Emissions FactorsThe emissions factors used in the 360°carbon calculator for the Energy, Travel, and Waste & Water categories comes from the UK Government's Department for Business, Energy & Industrial Strategy (BEIS).
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.
You can download a copy of all the factors used in the calculator. The spreadsheet includes a handful of factors that are not currently available in the calculator but will be available through the API.
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, th calculator will use the appropriate year's factors based on the expiry date of the BEIS factors.
For example, if you set the footprint year to start in January 2018, the calculator will use six months' worth of 2017 factors, and then six months' worth of 2018 factors. The basic assumption of this approach is that your carbon emissions are spread evenly through the year. Obviously, this is rarely the case, but since we ask for data that has been averaged over the year (usually by month) this approach will give a satisfactory result.
This approach also means that as factors change and are updated your previous footprints will reflect the factors available at the time – and you will generally see efficiency gains over time as decarbonisation takes place at the national level.