I think what they claim is possible, and after pondering it for a while here, I think I've got it simplified down.

What's important here is that there are two mediums (air & ground) with a speed differential between them. Typically when you want to use this differential you make a windmill. Anchor your generator to the ground and extract energy from the moving air. In essence, what they've done here is anchor the generator to the air and extract energy from the passing ground. Quite a bit less efficient, I'm sure, but doable.

Lets work it out in the ideal situation. Begin with a vehicle traveling same speed as the wind. The frictionless wheels are currently free-wheeling on the ground with no resistance. Consider this 'anchored to the air', since we are motionless relative to the surrounding air. Now, from this perspective the ground is moving past us and our tire is spinning in it's medium like a free-wheeling windmill blade spinning in it's medium. Next, you put a generator on your spinning wheel / fanblade. Now you're extracting energy from the system. You can put it in a battery, or you can use it to push yourself forward. Since it's not windy in the vehicle, you could even mill flour with it!

I use a bowl. You should get a bowl.

You mean like this? Cyanide & Happiness. Very apropos!

Car accidents suck, too, but most people still look.

I'm only on s02e8, but I literally want that whiny bitch John Connor to die as a direct result of his epic stupidity. Sarah Connor, too. I don't know, maybe the writers are geniuses working on some wicked character development. I mean, there's a lot of room for growth between the incompetent idiots that they are now to the leaders they're supposed to become. And Thomas Dekker must be a pretty good actor to inspire me to hate his character so much. I just don't think it was a wise choice on the writer's part. But because of the fan praise that's out there, I'm still watching it. Looking for some saving grace.

It took me a few years to get around to Firefly too, because I thought the fans were TOO enthusiastic about it. Turned out they were 100% right. So I'm giving TSCC the same chance. But it sure ain't no Firefly so far.