Help with a question

Hi, would someone be able to help me with this question?



Basically I don’t understand why the fuel with the highest energy released per mole of CO2 produced in combustion, is the one which is the lowest environment impact; I would have thought that the one with the lowest energy released has the lowest impact.

Thanks!

We use fuels to obtain energy. We want energy. We need energy.
The environmental impact comes from the carbon dioxide that is made as a by-product.
If you use the data to obtain energy per mol of carbon dioxide by dividing the energy by the mols of carbon dioxide you will see that ethanol provides more energy (wanted) per mol of carbon dioxide (not wanted).