Report Zero Metrics Glossary
Energy & Water Metrics
Total energy used inside the data centre boundary across IT equipment, cooling, power distribution, lighting, and building services. EDC represents the overall energy demand of the total facility.
Energy consumed directly by servers, storage, and network devices. This represents productive workload energy.
Energy used by all mechanical and electrical cooling systems, including chillers, CRACs, pumps, and fans, to maintain safe operating temperatures.
Energy produced by onsite backup generators.
The total volume of fuel consumed by backup generators
Electrical energy consumed by heat pump systems to raise recovered waste heat to a temperature suitable for reuse in heating applications such as district heating networks.
The use of a heat pump to raise recovered waste heat to a temperature suitable for a target application. Required when the Average Waste Heat Temperature (TWH) falls below the threshold needed by the receiving system.
Thermal energy produced as a by-product of IT equipment operation that is not used productively. Captured via heat exchangers, rear-door coolers, or direct liquid cooling and reported under WHE and ERF when reused externally or internally.
Total volume of water consumed by the data centre.
Volume of drinking‑quality water used by the data centre.
The volume of non-potable water drawn into the facility from external alternative sources — such as rainwater harvesting, greywater collection, or reclaimed surface water
The collection and storage of rainwater from rooftops or other surfaces for reuse within the facility. When used in cooling systems, harvested rainwater is a non-potable alternative water source counted under WIN-NID.
Water that has been treated and recovered from wastewater streams for reuse in non-potable applications such as cooling tower make-up. Classed as an alternative water source and counted under WIN-NID.
Capacity & Demand Metrics
A qualitative indicator showing whether current compute, storage, and network capacity can meet forecast demand without service risk.
The total volume of data received by the data centre over the reporting period, captured across all inbound network connections into the facility’s computer room.
The total volume of data transmitted out of the data centre over the reporting period, captured across all outbound netw cork connections from the facility’s computer room.
The total provisioned capacity for receiving data into the data centre computer room. Calculated by aggregating contracted bandwidth across all active inbound network connections.
The total provisioned capacity for transmitting data from the data centre computer room. Calculated by aggregating contracted bandwidth across all active outbound network connections.
The amount of data retained and actively processed by IT systems.
The total performance of all servers, calculated by summing their active state performance values based on EU Regulation 2019/424. Values can be derived from declared data, interpolation, manufacturer inputs, or recognised estimation methods.
The total installed raw storage capacity available across all storage systems.
A unit of digital data equal to one million gigabytes or 10¹⁵ bytes. Used in Report Zero to express data traffic volumes (TIN, TOUT) and storage capacity (CSTOR) at scale.
A benchmark developed by SPEC for measuring server energy efficiency across a range of workload levels. Used in ISO 30134 as a basis for aggregating and normalising compute capacity figures in metrics such as CSERV.
The maximum continuous electrical power capacity that the data centre’s electrical and mechanical infrastructure is designed to deliver to IT equipment under normal operating conditions.
The total electrical power capacity currently unallocated and available for new IT load.
The total energy that can be consumed over a given reporting period before reaching the contracted or physical limit of the facility’s power supply.
The electrical power drawn directly by IT equipment: servers, storage arrays, and networking hardware. Excludes power consumed by facility support systems such as cooling, lighting, and power conditioning. The primary denominator in PUE, CUE, and WUE.
Efficiency & Performance Metrics
A ratio comparing total facility energy use to IT energy use.
A measure of how effectively cooling systems convert input energy into useful cooling output.
The proportion of total site energy consumed by cooling systems.
A measure of how much water is used per unit of IT energy consumption.
Renewable Energy & Heat Reuse
The share of a data centre’s total energy consumption that is supplied by renewable sources from the grid.
A portfolio‑level metric showing the proportion of renewable or low‑carbon energy used across multiple data centre sites.
The total amount of renewable energy consumed.
The quantity of electricity consumption matched with Guarantee of Origin certificates over the reporting period. GOOs confirm that an equivalent volume of electricity was produced from renewable sources. Certificates are procured separately from physical electricity supply.
Renewable electricity sourced through long-term Power Purchase Agreements directly contracted with specific renewable generation assets. PPA-backed energy includes verified certificates of renewable origin.
Electricity generated directly at the facility from renewable sources.
Renewable electricity drawn from the national or regional grid rather than generated on-site or from Power Purchase Agreements.
The carbon emission factor applied to renewable electricity matched with Guarantee of Origin certificates.
The carbon emission factor applied to renewable electricity sourced via Power Purchase Agreements.
The carbon emission factor applied to renewable electricity sourced from On-Site Generation.
An electronic certificate confirming that one megawatt-hour of electricity was produced from a renewable source. Consumers purchase GOOs to make market-based renewable energy claims independent of physical electricity delivery. Counted under ERES-GOO in Report Zero.
A long-term contract between an energy buyer and a renewable generator fixing the price and quantity of electricity to be supplied. PPAs support new renewable capacity development and allow buyers to claim the renewable attributes of the contracted output. Counted under ERES-PPA in Report Zero.
The ratio of energy exported from the data centre for productive reuse (EREUSE) to total facility energy consumption (EDC). Measures the degree to which the facility recovers and usefully re-exports its waste heat.
The heat that is used or reused outside of the data centre boundary, and which substitutes partly or totally energy needed outside the data centre boundary.
The mean temperature of thermal energy recovered from IT equipment or cooling infrastructure and made available for reuse over the reporting period.
Carbon & Emissions Metrics
The quantity of CO₂ equivalent emitted per unit of electricity generated, expressed in gCO₂e/kWh. Varies by grid region and time of day depending on the generation mix active on the network.
A standardised unit for expressing greenhouse gas emissions. Different gases such as methane and nitrous oxide are converted to their CO₂ warming equivalent using Global Warming Potential factors, enabling all emissions to be reported as a single comparable figure.
A coefficient that converts an activity quantity — such as kWh of electricity consumed — into an equivalent quantity of greenhouse gas emissions in kgCO₂e. Published by grid operators, government bodies, and standards organisations.
An EU legislative framework requiring member states and large energy consumers to improve energy efficiency and report energy use. Data centres above certain capacity thresholds are subject to mandatory reporting obligations including REF disclosure.
A dimensionless efficiency ratio for heat pumps and refrigeration systems. Calculated as useful heat or cooling output divided by electrical energy consumed.
The Greenhouse Gas Protocol — the globally dominant accounting standard for measuring and reporting corporate greenhouse gas emissions. Defines Scope 1, 2, and 3 categories and specifies both location-based and market-based methods for Scope 2 reporting.
The ratio of total carbon emissions to IT energy consumption.
Direct greenhouse gas emissions from sources owned or controlled by the operator. Scope 1 consists primarily of CO₂e produced by combustion of fuel in backup generators during outage events and scheduled test runs.
Indirect greenhouse gas emissions from purchased electricity, calculated using the emission factors of specific electricity products procured by the organisation — such as PPAs, green tariffs, and GOO certificates. Reflects the impact of procurement decisions on the reported carbon footprint.
Indirect greenhouse gas emissions from purchased electricity, calculated using the average carbon intensity of the local grid at the reporting location. Does not reflect any renewable energy procurement instruments; all consumers on the same grid receive the same emission factor regardless of their contracts
Energy consumed by heat pump systems to upgrade waste heat recovered from IT equipment to temperatures suitable for reuse
A long-term contract between an energy buyer and a renewable generator fixing the price and quantity of electricity to be supplied. PPAs support new renewable capacity development and allow buyers to claim the renewable attributes of the contracted output. Counted under ERES-PPA in Report Zero.
The share of electricity from the grid generated from renewable sources, expressed as a percentage. Derived from published grid emissions factors and used in location-based carbon calculations.
A compliance metric under the EU Energy Efficiency Directive (EED) expressing the proportion of total energy consumption attributable to renewable sources, includes energy backed by Guarantees of Origin (GOOs) or Power Purchase Agreements (PPAs).
The combined greenhouse gas footprint of the facility, covering direct Scope 1 emissions from on-site fuel combustion and indirect Scope 2 emissions from purchased electricity.
