Computers get more advanced every year. Entire industries, from integrated circuit manufacturing to software development, have grown to depend on the ever-increasing power of computers. But one area that has not improved is the amount of power it takes to run them.

The electrical outlet provides high voltage alternating current, so power supplies are needed to transform the AC power into low-voltage direct current needed for the electronic devices that make up the modern world. Power supplies can be internal to the device, as with televisions and desktop computers and servers; or they can be external, like those that come with cellular phones and laptops.

While the power “brick” has slimmed down over the last 20 years, its energy consumption remains piggish. Internal power supplies run at an average of 65 percent efficiency.

Manufacturers are capable of making far more efficient power supplies, but thus far the major computer makers, from HP and Gateway to Apple, have done little to improve that particular aspect. Increased processor speeds and ever-increasing memory are big selling points for end-users, but the advantage of having a more energy-efficient computer has not become apparent to most purchasers. Despite the real advantages, manufacturers are loathe to spend more money on the efficiency of power supplies, particularly when prices are constantly being driven lower.

In 2001, the Natural Resources Defense Council hired Ecos Consulting, a Portland-based firm focused on energy efficiency, to study power supply efficiency. The firm looked at the number of power supplies in use, basic applications and technologies, energy efficiency differences, and national energy-saving opportunities. Ecos reported that improving power supply efficiencies could save more than 1 percent of total electricity use in the United States by expanding market opportunities for already existing technology.

Ecos’ Suzanne Foster Porter said the savings are on the order of 85 kilowatt-hours (kWh) per year for a desktop computer and 300 kWh annually for each server.

“It also reduces cooling loads for the building,” she said. “They typically say it’s one cooling degree per watt.”

Multiplied by the number of computers in a typical office or server farm, the overall savings can be significant.

But the process of building consumer demand to a critical mass appeared a daunting task. In 2004, the Northwest Energy Efficiency Alliance and Ecos started the 80 PLUS Initiative to pay computer makers to pursue power supply efficiency, thus defraying the additional costs of improving the energy profile of their devices.

“80 PLUS is not a regulation, like a regulatory standard, but it’s what we call a market incentive program," Porter said. "It’s an electric utility-funded incentive program."

In addition to the direct savings from using electricity more efficiently, 80 PLUS has another significant advantage in improved power quality.

"There's the efficiency part of it, where it has an efficiency of at least 80 percent. The second benefit is that it has a power factor of 90 percent or better," said Scott Gibson, an engineer in the Energy Services Group at Snohomish County Public Utility District, north of Seattle.

Real power is the capacity of the circuit for performing work in a particular time. Due to reactive elements of the load, the apparent power, which is the product of the voltage and current in the circuit, will be equal to or greater than the real power. The power factor of an alternating current electric power system is the ratio of the real power to the apparent power. Gibson said when the power factor is kept to at least 90 percent, harmonics in the system are filtered out, resulting in much less demand for amps in the circuit.

“An 80 PLUS computer usually uses about 50 percent of the amps that a standard computer does,” Gibson said. “There’s a tiny bit of that due to the improvement in efficiency, but most of that is due to the efficiency in power factor.” 

The difference, he said, means schools can add computers without needing to rewire the building for the additional load. Unused classrooms can thus be converted into computer labs.

“Older buildings were not designed to accommodate the electric plug loads that come from these devices, so we’re not always able to install the needed number of computers in a classroom," said Ken Ainsworth, technology director for the Marysville School District in Washington state. "The reduction in energy consumption from each 80 PLUS-qualified computer ultimately means that more of our students will have access to these essential educational tools.”

Gibson said another advantage associated with the improved power factor is that building designers will be able to reduce the amount of copper in new office buildings because the more efficient 80 PLUS computers will no longer require what he refers to as "super-sized" electrical systems to support them.

“In the last 10 years, engineers and architects have been educated in how to design a building correctly to mitigate the problems caused by computers,” he said. “There’s a lot more copper used in a building because of the problems caused by computers. A lot of money goes into wiring these buildings just because of these harmonics. If the harmonics go away, then people can save a lot of money on copper. Right now you couldn’t go to an electrical design firm and tell them that they need to go back to the way that they used to wire buildings and not use so much copper.”

Although major computer makers such as Dell, HP and IBM have yet to commit to 80 PLUS standards, the U.S. Department of Energy is planning to include the standards in its Energy Star certification requirement. As of July 2007, computers will have to incorporate 80 PLUS power supplies to earn an Energy Star rating, Gibson said.