Emissions FactorsThe emissions factors used in the 360°carbon calculator for the Energy, Travel, Flying and Waste & Water categories comes from the UK Government's Department for Business, Energy & Industrial Strategy (BEIS).
The factors for Expenditure and Food come from other sources.
The FactorsThe factors are updated annually and previous years' factors generally expire on the 30th of June after the publication of the year's new factors. We aim to update the factors we use in the calculator within a month of the new factors being published – BEIS sometimes issues updates fairly quickly after releasing the new factors.
Carbon Dioxide EquivalentsWe report all carbon emissions in terms of kg or tonnes of CO₂. Behind the scenes, most of the factors we use are denominated in kg of CO₂e. The “e” in CO₂e stands for “equivalents” – equivalents take into account the effect of other greenhouse gases. The other gases included are, typically, methane (CH₄), and Nitrous Oxide (N₂O) which each have a Global Warming Potential (GWP) that can be used to render them as the equivalent CO₂. This gives a more accurate idea of the overall impact of our emissions on the environment.
Well to TankMany of the factors we use include “Well to Tank” emissions. These are the emissions associated with extraction, refining and transportation of raw fuel prior to its usage. Including WTT emissions in the total figure adds approximately 10% to the base emissions factors, but helps to give a more realistic idea of the full impact of our use of fossil fuels.
BaselinesOur database contains factors going back to 2016, allowing you to calculate footprints from the beginning of 2017 – this is in order to allow organisations to establish a baseline for their calculations against which future footprints can be compared. (Prior to 2016 the BEIS factors don't cover all the areas we wanted to include in the calculator.) If you have complete data for a previous year that covers all five calculator categories you could use that to calculate a baseline and track your progress over a known baseline. If that baseline comes from a year when you weren't really thinking about energy saving or other carbon footprint reducing activities, even better!
Emissions CalculationsIn calculating emissions for footprints the calculator uses a “sliding window” on the set of factors mentioned above. Depending on the start point (month and year) for your footprint, the calculator will use the appropriate year's factors based on BEIS advice:
"You should use the version of the factors that correlates with the data on which you are reporting (for example, factors labelled as 2021 should be used for data from calendar year 2021). If you are reporting on an April to March year, the factors from the calendar year in which the greatest portion of your data falls should be applied (for example, the 2021 factors should be applied to data in reporting year 01/04/21 – 31/03/22, the 2020 factors should have been applied to data in reporting year 01/04/20 – 31/03/21). Users that operate a July to June reporting year should apply the newest set of available factors."