Well-to-Tank (WTT) Upstream Fuel Factors

164 well-to-tank (wtt) upstream fuel factors held in the GreenCalculus MasterBrain, drawn from UK DEFRA/DESNZ 2026. Values are read live from the data layer on every page build, so nothing here is re-typed and nothing can drift from the figures the calculators use. They span 6 units of measurement — 69 of them in kg CO2e per kWh — which is why the spread below is reported per unit and never blended.

Where these factors are used

Well-to-Tank Emissions sets out how factors in this group are applied, and Scope 3 Cat 3 Well-to-Tank Fuel Calculator draws on them directly. The published dataset these rows are drawn from is UK DEFRA Well-to-Tank (WTT) Emission Factors 2026 — Complete Upstream Fuel Dataset, which carries a DOI for citation.

What this group contains

Figures are computed per unit and never blended: a median across different units would be arithmetically valid and physically meaningless. 1 further unit in this group has fewer than 3 factors and is counted above but not described.

What has changed

Change history is reconstructed from every released edition of the data layer, v2025.13 to v2026.107. A factor absent from this table has held the same value throughout. A change shown as a dash moved off zero, where a percentage has no meaning.

Sources, citation & machine access

Cite the upstream publisher for the values themselves. The reference below credits this compilation and, more usefully, pins the edition you read.

Say, Jeremiah (2026). Well-to-Tank (WTT) Upstream Fuel Factors (MasterBrain v2026.110). GreenCalculus. https://greencalculus.com/factors/well-to-tank-fuel-factors/

Cite this factor group

Values change between editions. Quoting the MasterBrain version is what lets a reader resolve the exact number you used — see the change record above for factors in this group that have moved.

For a reference manager — BibTeX, then RIS:

@misc{greencalculus_fuels_wtt_2026,
  author       = {Say, Jeremiah},
  title        = {Well-to-Tank (WTT) Upstream Fuel Factors},
  year         = {2026},
  howpublished = {GreenCalculus},
  note         = {MasterBrain v2026.110},
  url          = {https://greencalculus.com/factors/well-to-tank-fuel-factors/}
}

TY  - DATA
AU  - Say, Jeremiah
TI  - Well-to-Tank (WTT) Upstream Fuel Factors
PY  - 2026
PB  - GreenCalculus
ET  - MasterBrain v2026.110
UR  - https://greencalculus.com/factors/well-to-tank-fuel-factors/
ER  - 

Every factor on this page is readable from the open endpoint. No key, no signup:

https://greencalculus.com/wp-json/greencalculus/v1/factors/fuels_wtt

curl -s "https://greencalculus.com/wp-json/greencalculus/v1/factors/fuels_wtt?limit=500"

import requests
rows = requests.get("https://greencalculus.com/wp-json/greencalculus/v1/factors/fuels_wtt", params={"limit": 500}).json()["factors"]
print(len(rows), "factors in fuels_wtt")

Or the same rows as a spreadsheet — every factor with its source, the edition it last changed in, and its own link:

https://greencalculus.com/wp-json/greencalculus/v1/factors-export?page=well-to-tank-fuel-factors

Download this table as CSV

Both responses carry an X-GC-Version header, so a consumer can detect a new edition without diffing the payload. The CSV filename carries the edition too, so two downloads months apart do not collide.

All factors

Last changed names the data-layer edition in which a factor last took a new value, reconstructed from every released edition since v2025.13. A dash means the value has not moved since tracking began — which is the answer to "is the figure I used last year still current?".

Common questions