Chapter 09 · Sustainability & AISustainability & AI
Model training
Definition
The process of fitting a model's parameters to data by optimising an objective — the phase of the AI life cycle where computation, and thus energy demand, is concentrated.
References
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Overview
What it means
Training runs many passes over data to adjust millions or billions of weights, using specialised accelerator hardware. Landmark analyses (Strubell et al. 2019; Patterson et al. 2021) showed training emissions vary enormously with model scale, hardware and grid carbon intensity — and that design choices can cut them dramatically.
How it is used
For sustainability assessment, training is the first accounting boundary: the IEA and researchers increasingly treat it separately from inference. The EU AI Act requires general-purpose model providers to document known or estimated training energy consumption.
Why it matters
Training is where AI's footprint is most measurable and most concentrated — and where siting, hardware and timing decisions have the largest marginal effect. It is the natural starting point for any organisation disclosing AI-related emissions.