DCiE was developed by members of the Green Grid, an industry group focused on data center energy efficiency. DCiE, which is expressed as a percentage, is calculated by dividing IT equipment power by total facility power.
DCiE = IT Equipment Power/Total Facility Power x 100%
How to Determine DCiE:
1. Take a measurement of energy use at or near the facility utility's meter. If the data center is in a mixed-use facility or office building, take a measurement only at the meter that is powering the data center. If the data center is not on a separate utility meter, estimate the amount of power being consumed by the non-data center portion of the building and remove it from the equation.
2. Measure the IT equipment load, which should be measured after power conversion, switching and conditioning is completed. According to The Green Grid, the most likely measurement point would be at the output of the computer room power distribution units (PDUs). This measurement should represent the total power delivered to the server racks in the data center.
DCIE is the reciprocal of Power Usage Efficiency (PUE). PUE is defined as the total facility power divided by the IT equipment power. That means that DCiE = 1/PUE.
According to the Uptime Institute, the typical data center has an average PUE of 2.5. This means that for every 2.5 watts coming "in" at the utility meter, only one watt is delivered out to the IT load. Uptime estimates most facilities could achieve 1.6 PUE by using the most efficient equipment and best practices.