Case Study: 80 PLUS Computer Power Supply

This study will discuss a successful Market Transformation (MT) program that has substantially improved energy efficiency in an area that few of us think much about. The 80 PLUS program, which started in 2004, created specifications for efficient computer power supply units (PSUs) that have expanded to become industry standards that are still in force today and have contributed to big energy savings in the PC and server markets.


The 80 PLUS program emerged during a period of huge growth in the computer industry. Alongside constant growth in personal computers, from 2000-2005, server shipments increased by 15% each year resulting in a near doubling of servers in U.S. data centers. From 2005 to 2010 the growth rate continued at a slower but still substantial rate of 5%. Taken as a whole, the effect on power demand was enormous.

A key component of a computer is its PSU. From the source of power in a building to where you plug in to the computer being operated, there is a surprisingly large loss of energy. This is the problem that 80 PLUS sought to solve.

Computer PSUs need to convert alternating current (AC) coming from external sources to direct current (DC) which the computer runs on. The “80” in 80 PLUS represents a performance target for the percentage of power yielded from an AC power source. 80 PLUS promoted the idea that PSUs ought to be “80 percent efficient” or better in this conversion. To understand this, we can start with the power a computer requires to operate and then look at the amount of power it draws from its source. To measure efficiency of the PSU the calculation looks like this:

Power Required by the Computer = 500 watts

Power Drawn from Source = 833 watts

PSU efficiency = 500 watts / 833 watts = 60%

In this example 40% of the power from the source was lost (in the form of heat). However, if we were to make our PSU 80% efficient rather than 60% we would only draw 625 watts from our source, saving over 200 watts.

At scale, such improvements in PSU efficiency would lead to a significant energy savings.

The Market Transformation strategy

Efforts to increase PSU efficiency began in 2002 when the California Energy Commission, Pacific Gas & Electric Company (PG&E), and the U.S. Environmental Protection Agency (EPA) commissioned Ecos Consulting and the Electric Power Research Institute (EPRI) to develop a methodology for testing PSU performance for PCs. As often is the case with market transformation, a rating, a practice or a rule paved the way for standard-setting that provided manufacturers both with a market opportunity and pressure to comply.

In 2004, an 80 PLUS market transformation idea was presented as an initiative at the ACEEE Market Transformation Symposium. In addition to the groups mentioned above, partners including Consortium for Energy Efficiency (CEE), NEEA, California’s other investor-owned electric utilities, and the New York State Energy Research and Development Authority (NYSERDA) collaborated on the project. The program’s initial objective was for PSUs rated 80 PLUS or better to become the default product in desktop units.

The program was launched in spring of 2004 to overcome initial market barriers including awareness of 80 PLUS standards and opportunities among market actors, a limited number of choices and low supply of products and costs that were prohibitive for PSU manufacturers.

One example of the availability challenge was the experience of Dell Computers. In early 2005 Dell evaluated two 80 PLUS suppliers.  One of the suppliers’ units was in the prototype phase and was not yet ready for mass production. The other vendor did have a complete unit, ready for mass production, but critical differences between the electrical specification and Dell’s requirements made it a technically unviable option.

Another case was that of a system integrator (a business that assembles computers from purchased components) who reported having to wait several months before they were able to obtain the 80 PLUS power supplies and build units.

The single most important market barrier was for manufacturers who faced a cost differential for 80 PLUS PSUs versus standard PSUs. “Cost is the big one,” reported a participating PSU manufacturer. “The technology is there, everybody has the ‘know-how,’ but it is cost that is the barrier.” Confirming this statement, the 80 PLUS program’s survey team observed that all of the participating PSU manufacturers interviewed reported that there was a price difference estimated to be between $10 and $20.

To address these barriers the strategy of the program included the following measures:

  • Reducing the incremental cost and increasing supply of efficient power supplies by
    offering buy-downs to power supply manufacturers.
  • Aggressively recruiting, through ongoing meetings and communications, SIs and OEMs to
    carry and promote 80 PLUS computers.
  • Providing supporting evidence and testimony so that the revised ENERGY STAR
    computer specifications will include a minimum of 80 PLUS requirements.
  • Increasing the number of efficiency program administrators to help promote 80 PLUS to customers within their service territories.
  • Meeting with key commercial sector end user organizations to educate them about the
    energy and non-energy benefits of 80 PLUS.

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