Car transport: Use custom fuel consumption

[han16nah]

Instead of using one of the predefined emission factors, users can also put in their specific fuel consumption (e.g., if they track it themselves).
We should implement this.

• get manufacturing emissions separately
• calculate emission from the exact fuel combustion (needed: emission factors for the fuel combustion)

[alexbercik]

I have been thinking about this too... Another reason for using this is that different countries / provinces use different fuels. For example here in Ontario the government blends 10% ethanol and some biofuel into gasoline which lowers the CO2 emissions. This could all be taken into account automatically when we input the location and type of car

[alexbercik]

Each government publishes fuel burn estimates in the annual UN "National Inventory Submissions" reports. We could use these values for each country
https://unfccc.int/ghg-inventories-annex-i-parties/2022