A guide to fuel activity_id

Climatiq’s database draws on many different sources for fuel emission factors and each source names their activities in a different way. Climatiq’s Activity ID contains a normalized, standard fuel name, allowing you to easily find emission factors and perform calculations across different years, regions, and sources.

We have also revised some of the emission factor names to give them a more consistent format while keeping them close to the original name given by the source.

What is the Activity ID?

Climatiq assigns an activity ID (field: activity_id) to every emission factor in the database. The same Activity ID can be shared between many emission factors for the same activity; our normalization process groups together emission factors describing the same activity across all regions, years, sources, LCA stages and unit types. See more details in this guide.

The Activity ID (field: activity_id) contains two components for fuels:

• “type”: this is the normalized fuel name (e.g. motor gasoline)
• “fuel_use”: some sources provide a general (stationary or mobile) or specific (e.g. aviation) use

The next two sections explain the changes we have made to these two components.

Changes to fuel type

Climatiq has undertaken an extensive process of improving the normalization of activity_id for fuels, reducing the number of unique “type” by one-third without reducing the number of emission factors.

We have, as far as possible, used the most common fuel name as the normalized fuel_type and this is usually the IPCC name. The key examples of changes we have made are:

• gasoline, petrol, motor_gasoline → motor_gasoline
• avgas, aviation_gasoline, aviation_gas → aviation_gasoline
• lignite_coal, lignite, coal_lignite → coal_lignite
• anthracite, anthracite_coal, coal_anthracite → coal_anthracite

We group together terms that would tend to be used in similar applications, hence we group coal types together under the prefix “coal” to keep these together when sorted alphabetically. For the same reason we have chosen aviation_gasoline (rather than gasoline_aviation) to keep it consistent with aviation_turbine_fuel.

Gross and net calorific value labels

Where activity is measured using energy (unit_type “energy”) e.g. kWh or GJ, some sources, most notably the UK Government (BEIS, DEFRA), provide two emission factors, one using gross calorific / higher heating values (gross CV) and one using net calorific / lower heating (net CV) values.

Fossil fuels tend to be invoiced on a gross CV basis when they are not invoiced on a volume or weight basis. Natural gas is the most common example of this. The UK Government’s guidance (opens in a new tab) notes:

"In general, unless you have specific knowledge about your fuels that would lead you to choose “Net CV”, organizations should use “Gross CV” factors by default. If you are unsure on what basis you are billed for energy then ask your energy supplier, or if you know the the quantity (volume or weight) of fuel purchased then use that instead."

To make it easier to switch between unit_type (weight, volume, energy), we have removed the _gross suffix from the “type” for all fuels. The _net suffix remains where appropriate. For example:

• natural_gas, natural_gas_gross, natural_gas_upper_heating_value → natural_gas
• burning_oil, burning_oil_gross → burning_oil
• burning_oil_net → burning_oil_net
• natural_gas_net → natural_gas_net

Biofuels are more usually measured on a net CV basis (for unit_type “energy”) and so the emission factors are normally provided by the sources on a net CV basis. We are therefore making that explicit in the Activity ID by using the _net suffix where applicable:

• biodiesel → biodiesel_net
• bioethanol → bioethanol_bio_100_net

Biofuel-specific changes

To make it easy to find biofuels and biofuel blends and understand the proportion of biofuels in fuels we label fuels with a biogenic element with a suffix bio_x where x is the percentage of the fuel that comes from biomass.

For some sources the biofuel blend is not a specific percentage but represents the average blend for the particular region. In this case we use the suffix bio_average. The main examples of this are vehicle fuels sold by petrol / gas stations, natural gas supplied through the mains and “renewable” or “development” fuels.

Examples:

• biodiesel_100percent, biodiesel_biofuel, biodiesel → biodiesel_bio_100
• wood_chips → wood_chips_bio_100
• ethanol_100percent, ethanol → bioethanol_bio_100
• gasoline_10_percent_bioethanol_blend → gasoline_E10_bio_10
• gasoline_with_biofuel → motor_gasoline_bio_average

Any of these may be suffixed with _net where applicable (see above).

Note that the emission factor name will still remain close to the name given by the source, so that you will still be able to find it.

Biofuels - biogenic emissions

We have made it easier for companies to report biogenic emissions where they may be required by international accounting and reporting standards including the Greenhouse Gas Protocol, CSRD and GRI.

Where biogenic emissions were previously reported under two separate activity_id they are now reported under one activity_id with different LCA Activities. For example:

To obtain the scope 1 emissions from fuel combustion you can continue to use the LCA_activity fuel_combustion. To obtain the biogenic emissions you will need to use the new LCA_activity biogenic_co2_combustion.

See our detailed guide on calculating and reporting biogenic emissions here.

Changes to fuel use

Greenhouse gas emissions from the same fuel can vary a small amount depending on what equipment (e.g. car, truck, lawnmower, generator) is being used. The emission factors for CO2 are not affected, just the emissions factors for Methane (CH4) and nitrous oxide (N2O) which vary according to the combustion efficiencies and different types of emissions-limiting filters and devices that are fitted. As CH4 and N2O typically form a tiny proportion of emissions these difference are usually far too small to make a difference in reporting. However, Climatiq hosts a wide range of emission factors for different fuel uses where the sources provide these.

At a high level the split is between stationary and mobile. Some sources then provide additional specific uses. As for fuel names, different sources use different terms for the same fuel use. We have normalized these fuel use terms to make it easier to select the right emission factors.

Key examples of fuel_use changes are:

• stationary_combustion → stationary
• mobile, transport → mobile
• transport_aviation → mobile_aviation
• electric_power, electricity_generation → electricity_generation
• residential, domestic → domestic

The fuel_use “na” is still used where the source does not specify a particular use and the emission factor could be applied to any use.

In some cases we have changed the type and fuel use; for example see the two complete Activity IDs below:

• fuel-type_compressed_natural_gas_cng_heavy_duty_vehicles-fuel_use_transport → fuel-type_cng-fuel_use_mobile_hdv
• fuel-type_diesel_oil_euro_iv_or_higher_heavy_duty_vehicles-fuel_use_transport → fuel-type_diesel-fuel_use_mobile_hdv_euro_iv_higher

Note that although sources may specify a fuel use it does not necessarily make that emission factor invalid for another use. The difference between emissions from the same fuel but different uses is typically insignificant (<1%).

Abbreviations

Abbreviations are used in the fuel_type and fuel_name where these are commonly used in the source fuel names or fuel uses. The abbreviations are:

Fuels

LPG - liquefied petroleum gas

LNG - liquefied natural gas

CNG - compressed natural gas

HVO - hydrotreated vegetable oil (a form of biodiesel)

ME / FAME - fatty acid methyl esters (a form of biodiesel)

Fuel uses / vehicles

LDV - light-duty vehicle

HDV - heavy-duty vehicle

MHDV - medium and heavy-duty vehicles

HDPI - vehicle with High Pressure Direct Injection fuel system

SI - vehicle with Spark Ignition fuel system na - not specified by the source

Others

CV - Calorific value / heating value.