This one is spreading around the "sustainable blogosphere" faster than Avian Flu -- Green Car Congress has a report on the efforts of a Canadian engineer to add photovoltaic panels to his Prius. The goal isn't to make the Prius entirely self-sufficient, but to boost its overall efficiency: the engineer, one Steve Lapp, reports a better than 10% boost in mileage using a rough, non-optimized version of the system, from ~52 miles per gallon to ~59 mpg. The "PV Prius" is very much a proof-of-concept demo -- I'd imagine that Toyota's designers will be appalled at how the big solar panel breaks up the smooth lines of the car -- but it's a good example of how the integration of local generation has the potential to enhance overall energy efficiency.
There's still much work to do in order to figure out right number of panels, energy flow to batteries, and myriad other technical details. There's also the larger question of the overall efficiency of the photovoltaics, and whether future adoption of cheaper, low-efficiency polymer PV or expensive, higher-efficiency nano PV would have a better payoff. Still, expect some day to see "Sun-In Hybrids" shoulder-to-shoulder with "Plug-In Hybrids."








