80 Plus expands podium for Bronze, Silver & Gold

Power | The Silent Front

March 19, 2008 by Mike Chin

Regular readers of Silent PC Review were introduced to the 80 Plus program in a review of the Seasonic SS-400HT, the first power supply approved by the program some three years ago. Since then, SPCR has seen and reviewed many power supplies from umpteen companies that have been 80 Plus approved. The program has helped to make energy efficiency an important aspect of computer power supply performance, and the 80 Plus mark has come to represent both green and technological advancement.

Now, the program's has been expanded with recognition of higher efficiency models using the Olympic medal colors of Bronze, Silver and Gold. It's differentiation that has been called for by many manufacturers for some time, and it may set the stage for continuing competition in the push towards ever higher efficiency.

One was not enough.

What about three?

Before we delve into the details, let's take a step back for a quick review of 80 Plus.

The 80 Plus program is essentially an electric utility-funded incentive program to integrate more energy-efficient power supplies into desktop computers and servers. It calls for a computer power supply to be 80% efficient or better at 20%, 50% and 100% of rated power, and to have a power factor of at least 0.9.

Higher efficiency PSUs typically cost $5 to $10 more than commodity power supplies. Since computer manufacturers continually seek ways to reduce costs by pennies or even fractions of pennies, this incremental cost is substantial. 80 Plus, funded by electric utilities in the U.S. and Canada, was specifically designed to overcome this market barrier by providing incentives to computer manufacturers who use the highly efficient power supplies in their products. For every desktop computer and server sold in a participating utility service territory, the program pays $5 and $10 respectively to cover the incremental cost of installing 80 PLUS certified power supplies instead of conventional power supplies.

80 Plus has been quite successful. Energy Star's Computer Specification (V4), which went into effect last July, includes 80 Plus power supply requirements for desktop computers. This effectively means that virtually every major computer maker in the US is now using 80 Plus approved power supplies for some its products. There are nearly 500 models on the 80 Plus list of approved power supplies today, and virtually every brand is represented. Funding is now abetted with fees for testing charged to the manufacturers.

Still, 80 Plus power supplies are far from ubiquitous. "We processed rebates for about 230~240,000 power supplies last year, "says Ryan Rasmussen, 80 Plus program manager,"and that is about a half percent of the 40 million desktop systems sold in the US in 2007." This does not include 80 Plus power supplies sold through retail channels to DIYers and other end-users; that number is difficult to estimate. Mr. Rasmussen says they are just starting to discuss ways to implement the 80 Plus rebate program for retail models sold through big stores and chains. In any case, until the 80 Plus movement is clearly self sustaining, Mr. Rasmussen says the rebate program is definitely worthwhile and requires the continued support of utilities and other organizations interested in this market transformation.

The new Bronze, Silver and Gold subcategories are meant to help expand the branding of 80 Plus and to enable further benefits for participating manufacturers who are moving ahead of the curve. While the three metals are obvious echos of the Olympics awards, the same scheme is used in another major green-oriented program, EPEAT - Electronic Product Environmental Assessment Tool. (See article on EPEAT in EPCR.) The Climate Savers web site uses EPEAT to identify "smarter computing products that save you money (by being more energy efficient) while helping you fight climate change". Mr Rasmussen says "Harmonization between different programs with similar environmental concerns" was the reason for the new labelling.

There are now four categories into which 80 Plus approved power supplies fall: The original, and three higher spec categories. At time of publication, there were 425 models in the general 80 Plus category, 37 in Bronze, and just one in Silver. (For early adopters, the one silver model is a reference design by NXP, not available for purchase.) The new logos may not be used in print promotion, but it's probably impossible for 80 Plus to control online use of the logos by eager marketers.

80 Plus
Power Factor
0.9 (100% load)

We recently tested a new new Enermax power supply whose model designation seems directly tied to the 80 Plus category it achieved: Modu82+ 625W. A copy of the 80 Plus report, which is not yet on the 80 Plus site, was sent with the sample; it showed 82% - 85% - 82% targets being met. Our testing results of the sample reached new highs in efficiency (albeit by only small margins).

The advanced metal categories are far enough above the base 80 Plus requirements that we're not likely to see a surge of qualifying products flooding the market any time soon. Targets prove irresistable for human beings, however, and these may well do the task they're meant to do: Encourage further innovation to accelerate computer energy efficiency improvements and bring them to market sooner at prices low enough for broad acceptance.


My only quibble with the 80 Plus program is that the qualifying tests are conducted at normal room temperature, typically 25°C. (Thermal conditions during each test are not disclosed in the test reports for public consumption.) This is fine at 20% load, but by 50% load, and certainly at 100% load, the temperature of the actual working environment for any PSU rated higher than about 300W will invariably be hotter than the typical room. Not only does a PSU have to deal with its own internal heat generated during the AC/DC conversion, but also the heat of the components in the computer system it is powering.

As some of the approved models in Bronze are rated for very high output (750W to 1200W), at 50% or 100%, the heat they're generating is prodigious. Even at 82% efficiency, the heat produced with 1000W output comes to 219W, which will invariably cause an increase in the operating temperature of the PSU and its immediate environment inside a computer. Why does this matter? The efficiency and capacity of electronic components such as capacitors decreases as temperature rises. At high loads with real applications inside a real chassis, a PSU gets hot and its efficiency tends to decline. By conducting the qualifying tests in unrealistically cool conditions, many of the higher power models that fare well in the 100% load test get off easy. A more thermally rigorous test would see fewer high power units achieve such high efficiency numbers.

Adding thermal requirements and conditions to 80 Plus could complicate testing. It may also make it more difficult to achieve 80 Plus qualification. Then, there's the question of what to do about the nearly 500 models that 80 Plus has already qualified. Still, from the perspective of realistic testing, the absence of thermal requirements in 80 Plus today seems a deficiency that should be addressed.

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