Elon Musk does not think highly of hydrogen fuel cell cars. The entrepreneur and Tesla Motors co-founder discussed the technology during a recent speech to employees and customers at a Tesla service center in Germany, where he flatly described hydrogen-powered cars as "bullshit."

As Wired reports, the comments came during a discussion about critics of electric vehicles such as Tesla's Model S. "There are lots of people who say electric cars are never going to happen, and that we should just burn hydrocarbons forever," Musk said. "And then they'll say certain technologies like fuel cell, and it's like, oh god, fuel cell is so bullshit."

"They don't really believe it," he added, once the audience applause died down. "It's like a marketing thing."

Elon Musk's comments on hydrogen fuel cells begin at the 29-minute mark.

HyundaiMercedes, and other automakers have begun developing hydrogen fuel cell cars, and Toyota this month said it doesn't see much of a market for all-electric offerings like the Model S. Musk countered this week by arguing that hydrogen fuel cells, even in the "best case," can't equal what lithium ion batteries currently offer in terms of cost and range. He also said such technology would require more cost-intensive distribution systems while posing serious dangers to consumers, since hydrogen is a flammable gas.

"It's suitable for rockets," he added, "but not for cars."

Musk also revealed new plans for the Model S in this week's speech, saying he hopes to open up the car's infotainment system to third-party apps by the end of 2014. The car's 17-inch display currently runs on Linux, and Tesla is considering adding an Android emulator in the future. Musk says he plans to include Google Chrome as the system's default browser by late 2014.