Emission Factor Uncertainty

Where uncertainty estimates are available by the publication source, these values are used.

However, when these estimates are not available, a best-effort single parameter uncertainty estimate is performed using GHG Protocol methodology, using context and data available in methodology documents.

In a similar way to how volume uncertainty levels are organised, EF uncertainty in Carbon+Alt+Delete follows a predefined list of reference options to keep classification transparent, traceable, and manageable.

For each option, an emblematic example is central to define the context in which this uncertainty option is applicable. You can find these examples in the table below, together with their individual indicator scores for each of the uncertainty indicators. For EF uncertainty, two more parameters come into play; the Basic Uncertainty Factor Process Type, reflecting a general industry-wide average uncertainty, as well as the share of non-CO₂ emissions in each factor, reflecting the scientific uncertainty of non-CO₂ GWP values.

Please note at that EF uncertainty in the tool reflects both emission factor and GWP uncertainty. For more info, see background and theory.

For the source of the uncertainty factors and the definitions of each parameter in the pedigree matrix, please consult the following sources.

GHGP Quantitative Uncertainty Guidance

GHGP Scope 3 Uncertainty Calculation Tool

Section 7.3 of Ecoinvent v2.0 data model methodology (referenced source for pedigree matrix)

EF uncertainty	Emblematic example	Reliability	Completeness	Temporal rep.	Geographical rep.	Technological rep.	Basic Uncertainty Factor Process Type	Share of non-CO₂ emissions
Very Good	Emissions per liter diesel - mobile combustion (UK Gov)	Very Good	Very Good	Very Good	Good	Very Good	Combustion process	0.9516%
Good	Emissions per kWh electricity - electricity (AIB)	Good	Good	Very Good	Very Good	Good	Electricity	0.0000%
Fair	Emissions per kg steel - good and services (UK Gov)	Fair	Fair	Very Good	Good	Fair	Industrial Products	0.0000%
Fair (fugitives)	Emissions fugitive emissions R-32 (IPCC)	Fair	Good	Very Good	Very Good	Good	Direct emissions, Other GHGs	100.0000%
Poor	Emissions per EUR meat bought - Goods and Services (Exiobase)	Poor	Poor	Very Good	Good	Good	Agricultural Products	0.0000%
Poor (Assets)	Emissions per m2 concrete building - Assets (ADEME)	Poor	Poor	Good	Good	Fair	Infrastructure	0.0675%

This is an active development and is subject to improvement over time. Last update: April 2024.

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