The calculator uses a figure of 100 g CO2 / mile.
This is based on an overall figure of 49 g/km i.e. 80 g / mile (or 0.080 kg / mile) - from the AEA Report . This gives a range from 19 g/km to 71 g/km for intercity trains depending on route, engine type (diesel or electric) and passenger load (ranging from 44% to 68%).
Allowance is needed for the fossil fuel used in oil exploration and refining (which is overall around 85% efficient - see car sources page), and for train and track manufacture and maintenance. So the figure of 80 g / mile is adjusted to 100 g / mile.
|g / km||g / mile||Source||Notes|
|49||80||[AEA, 23]||The most detailed source, and the one used as a basis|
|49||80||[CG, 10]||Recommended by CG, summarising several sources|
|60||100||||giving DEFRA as the original source|
|80||130||[MH, 3]||(underground / metro)|
So the factor used by the Carbon Independent calculator is in the middle of the range of published estimates.
See Reference List