Managing Plug Load – The Next Challenge for Energy Efficient Buildings

“Plug load? Seriously? With all the things that I need to do in my facilities you want me to worry about managing plug load power use? It can’t be that big a deal.”


Studies from many countries consistently show that “miscellaneous” load is a quarter to a third of power consumption in office buildings, and it keeps growing as facilities become “smarter”. When HVAC and lighting get more efficient, plug load can be 50% or more of energy use. Recent research from UC-San Diego shows that IT equipment accounts for more than 70% of electrical base load in “mixed-use” campus buildings that have server rooms. http://www.solaripedia.com/files/753.pdf Managing plug load power use is a big deal, and gets bigger as we put more electronic equipment into every type of building.


Graphic source: http://www.legrand.us/wiremold-pages/wiremold-white-papers/plugload.aspx

“So, what should I do?”

1Managing plug load is challenging, but essential … baseline measurement and analysis of the plug load.  You have to know what equipment is in a building, who is responsible for it, and what its power consumption characteristics are.

2. Kill the Zombies. In every building there is unused and unnecessary equipment … servers, printers, fax machines, copiers, UPS’s … that are using electricity but not doing anything. Clean house and get rid of unused equipment.

Next, you need a power management plan to turn off or turn down electronic equipment when idle. Desktop PC power management software can produce big returns. Energy Star power down settings need to be turned on and kept on for all equipment. Smart power strips or sensors can turn off peripheral devices and AC/DC converters. Even servers can be managed for variable power use.  If your utility offers it, take advantage of PG&E’s subsidy programs that will fund plug load power management technologies. 

Finally, get smart about what you buy. Work with IT and Purchasing departments to design, specify and buy energy efficient equipment and systems. The EPA now has Energy Star labels for not only office equipment and appliances, PC’s, and monitors, but for UPS’s, servers, and data storage systems as well.  

Energy Star is good as minimum standard, but with a little more effort your facilities can significantly reduce plug load power use, and your energy bills. A well thought-out plan for addressing “miscellaneous” energy use belongs on your to-do list for 2012.

Richard Hodges, www.GreenIT.net

IFMA-SF Sustainability Chair

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