Danish engineer Ulrik Poulsen is selling the "Poulsen Hybrid", an aftermarket modification package that can convert any vehicle with fifteen-inch or larger wheels into a hybrid gas-electric vehicle. The system is simple: two electric motors snap onto the outside of the rear wheels and provide 7HP of additional power — plenty to keep a car at highway cruising speed. Batteries are recharged using regenerative braking while on the road and a wall plug-in when at home.
The system starts at $3,500 without batteries. Lead-acid batteries will cost another $450, while a lithium-ion pack will cost $4,500. So not cheap, certainly, but an interesting option for tinkerers or those who have old cars they love but don't want to buy a whole new hybrid. (Or those who find the bolt-on drive of the Poulsen system appealing in a Back to the Future II sort of way.)
Initial orders are being taken now, but it looks like Poulsen hasn't quite yet made his hoped-for 2008 shipping date.