Why biogenic CO2 is treated differently
A tree takes carbon dioxide out of the air as it grows. Burn the wood and the CO2 goes back. The government's methodology paper describes biogenic CO2 as "the CO2 absorbed and released by living organisms during and at the end of their life", and says that "by convention, this is assumed to be in balance in sustainably managed systems". Fossil fuels are different: their carbon was locked away underground for millions of years, so burning them adds new CO2 to the air.
That convention is why reporting rules keep the two apart. It doesn't mean the CO2 from a wood boiler is harmless on the day it is released. It means reports show it on its own line, so readers can see it and judge it, rather than adding it to fossil emissions or dropping it.
What the rules say
- GHG Protocol Corporate Standard: "Direct CO2 emissions from the combustion of biomass shall not be included in scope 1 but reported separately."
- GHG Protocol Scope 3 Standard: the same applies in your value chain. Biogenic CO2 must be in the public report, separate from Scope 3. The rule covers only CO2 from burning or breaking down biomass, not methane or nitrous oxide, and not the emissions from growing, processing or transporting it.
- The government factors: the Bioenergy sheet's direct factors for biofuels are "only made up of CH4 and N2O emissions", and a separate "Outside of scopes" sheet gives the CO2. The waste factors also leave biogenic CO2 out.
The three numbers for a biomass fuel
So a wood or biofuel line in a footprint has three parts:
| Part | Where it goes | Wood pellets, kg CO2e per tonne (2026) |
|---|---|---|
| Methane and nitrous oxide from burning | Scope 1 | 57.25249 |
| Growing, processing and delivering the fuel | Scope 3, category 3 (well-to-tank) | 177 |
| CO2 from burning | Outside of scopes, reported separately | From the "Outside of scopes" sheet |
For pellets, the supply chain is bigger than the Scope 1 figure. Other wood fuels in the 2026 set: wood chips 45.05983 kg Scope 1 and 30.4 kg well-to-tank per tonne; wood logs 48.73751 kg and 52.14 kg.
A worked example
A business heats its premises with a pellet boiler that burns 30 tonnes of pellets a year:
- Scope 1: 30 × 57.25249 = 1.72 tonnes CO2e
- Scope 3, well-to-tank: 30 × 177 = 5.31 tonnes CO2e
- Biogenic CO2: 30 tonnes × the "Outside of scopes" factor for wood pellets, shown as a separate line in the report
Per kWh of fuel, pellets are 0.01193 kg CO2e in Scope 1 and 0.03744 kg well-to-tank, against 0.24677 kg for heating oil in Scope 1 alone. That is why switching from oil to biomass shrinks Scope 1 so sharply, and why the separate biogenic line matters for an honest picture.
Things that trip people up
- Reporting biomass as zero. The Scope 1 figure is small, not nothing, and there is Scope 3 and a biogenic line as well.
- Putting biogenic CO2 in Scope 1. It makes your footprint look worse than it is under the rules, and isn't comparable with other firms.
- Leaving it out completely. The GHG Protocol requires it in the public report. Leaving it out invites the question "where's the CO2 from the boiler?"
- Treating blended fuels as all-fossil or all-bio. Forecourt diesel and petrol contain some biofuel, and the government's average blend factors already allow for it. For pure biofuels such as HVO, use the biofuel's own factors.
Our posts on what CO2e means and well-to-tank emissions explain the other two parts of the table, and the guide to Scope 1, 2 and 3 covers the scopes themselves.
How Carbon Recycling helps
Add wood fuel, biogas or a biofuel with the "Any DESNZ factor" option: search for the fuel and Carbon Recycling applies the government's Bioenergy factor for your reporting year as Scope 1, with the matching well-to-tank factor available as a Scope 3 entry. Carbon Recycling doesn't hold the "Outside of scopes" figures, so work the biogenic CO2 out from that sheet and record it in the entry's note, which keeps it next to the Scope 1 line for your report and your method note.