The scientific method that represents power production efficiency in power stations and vehicle energy efficiency are called Sankey diagrams. I have attached one below. They are good at illustrating the problem with power stations.
Power production efficiency in power stations and vehicle energy efficiency, in any type of vehicle, are totally different matters. ItÂ’s wrong to confuse the two.
After the electricity is made in a power station, losing 70% to heat losses, it loses more in transmission to the city and more in transforming the current to the NGT system. After that the electric cable and the vehicle lose even more. The total efficiency is hard to calculate on the NGT, but it will be in the region of 10%.
Diesel engines with intercoolers, turbo chargers with digitally-controlled fuel injection produce very high efficiency-up to 50% is not uncommon. They are used on the new First Bus double-deckers.
Electrical vehicles have an advantage over diesel because they accelerate and decelerate faster. Also they produce no local pollution.
Both types of motors suffer on urban travel because they constantly stop and start.
The diesel still has a big very big edge in overall fuel efficiency over power station produced electricity vehicles such as the NGT.