Ruf set to take Porsche into new green territory

They're calling it 'emotion without emission'. That might not be possible in a silent Porsche, given the loss of those beautiful husky contralto tones, but the compensation comes in the results of Bavarian specialist tuning house Ruf's speedy development of all-electric 911s - a trip that's set to culminate in the first car able to regurgitate power back into the electricity grid.

Meet the Greenster, Ruf's 21st Century take on a 50 year old formula that seems to have found the secret to eternal youth. They've Targafied the roof, Speedsterised the windscreen - and replaced Ferdie's hallmark boxer six with a Siemens electric motor generating 270kW and a rip-snorting 940Nm of torque.

The project started life as the eRuf, a standard 911 bodyshell implanted with a 152 kW electric motor putting out 650 Nm of torque. Its 96-cell lithium iron phosphate battery pack was good for 51 kWh. That translated into estimates of a 240-320 km range, although no one made it clear what kind of drive conditions that was in.

In addition to a relatively tardy 10-hour charge time, a big problem for the eRuf was that the front-mounted battery pack weighed nearly 550kg, adding a whopping (net) 450kg to the mass of the donor vehicle.

Partial compensation came with the instant availability of all that torque - one of the great performance advantages of electric power - helping the car reach 100km/h in around seven seconds. That's no cause for shame in the greater scheme of things, but with petrol powered 911s bettering that for 30 years or more, it was never going to be acceptable for Ruf -- one of the marque's more reputable outsource performance tuners.

Now comes the company's second crack at it. The new new battery pack is better in every way. For a start, it's 30 per cent smaller -- so you get some of your bootspace back. It also absorbs and releases more power, and it does it faster -- so it's quicker to charge (an hour on a 400V outlet, Ruf says) -- and it delivers more efficient brake power regeneration.

What's next? How about a twin-motor version fitted with a bi-directional network connection which raises the green bar with the facility to feed power back into the grid!