Overview
ISO/IEC TR 23050:2019 is a Technical Report from ISO/IEC that defines how to treat data centre resource metrics when electrical energy is stored and exported from within data centre boundaries. It introduces the Excess Electrical Energy Factor (XEEF) as a Key Performance Indicator (KPI) to quantify electrical energy exported from a data centre to an external electrical grid. The report complements the ISO/IEC 30134 KPI family (PUE, REF, ERF) and provides a consistent approach to measurement, determination and reporting of exported energy without setting performance targets.
Key topics and requirements
- Definition of XEEF: XEEF = E_Excess / E_IT
- E_Excess = annual electrical energy exported from the data centre (kWh)
- E_IT = annual electrical energy consumed by IT equipment (kWh)
- Scope and boundaries: Clarifies what counts as data centre gross energy input and distinguishes local generation (considered outside the data centre boundary) from exported energy.
- Energy flow and storage types: Discusses energy storage technologies (electrical, thermal, mechanical) and how stored energy used internally affects PUE vs. energy exported (XEEF).
- Measurement and reporting: Specifies sections for determination, measurement and standardized public reporting constructs (including trend tracking and supporting information).
- Grid interface considerations: Notes requirements for converters/reversible UPS or power-electronic interfaces that measure and orient energy flows, comply with local grid rules, and support export without jeopardizing critical loads.
- Relationship to other KPIs: Explains complementarity with PUE (ISO/IEC 30134-2), REF (ISO/IEC 30134-3) and ERF (ISO/IEC 30134-6) and how using gross vs. net energy can affect KPI calculations.
Practical applications and users
Who benefits from ISO/IEC TR 23050:
- Data centre operators and facility managers - to quantify and report exported energy and integrate storage/export in sustainability metrics.
- Energy managers and sustainability teams - to incorporate exported energy into carbon and grid-balancing analyses.
- Design and engineering teams - to specify reversible UPS/power electronics and metering for export-capable facilities.
- Utility partners and grid operators - to understand exported energy sources and contractual/technical interfaces.
- Auditors and standards bodies - to validate KPI calculations and public reporting.
Practical uses include KPI reporting, grid-balancing programs, business case analysis for storage and export, and policy/contract development for energy export agreements.
Related standards
Keywords: XEEF, Excess Electrical Energy Factor, data centre metrics, energy storage, energy export, PUE, REF, ERF, ISO/IEC 30134, data centre sustainability.