When BMW can't even tell you what's powering a concept car, you know just how much free reign the designers have been given. This, after all, is a company with Motor in its name - and not to be able to imagine that side of the equation - or, at least, reveal it - is telling in itself.

So don't expect to see the Vision Next 100 in a showroom anytime soon; it is a concept car in the purest sense. Instead, you can delve into the details and pull out the threads that BMW - and others - expect to be dominating our car landscape in the coming generations: from autonomy, through to manufacturing techniques, aerodynamics and interior digital treatments and connectivity options.

The key - unanswered - question from the reveal remains whether customers will fall in line with the regulations being set and the car makers' response to them. BMW won't release its 2015 sales figures for a while yet, but reports suggest less than 30,000 BMW i cars were sold globally over the past 12 months - hardly a return on the mega-bucks investment required to launch the brand.

BMW boss Harald Kruger insisted on Monday that its investment in electric technology was "a marathon not a sprint" and highlighted how BMW i technology is filtering back to the main brand via its plug-in hybrids. He may well be right - advances in consumer understanding, infrastructure and incentives, as well as punitive legislation against combustion engined cars - could finally tempt and force car buyers' hands in equal measure.

But for now, he must face an anxious wait - and that must, in part, explain why we still don't know what the BMW of 2116 will be powered by.