Solutions for the Plug Load Challenge

Often it’s not how we design buildings that impacts actual energy performance but what we, the occupants, do in those buildings that counts. It’s becoming increasingly clear that occupancy factors, such as behavior, have a significant impact on a building’s energy savings potential. One of these occupancy or “behavioral” factors is plug loads: the amount of energy used by devices that are plugged into wall outlets. Plug loads are one of the largest and fastest growing electric end-uses in commercial buildings in the United States. How many occupants plug in space heaters or table lamps to make their personal space more comfortable? Behavior can be a hurdle to addressing energy savings – it’s both challenging to control and complicated to measure. A recent study released by NBI and Ecova (formerly Ecos Consulting), Commercial Plug Load Savings and Assessment, tackles the challenge by looking at some of the most common plug load culprits — computers, monitors and printers. The study characterizes the energy consumption of plug load devices for two commercial buildings in California and explores strategies to cut plug load energy use.Conducted on behalf of the California Energy Commission’s Public Interest Energy Research (PIER) Program, the study investigated electricity consumption of plug load devices in two recently LEED‐certified buildings in California — a 95,000 ft2 public library and a 14,000 ft2 small office  – and  explored opportunities for energy savings. The research team, led by Ecova and supported by PECI and NBI, inventoried the plug loads and recorded detailed meter files on a set of small, commonly used office devices such as computers, monitors and printers.  Energy use was measured and analyzed and several savings strategies assessed. These included a variety of cost-effective strategies involving software and hardware and addressing occupant behavior.With all the recent attention paid to tenant behavior (see NBI and Ecotope’s recent Sensitivity Analysis: Comparing the Impact of Design, Operation, and Tenant Behavior on Building Energy Performance) it should come as no surprise that the research team included behavior as one of three primary strategies to reduce plug load energy consumption. This “behavior strategy” involved increasing occupant awareness of efficiency settings and encouraging users to flip the switch on power strips and turn off devices when not in use.The key takeaway? While the range of savings potential may vary widely by office, a low‐ to no‐cost approach can be the first energy savings action to reduce plug loads by 19%-40%, even in buildings already employing green and energy efficient strategies.This work supports NBI’s latest efforts in advancing deep energy savings in existing buildings. Report findings can be used to suggest savings opportunities and facilitate tenant adoption of strategies to reduce plug loads in small offices. For a complete list of energy reduction opportunities identified in the study, read the Plug Loads Executive Summary and full report. Watch the Plug Loads webinar.