupancy sensors to turn off outlets save 67 kWh per year per workstation, computer power management software saves 106 kWh, and a foot-pedal operated power strip saves 42 kWh.
What is the cost?
Costs for advanced power strips, computer software, and timer devices range from $17 to $55 per installation. The simple payback for computer software is two to four years, while advanced power strips have paybacks of about eight years.
What is the status/availability of the technology?
This technology is readily available through multiple vendors.
What kinds of incentives/programs are available?
Right now, this technology would typically be evaluated under prescriptive programs in most areas. Incentives will vary depending on the program, but are typically $10-20/power strip. In jurisdictions without a prescriptive program, projects with 30+ workstations might be large enough to be eligible for a custom rebate incentive.