Can a plug-in car really save you thousands every year?

Emission impossible

BMW i8

To plug in or not plug in Etc

Do plug-in electric cars save you money? Although environmental considerations may also play a part, let's be honest: for most people that's the killer question. The harsh truth is that the supposed planet-saving properties of EVs aren't enough to swing it. Plug-in electrics need to be cheaper, too.

The answer is arguably even more complicated than the debate over the environmental advantages of electric cars. Certainly on the face of it, it certainly seems there are major savings to be made. Even if petrol and diesel prices having fallen far from their £1.50-plus peak, the per-mile energy cost of electric cars is significantly cheaper.

Problem is, all kinds of factors come into play, from purchase prices and leasing deals, to company car tax, congestion zone charges and fuel prices at the pump. How you use you car will also have a huge impact on comparative costs.

We've attacked the cost conundrum by looking at a trio of case studies that straddle the car market from entry-level to ubercar. We're looking at the UK market, but the same issues apply throughout the world.

In each price bracket we're comparing traditional cars with a plug-in ride. Just to be clear, that can be either a pure electric car or a hybrid with both a combustion and electric motors. That's in order to compare cars that are as alike as possible in terms of cost and utility.

Typically, plug-in hybrids have bigger batteries than conventional hybrids and longer operating ranges in pure electric mode. Battery-electric cars or pure EVs with no combustion engine are, of course, also plugins. Plug-in hybrid technology is fairly complex and costly, so it's no surprise to find that the cheapest plugins are actually pure electric cars.