I had a full tank of petrol but now it is nearly on red, has this flooded in to the engine? Will it just be an electrical fault?

It was on the discovery channel because some dude was trying to find the most efficient rout to travel and he could only travel by those things like electric or corn oil no gas or diesel; like one thing he rode was an electric scooter and a corn oil plane and a bunch of other things like that. I have only seen one episode it aired a little while back and is not an anymore from what i can tell. But any way he was riding some cool bike that when you pedal it it builds up electricity in the motor so you can drive by the push of a button. I think it was called an eBike but im not shure. if anyone knows what im talking about please tell me what the bike is called i would very much like to have one. Thanks