How ZeroCarbonDrive works: every number on this site is traced to a primary source — a regulator’s document, a statistical agency, a peer-reviewed paper or a company filing — and labelled with the date it was verified. Where a figure is a manufacturer’s own claim rather than a verified measurement, it says so. Where the honest answer is that nobody has published the number, we say that instead of estimating.
Last updated: 13 September 2026.
Source hierarchy
When two sources disagree, we use the one higher on this list and say that the lower one differs:
| Rank | Source type | Examples |
|---|---|---|
| 1 | Regulator and standards bodies | FAA, EASA, CAAC, ICAO, EPA, NHTSA — type certificates, special conditions, airworthiness directives, published test procedures |
| 2 | Statistical agencies and official datasets | EIA, IEA, DESNZ conversion factors, FuelEconomy.gov, AFDC, Our World in Data |
| 3 | Peer-reviewed research | Journal papers with a DOI, for anything about atmospheric effects, lifecycle emissions or degradation |
| 4 | Company filings and investor relations | SEC filings and IR releases: useful for dated milestones, treated as claims about the company’s own programme |
| 5 | Aviation and energy trade press | Used for named, dated events when no primary document is public |
Press releases, marketing pages and order books are not sources for facts about capability. They are sources for what a company said, on a date.
The words we do not mix up
- Announced is not built. First flight is not certified. Type certificate is not operator certificate. A programme can hold one and not the others for years, and our trackers keep them in separate columns.
- Tailpipe is not well-to-wake. An emissions number is meaningless without its accounting boundary, so we state the boundary next to the figure.
- Cell-level is not pack-level. Battery specific energy quoted from a laboratory cell is typically 25–40% higher than what an installed, cooled, certifiable pack delivers.
- CO₂ is not CO₂-equivalent with radiative forcing. For aviation the difference is roughly a factor of 1.9, which is large enough to reverse conclusions.
Dates and updates
Pages that track a moving situation carry a “last verified” date at the top. That date changes when the figures are actually re-checked — not when the page is touched for an unrelated edit, and never to make a page look fresh. When a figure changes, the change is described rather than silently overwritten.
Corrections
If a number here is wrong, we would rather hear it than keep it. Corrections are made on the page itself, with a line stating what was wrong and when it was fixed, so that anyone who read the earlier version can see what changed. Write to us through the contact page.
How our calculators work
Every calculator on this site runs entirely in your browser. Nothing you type is transmitted, stored or logged, and none of them requires an account or an email address. Each one shows the conversion factors it uses, the vintage of those factors, and what is excluded from the result. Where a factor set is published by a government — as with the flight emissions factors — we use the published value rather than deriving our own.
AI assistance, stated plainly
Research and drafting on this site are assisted by AI tools. That assistance is bounded by the rules above: a figure is only published when it traces to a source in the hierarchy, and the source is linked next to the claim so you can check it yourself rather than trusting the process. No page is published without passing an automated quality gate that verifies word count, source presence, link liveness and internal-link limits, and pages that assert numbers get the sources printed on the page.
What we do not do
- We do not publish an estimate dressed as a measurement.
- We do not republish a company’s range or performance claim as a fact.
- We do not use “studies show” without naming the study and its year.
- We do not update a date to simulate freshness.