# Does fly ash from a coal power plant carry any of the plant's emissions?

Canonical: https://senseible.earth/answers/fly-ash-from-power-plant-carbon-allocation

Usually almost none. Many product footprint rules and EPD programmes treat fly ash as a waste or a low value by product, so only its collection, drying, grinding and transport are counted. Some use economic allocation, which adds a small share, so ask what rule a cement or brick supplier used.

## Common practice

- Fly ash as waste: zero share of combustion emissions, only handling and transport counted.
- Fly ash as co product: a share by economic value, small because ash sells cheaply.
- Never by mass, which would load most of the plant's CO2 onto ash.

## What to count yourself

Trucking or rail from the plant to your site, any drying, and grinding power. These are real and often larger than people expect over long distances.

## Why it matters

Fly ash lowers clinker or clay use, so blended cement and fly ash bricks often show lower figures. Make sure the supplier's rule is stated so the comparison is fair.

## What Senseible does here

Senseible reads freight, fuel and electricity invoices into a dated, fingerprinted record, so the transport and processing behind your fly ash figure can be traced back to the documents.

- [Fly ash brick footprint](https://senseible.earth/answers/fly-ash-brick-carbon-footprint-per-1000)
- [Truck freight factor India](https://senseible.earth/answers/truck-freight-emission-factor-india)
- [Coal power CO2 per kWh](https://senseible.earth/answers/coal-power-plant-co2-per-kwh-heat-rate)

Sources: [ISO 14067:2018, Carbon footprint of products (iso.org)](https://www.iso.org), [GHG Protocol Product Standard](https://ghgprotocol.org/standards)

Last reviewed 2026-10-21.