A123 Systems Hymotion brand has just announced the availability of a $9,995 conversion kit that allows any 2004-2008 Prius to be converted to a plugin hybrid. The system comes stocked with A123's lithium battery cells to power the car for 20-20 miles without the need to use a drop of gasoline (assuming you can drive below the Prius built in 42 mph threshold at which point the gasoline engine unavoidably kicks in).
This is huge news for those early adopters waiting on GM, Toyota and others to develop mass produced plugin hybrids capable of running mostly gasoline free. It means that for about the price of a "pre-owned" Prius (~ $20k) plus the cost of the plugin conversion kit, they can have a plug-in vehicle today for around $30k.
What this means for the rest of America is still uncertain. Currently the kit is only being offered as an add on for one type of automobile, the second generation Prius. But that does not rule out the idea that if the concept takes hold, A123 might see fit to branch out and develop systems for other hybrids as well such as the Toyota Camry and Highlander hybrids and the Nissan Altima and Ford Escape hybrids, all based on the same Toyota hybrid technology.
This is certainly an important development in the evolution of the plugin hybrid. It signals significant momentum behinf A123's battery technology. They are offering the kit with free installation and a three year warranty. The batteries are good for 7000 charge cycles and can be recharged in 4 hours on standard 120 volt home electricity using a standard plug.