The special tools required are so expensive that GM dealers are leaving the Volt programme.

Sometimes new technology is self-limiting. Take the case of the Chevrolet's Volt range-extended battery car. Every Chevrolet dealer in the US who wants to be able to sell the Volt has to buy special tools, manuals and a charging station, so they can service them according to factory specifications.

From today, however, Chevrolet dealers are no longer allowed to remove a faulty battery (which weighs 200kg) from a Volt and send it back to the factory for repair or replacement.

Instead, they have to measure which segment is faulty and remove only that segment - which is going to save GM a fortune in shipping costs. But, and this is a very expensive but, in order to remove individual sections of the battery, it has to be de-powered - in other worlds it has to be dead flat.

And to do that without creating dangerous excess heat it has to be hooked up to a special battery de-powering rig, which costs $4735 (R40 000) from GM.

For some Volt dealers, who can count the number of Volts they have sold since it was introduced two years ago on the fingers of one hand, the maths just doesn't work, and a number of them have told GM “Thanks but no thanks”, and are no longer selling Volts.

GM won't specify how many dealers have left the programme, but says they were responsible for about one percent of sales - which is a lot worse than it sounds, because 70 percent of Volt sales come from just 300 dealers out of a US network of 3,079, 2614 of which are Volt-certified.

Now, if the remaining 2314 Volt dealers generated only 30 percent of sales, that implies that one in every 30, or close to 80 dealers, have given up on alternative-fuel GM cars.

Nevertheless, the issue puts smaller GM dealers between a rock and a hard place, because they will also need the same de-powering rig if they want to sell the Cadillac ELR, due for release in mid-2013, and which shares the electrical architecture (and battery) of the Volt.

The result will probably be that, in the medium to long term, only high-volume dealers in urban areas will be able to grab a piece of GM's alternative-fuel sales - and a number of disgruntled smaller retailers believe that's the way GM wants it.