Porsche would not consider offering a diesel engine as a means of complying with future CO2 emissions limits, but it is developing a hybrid drivetrain.

Porsche's head of research and development, Wolfgang Dürheimer, told Automobilwoche that executives are locked in intensive debate about how to meet the average 130g/km per vehicle requirement proposed by the European Commission.

Dürheimer said that diesel is not an alternative for the company because in the segments in which Porsche competes CO2 emissions would still be well above the required level.

He was quoted by Automobilwoche as saying: "In general diesel cars emit much less CO2 than their gasoline counterparts - however the diesel engine emits more NOx and particulate filters so on balance its environmental impact is no better than that of a gasoline engine. This fact is often overlooked."

On the issue of alternative drivetrains, Dürheimer said that Porsche is working intensively on developing a hybrid engine, which will make a significant reduction in emissions. "However, even with this technology we will not achieve 120g/km," said Dürheimer. This was the original limit set by the European Commission.

Dürheimer added that Porsche is developing a new engine for the Cayenne that uses 15% less fuel than its predecessor. "And with our hybrid drivetrain, we will achieve another significant reduction," he said.