Electronic Design

Multiple Standards Confound Power-Supply Designers

The melange of energy-efficiency standards used to be good for a “green” label. But how much difference really exists between them?

What's a poor power-supply designer to do? The U.S. alone has four standards for energy efficiency: Energy Star, Executive Order 13221 (1-W Standby), 80 Plus, and the regulations of the California Energy Commission.

Europe grapples with at least seven: the International Energy Star program, Blue Angel, the Group for Energy Efficient Appliances, the European Code of Conduct, EU Eco Label, Energy Plus, and Nordic Star. Then there's the Australia Greenhouse Office (Australia also participates in Energy Star), the China Energy Conservation Project, Korea's Energy Saving Office Equipment & Home Electronics Program, and Japan's Top Runner program. Many similarities weave through these programs, but there are enough differences to make powering a product for a global market an exercise in anxiety.

Fortunately, many of the programs are voluntary. Therefore, you could still play in those markets even if you don't meet their standby power of efficiency specs. But you won't get the compliance sticker, which would mean mean you'd most likely be positioning your brand as a "value leader" while sacrificing your profit margin.

A better approach would be to familiarize yourself with the programs out there, go to the key Web sites to get the latest updates, and then design your product to meet as many energy-friendly label criteria as practical. This should help you get yourself onto the most popular energy-program Web sites—and position your product among the green good guys.

That said, not every program is optional. The killer is California's program. If you can't prove you meet the specs, you can't sell your stuff in the Golden State. Some manufacturers recently got into a cold sweat and managed to get a six-month extension, but don't expect that to happen again.

Then there are the Japanese standards; different, practical, and frustrating—all at the same time. The Japanese pick the most efficient product in a particular market and let it set the specs that everyone else will have to live up to in a few years, at which point the goal posts will be moved again.

Across the Web, there are few resources comparing and contrasting energy-efficiency programs. One exception: Power Integrations maintains summaries and links in the Green Room section of its Web site, available at www.powerint.com/greenroom/index.html. Bookmark it. It's a good resource for further research.

In July 2001, President Bush signed Executive Order 13221, the "1-Watt Standby" Order. Under the order, federal agencies may only purchase products that meet Federal Energy Management Program (FEMP) standby energy-consumption standards.

As of January, standards were in place for desktop and laptop computers and monitors; TVs and media players; printers, scanners, and fax machines; and microwave ovens. Generally, the standards are for no more than 1-W standby power consumption. In a few instances, 2 W (desktops, fax machines, and microwaves) and even 3 W (combination TV/VCR/DVD players) are allowed.

However, if plans are for a desktop PC or other computer product to be connected to a local-area network (LAN) and operated continuously, agencies must select an Energy Star product with the lowest possible sleep power level. For a summary table, check out http://oahu.lbl.gov/level_summary.html. Manufacturers can find FEMP information at http://oahu.lbl.gov/.

The only mandatory power-consumption regulation in the U.S. that affects non-government consumers is the California Energy Commission's (CEC) Efficiency Requirements for External Power Supplies and Consumer Audio and Video Equipment Sold in California. As the California Air Resources Board has already shown, the state, with roughly 10% of the entire U.S. population within its borders, maintains the purchasing clout to affect national standards.

The above spec, currently known as CEC-400-2006-002-REV1 (July 2006), includes standby, no-load, and active-on efficiency requirements. It's available at www.energy.ca.gov/2005publications/CEC-400-2005-012/CEC-400-2005-012.PDF.

CEC-400 was adopted on December 15, 2004, and the requirements for external power supplies were to go into effect on July 1, 2006. Standards for compact audio and digital television adapters are set for Jan. 1, 2007.

These dates were a big part of the buzz at the Power Electronics Technology conference in Chicago back in November 2004 (see "California Sets Green Power-Supply Standards" at ED Online 9480 at www.electronicdesign.com).

The requirements got a mixed reception. First to complain were the set-top-box (STB) makers, who noted that their active power-consumption limit fell far below the power specifications of current products. The regulation stated that converter boxes had to consume less than 8 W in active mode and 1 W in standby.

STB makers noted that out of the entire existing base of offair-digital broadcast converters (which then comprised two boxes from Motorola, one from Zenith, one from Dexus, and two from Samsung), active power ratings ranged from 25 to 30 W. The companies insisted that if no compliant boxes were available by the end of 2006, when broadcasters were to pull the plug on analog TV, a crisis would ensue.

Then more "excitement" happened last February. According to the San Francisco Chronicle, a number of makers of "cordless phones, battery-powered drills, MP3 players, laptop computers, and other electronic devices" were "balking at new California regulations to reduce the amount of power the appliances use when charging or sitting idle while plugged into wall sockets."

In addition to the Consumer Electronics Association (CEA), other companies and organizations are asking the CEC to extend the deadlines. These include the Association of Home Appliance Manufacturers, Black & Decker, and Radio Shack. It's interesting that not every manufacturer was concerned about the original July 1, 2006 date. The Chronicle reported that Hewlett-Packard and Apple were content with the original deadlines.

As it happens, the Chronicle report was a little overwrought. In a press announcement from that period, the CEA said it welcomed an offer the CEC had placed on the table to consider delaying imposition of the standards.

Several months of tension ensued, but in the end, the CEC backed off. The July revision to CEC-400 pushed the effective date for "external power supplies used with laptop computers, mobile phones, printers, print servers, scanners, personal digital assistants (PDAs), and digital cameras" back to Jan. 1, 2007. Further, the effective date for "external power supplies used with wireline telephones and all other applications" was pushed to July 1, 2007.

Note that companies must start manufacturing external supplies that meet CEC-400 requirements by these dates. They still have five years to sell off existing stock for the repair or replacement of products they've already sold.

So what are the standards worldwide? Let's start with CEC-400. While there are specs for almost everything that uses electricity, much of the attention seems focused on external supplies—the ubiquitous wall-wart and the laptop ac-dc converter. It's not that any one of them burns so much power while sitting idle. It's that there are so many of them, always plugged in, always burning that power.

With respect to external power supplies that operate from nominal 115-V, 60-Hz power, CEC-400 specifies both efficiency and no-load power consumption. Supplies rated up to 1 W (according to their nameplate) must exhibit at least 49% efficiency. Supplies rated for more than 49 W must be at least 84% efficient.

In between, you take the natural log of the nameplate output, multiply it by 9, and add that number to 49%. (The specification expresses this in terms of , rather than as a percent.) Starting on July 1, 2008, the base efficiency numbers go up to 50 and 85%. In terms of standby power, if the supply is rated for less than 10 W, no-load consumption cannot exceed 0.5 W. For supplies rated from 10 to 250 W, maximum no-load consumption cannot be more than 0.75 W.

That covers many consumer products. But home-entertainment products such as TVs, DVD players and recorders, digital TV (DTV) adapters, and compact audio products have standby power requirements, but no efficiency targets. Also, their effective dates vary.

Maximum standby power requirements for TVs and DVD devices kicked in last January. They're both 3 W. DTV adapter and compact audio products have until next January, at which point DTV adapters may consume no more than 1 W in STB standby-passive mode and 8 W in STB-on mode. The spec for compact audio products says "2 W in Audio standby-passive mode for those without a permanently illuminated clock display. 4 W in Audio standby-passive mode for those with a permanently illuminated clock display."

Like all of the voluntary standards, Energy Star is a labeling program that relies on companies testing their own products according to established methodologies and reporting the results.

A product that meets or exceeds basic energy requirements can be marked with a special label indicating its energy-efficiency characteristics. The product is also listed on the Energy Star Web site, which lets consumers compare products with otherwise roughly equivalent performance characteristics for energy efficiency.

The U.S. Department of Energy and the Environmental Protection Agency (EPA) sponsor the Energy Star certification program. Australia, Canada, Japan, Taiwan, and the European Union have Energy Star programs that are closely related to the U.S. model, but more limited.

Australia's Energy Star is primarily concerned with office equipment and consumer electronics. In Japan, Taiwan, and the European Union (EU), programs focus on office equipment. There's also interest in Mexico, China, and Brazil in implementing Energy Star, but these are developing relationships.

Interestingly, there's a link between voluntary Energy Star and the prescriptive California Commission. In baseline standards for electronic products such as external power supplies and home entertainment equipment, Energy Star tends to mirror CEC-400, so it's not as if one type of program is more technically rigorous than another.

80 PLUS: 80 Plus is an incentive program funded by electric utility companies to integrate more energy-efficient power supplies into desktop computers and servers. To meet the program standard, supplies must achieve 80% or greater efficiency from full rated power down to 20% of rated power ( explicitly, at 20%, 50%, and 80%).

In addition, the full-load power factor must be at least 0.9. Participating utilities fund a rebate system that rewards OEMs and system integrators with cash for each server or PC they sell powered with an 80 Plus power supply. Details can be found at www.efficientpowersupplies.org/methods.asp.

In Europe, the European Commission and the European Association of Consumer Electronics Manufacturers (EACEM) developed codes of conduct for consumer products. An initial agreement in 1997 addressed standby power levels in TVs and VCRs. In 2000, a second agreement for reducing the standby losses of audio equipment was concluded. Then in 2003, a new agreement for TVs and DVDs was reached.

A 1999 initiative on Policy Instruments to Reduce Stand-by Losses of Consumer Electronic Equipment led to two codes of conduct—one for external power supplies and another for DTV services. A further code for broadband communication equipment is under development.

For external power supplies, the target-for products released after January 1, 2005 varied by capacity, with standby power ranging from 0.3 W for supplies rated at less than 15 W to 1 W for supplies rated between 60 and 150 W. By January 1, 2007, all supplies are supposed to have the same maximum no-load power consumption: 0.3 W.

For TVs, the code of conduct includes a feature reminiscent of U.S. fleet specifications for automobile fuel economy. The present maximum permitted standby power level is10 W, but the average standby of all units from any one manufacturer must be less than 6 W. By 2009, the "fleet" average must be reduced to 3 W, still with no models consuming more than 10 W.

One interesting thing about the European code of conduct for external supplies is that the population of manufacturers and their supplies is small enough to be comprehended in a single graph. The results from 2005 were presented in March of this year. With nine companies reporting on 130 models, 92% of the power supplies tested met the criteria (see the figure).

Of course, the code of conduct isn't the only standard in Europe (see "Energy-Efficiency Standards Around The Globe" at www.electronicdesign.com, ED Online 13111). The EU Eco Label, Energy Plus, the Group for Energy Efficient Appliances (GEEA), Germany's Blue Angel, and Nordic Swan are out there, too (see the table).

And don't forget about the Asian market. The China Energy Conservation Project hasn't had much to say about electronics, but that will change. Korea's voluntary Energy Saving Office Equipment & Home Electronics Program and Japan's Top Runner program shouldn't be ignored either.

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