THE SIM Electromagnetic Working Group carried out a supplementary comparison of energy standards at 50/60 Hz under the guidance of the Committee Consultative of Electromagnetism. This supplementary comparison, identified as SIM.EM-S7, aimed at providing a link to various NMIs in the SIM region to the SIM International Comparison 50/60 Hz Energy conducted by NIST an completed in year 2007. Measurements in this supplementary comparison were conducted from May 2010 to March 2012. The reference standards used in this comparison in energy were capable of measuring power and energy with high accuracy. This feature of the standards allowed to carry out the SIM.EM-S7 supplementary comparison of 50/60 Hz energy and the SIM.EM-K5 key comparison of 50/60 Hz power which was published in 2014.