To this day hybrid vehicles still don’t offer sufficient improvements in fuel-economy, performance and reliability to justify their cost over regular petrol and more efficient diesel powertrains, a factor that’s made Porsche execs more wary of launching petrol-electric versions of its own cars. While sister brands VW and Audi are pushing ahead with the launch of a new hybrid system co-developed between the three companies, Porsche will hold out until at least the end of the decade.

“Though there is still no decision on the planned introduction date of the hybrid version of our Cayenne SUV, I’m sure we’ll only introduce the new system with the start of the next SUV generation in 2010,” a Porsche manager told Automobilwoche. Audi, meanwhile, will launch a hybrid version of its Q7 early next year.

Porsche’s upcoming Panamera sedan, due in 2009, was also tipped to get a hybrid option but this too has been delayed. “We want to have time to analyze the experience with the Cayenne and, depending on what we find, launch the Panamera with hybrid drive then or perhaps as late as 2013,” the Porsche insider said.

According to another Porsche exec, the chances for hybrids in the US are not as great as originally thought. “The most optimistic forecast still only calls for a market share of 5%,” said Klaus Berning, Porsche’s head of distribution.