Everything you need to know about emission intensities
Emission intensities are used to determine the quantity of CO2e generated by a given activity. Thanks to these coefficients, a firm’s carbon footprint can be estimated when carrying out a carbon assessment.
How is an emission intensity calculated? What data should be collected and how should it be processed? Which databases index these different coefficients?
This article is here to answer all of your questions about CO2e emission intensities.
What is an emission intensity?
Definition of an emission intensity
An emission intensity is a coefficient that allows for an activity data to be converted into CO2e emissions. It gives the average rate of GHGs (greenhouse gases) emitted for a given activity.
Activity data, also known as physical data, quantifies the various activities involved in a firm’s operation. When considering a 3-scope carbon footprint, they can be of diverse nature, such as electricity consumption, purchase of services, transported tonnage, etc.
Emission intensities enable these activity data to be converted into greenhouse gas emissions, and thus to compare the respective carbon footprint of heterogeneous activities. This conversion then makes it possible to identify a firm’s most important emission items.
Emission intensities are listed in public or private databases, such as that of the French Resource centre for greenhouse gas accounting. They are calculated from studies that take into account the entire life cycle of an activity, good or service, to establish its climate impact. Read along to find out more about these databases.
A real-world example of using an emission intensity
In the case of a car, its use’s carbon impact can be calculated either from the consumed litres of diesel, or from the total travelled distance.
To find out the emission intensity of a specific type of petrol, you can visit the French Resource centre for greenhouse gas accounting’s website, where a quick search gives the following result:
(Source: the ADEME’s website)
How are emission intensities calculated?
There are two steps to calculating an emission intensity:
- Analysing the life cycle of a good or service;
- Converting these results into CO2 equivalent (CO2e).
Life Cycle Assessment
Life Cycle Assessment (LCA) is a study that measures the impact of a good or service on the environment. It is very comprehensive : not only does it include the carbon footprint, but also other environmental effects (biodiversity, water consumption, etc.).
It takes into account all stages of a product or service’s life cycle:
- Manufacturing (extraction of raw materials, energy consumption, etc.);
- Transportation (all stages of transport of materials or the final product during manufacture or distribution);
- Use (e.g. energy consumption to the product’s operation, such as electricity for a hoover or a car…);
- End-of-life (collection, recycling or disposal).
Listing these different stages enables deducing all the emissions produced at each phase of the product or service’s life cycle, from its design to its end of life.
Furthermore, this analysis is completed by a multi-criteria approach: both incoming and outgoing flows are taken into account. This includes everything that enters and leaves the product’s life cycle and generates pollution (iron, water, oil and gas resources, but also waste, gaseous emissions, rejected liquids, etc.).
The results are then consolidated into CO2 equivalent to convert all GHG emissions listed into a single denominator.
How does the CO2 equivalent work?
Emission intensity makes it possible to put all GHGs emanating from goods or services produced or used by a firm on the same level. This is known as the CO2 equivalent.
CO2 (or carbon dioxide) is not the only source of atmospheric warming. Other gases are involved, such as methane, nitrous oxide, fluorinated hydrocarbons, etc. In 1997, the Kyoto Protocol identified 7 distinct greenhouse gases (GHGs).
However, these gases do not all have the same impact. To describe the relative strength of a greenhouse gas, we use the term global warming potential (GWP). The time frame each gas remains active in the atmosphere is used to determine their respective GWP.
To compare GHGs (which do not have the same warming potential) they are converted into “CO2 equivalents“. CO2 is thus considered the reference gas. GWPs are determined by the IPCC and calculated over 100 years.
Example: CO2 has a GWP of 1 per 100 years, while methane has a GWP of 30 and nitrous oxide 265 (according to the 5th IPCC report). The IPCC thus considers that one tonne of methane has a global warming potential 30 times higher than one tonne of CO2.
The use of CO2 equivalent as an indicator makes it possible to cover all sectors equally. Indeed, while CO2 is the most common gas, accounting for about 75% of human GHG emissions, some sectors are very high emitters of methane or nitrous oxide, like agriculture.
Thanks to the CO2 equivalent, GHGs can be compared and aggregated, which makes it easier to analyse company activity data.
What are the main emission intensity databases ?
Emission intensities are calculated and listed in databases, which are provided by different types of organisations.
General public databases
These databases are often created and maintained by government authorities. These databases are public and access to emission intensity details and documentation is free. They are generalist, i.e. they cover all types of sectors.
In France, the Resource centre for greenhouse gas accounting made its Base Carbone available to all firms with over 5,000 emission intensities, and is still updating it. There are equivalents abroad: the Greenhouse Gas Equivalencies calculator, instituted by the Environmental Protection Agency (EPA) in the US, or the database produced by the Department for Environment, Food & Rural Affairs (DEFRA) in the UK.
Specific public databases
Less generalist public databases also exist, they are specific to a given activity sector. These databases are more precise than generalist ones and allow for a more detailed analysis of the impact of a firm’s activities.
For example, the French INIES only concerns the construction sector: the carbon footprint of different types of concrete is listed and analysed, where a generalist database would only list a single type. Similarly, Agribalyse focuses only on agricultural and food products.
These databases are often developed by concerned stakeholders. For example, the GLEC framework specialised in transport was initiated by over 50 firms in the sector. It lists all types of goods and provides details of each activity according to geographical area, tonnage, type of cargo, type of truck or cargo vessel used, etc.
These databases are essentially different from the previous ones in that they are developed by private organisations and are lucrative.
Some of these databases have more numerous and detailed intensities than public databases, with more documentation. This is the case of ecoinvent, listing almost 15,000 emission intensities.
Creating your own database
It is also possible to calculate one’s own emissions intensities, based on the life cycle of the goods and services used or produced.
Calculating your own emission intensity may be recommended for specific activities, such as industrial activities that require the purchase of few raw materials.
Building your own database may require an expert’s support to become familiar with collecting activity data, its processing and the calculation of emission intensity. However, it establishes a very precise action plan adapted to a firm’s activities.
Relying on different available databases enables using the most accurate emission intensities for a firm’s specific activities, and this to precisely establish its carbon footprint.
carbometrix integrates data from general public and private databases, as well as from specialised databases. This is done to precisely calculate your firm’s carbon footprint and propose a detailed action plan to reduce your emissions. Would you like to have your firm’s carbon footprint assessed? Get in touch with us today!