Earlier this year we told you about "Mean Green Machines," a twist on the Discovery channel show "Mean Machines." As you may have guessed by the title, the addition of the word "green" meant the twist would be an eco-friendly focus. At the time the show was only available on the Canadian Discovery channel. Well now that Planet Green has officially launched, guess what made its debut for U.S. audiences last night? You guessed it: lucky Americans can now enjoy watching the weekly challenges that pit green vehicles against traditionally-powered transportation to see which comes out on top.

Planet Green's executive producer Alon Orstein is hopeful that the show will provide a unique look at alternative transportation.

"The transportation sector is such a critical component for Planet Green, we wanted to have a show that could get at some of this green technology and do it in a fun and entertaining way," Orstein says.

"Some of the individuals behind these are really interesting -- they're passionate about their work and their vehicles," Orstein says. "The green machines give their carbon counterparts a run for their money."

Future episodes this summer will include a Zero motorcycle versus a Yamaha YZ250, with Neal Saiki, former NASA engineer, who made the first human-powered helicopter, and his new Zero motorcycle, a zero-emissions motocross bike. In another show, Jonathan Goodwin, who converted governor Arnold Schwarzenegger's SUV into a biodiesel one, takes a biodiesel Escalade and challenges a tricked-out H2 Hummer.

If you missed the American debut of "Mean Green Machines" last night, don't despair because you won't even have to wait a full week to catch the new episode. The show's regular time slot will be on Tuesday nights at 9 p.m., with two different back-to-back episodes. In the meantime you can watch the clip below for the first few minutes of the episode featuring Neal Saiki's Zero motorcycle.

» Motor Trends