SOMA

    SOMA AI Emission Factors changelog

    Every published version of the dataset, newest first, so an inventory can name the version it used. Current: Factor version soma-ai-ef-2026.10-dataset-v3.0.0. Last updated .

    Part of the SOMA AI Emission Factors cluster.

    How are the factors versioned?

    Each release of the SOMA AI Emission Factors (SAEF) gets a Zenodo record and a new version. The concept DOI 10.5281/zenodo.20443585 always resolves to the latest one, and each record DOI below resolves to exactly that version. SOMA's own factor version string, currently soma-ai-ef-2026.10-dataset-v3.0.0, names the copy of the dataset behind every figure on this site and in the API, so quote it beside the DOI when a reader has to reproduce a number. A published version never changes: a new release gets a new version.

    Version history

    1. Version 3.0.0, published

      Record 10.5281/zenodo.23371447. SOMA factor version soma-ai-ef-2026.10-dataset-v3.0.0.

      • Four-term lifecycle boundary (electricity, embodied hardware, data-centre construction and training) with a separate development line.
      • Effective-token basis with input weight W_in 0.30 and a per-run prefix-cache share; 0.3025 effective tokens per billed token at the default mix.
      • Three model classes (A small, B standard, C frontier), each the mean of its benchmarked members: 18 open-weight models on H100 and B200 from the ML.ENERGY Leaderboard v3. Versions 1 and 2 used a named proxy model per class.
      • Coverage of 210 countries, 27 eGRID subregions and 143 cloud regions, with water for 17 regions using AWARE 2.0.
      • Monte Carlo uncertainty ranges.
      • The reasoning uplift for Tier 2b applies to output tokens only.
      • Headline spreads on the inference footprint: class A to C about 12x, Singapore to Sweden about 9x (electricity only about 13x).

    2. Version 2.0.0, published

      Record 10.5281/zenodo.22767475. SOMA factor version soma-ai-ef-2026.09-lifecycle-v2.

      • Added regions France (eu-west-3), Finland (europe-north1), UK (europe-west2), Belgium (europe-west1) and Iowa (us-central1).
      • Completed the carbon rows for us-west-2, us-south-central and us-south.
      • Corrected two v1 rows: us-east-1 class B carbon from 0.04380 to 0.04378 kg CO2e per M tokens, and Sweden class C water from 1.254 to 1.253 L per M tokens.
      • Introduced lifecycle add-ons (embodied hardware and training amortisation).
      • Restated the headline regional spread from 13x to 12x electricity only and about 6x with add-ons, the earlier figure being a rounding artefact.

    3. Version 1.0.0, published

      Record 10.5281/zenodo.20443586. SOMA factor version soma-ai-ef-2026.09-lifecycle-v1.

      • First release, accompanying arXiv 2606.10660 v1.
      • Four classes (small, mid, large MoE, large dense).
      • Electricity-only factors per region and class.
      • Regional spread about 13x, Singapore to Sweden.

    The browsable tables for the current version are on the SOMA AI Emission Factors (SAEF) page.

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