for example the typical compounded efficiency of the energy chain from crude oil at the well to useful transport services is about per cent only assuming single occupancy of a passenger car with five seats while in this case the efficiency of transforming primary to final energy is as high as per cent including transport refining and distribution the efficiency of transforming final to useful energy efficiency is only about per cent that is the result of per cent engine efficiency and per cent efficiency of drivetrain and car full occupancy of the car would increase the compounded efficiency from to per cent