Most of the more than 100 million smart speakers and video streaming devices installed in America's homes are quite energy efficient, the Natural Resources Defense Council (NRDC) said today in the first independent report on their electricity use. However, energy consumption could more than double for televisions awakened and controlled by voice commands if simple TV design improvements are not made, adding up to $2.5 billion to U.S. energy bills every year.
The NRDC report, "Energy Impacts of Smart Speakers and Video Streaming Devices," said smart speakers and streaming devices each annually consume only $1.50 to $4 worth of electricity even though they remain partially on around-the-clock, connected to the internet and waiting for a command. Most of the leading speakers tested, such as Amazon Echo's Alexa, used less than 2W of electricity in standby mode. The streaming devices, like Roku and Google Chromecast, consumed 3W or less in standby-far less than conventional set-top boxes supplied by cable, satellite and telephone companies-to access a wide variety of content.
"It's heartening to find that the millions of smart speakers and video streaming devices in use across America were designed with energy efficiency in mind,'' said Noah Horowitz, report co-author and director of NRDC's Center for Energy Efficiency Standards. "These popular devices aren't wasting energy, which means consumers benefit from lower electricity bills and less power plant pollution."
However, he cautioned the picture changes dramatically when smart speakers are linked to some new TVs, with electricity consumption mushrooming from less than 1W to more than 20W in standby mode. That can double a television's overall annual energy use and add about $200 in energy costs over a television's lifetime.
Without design improvements like those made by a few TV manufacturers, annual national electricity consumption could potentially increase by three to six large (500MW) coal-burning power plants' worth of electricity, adding as much as $1.3 to $2.5 billion to U.S. consumers' electric bills every year even if just one-fourth to one-half of all TVs are connected to smart speakers.
"Our report should be a wake-up call for all TV manufacturers to improve their products to support hands-free operation without needlessly sucking massive amounts of energy as the next big energy vampires in our homes. Up to $2.5 billion in extra electricity costs would be an appallingly high price for consumers and the environment to pay just to wake our TVs with a voice command."
NRDC retained Pacific Crest Labs to test the power use of a cross-section of smart speakers, video streaming devices, and televisions when linked to either gadget. The findings:
The Amazon Echo-2nd Generation, Apple HomePod, Google Home, and Google Home Mini smart speakers each used less than 2W in standby despite continuing to "listen" for the activating word-such as Alexa, Google, or Siri-to return to full power mode. The Harman Kardon Invoke, which uses Microsoft's Cortana voice assistant, used 3.8W. All of the devices use very little additional energy while in use. As of 2018, there were more than 50 million smart speakers installed nationally, representing $102 million in annual electricity costs.
The video streaming devices tested-Amazon Fire TV, Apple TV, Google Chromecast Ultra, and Roku Ultra-receive content via a wireless internet connection for viewing on a television. They spend most of their time in standby mode. Amazon Fire TV and Apple TV used less than 1W in standby, whereas the Google Chromecast Ultra used 2.2W and the Roku Ultra consumed 2.7W. None of the devices we tested drew more than 3.5W when streaming video.
The national annual energy use of video streaming devices totals $94 million in consumer electricity costs. If all of the devices used less than 1W in standby, Americans would save about $26 million annually. However, video streaming devices use far less electricity than traditional set-top boxes, and consumers could save about $50 a year by turning in their old set-top boxes and using streaming devices and apps instead.
Horowitz's blog on the report can be found here.