Audi says: Concept showcases advanced technology of the original E-tron in a more compact yet no less appealing package.

Spec sheet: Lightweight (1350kg) aluminium and carbon fibre-reinforced plastic body powered by two electric motors and a lithium-ion battery pack.

Giving any two concepts the same name will always cause confusion, especially when they’re similar-looking, made by the same company and launched within months of each other. Audi’s second E-tron concept is such an offender – launched in Detroit in January 2010 not four months after its namesake predecessor at September 2009’s Frankfurt show – but despite this blip in Audi’s otherwise super-slick marketing the second car is also exciting from a green design viewpoint. At 3930mm, it is 290mm shorter than the original E-tron, 110mm narrower and 10mm lower, making it a potential future ‘R4-sized’ production car compared to the original’s more R8-like proportions. The exterior design is arguably more coherent than the already very clean original E-tron with uninterrupted flowing lines and some construction techniques that could only be made due to the lightweight materials used. For instance, as project leader Steve Lewis points out, the large all-in-one nature of the carbon fibre-reinforced plastic bonnet and fender panel would be very hard to make out of steel and could lead to new more efficient production techniques – while pleasantly reducing the number of shut lines on the concept. Inside the second E-tron is similar to the first one – all stretched leather and satin metal – and showcases eco-focused slim seats featuring aluminium-frames and carbon fibre seat panels but with more exposed carbon fibre, especially in the interior door panel area. Again, it’s a thoroughly taut and muscular piece of sculpture, and according to interior designer Florian Flatau, consciously avoids the cutesy soft look of many recent eco car designs.