A Prius which emits nothing while running or charging.
This idea started when I was a bit toasted and arguing about whether ULEVs or SULEVs are better. So my idea is: Ok, so at home, you have a PV charging station loaded with mondo-capacitors to charge it to say 60% with what is in them from previous exposure to sun. Then, If you want 100%, the pannels trickle-charge into the car after the capacitors have been depleted. Then for night chargings you hook it up to one of these bad boys.
It would have around 175 C batteries in the trunk to recieve the charging.
Then on REAL shitty days, when both charging methods are not possible, it would run on home brewn biodisel....
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Most of you will probably think my idea is stupid but whatever. Also, this in no way will ever solve PO. It's just that I'm a greenie and proud to admit it, and just "do my part".