Water Usage Effectiveness (WUE)

WUE measures litres of water consumed per unit of IT energy, but on-site WUE hides the water spent upstream at the power plant.

Defining WUE

Water Usage Effectiveness is the ratio of water consumed to IT energy delivered, usually litres per kilowatt-hour. A low on-site WUE means the building itself consumes little water for cooling. It is a useful operational metric, but it stops at the fence line.

# On-site vs source WUE
site_water_L = 1_800_000     # litres/day, building cooling
it_energy_kWh = 2_400_000    # kWh/day IT load
wue_site = site_water_L / it_energy_kWh
print(round(wue_site,3))     # litres per kWh, on-site only

# Source WUE adds upstream power-plant evaporation
plant_water_per_kWh = 1.8    # litres/kWh, wet-cooled grid mix
wue_source = wue_site + plant_water_per_kWh
print(round(wue_source,3))   # true footprint is much larger

Why source WUE matters

A campus can report an impressive on-site WUE while its grid power quietly carries a large evaporative footprint at distant plants. Source WUE, which adds that upstream water, gives the honest total. For grid-supplied sites, the upstream term often dominates.

How MetroVolt reads on this metric

MetroVolt collapses the upstream term. Because its generation consumes almost no water, a MetroVolt-powered campus can achieve a low source WUE, not just a flattering on-site one. The metric finally reflects reality because the reality, near-zero generation-side water, matches it.

Use the honest metric

Throughout the water story we emphasize source-level water where possible, because that is what a stressed basin actually loses. On-site WUE improvements are real but partial; changing the generation architecture is what moves the source number.