A good review here with realistic report on economy you can expect:
http://www.businessgreen.com/bg/review/ ... f-the-yearThe official NEDC all-electric driving range for the GTE is 31 miles. As with the official economy figure, this is not likely to be realistic in real-life driving. We averaged between 15 and 23 miles of electric range on a fully charged battery in normal driving.
The GTE does have an excellent and very efficient petrol engine, and without any battery assistance we averaged 48.6mpg at 70mph on the motorway – in ‘B’ mode, which increases the level of regeneration when decelerating and braking.
Overall, after a week with the car, we averaged 44.5mpg. This was comprised of around 50 miles of pure electric running and 500 miles of long distance driving – so you can see the potential to improve on this figure with more all-electric journeys.