Calculate overall data center energy efficiency combining power, cooling and IT load metrics.
DCiE is the inverse of PUE expressed as a percentage — it directly answers what fraction of total facility power reaches IT equipment, making it a more intuitive companion metric to PUE for stakeholders unfamiliar with ratio interpretation. CUE (Carbon Usage Effectiveness) extends the PUE family into sustainability reporting: it divides total carbon emissions attributable to the facility by the energy delivered to IT equipment, giving a carbon-per-useful-kWh figure that falls as either the facility's energy mix gets cleaner or its overall efficiency (PUE) improves.
DCiE
DCiE% = (1 / PUE) × 100
Carbon Usage Effectiveness
CUE = total_carbon_emissions_kg / IT_energy_kWh
PUE is a ratio where lower is better and values below 1 are impossible, which can confuse non-technical audiences; DCiE reframes the same information as a percentage of power reaching IT equipment, where higher is better and the scale (0-100%) is more immediately intuitive for executive reporting.
Two levers: improving overall facility efficiency (lower PUE means less total energy consumed per unit of IT work), and sourcing cleaner energy (renewable power purchase agreements, on-site solar/wind, or a grid with lower carbon intensity) — CUE captures both energy efficiency and energy sourcing in one metric.
Only with caution — grid carbon intensity varies enormously by region (a facility on a hydro/nuclear-heavy grid will show a much lower CUE than an identical facility on a coal-heavy grid) even with identical IT efficiency, so CUE differences often reflect location and energy sourcing as much as operational efficiency.