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+# Energy and carbon
+
+The co-op shows members how much energy its inference uses, and what carbon that
+represents. This page says where those numbers come from and where they are weak.
+The [model list](models.md) covers which providers we use and their energy
+sources; this covers how we count.
+
+## What we measure
+
+**Output tokens, per model, per day** — read from our own gateway logs. Nothing
+is required of your client, and no per-member figure is published: the dashboards
+show co-op totals.
+
+We count **output tokens only**, deliberately. That is the unit
+[GreenPT's published metric](https://greenpt.com/blog/introducing-a-new-ai-metric-to-drive-sustainability)
+uses ("mWh per 100 tokens"); input tokens are excluded so comparisons hold across
+prompts, workloads and models. It also means these figures are **not** total
+compute.
+
+## How tokens become energy and carbon
+
+```
+energy = output tokens × (Wh per 1,000 output tokens)
+carbon = energy × grid intensity of the electricity (gCO2e per kWh)
+```
+
+Both factors are held per provider in one table, with the source recorded for
+each row, in the portal's
+[`metrics_snapshot.py`](https://git.inference.coop/code/member-portal/src/branch/main/metrics_snapshot.py).
+
+### Measured: GreenPT
+
+GreenPT returns an `impact` object with every call — energy in watt-milliseconds,
+emissions in µgCO2e — so these are fitted from their own numbers rather than
+imported from a third party. Measured 2026-10-28 by regressing energy against
+output tokens across prompt sizes (R² ≥ 0.999; there is a real per-request
+overhead, because their energy derives from inference *time*):
+
+| Model | Wh per 1,000 output tokens | Implied grid intensity |
+|---|---|---|
+| `greenpt/deepseek-v4.1-flash` | 0.36 | ~193 gCO2e/kWh |
+| `greenpt/glm-5.3-flash` | 1.08 | ~193 gCO2e/kWh |
+| `greenpt/green-r` | 0.55 | ~24 gCO2e/kWh |
+
+`green-r` is roughly an order of magnitude cleaner per unit of energy, which is
+where GreenPT's claim of up to 40% lower CO2 per query comes from.
+
+### Estimated: everyone else
+
+Providers that do not disclose impact — Tinfoil, Regolo, PublicAI — use a
+**documented order-of-magnitude proxy**: 0.5 Wh per 1,000 output tokens at an EU
+grid average of 250 gCO2e/kWh. It exists so a day's total is never quietly
+missing models. It is an estimate, and it is labelled as one everywhere it
+appears. Refining a factor is a data edit, not a code change.
+
+## What this does not cover
+
+- **It is a floor, not a total.** Embedding, audio and image requests carry no
+  completion tokens, so their compute is not counted at all. This is the largest
+  known gap.
+- **Estimates for non-disclosing providers.** The proxy is an order-of-magnitude
+  figure, not a measurement of what a given provider actually draws.
+- **GreenPT's energy is itself estimated** — from time and documented hardware
+  power — so our per-token figures are an efficiency ratio, not a per-call meter
+  reading.
+- **Training emissions are not included**, for any model we serve. Nobody in this
+  market can verify them yet.
+
+## Where to see the numbers
+
+The [member dashboard](https://dashboard.inference.coop) has them under
+"Co-op usage" — by day, alongside membership, requests and spend. Operators see
+the same series on the admin panel's Trends tab.
+
+## Units, for the curious
+
+`Wh` is a watt-hour (a 100 W bulb for one hour is 100 Wh). `kWh` is 1,000 Wh.
+`gCO2e` is grams of carbon-dioxide equivalent. Converting between them is where
+mistakes hide: µgCO2e per mWh and gCO2e per kWh are the same ratio, and Wh to kWh
+is a factor of 1,000.