“Most energy use in personal computers takes place when no one is there,” says Bruce Nordman, a researcher in the Environmental Energy Technologies Division of Lawrence Berkeley National Laboratory (Berkeley Lab). Summing up what many probably intuit but don’t think much about, PCs are fully on and using considerable energy even if they are idle. This is also true of game consoles and set-top boxes. And this is wasted energy.
Sleep modes that dramatically reduce PC power use have been available for many years, but this does not reduce the waste of energy if the PC is always fully on. Reducing energy use, of course, lowers energy bills, and reduces the emissions of climate-changing greenhouse gases.
Residential and commercial buildings use more than 70 percent of the 3,600 terawatt-hours (trillion watt-hours, TWh) of electricity used in the U.S. each year. Electronics already account for more than 10 percent of a building’s electricity. More than half of this load (currently at least 150 TWh/year) is digitally networked, and the portion is rising.
Today’s sleep mode cannot be used if a PC needs to stay connected to the Internet because it can’t engage in ongoing conversations with the network in this mode. Without the computer’s persistent network presence, it loses its connection to the Internet, and to other devices on the local network.
Nordman, who instigated a research program called Energy Efficient Digital Networks, became aware of a possible solution thanks to Ken Christensen, a faculty member of the University of South Florida, in 1997. Christensen and a colleague wrote a paper addressing the problem of how to provide power management to computers that are network-attached, which, these days, includes most PCs in the United States.
In 2003, Nordman and Christensen began collaborating on an approach to reducing the energy use of network-connected devices. Called proxying, this approach hides the sleep mode state of the device from the network.
The PC transfers its network presence operation to the proxy, a small portion of the hardware, while the rest of the computer’s hardware goes into its sleep mode, saving energy (typically 95 percent). The proxy responds to requests from the network to maintain the PC’s presence. If a larger response (such as accessing a file) is needed , the proxy will wake the rest of the PC.
“Proxying is a like your reptilian brain,” says Nordman. “It keeps your heart beating when you go to sleep, it listens for noises indicating danger and wakes you if it detects one, but it doesn’t wake you up for unnecessary reasons like birds tweeting.”
To make proxying a reality on computers in the marketplace, the researchers needed to find a way to get as many computer, printer, and other electronic device manufacturers as possible to include proxying hardware and software in their products. A key for proxying is that it does not necessarily require new hardware or increase sleep power, so it is a highly cost-effective way to save energy.
Nordman provides technical assistance to the U.S. Environmental Protection Agency’s (EPA’s) ENERGY STAR program for its efforts to define and identify the most efficient personal computers in the marketplace. In 2003 he began to champion the inclusion of network connectivity proxying in the ENERGY STAR specification. The EPA and the PC manufacturing community responded, and a growing awareness spread through the industry that here was an energy efficiency issue they needed to address, and one which had a relatively simple, inexpensive solution—with no need to develop new hardware technology.
To move the process forward, Nordman and his colleagues attended conferences and technical meetings to discuss proxying as a way of improving the energy efficiency of electronics. As an industry consensus began to build, Ecma International, a non-profit technology standards development body based in Geneva, was approached about developing an Ecma standard for network proxying.
Ecma formed a committee of experts from AMD, Apple, Hitachi, HP, Intel, Lexmark, Microsoft, Oce, Realtek, Sony, and Terra Novum, as well as Nordman, and Christensen, to develop the standard collaboratively.
After a little over a year of intensive work, Ecma International published their “Proxzzzy Standard for network connected sleep states in Information and Communications Technology (ICT) devices” as ECMA-393 on their public website for unrestricted download in April of this year.
In their announcement, the organization noted that “The energy savings potential of Proxzzzy enabled devices is measured in billions of dollars per year for PCs, and grows even larger when application to game consoles, printers, set-top boxes and other digital devices is considered.”
The announcement also quoted Katharine Kaplan, Acting Branch Chief ENERGY STAR Products at EPA, who said "This standard, the product of public/private partnership, is a great example of the leadership IT companies can offer in developing energy saving solutions that deliver users a better experience and also help to fight climate change."
The EPA will use the standard in the ENERGY STAR Computers Version 5 specification to deliver greater energy savings and will look to do the same in other ENERGY STAR categories.
Last summer, Apple became the first electronics manufacturer to incorporate network proxying into the control software of some models of its computers. In December 2009, network proxying migrated to the hardware of Apple computers. Other computer manufacturers are expected to introduce products soon.
“The standard wouldn’t have been possible without the support of the ENERGY STAR program,” says Nordman. “They provided the mechanism for getting the industry interested in and motivated to address the problem.”
“What’s particularly exciting is that technology standards are a new tool for saving energy, one with great advantage for cost-effectiveness and in ability to permeate markets,” he adds.
Made possible through funding from the CEC PIER Buildings program.