Gigawatts (GW)

Plain English. A gigawatt (GW) is a billion watts — roughly the output of a large nuclear reactor, enough to power a mid-sized city. It has become the unit in which AI data-centre scale is quoted, because the industry now plans in whole power stations rather than server racks.

Why it moves money. Power is the binding constraint on the AI buildout, so gigawatts are the honest currency of ambition. A gigawatt of data-centre capacity translates to roughly tens of billions of dollars in capex once chips, buildings and grid connections are counted, and the electricity to feed it must be contracted years ahead. When a company announces gigawatts it is really announcing capital commitments and a bet on power it may not yet have secured. This is the physical layer under hyperscaler capex and the ceiling behind tokens per megawatt.

What to watch. Whether announced gigawatts come with signed power contracts and grid approvals, or are aspirations. Watch the gap between capacity pledged and megawatts actually energised — that gap is where the schedule risk and the write-downs live.

From the signals. Meta and BlackRock put US$14bn into a single gigawatt in El Paso. AMD and Anthropic framed a deal in gigawatts, not chips. Texas's interconnection queue reached 474GW before the state stopped approving centres.