WP#35 - Water Usage Effectiveness (WUE): A Green Grid Data Center Sustainability Metric
The Green Grid · Michael Patterson, Dan Azevedo et al.
The Green Grid paper (WP 35, 2011) that defines Water Usage Effectiveness (WUE) as the water companion to PUE and CUE.
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Overview
The paper introduces Water Usage Effectiveness (WUE) as the water companion to PUE and CUE. WUE divides annual site water use by IT equipment energy and is expressed in L/kWh. A source-based variant, WUEsource, adds the off-site water consumed in generating the electricity. The full text requires sign-in; this page relies on public summaries.
Site water includes cooling-tower or evaporative make-up water and humidification; potable use by occupants is commonly excluded. For WUEsource, off-site water is added as the energy water intensity factor times total energy. The gap between a facility's site and source WUE therefore shows where the water is actually consumed.
Used together with PUE and CUE, it makes energy-water-carbon trade-offs visible, particularly for evaporative cooling: a cooling choice that lowers PUE can raise WUE. The record gives no calculation procedure, typical values or thresholds; the paper is a definition and scope document.
Key points
- WUE = annual site water usage (L) / IT equipment energy (kWh), in L/kWh.
- WUEsource adds off-site water used to generate the electricity (energy water intensity factor x total energy).
- Site water includes cooling-tower/evaporative make-up and humidification.
- Potable use by occupants is commonly excluded.
- With PUE and CUE it exposes energy-water-carbon trade-offs, notably for evaporative cooling.
Using it in design
- In the water module, compute WUE_site = annual make-up + humidification water (L) / IT kWh from the hourly cooling model (evaporation ~ heat rejected, cycles of concentration for blowdown).
- Add an optional WUE_source using a regional EWIF (L/kWh) catalog.
- Display WUE next to PUE to make the evaporative versus dry-cooler trade-off explicit.
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Who should read it
Design and sustainability teams selecting cooling systems and reporting water use.
Related standards
- ISO/IEC 30134-9
- EN 50600-4-9
Publication details
- Authors
- Michael Patterson; Dan Azevedo; Christian Belady; Jack Pouchet
- Publisher
- The Green Grid
- Year
- 2011
- Document number
- WP 35
- Document language
- English
- Source type
- Industry body
- Access
- Citation only
- Licence
- Copyright retained; citation only — the publisher’s terms apply to the original document
Citation
Michael Patterson; Dan Azevedo; Christian Belady; Jack Pouchet (2011). WP#35 - Water Usage Effectiveness (WUE): A Green Grid Data Center Sustainability Metric. The Green Grid. WP 35. https://www.thegreengrid.org/en/resources/library-and-tools/238-WP%2335---Water-Usage-Effectiveness-%28WUE%29%3A-A-Green-Grid-Data-Center-Sustainability-Metric
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