If these companies didn't minimize their corporate taxes through any (legal) means possible, then they are doing a disservice to their shareholders. I would argue that they are doing a criminal disservice by not minimizing their taxes - they are not maximimizing the return on investment to their shareholders. Assuming that the money saved in taxes doesn't end up all being spent on hookers and blow for the top executives of a company, minimizing taxes helps the business grow. If you think paying taxes is such a great idea, go ahead, volunteer some extra money to the tax department, or avoid taking any of your legal deductions.

A kWh is a measure of energy, and a gallon (US) of regular gasoline (http://en.wikipedia.org/wiki/Petrol#Density) contains about 9.67 kWh of energy. 15 kWh is roughly 1.55 US gallons. 100 km is roughly 62.1 miles.
The mileage 15 kWh / 100 km is equivalent to about 64.5 miles per US gallon.
I hope I got that right.