This prototype reduces CO2 emissions by nearly 300 lbs/yr relative to the Energy
This prototype reduces CO2 emissions by nearly 300 lbs/yr relative to the Energy Star standard


Energy efficient computers have the potential to significantly reduce California's electricity consumption, with a savings potential of 70% or more beyond the Energy Star standard. With most Californians using computers regularly at home and at work, this is a huge opportunity. If Californians with inefficient hardware or power management change their settings and choose more efficient computers when they upgrade, achieving 75% savings over conventional computers and monitors, Californians could save enough energy to power over 886,000 households.

But the benefits of efficient computers are not limited to energy savings. For example, the Electronic Product Environmental Assessment Tool (EPEAT) is a tiered standard similar to LEED that considers multiple sustainability factors. To qualify, a computer must address several sustainability considerations including materials selection, design for the full lifecycle, energy efficiency, and corporate sustainability policy. EPEAT certification is required for Federal agency computer purchases, and is a valuable tool in making it easy for corporations to specify efficient and environmentally friendly hardware.

There are more practical advantages to energy efficient computers as well. Setting computers to hibernate after a period of inactivity increases data security - if a person walks away from a computer, it will automatically hibernate, so content is not visible on the screen and cannot be viewed without entering the login username and password.

Energy efficient computers have numerous other advantages as well, such as less intensive fan use, resulting in quieter operation. The reduced heat generation associated with energy efficient computers also means that parts can be built smaller and closer together, improving performance. Plus, office buildings with more energy efficient computers don't require as much cooling, saving further on energy bills.

Energy efficient monitors are also a great opportunity - since LCD monitors use less power than similarly sized CRT monitors, users can simultaneously reduce their electricity consumption and benefit from a flat screen.

With so many benefits, it's no wonder that computer energy efficiency technologies are going mainstream, and that Energy Star and EPEAT certification are becoming standard practice for consumers and corporations.


Photo Credit:  Courtesy of the California Energy Commission and Ecos Consulting

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This ultimate efficiency computer can save nearly 70% relative to the Energy Sta
This ultimate efficiency computer can save nearly 70% relative to the Energy Star standard
Ultra-Efficient Computing

In 2007, Ecos Consulting, the Electric Power Research Institute, and the California Energy Commission decided to test the limits of energy efficient desktop computers. Focusing on reducing power consumption during idle and active modes, their goal was to create both market-ready and ultimate-efficiency computers that would still have good performance.

The team started by selecting the most efficient available motherboard and chips - one of the most important steps in creating an efficient computer. They used processors that can dynamically scale performance to match program requirements, saving energy when processing demands are low, and selected components with low electrical losses.

Next, the team reduced idle power consumption by an additional 25-36% by selecting efficient components. 80 Plus certified power supplies and efficient case fans saved about 7 Watts. Using a single, larger memory chip instead of two smaller ones saved another 1 or 2 Watts, without impacting performance. The team also specified a hybrid hard drive, which supplements the traditional spinning disk with a flash buffer, saving 5 or 6 Watts. New, flash-only hard drives, which have emerged since this research was completed, can save even more energy by eliminating the spinning disk altogether. Plus, these hard drives are faster than traditional hard drives, improving performance.

Putting everything together, the team found that nearly all of their prototypes had sufficient performance to run typical office software under the Microsoft Vista operating system, while consuming 40 to 70% less energy than Energy Star qualified computers.

This translates into a huge savings potential: if all U.S. enterprises adopted the ultimate efficiency computer, corporations could eliminate 11.2 million tons of CO2 emissions, save 16.7 billion kilowatt-hours, and save $1.67 billion in electricity costs.


EEC chart

Computers spend most of their time in idle mode, and efficiency improvements in this mode do not impact processing performance, so idle mode savings are an easy way to make a big impact.


Photo and Chart Credit:  Courtesy of the California Energy Commission and Ecos Consulting

This notebook is rated EPEAT Gold, the highest possible sustainability ranking
This notebook is rated EPEAT Gold, the highest possible sustainability ranking
Sustainable Procurement


At the heart of Silicon Valley, the businesses and residents of San Jose are at the forefront of computing. And as one of the ten largest cities in the United States, the City of San Jose is itself a major user of computers. So it's not surprising that as part of its sustainability initiatives, the City of San Jose decided to push the envelope in sustainable computing, becoming the first city to require purchase of EPEAT qualified computers.

San Jose was drafting an RFP for computer purchases in early 2006, just as the EPEAT standards were finalized. Even though no products were yet officially certified, they knew that about 60 models would qualify, so they decided to insert the requirement into the RFP. The requirement was a great success, and has been standard practice in the city ever since.

The city likes the EPEAT system because there are many qualified models available, there are measurable benefits, the standard covers all aspects of sustainability, and the requirement is easy to specify & implement. Plus, the city has found no difference in performance between EPEAT-certified and non-certified computers. In fact, the program has been such a success that by March 2008, the city had purchased 1,776 computers and 1,770 monitors. Thanks to their EPEAT program, by March 2008 the city had saved:

• 1.5 Gigawatt-hours of electricity
• 1 million pounds of materials
• 52,000 pounds of carbon equivalents
• 2.7 million pounds of air emissions
• 6,000 pounds of water emissions
• 60 pounds in toxic materials usage
• 2,100 pounds in hazardous waste
• $126,000



Photo Credit:  Courtesy of Sony Electronics:  SONY VAIO TT Series

Energy Star qualified computers like this one come with automatic power manageme