Fuels associated with biofuel blends by DEFRA

The data contained within this methodology is used as a reference for calculating greenhouse gas emisisons associated with blended fuels.

The methodology

Emissions model

The emissions calculation methodology is based upon emissions factors which relate mass, volume, or energy-based quantities of biofuel with their associated quantity of greenhouse gas emissions.

• 'direct' emissions represent those greenhouse gases emitted during combustion

• 'indirect' emissions represent those greenhouse gases emitted in association with stages in the fuel production chain such as raw material extraction and delivery, and therefore considered to 'embodied' within the fuel.

• 'life cycle' emissions are the sum of direct and indirect emissions which contribute to atmospheric CO₂ concentrations.

• Emissions which are 'outside of scopes' are equivalent to the CO₂ absorbed from the atmosphere during growth of the biomass. These do not cause a net contribution to atmospheric CO₂ concentrations.

Model data

Emissions factors relating to the following calculation requirements are available for each biofuel type:

• direct emissions by mass: direct CO₂e emissions per unit fuel mass
• indirect emissions by mass: indirect CO₂e emissions per unit fuel mass
• life-cycle emissions by mass: total/life-cycle CO₂e emissions per unit fuel mass
• non-scope / biogenic emissions by mass: biogenic CO₂ emissions per unit fuel mass
• direct emissions by volume: direct CO₂e emissions per unit fuel volume
• indirect emissions by volume: indirect CO₂e emissions per unit fuel volume
• life-cycle emissions by volume: total/life-cycle CO₂e emissions per unit fuel volume
• non-scope / biogenic emissions by volume: biogenic CO₂ emissions per unit fuel volume
• direct emissions by energy: direct CO₂e emissions per unit fuel energy
• indirect emissions by energy: indirect CO₂e emissions per unit fuel energy
• life-cycle emissions by energy: total/life-cycle CO₂e emissions per unit fuel energy
• non-scope / biogenic emissions by energy: biogenic CO₂ emissions per unit fuel energy

Similar methodologies

The DEFRA methodologies for biofuels and blended fuels are also available.

How to use this category

Choosing a specific activity type

To use this methodology, specify the fuel type using the fuel drill down choice.

Activity data required

Since emisisons according to this methodology are directly proportionate to fuel quantity, the quantity of fuel used must be specified using either the mass, volume or energy profile item values.

Results and calculation

CarbonKit returns the quantity of greenhouse gas emissions associated with the quantity of fuel specified. The following discrete amounts are returned:

• directCO2e: direct CO₂e emissions
• indirectCO2e: indirect CO₂ emissions
• lifeCycleCO2e: life-cycle CO₂e emissions
• bioCO2: biogenic CO₂ emissions

Notes

Default units

The CO₂e emissions factors contained within this methodology are presented in a mixture of units. Each fuel is prepresented by per unit energy emissions factors of the form kg [emissions] per GJ. In addition, diesel and petrol are represented by volumetric emissions factors (kg [emissions] per litre), while CNG is represented by a mass-based one (kg [emissions] per kg).

For consistency, and user flexibility, all fuels have been provided with a full suite of volumetric, energetic and mass-based emissions factors. The mass-based factors for iesel and petrol, and the volumetric factors for CNG, were derived from the existing mass/volume factors using density values published in the same DEFRA GHG Conversion Factors source documentation.

Users of CarbonKit can, of course, choose to specify their consumption in any appropriate unit with the CarbonKit handling any required conversions.