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AI and energy: what the electricity numbers mean
Estimates of AI's power use vary widely because they measure different things, from a single query to all data centers, so here is how to compare them.
Evidence: 1 source · 1 official record
The short version
- Data centers use electricity for computing and for cooling. Only part of that is AI.
- Per-query energy estimates vary widely with the model, the hardware, and the length of the answer.
- Electricity use is not the same as emissions. Emissions depend on how the power is generated.
- The International Energy Agency publishes independent analysis of data center and AI electricity demand.
Headlines about AI and energy can be hard to compare. One says a single chatbot answer uses as much power as a light bulb for a few minutes. Another says data centers could need as much electricity as a whole country. Both can be reasonable estimates of different things.
Know which number you are looking at
| Measure | What it covers | Common unit |
|---|---|---|
| Per query | One request to a model | watt-hours (Wh) |
| Training run | Building one model | megawatt-hours (MWh) or more |
| A data center | Everything in one facility | megawatts (MW) of capacity |
| All data centers | A country or the world | terawatt-hours (TWh) per year |
Capacity is not consumption. A data center "of 1 gigawatt" describes its maximum power draw, not how much energy it uses over a year.
AI is a share of data centers. Data centers also run cloud storage, streaming, and other services. Good estimates say how much is attributed to AI and how.
Electricity is not emissions
The climate effect depends on the source of the electricity. A data center powered mostly by renewables or nuclear has much lower emissions per unit of electricity than one powered by coal. Contracts to buy clean power are not always the same as using it at every hour.
Water
Many data centers use water for cooling, and power plants use water to generate electricity. Local effects matter most, particularly in regions already short of water.
Where to find independent figures
The International Energy Agency's Energy and AI analysis gives independent estimates and scenarios. Utilities, grid operators, and local planning documents are also good sources for specific projects.
How we report energy
We name the measure, the unit, and the source of every estimate, and we say when a figure comes from a company that has an interest in it.
Limits and open questions
- Most AI companies do not publish detailed, comparable figures for the energy and water used by their models.
- Forecasts of future demand differ widely, depending on assumptions about efficiency gains and adoption.
Evidence and sources
- Document or data Energy and AI