# How should we explain a big change in BRSR emissions from last year?

Canonical: https://senseible.earth/answers/explain-big-change-in-brsr-emissions

Split the change into its causes: more or less production, a different fuel or power mix, a new emission factor, a change in boundary, or a corrected error. Give the size of each in tonnes and restate last year if the method changed, so readers compare like with like.

## Five usual causes

- Activity: output went up or down.
- Mix: a fuel switch, solar added, or more grid power.
- Factor: a new CEA database version or a new fuel factor.
- Boundary: a plant added, closed or sold.
- Correction: last year's figure had an error.

## How to write it

- One line per cause with the tonnes it explains.
- Show intensity alongside the total, since output changes move totals.
- If a factor or boundary changed, restate last year's figure on the new basis and say so.

## What not to do

Do not credit reductions to projects when the drop came from lower output or a new factor. A reviewer will check.

## What Senseible does here

Senseible reads kWh, litres and kg from electricity bills and fuel invoices into a dated record per site, with the factor and source on every line, and prepares BRSR drafts from that data. Reports are self-declared drafts.

- [Emissions fell but intensity rose](https://senseible.earth/answers/emissions-fell-but-intensity-rose)
- [Restate after finding an error](https://senseible.earth/answers/restate-emissions-after-finding-an-error)
- [Which intensity metric to use](https://senseible.earth/answers/which-carbon-intensity-metric-to-use)

Sources: [GHG Protocol Corporate Standard](https://ghgprotocol.org/corporate-standard), [CEA CO2 Baseline Database](https://cea.nic.in/cdm-co2-baseline-database/?lang=en)

Last reviewed 2026-10-23.