"nightjar .uk.com" nightjar@insert my surname here wrote in message
...

Current petrol engine efficiency averages 32%,

Nope. 25% You are on about peak.

Waiting at a traffic lights with the running engine, the efficiency of a
petrol engine is 0% When an electric car is at the traffic lights it is at
100% efficiency. IC engine efficiency decreases very, very much at low
power demand. Diesel engines loose efficiency at low power demand too,
but not as much as a petrol engine. Both as still crap.

So when a 200hp engine has to deliver only 5hp for crawling in city traffic,
the efficiency is extremely low indeed. And they also pollute like hell and
ruin people's lungs.