Thanks, marktm. I just bought a 2014 Leaf and it shows I'm getting 3.4miles/kWh, so I know it's costing me between 3p and 4p a mile. I wish the 2012 had a similar function on its display, but it doesn't seem to. But I'm guessing it's not substantially different. This compares very favourably with the 14p/mile I would be getting in the UK currently from a petrol engine doing 40mpg and with petrol costing £1.45/litre.