Re: @ bazza
"What is the fuel-energy conversion efficiency of a modern all electric car compared to a modern petrol driven car?"
Well I look at it like this - just comparing the basic energy per mile for both.
Tesla S 85kWh for ~250 miles = 1.2MJ/mile (85e3 W *3600 s /250)
My slightly lower weight but less aerodynamic diesel ( 55mpg measured over the last 1400 miles) = 3MJ/mile. ( 36MJ/L * 4.5 / 55 )
So it all comes down to electric generation/distribution/charging/discharging losses vs refining/transport losses. The electrical losses are the big variable country-country and indeed station-station with older coal-fired stations being particularly bad and gas, nuclear/wind/solar/hydro increasingly better.