This post originally appeared on Orphan Road.

My last post on fuel efficiency generated quite the comment thread. If you didn’t like Aptera’s 300 mpg car, here are a few of the other contenders vying for the Automotive X Prize — $10 million for a car that gets at least 100mpg. There are some great looking cars there. I have no idea if any are production-ready. Gasoline will need to get way, way more expensive before people start using these things, though.