Newly manufactured models of external power supplies (EPS)—those small black boxes connected to many of the electronics in your home—will now be a lot more energy efficient thanks to new energy efficiency standards from the Department of Energy (DOE). The amended efficiency standards, which are expected to cut EPS power use by 33 percent, have applied to units manufactured or imported since February 10, 2016. DOE estimates that over the next three decades, these standards will decrease energy consumption nationwide by 93 billion kilowatt hours and reduce CO2 emissions by 47 million metric tons—equivalent to the yearly emissions from about 10 million cars. In addition to the environmental benefits these new standards bring, consumers will also save money on their energy bills—about $300 million annually. Energy Secretary Ernest Moniz said of the efficiency standards, “Appliance efficiency standards and high quality appliances go hand-in-hand, and represent a huge opportunity to help families and businesses save money by saving energy.”

These EPS standards represent even more progress toward the President's goal of reducing CO2 emissions by 3 billion metric tons by 2030 through efficiency standards. Standards already adopted during this administration are expected to reduce emissions by 2.2 billion metric tons through 2030 and save consumers and businesses about $447 billion over the life of the products. Previous HVAC efficiency standards addressed a major source of building energy use: heating and cooling. Lighting standards and the new EPS standard are addressing another major source of energy consumption: "plug load," also known as "phantom loads” or “vampire loads."

External power supplies waste a lot of energy each year. Although the EPS on your laptop’s charger may not use that much energy, the combined energy consumption from the estimated 1 billion such devices in the United States makes a big impact. That number continues to grow as around 340 million new adapters are shipped out every year, adding about two more units to each home in the United States. What exactly do these little black boxes on your electronics do to consume so much energy?

An external power supply is a power circuit that converts the 110 volt alternating current (AC) that comes from your home’s wall outlets to low voltage direct current (DC), perfect for powering your cell phone, tablet, laptop, Bluetooth device, or game console. Even when not in use, many plugged in electronic devices and appliances continue to consume electricity on “standby” mode, which represents 5-10 percent of a household’s energy use, according to DOE’s Lawrence Berkeley National Laboratory, and roughly 1 percent of global CO2 emissions. Slowly and silently drawing electricity, it’s easy to see why external power supplies have been called energy vampires.

The Energy Independence and Security Act (EISA) of 2007 (Public Law 110-140) mandated efficiency improvements for one type of power supply (Class A), a narrow range of products compared to those available today. In February 2014, the initial efficiency standards were updated to apply to a broader range of EPS products and levels of energy efficiency. Class A products were categorized into 4 new classes with higher efficiency levels, Classes B, C, D, and E. In these new groups, there is a large decrease in the allowable standby power for high volume applications.

The final rule incorporated feedback from multiple stakeholders, including consumer, industry, and environmental groups in an effort to balance energy savings with technological and economic feasibility. These new energy efficiency standards show that even seemingly small, incremental changes in policy can have a big impact. Along with introducing more renewables into the grid, increasing energy efficiency is a cost effective way to fight climate change, clean our air, and reduce energy bills for consumers.


Author: Anthony Rocco