Water
Every data center pays to reject its heat in some mix of two currencies, water and energy. Evaporation is thrifty with electricity and spends water; dry cooling spends electricity and saves water; warm-water liquid cooling narrows the gap by letting heat leave hotter. Microsoft's 2024 zero-water design stated the trade openly, which is to its credit. Faraday's read: water claims deserve the same scrutiny as financial ones. Ask whether a figure is withdrawal or consumption, site or source, ratio or total, direct reduction or replenishment elsewhere, and in which basin. The best disclosures answer those questions unprompted. When a report leaves them unanswered, the silence is usually informative.
Knowledge check
Why can a company report an improving water usage effectiveness while its total water use rises?
Show the answer
Water usage effectiveness is a ratio of water to information technology energy. If the fleet grows quickly, energy rises faster than water, so the ratio falls even though the absolute volume consumed goes up. That is why readers should look for totals as well as ratios.