I recently bought a TDI

I used to drive a car that used about 7 liters of premium gasoline per 100 km. Since I do a lot of driving, I jumped on the opportunity to purchase a Jetta TDI, anticipating lower fuel costs.

Here is my first assessment of my ecological performance, using the conversion figures as per the Canadian GHG summaries.

What I used to do on about 63 liters of premium gasoline I now do on about 45 liters of diesel fuel, I am using about 25% less fuel! By using less fuel and one requiring less energy input in the refining process, the proportional GHG reduction at the refinery level is about 27.5% (using the price difference as indicator of energy requirement).

The GHG emissions (in CO2 equivalents) from my use of the car changes from 7 x 2.45kg/l = 17.15kg/100km (for the premium gasoline powered vehicle) previously to 5 x 2.80kg/l = 14.00kg/100km. My environmental footprint is reduced by about 18%.

SOx (and with it PM) is a wash as both fuels have similar S-content.

All in all, I am satisfied with my GHG reductions so far.

In ecolonomic speak (ecological and economic benefits), there is a pretty good correlation between the 25% financial benefit and the over 18% GHG reduction.