# Data sources

*Last reviewed: 2026-07-22. Changes are listed in the
[changelog](#changelog) at the bottom of this page.*

The carbon estimate is only as good as its inputs. This page lists
each input, where it comes from, and how often we update it.

## Energy formula coefficients (α, β)

- **Source**:
  [EcoLogits v0.4 — LLM inference methodology](https://ecologits.ai/0.4/methodology/llm_inference/).
- **Values**: α = 8.91 × 10⁻⁵, β = 1.43 × 10⁻³ (Wh per output token).
- **Updates**: when EcoLogits publishes a new methodology version
  with new coefficients, we evaluate it, bump the
  `methodology_version`, and note the change in the dashboard's
  footer with the effective date.

The coefficients were derived from a regression across published
benchmarks on a fleet of representative GPUs. They are an *average*;
real hardware varies.

## Model active parameters

- **Source priority**:
  1. **EcoLogits registry** — models with verified architecture
     details (`accurate`).
  2. **Provider documentation** — values published by the model
     creator (`accurate` or `medium`, depending on whether the
     statement is unambiguous).
  3. **Research papers and credible leaks** — peer-reviewed
     architecture descriptions, technical reports (`medium`).
  4. **Name-based estimates** — `llama-70b` → 70B (`gross`).
- **Updates**: when a new model lands, we look up its parameter count
  in this priority order and tag the `accuracy` band accordingly.
  Re-evaluation happens monthly and on demand when a model's source
  upgrades.

For Mixture-of-Experts models we use the **active parameter count**
(parameters used per token), not the total parameter count. This
distinction matters: a 600B-parameter MoE that activates 20B per
token has the energy profile of a 20B dense model, not a 600B one.

## Grid carbon intensity

- **Source**:
  [Ember Climate yearly electricity data](https://ember-climate.org/data/data-tools/electricity-data-explorer/)
  (CC-BY 4.0) — annual averages by country. Where a regional grid
  operator publishes finer-grained, permissively-licensed data, we use
  the regional value instead: RTE (France), PJM (US Mid-Atlantic),
  CAISO (US California), ERCOT (US Texas), BPA (US Pacific Northwest),
  EirGrid (Ireland), National Grid ESO (UK), Hydro-Québec, AEMO
  (Australia), among others. The
  [IEA figure](https://www.iea.org/data-and-statistics) is used for
  the `global` aggregate only.
- **Per-region provenance**: every region's entry records its source
  and source URL in our config, so each number is traceable to the
  operator or dataset that published it.
- **Aggregation**: where a region maps to multiple countries (e.g.
  `eu-west` covers FR, DE, NL, IE), we use a population-weighted
  average for the region.
- **Updates**: annually, as each upstream publishes its new dataset.
  Switching dataset versions bumps the `methodology_version`.

We do not use real-time grid carbon intensity (which would require
per-request lookups against a service like ElectricityMap). It's on
the roadmap; the trade-off is that real-time numbers introduce
sampling noise we'd need to explain. Annual averages are coarse but
boring, and "boring" is a feature in a methodology document.

### Sample values

| Region | Approx. gCO₂e/kWh | Notes |
|--------|-------------------|-------|
| `eu-west` | ~280–340 | Population-weighted Western Europe average. |
| `eu-north` | ~50–80 | Mostly hydro/nuclear (Sweden, Norway, Finland). |
| `us-west` | ~250–320 | California heavy renewables, broader West mixed. |
| `us-east` | ~370–450 | Higher fossil share. |
| `india` | ~700–800 | Coal-dominant grid. |

Specific values per region are in the dashboard's settings page; the
table above is for orientation.

## Pricing data

- **Source**: each upstream provider's published price list,
  refreshed daily.
- **Updates**: within one business day of an upstream change going
  live.
- **Storage**: the price applied at the moment of a request is
  stored on the generation record, so historical bills are stable.

Pricing isn't strictly part of the carbon methodology, but it is part
of the per-request routing decision (cost is the tie-break after
carbon in auto mode) so the source is documented here for completeness.

## Everyday equivalence factors

The "km driven / phone charges / tree-days" framing shown next to a
carbon figure uses three published conversion factors:

| Equivalent | Factor | Source | Vintage |
|------------|--------|--------|---------|
| Phone charge | 12.4 gCO₂e/charge | [US EPA Greenhouse Gas Equivalencies Calculator](https://www.epa.gov/energy/greenhouse-gas-equivalencies-calculator-calculations-and-references) | 2022 US grid |
| Car travel | 106.7 gCO₂e/km | [European Environment Agency](https://www.eea.europa.eu/en/analysis/indicators/co2-performance-of-new-passenger) | 2024 EU new registrations |
| Tree uptake | 60.3 gCO₂/tree-day | [European Environment Agency](https://www.eea.europa.eu/articles/forests-health-and-climate-change) | ~22 kg/tree/year |

These convert a measured number into everyday terms; they are not
inputs to the emissions estimate. The scope and known weaknesses of
each factor — including that the car figure covers new registrations
rather than the on-road fleet, and that the tree figure is a rule of
thumb without a single underlying study — are set out under
[everyday equivalences](methodology#everyday-equivalences) on the
methodology page.

## What we deliberately don't include

- **Hardware embodied carbon.** Manufacturing emissions for the GPUs
  serving inference are non-zero but we don't have a defensible
  per-token allocation. Until we do, omitting the number is more
  honest than guessing.
- **Cooling overhead.** Data-centre cooling adds 10–30% to the energy
  used by compute (Power Usage Effectiveness, PUE). The EcoLogits
  formula incorporates an average overhead; provider-specific PUE
  refinements are pending more data.
- **Network transport.** Energy used to move bytes between the
  gateway, the upstream, and the user is small relative to inference
  and is not counted.
- **Training emissions.** Documented separately on the
  [limits page](limits).

## Changelog

- **2026-08-19** — Everyday equivalence factors documented with their
  sources and vintages (#438); phone-charge and car factors corrected
  to match the bodies they cite.
- **2026-07-22** — Grid-intensity source corrected: country averages
  come from Ember Climate (CC-BY 4.0), refined by regional
  grid-operator data; the IEA figure is used for the `global`
  aggregate only. Added the per-region provenance note.
- **2026-07-06** — API parameters, endpoints, and metadata field
  names corrected to match the backend (#279).
- **2026-04-29** — First published (#117).