It’s official: Audi’s e-tron is a go.

Audi of America President Johan de Nysschen says an electric vehicle based on the high-performance e-tron concept will debut in the United States in two to three years.

The sleek two-seat sports car was unveiled at the Frankfurt auto show last month, but at the time Audi would not confirm plans to produce it. Now de Nysschen says the car is on its way.

“I expect we will see running examples in the next 24 months,” he says.

The e-tron concept is powered by four electric motors, one on each wheel. Audi says the car has a range of 154 miles using a lithium ion battery positioned behind the passenger cabin.

The show car is 168 inches long — about midway between Audi’s TT and R8 sports cars–and 75 inches wide.

The e-tron uses a space frame. All the added-on body parts, including the doors and roof, are made of a fiber-reinforced plastic.

Audi also is developing hybrid vehicles. The first on the U.S. market will be the Q5 crossover, scheduled to debut in the 2011 model year.

Electric carmaker Tesla Motors is launching a maintenance plan where mechanics travel to owners’ homes or offices to perform repairs and tune-ups.

Tesla, which makes the US$109,000 Roadster electric car, said the plan is convenient for customers who won’t have to bring their vehicle to a showroom, while cutting costs by making a large network of Tesla service locations unnecessary.

“You know how there’s a Chevy dealer on every block or strip mall? We don’t intend to have a footprint like this,” spokeswoman Rachel Konrad said.

But the service won’t be cheap. The carmaker will charge vehicle owners $1 for every roundtrip mile its technicians travel, from showroom to garage, with a minimum charge of US$100 per trip.

For the Tesla driver in Manhattan, where the company opened a store over the summer, the cost won’t be much.

But for Roadster devotees in Honolulu, that’s a charge of about $4,800 per trip – not including the cost of repair.

Still, Konrad said the maintenance cost will still be low because electric cars have fewer moving parts and require less “care and feeding” than vehicles powered by internal combustion.

The company said a recall of hundreds of Roadsters in May to address a steering problem was in part the inspiration for the plan.

Rather than ask owners to bring the vehicle to a showroom – there are only four currently in the US – it sent technicians to repair the cars at their homes and offices. The response was overwhelmingly positive, Konrad said.

The San Carlos, California-based start-up has so far sold about 700 Roadsters, its only vehicle on the market now. The company in June was approved for $465 million in loans from the US Department of Energy to help it build next-generation electric cars.

It has plans to introduce an electric sedan, the Model S, which it hopes to price under $50,000 after government rebates when it goes on sale in 2011.

The new service plan will be standard for all new Tesla vehicles and current owners will have their warranties updated so they are covered by the new plan, Konrad said.

Toyota Motor Corp. has joined the growing ranks of automakers planning to bring advanced battery-powered vehicles to showrooms in the near future.

The Japanese automaker said it planned to have a plug-in version of its popular Prius hybrid for sale in the U.S. within three years.

“The target is 2012 to be coming to market with them,” Irving Miller, a group vice president for Toyota’s U.S. sales unit, said at a Los Angeles conference on climate change, Bloomberg News reported.

Before that, “we’re going to study the challenges of consumer demand,” he said.

Toyota had earlier announced its intention to bring 150 plug-in Priuses to the U.S. by the end of this year, but they are going to be doled out to vehicle fleets in what amounts to a large-scale road test.

Friday’s announcement by Miller was the first time Toyota had set a date for making the plug-in version of the Prius available to consumers.

Toyota will have plenty of company. General Motors Co. plans to have its Chevy Volt plug-in hybrid in showrooms by the end of 2010, and Ford Motor Co. plans to have an all-electric version of its Focus compact on the market by 2011.

BMW and Nissan Motor Co. have electric vehicles planned for the U.S. market by 2012, and various niche manufacturers such as Tesla Motors Inc. are developing plug-in hybrids or electric-only vehicles.

In his remarks, Miller was more restrained about the sales prospects for a plug-in Prius than some of Toyota’s rivals have been when discussing their advanced-powertrain cars. That caution is a result of the consumer response in California to Toyota’s battery-powered RAV4 sport utility vehicles early in this decade, he said.

“We had a lot of people raising their hands for the RAV4 EV,” he said. “As soon as we made them ready for sale, that line evaporated very quickly.”

The standard Prius hybrid, which has an EPA rating of 50 miles per gallon in city-highway driving, combines an electric motor with a conventional gasoline engine to achieve improved fuel economy.

A plug-in version would have more powerful batteries that would enable the car to travel a certain distance — perhaps as much as 10 miles, although Toyota has been unclear on this point — on electric power alone. The batteries could be recharged by plugging the car into a household outlet.