Stuttgart - The Porsche tuning firm Ruf has announced that it is building an electric-drive Porsche Cayman supercar equipped with a 150 kW/204 hp electric engine with a range between 250 and 300 kilometres.

The firm, which normally gives Porsche cars a horsepower boost, will provide power to the motor with a lithium-ion battery pack. The top speed will be at least 200 km/h.

Ruf will reveal a version of the car in October but it has yet to reveal how many cars it plans to produce and their prices.

The California-based firm Tesla has so far dominated the electric-drive sports car market with its Tesla Roadster that sells for 100,000 dollars. It is, however, expected that the electric Porsche Cayman will cost far more. (dpa)