Efficient and Zero Net Energy-Ready Plug Loads

Plug loads are devices plugged into common electrical outlets. Modern buildings contain hundreds of these devices that when aggregated are responsible for at least 25 percent of electricity use in California buildings. The amount of electricity consumed by plug loads is increasing because the “Internet of Things” (a system of interrelated computed devices and machines that automatically transfer data over a network) is, to a great extent, the “Internet of Plug Loads.” This project developed technologies that will reduce the electricity consumption of plug loads. The project team investigated two crosscutting strategies in detail: (1) technologies to reduce standby power use to near zero, and (2) methods to increase the use of direct current as a power source. The researchers developed two new approaches to reduce standby to near zero that could apply to a wide range of devices. Prototype direct current appliances were developed to demonstrate electricity savings by bypassing power supplies and avoiding other losses. Networks of direct current-powered devices can save even more electricity and provide other benefits like resiliency during power outages. The project team also identified a unique category of electricity-using devices that provide life safety, health, and security to building occupants. The installation or use of devices in this category is dictated by building codes, health providers, insurance companies, and other entities —one of which would ordinarily prioritize energy efficiency. In the case of ground fault circuit interrupts, the project identified possible savings of 80 percent simply through adoption of the most efficient designs. Home medical equipment, particularly oxygen concentrators, is a rising category of electricity use where substantial savings are possible. This report also reviews the codes, standards, and other policies that affect electricity use of plug loads