The low efficient mechanical parts like engine, drive train, gearbox can all be Incorporated in a single unit ie the wheels. Battery to wheel efficiency is nearly 90% and petrol tank to wheel efficiency is as low as 15%. Extensive research is going on for upgrading of batteries which is the major component of EVs(Electric Vehicles). Li ion batteries, which are common now(used in cell phones, are good, fast charging and light are used in EVs. Charging is a fun thing. Roll down a plug from the charging spot and plug it onto a socket. For longer drives carry a battery kit for added life of the car.
The running cost being electricity for charging up batteries and considering depletion of conventional sources of energy and raising cost of petrol, these cars put a greater threat to the very existance of petrol cars. Some models of cars tap solar energy to charge the batteries. People will no longer wander in search of shades for parking. Park your car in sunlight for a while and you are ready to roll. Also when brake is applied you are actually charging the batteries. Smart uh?? The energy loss due to braking is converted into electric energy. The electric motor transforms itself to a generator and stores energy, a technique known as regenerative braking.
In India where most of the travelling is under 100 km per day, EVs are a smart option. RAVA Electric Car Company, Banglore is the leading producer of Electric cars in the world. (I wonder when they will come up with a decent design). Tata is going to launch Electric Indica in 2010 and they claim to offer 300km/charging. Tesla Roadster, a high power luxury car which reaches 100kmph in just 4sec is making news for good reasons. Hopefully better technologies will evolve and large scale production will make this no emission/no noise/no maintenance cars economicaly competent to the petrol cars. All automobile majors are into vast R&D projects eyeing a bright future for EVs.
Watch the siemens video.