Biogenic CO2 and accounting concepts

Biogenic carbon dioxide (CO2) emissions come from the combustion or decomposition of biomass - plant or animal material. The most relevant source of biogenic CO2 for many organisations is the combustion of biofuels such as biodiesel and ethanol.

The Greenhouse Gas Protocol (GHGP) and reporting regulations and standards including the Corporate Sustainability Reporting Directive (CSRD) / European Sustainability Reporting Standards (ESRS), require organisations to disclose biogenic emissions separately (often called ”outside of scopes”). However, as with many disclosures, this is only needed if the disclosure is relevant to (would affect the decision of) stakeholders (opens in a new tab).

Biogenic emissions are only likely to be relevant if the company burns a lot of biofuels or agriculture / land-use change forms a large part of its supply chain. Even if biogenic emissions are not relevant for mandatory corporate reporting they may still be relevant for internal reporting purposes or for reporting against the Global Reporting Index (GRI).

Climatiq has a simple way for organisations that use biofuels to meet external and internal reporting needs.

The first part of this guide explains what biogenic CO2 emissions are and the accounting concepts. The second part explains how to use Climatiq endpoints to report biogenic CO2 and other emissions from biofuels.

What are biogenic CO2 emissions?

When plants (biomass) grow they remove carbon dioxide (CO2) from the air through photosynthesis and store it as carbon. When they are burned (combusted) this carbon is released as carbon dioxide and a small amount of methane (CH4).

Why are biogenic CO2 emissions reported separately?

Carbon dioxide emissions from burning biomass add to the stock of carbon dioxide in the atmosphere that traps heat and causes climate change. Unlike fossil fuels, however, the carbon dioxide added to the atmosphere was typically removed from the atmosphere within the past few years and so the net addition to the atmosphere is taken to be zero.

Rather than include both the removal and emissions in scope 1 the accounting has been simplified by requiring that neither are included.

This leaves a gap in reporting, though; if a company reports reduced scope 1 emissions then this could be because they use less energy or a cleaner fossil fuel or biofuels. It could even be that they have increased energy use but balanced that by using biofuels. Biogenic emissions are needed to complete the picture.

From a more strategic point of view, biogenic emissions are also needed to understand the company’s dependence on biomass as an energy source. This should then prompt stakeholders to ask questions about the biofuels such as whether they are they are from sustainable sources.

There is a huge amount of debate over the use and reporting of biogenic emissions and this guide is intended only to provide the information that is needed to report biogenic CO2; for more information see, for example, the GHG Protocol draft guidance (opens in a new tab).

Note that carbon emissions from the degradation of biomass (e.g. due to soil loss or from waste treatment as compost) are even more complex and are outside of the scope of this guide.

What emissions are reported in each scope ?

Scope 1 should include direct emissions of methane (CH4) and nitrous oxide (N2O) from sources owned or operated by the reporting organisation including emissions from combustion of fuels. Focusing on fuels, methane emissions come from incomplete combustion of fuels and nitrous oxide emissions come from the combination of nitrogen in the fuels and oxygen in the air during combustion.

These emissions, unlike biogenic CO2, are additions to the stock of greenhouse gases in the atmosphere. They must therefore be reported in scope 1.

The same logic applies to scope 2 - only CH4 and N2O emissions from biofuel combustion in electricity generation are reported in scope 2.

Scope 3 is more complex as it potentially includes emissions (and removals) from agriculture and other land-use and changes in land-use. The GHG Protocol draft guidance addresses this in detail. In brief, and at present, scope 3 reporting typically includes long-term changes in carbon stocks (e.g. from deforestation) but excludes short-term changes (e.g. planting and then burning biofuels).

Using Climatiq’s data and endpoints to report biogenic emissions

How do I report biogenic (outside of scopes) and scope 1 emissions?

If you have access to the Energy feature then biogenic emissions are included, where applicable, in the API response.

If you want to use the estimate endpoint then there are two stages to reporting emissions:

1. Find the right emission factor

2. Estimate emissions

1. Find the right emission factor

All biofuels and biofuel blends are identified by the text “bio_” within the fuel type in the activity_id where the activity_id takes the format fuel_type…fuel_use:

Examples:

• biodiesel_bio_100
• gasoline_E85_bio_85
• motor_gasoline_E10_bio_10
• motor_gasoline_bio_average

The number or text after bio_ is the percentage of the fuel that is biofuel. For pure biofuels this number is 100. Most vehicle fuels contain some biofuel. In Europe and North America this is typically 10% for gasoline / petrol and the fuel is referred to as E10 (for 10% ethanol) and the fuel_type is therefore “motor_gasoline_E10_bio_10”. As blends sold in petrol / gasoline stations change over time, some sources (e.g. BEIS) use “average” for consistency in naming and this is reflected in the fuel_type e.g. “motor_gasoline_bio_average”.

2. Estimate emissions using the source_lca_activity

All emission factors have one or more source_lca_activity that refer to the lifecycle stage that emissions come from. For scope 1 you need to use the source_lca_activity fuel_combustion and for biogenic CO2 (outside of scopes) use biogenic_CO2_combustion. You will need to use the estimate endpoint to calculate biogenic CO2 emissions. The API calls are identical apart from the source_lca_activity:

Scope 1

{
    "emission_factor": {
        "activity_id": "fuel-type_biodiesel_bio_100-fuel_use_na",
        "data_version": "^16",
        "source_lca_activity": "fuel_combustion"
    },
    "parameters": {
        "weight": 1000
    }
}

Biogenic CO2 / Outside of scopes

{
    "emission_factor": {
        "activity_id": "fuel-type_biodiesel_bio_100-fuel_use_na",
        "data_version": "^16",
        "source_lca_activity": "biogenic_co2_combustion"
    },
    "parameters": {
        "weight": 1000
    }
}

You can also report upstream emissions from fuel production under scope 3.3 (Fuel and Energy-Related Activity) using the source_lca_activity “well-to-tank” where the source provides the relevant emission factor. For more information on using the estimate endpoint see the guide here. For more details on LCA activities see the guide here.

How do I report biogenic CO2 emissions related to scopes 2 and 3?

Global Reporting Initiative (GRI) requires organisations to report biogenic CO2 emissions from scope 2 (purchased electricity, heat and steam) and scope 3 separately from those scopes. Other reporting standards and regulations (e.g. GHGP, CSRD / ESRS E1) only require these to be reported if they are material / relevant (would affect the decision of a stakeholder). In practice, few sources publish the emission factors required to make these disclosures and few, if any, organisations report these emissions.

Scope 2

The UK Government (BEIS) is the only source we are currently aware of that publishes biogenic emissions from electricity generation (scope 2) and this is because biomass forms a significant proportion of the UK’s electricity fuel mix. To report biogenic emissions from electricity generation in the UK use source: “BEIS”, activity_id: “electricity-supply_grid-source_supplier_mix” and source_lca_activity: “biogenic_CO2_combustion” using the estimate endpoint as explained for scope 1 above.

Scope 3

Many purchased goods, mainly agricultural goods, contain some element of biogenic CO2 emissions - either from combustion of biofuels or from land-use (e.g. soil loss) or land-use change (e.g. deforestation) but these are not always separately identified in the emission factors by the sources Climatiq uses. If you are looking for a way to calculate land-use & land-use change emissions please reach out to us through the contact form (opens in a new tab).