Plug load energy analysis: The role of plug loads in LEED certification and energy modeling

Plug loads use 12% of site energy in U.S. office buildings and their relative importance is projected to increase. We studied the predicted and simulated plug load energy consumption using data submitted to the U.S. Green Building Council for LEED certification, and surveyed 92 energy modelers on their simulation techniques. 660 LEED for Commercial Interiors projects and 429 LEED for New Construction projects were analyzed. This is the first study to analyze LEED submittal data related to plug loads. The survey results indicated that 40% of modelers use between 10.8 and 16.1 W/m(2) for their peak plug load estimates in offices, and 68% of modelers estimate average plug load energy use intensity to be at or less than 10.8 W/m2. LEED results show that 73% of the projects under LEED-CI that attempted the credit dedicated to plug loads earned 2 of 2 points available (90% or more of eligible equipment is ENERGY STAR rated). Under LEED-NC, the median peak and average plug load power intensity reported are 10.8 and 4.0 W/m(2), respectively. LEED-NC submittal data showed that eQUEST is the most used tool for compliance. Only 5 of 429 LEED-NC projects attempted exceptional calculations for efficient plug loads. (C) 2014 Elsevier B.V. All rights reserved.