# How do I calculate emissions for a hydrogen fuel cell bus?

Canonical: https://senseible.earth/answers/hydrogen-fuel-cell-bus-emissions-per-km

The bus emits only water, so the footprint lies in the hydrogen. Multiply kg of hydrogen used per km by the CO2 per kg from its production: high for hydrogen from natural gas, low for electrolysis on renewable power. Ask the supplier for that figure.

## Scopes

No Scope 1 from the bus itself. Emissions from producing bought hydrogen sit in Scope 3 Category 3. If you make hydrogen on site, the electricity or gas you use is Scope 2 or Scope 1.

## Compare fairly

Set a diesel or electric bus beside it on the same route, with the same km and passengers, before claiming a saving.

## What Senseible does here

Senseible reads bills, fuel invoices and production records into dated, fingerprinted records, so the figure you send a buyer can be traced to its documents.

- [SMR hydrogen CO2 per kg](https://senseible.earth/answers/smr-hydrogen-co2-per-kg)
- [Grid hydrogen intensity](https://senseible.earth/answers/grid-electricity-hydrogen-carbon-intensity)
- [Electric vs diesel bus depot](https://senseible.earth/answers/electric-vs-diesel-bus-depot-indian-grid)

Sources: [GHG Protocol Corporate Standard](https://ghgprotocol.org/corporate-standard), [GHG Protocol Corporate Value Chain (Scope 3) Standard](https://ghgprotocol.org/corporate-value-chain-scope-3-standard), [International Energy Agency](https://www.iea.org)

Last reviewed 2026-10-22.