Power Usage Effectiveness Measures a Data Centre's Overhead, Not Its Value

A patient's chart in Thunder Bay, a bank card in Halifax: the request travels to a building humming with servers, storage, network equipment, backup power and cooling. The Conversation Canada's framing is deliberately unromantic — not mythical “AI factories,” not innocuous warehouses, but industrial infrastructure with real appetites for electricity, water and land. Which raises the question of what the standard numbers actually tell you. Power usage effectiveness (PUE) is a facility's total energy divided by the energy its computers use; the theoretical ideal is one, meaning every watt beyond the servers is a watt of overhead. Natural Resources Canada's best-practice guide makes the obvious point that PUE ignores the useful work the servers perform. A facility can score beautifully and still be doing very little, and efficiency is not the same as local impact. Canada's Responsible Data Centre Development Principles, unveiled on Sept. 3 by the federal government and the Federation of Canadian Municipalities with 23 industry signatories, sit on top of that gap. They are a common national baseline — and, explicitly, not binding federal law, a permit or an approval. A ratio can tell you how tightly a building runs. It cannot tell you what the building owes the grid it sits on.