Carbon Usage Effectiveness (CUE) is a sub-aspect of Power Usage Effectiveness (PUE) for determining the carbon dioxide emissions of data centers
. The CUE value is determined by the carbon dioxide emissions of a data center, which are set in relation to the energy consumption of the data center in kilowatt hours (kWh). The dimension for the CUE value is kgCO2/kWh. The lower the CUE value, the less carbon dioxide is emitted by the data center. The ideal value would be 0.