Why PCs Should Get More Sleep

REDMOND, Wash., March 21, 2007 — A single incandescent 100-watt light bulb left on around the clock for a year costs more than US$80 to power. Generating that power releases about 1,350 pounds of carbon dioxide emissions into the atmosphere — a major contributor to global warming.

According to Dean DeWhitt, director of Microsoft’s Windows Kernel team, that is about the same amount of power many PCs consume while not in use. Yet, while few people would leave a light bulb on for a year, many people keep their PCs running with screen-savers at all hours, which actually consumes more energy than an idling PC. What’s more, many large organizations constantly leave their PCs running so they are available to receive security patches and updates.

“While education may be the key for many consumers, businesses are forced to balance cost and environmental impact against their own security and operations requirements,” says DeWhitt. “New power management features in Windows Vista are designed to help them with this challenge.”

In fact, Microsoft today announced the results of an independent study from UK-based PC Pro Labs, which looks at the energy consumption of Windows Vista and the potential reduction in carbon dioxide emissions. “Power Consumption, Windows Vista versus Windows XP” compared energy usage between Windows XP and Windows Vista, clearly showing that the power management features in Windows Vista could help reduce the carbon dioxide generated in an organization, equal to 45 tonnes per year for a 200-seat business. In addition, the study found that these features could also deliver savings on energy bills of up to £46 per desktop PC per year.

The study is based on real-world usage of desktop computers in the work environment of 800 desktop PC users. The cost savings and reduction in carbon dioxide emissions are due to the “Sleep” mode in Windows Vista, which automatically activates after one hour of non-use.

Known as Standby or Hibernate in previous versions, Sleep is a state where a machine and monitor can become available instantly if needed, but are each using only two to three watts of electricity in the meantime. While other versions of Windows have had success with standby modes, according to DeWhitt, Windows Vista’s version of Sleep provides by far the best user experience to date.

Environmental Groups Shed Additional Light

During development of Windows Vista’s power management capabilities, DeWhitt’s team sought to collaborate with the Environmental Protection Agency (EPA) and the National Resource Defense Council (NRDC) to understand how they could develop the technologies with the environment in mind.

“We heard from customers that they were very focused on the cost savings of power management features, but we knew that there could also be some benefit to the environment,” he says. “The EPA and the NRDC really helped clarify the potential environmental impact of this technology beyond the cost efficiency.”

With this knowledge, the team’s mission evolved from pure savings toward a more “green” focus on energy consumption and conservation. With environmental experts plugged into the process, the team set about delivering the best user experience possible while lowering energy use.

To explain the dramatic difference power management can make, the team published research that showed that a typical desktop PC and LCD monitor sitting idle for a year (outside of business hours) would consume 632 kilowatt hours of energy — compared to 34 in sleep mode. That’s a savings of 598 kilowatt hours per PC per year.

The NRDC’s senior scientist Noah Horowitz puts it another way. “If the majority of U.S. computer owners take advantage of the enhanced energy saving features in Windows Vista, we could easily cut our nation’s electric bill by about $500 million per year, and prevent 3 million tons of global warming pollution from being emitted from electric power plants,” he says. “This is the equivalent to preventing the pollution from 390,000 cars — approximately the number of cars in the city of Seattle.”

The implication of his point is echoed by all concerned — while the ability of Windows Vista to intelligently manage power consumption is an important piece of the puzzle, getting people to adopt power management into their computing routines is what really has the potential to create a broad impact.

“Having previewed the energy saving features of Vista, it is obvious to me that Microsoft has put a lot of effort into improving the overall power management experience,” says Steve Ryan, program manager for the EPA’s Power Management Outreach Campaign. “Also gratifying has been Microsoft’s efforts, through written articles and speaking engagements, to educate software developers and other IT professionals on the importance of power management. If everyone took full advantage of these features at home and work, our country could reduce its annual electricity use by tens of billions of kilowatt hours.”

Making Sleep More User Friendly

According to DeWhitt, the way to achieve this broad participation is by making the features easy to use and turning them on by default so users don’t have to learn or make value decisions. A number of changes implemented in Windows Vista make going into Sleep mode a seamless and natural experience, which he hopes will encourage people to take advantage of Sleep.

During use, Windows Vista also keeps close tabs on what the computer is doing, what it is running, and how busy the machine is. Windows Vista can speed the computer’s processor up when a higher level of performance is needed, and bring it back down to a low power level when the machine is less active.

The system also improves Sleep’s responsiveness. The team redesigned the way Windows Vista “remembers” its current state, making it much quicker to respond when a user puts the PC to sleep or awakens it. In fact, computers resume from Sleep in under two seconds.

“You should immediately see the screen go dark,” he says. “So it’s a really crisp, responsive experience both going into sleep and coming back.”

Centralized Management and IT Control

When it comes to environmental impact, the biggest potential for power management to make a difference lies with large organizations, which often deploy hundreds if not thousands of PCs, all of which could be saving significant amounts of energy with the new system.

But while ease of use may compel individuals to adopt good power management practices, the key for most large organizations is the ability to control power management centrally. For instance, a company can decide that PCs in their network will go to sleep after 15 minutes of inactivity.

“There are various technical and behavioral reasons why individuals and organizations do not take advantage of a system’s power management features,” says the EPA’s Ryan. “One of the things we’ve needed is an improvement in technology and a reduction to the technical barriers of implementing power management. Windows Vista is one example of improving the technology landscape.”

All of the power management features in Windows Vista are available for central IT control, and can be set or turned off however the company chooses. Windows Vista also provides the IT department with the ability to program power management settings directly into a computer’s start-up routine.

If a security patch or important update comes out and must be immediately deployed to thousands of machines, the IT department can use software such as Microsoft System Center Configuration Manager 2007 or another third-party solution to “wake” those machines so the patch can automatically be installed if the computer is connected to the network.

This helps overcome a barrier that many companies have faced in balancing power management against security of their networks, since one major reason that some companies leave their computers running all the time is that they need to have the PCs available in case an update or patch must be rapidly deployed.

According to Ryan, allowing IT pros to control power management across all PCs in a network is a simple improvement that gives large organizations the ability to create enormous value.

To explain this, Ryan points to a study by the EPA’s Energy Star program of General Electric — in 2001, the EPA began examining the impact of GE employing the power-management functionality of Windows XP and Windows 2000 across 75,000 PCs, setting monitors to shut down after 15 minutes, the PC itself after 30 minutes, and moving into a full “hibernate” mode after three hours.

The result was a savings of $2.5 million per year in energy. The EPA estimates it was enough to power 23,000 homes each year. The reduction in carbon emissions associated with that energy was estimated at 20,000 tons — the equivalent of planting 5,600 trees.

For all involved, the hope is that the vastly improved Sleep functionality developed for Windows Vista will drive many more large organizations to adopt these kinds of green technology policies.

“For the past six years, EPA has been working to increase the number of computers and monitors across the country that are actively managed in this way,” says Ryan. “While we have had much success, there is still a long way to go, with an enormous potential to save energy and help reduce greenhouse gas emissions.”

For the makers of Windows Vista, the extent to which that potential is realized boils down to the success of the team’s “people-ready” design philosophy and how users and organizations respond to the tools they’ve put in place.

“If you think about the installed base of PCs being over 600 million, the potential impact of this is mind boggling,” says DeWhitt. “Ultimately, PC users will decide how much of a difference power management can make. What we’re trying to do at Microsoft is give people a way to use personal computers that delivers a great user experience and is also a very efficient way to use personal computers. The energy savings associated with these efficiencies, scaled over millions of PC users, can really add up.”