With over 14 car manufacturers working actively on putting plug-in electric cars on the road soon, many experts have concerns that there will be power shortages during peak hours with all the plug-in hybrids getting on the grid to charge their batteries. This seems to be a myth according to many experts who say that the existing capacity on the US grid could charge 173 million plug-in hybrid cars in the US. The caveat being that the car owners must be responsible enough to charge the car during the night hours when businesses will not be impacted. Another idea is to meter the charging of electric vehicles to ensure that responsible owners who charge during off peak hours get a rebate while those who have urgent need to re-charge during peak hours will pay more.
Other concerns with plug-in hybrids are in regards to what can be done with the large lithium batteries once they are spent. How do you dispose off the large number of batteries? Can they be recycled?
State governments such as California are also pushing hydrogen technology. It seems that there is a lot more research funding available for hydrogen powered vehicles than there is to improve the battery technology for plug-in electric or hybrid cars. Hydrogen cars will bring their own challenges in terms of the energy required to create hydrogen in the cylinders, etc.