Electric car sales could jump to 86% of US light vehicle sales in 2030 if consumers don't have to buy batteries themselves, a University of California, Berkeley, study released on Monday concluded.

Better Place and emerging rivals plan to offer pay-per-mile plans, similar to cell (mobile) phone minutes. A family would buy a car but Better Place would own the battery, offer charging stations, and swap out batteries as needed to extend the driving range, Reuters said, citing the report.

The cost of building charging systems would be more than US$320bn over the next couple of decades, although health-related savings due to reduced vehicle pollution could be $210bn, according to the study by economist Thomas Becker.

The main benefit to drivers would be cars with price tags and operating costs similar to or less than petrol models.

Renault -Nissan is making cars for the Better Place project and the latter has said its system would be cheaper than using petrol.

The Berkeley analysis predicted the per-mile cost of making and charging batteries, including the cost of building a charging system, would be similar to or sharply less than a petrol car, depending largely on whether prices of petrol rise.

Renault is working with authorities around the world, as well as the US, to provide recharging points at work and en route while 'quick drop' stations would be established at dealers - and possibly fuel stations and motorway service areas - where an automated system could simply exchange a battery for a fully charged unit in three minutes.

Christine Tissot, general manager for the French automaker's electric vehicle business development, last week said at the Kangoo EV launch the Alliance already had agreements in place with government authorities and utilities around the world.

She also said that discussions were being held with other carmakers to try and introduce common standards for batteries and ways to charge them.

"We don't want to find a situation as in the mobile phone industry where every manufacturer has different connectors. Batteries are very expensive so it makes sense to standardise where we can."

Similar views were expressed by Toyota R&D chief Masatami Takimoto in Japan last month.

He told just-auto battery rental schemes may eventually be one solution to the range question but said that it was "too early" for them to be a practical proposition yet. "As an idea, battery exchange is interesting. The battery technology is continually evolving. When a battery can be standardised so that it could be used by all [auto] manufacturers then [an exchange system] would be feasible."