Berkeley Lab Researchers Are Developing Energy-Efficient Digital Network Technology

BERKELEY, CA —Scientists at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) are working with industry to develop technologies to make electronic networks — whether they are used for the Internet, consumer electronics, or both — more energy-efficient. They are also developing specifications and information programs to speed the adoption of energy-efficient technologies in the marketplace.

	John Busch, is a scientist in Berkeley Lab’s Environmental Energy Technologies Division and the principal investigator for the Energy-Efficient Digital Networks project.

“The purpose of this research is to reduce electricity use of electronics used in digital networks,” says John Busch, a scientist in the Environmental Energy Technologies Division and the project’s principal investigator.

Studies suggest that total energy consumption of electronics in the U.S. is more than 70 trillion watt-hours per year (TWh/yr) of electricity, costing billions of dollars, and equivalent to at least 50 million metric tons of carbon dioxide emissions per year. Most of these electronics are already networked, and the number of devices continues to grow.

Some estimates suggest that one-third of this energy could be saved with full use of power management on desktop computers, currently the most common of devices on the Internet.  

However, a lot of PCs don’t use their power management features, often because they don’t stay connected to the Internet when they go into power-saving modes. Also, the number of power-consuming electronic devices used to connect to the Internet in homes is increasing.

Thanks to funding from the California Energy Commission’s Public Interest Research Program (PIER) and the U.S. Environmental Protection Agency, Berkeley Lab scientists have begun studying a variety of ways to reduce the energy use of computer networks. The Commission’s PIER funding is $1.3 million.

The project has three components related to networks, and three addressing consumer electronics.

“Most Ethernet links never vary the rate at which data is transmitted, even if very little data is moving along the link. Higher data rates require more power, so increasing energy is being used to transmit small amounts of data most of the time,” says Mike Bennett of the Lab’s Information Technology Division. Berkeley Lab researchers are working with private-sector companies to standardize a technology called “adaptive link rate (ALR).” ALR allows network links to switch speeds quickly in response to changes in data transmission rates, which will save substantial amounts of energy.

Keeping sleeping PCs connected

Bruce Nordman is the principal contact for the Energy-Efficient Digital Networks project

Another project component will look for a way to allow a PC to maintain a continuous network presence even when it’s in sleep mode. “Many PCs in commercial buildings today don’t use their power management controls [which puts the PC into sleep mode after a period of inactivity] because they lose their network connectivity,” says Berkeley Lab researcher Bruce Nordman.

This project will examine proxying as an energy-saving strategy: transferring the sleeping PC’s network connectivity to a built-in network interface or an external device such as the local network switch. This proxy responds to routine network traffic as the PC sleeps, and it awakens the PC only when necessary.

A third project component will develop energy-efficient specifications for network equipment, which could be adopted by organizations like Energy Star to help manufacturers and consumers move to more efficient technology.

Making the black boxes more energy-efficient

Three tasks are aimed at making consumer electronics more efficient. One aims to get more use out of energy-saving technologies already present in the standard but not widely used in products. Another will focus on making it easier for consumers to put products in the “sleep” and “off” states when they use handheld remote controls and other control devices, and to automate transition to these states when the devices are not in use.

One project is studying set-top boxes (STBs), which control the transmission of digital video and audio. “Energy use by STBs is increasing rapidly,” says Environmental Energy Technologies researcher Alan Meier. “Consumers are using them to allow reception of digital, high-definition content. More homes have multiple STBs, manufacturers are equipping them with more functions, and STBs are controlling an increasing number of other products. In this project, we are identifying ways to increase the energy efficiency of these devices.”

Finally, a market-oriented component will provide builders with lists identifying the most energy-efficient models of hard-wired and builder-installed equipment to specify in new homes. “Previous Berkeley Lab research shows that new types of builder-installed products, such as structured wiring systems for smoke alarms, doorbells, and garage door openers and other remotely operated devices are significantly increasing energy consumption by these products,” says division researcher Rich Brown. “This will help builders install the most energy-efficient equipment.”

Berkeley Lab is a U.S. Department of Energy national laboratory located in Berkeley, California.  It conducts unclassified scientific research and is managed by the University of California. Visit our Website at www.lbl.gov.

Additional Information

• For more information on the Energy-Efficient Digital Networks project, see: http://efficientnetworks.lbl.gov/enet.html