Not content with seeking to control the information super-highway, Google wants to influence what kind of car you drive.

The online search company has unveiled a new, hyper-advanced model of hybrid car that can be charged directly from the grid, and, when its battery is not in use, the stored electricity can be sold back to the utility company.

The result of the technology will delight Hollywood’s carbon-battling, hybrid-driving activists, such as Leonardo DiCaprio. A standard Toyota Prius gets about 45mpg; a converted plug-in Google Prius gets more than 70mpg.

Google says that by selling electricity back to the grid the cars can ease peak electricity demand – during heatwaves, for example – which is often met by emergency power from some of America’s dirtiest coal-burning power plants.

Even if the car results in more electricity being used during normal periods, Google says that the power from the grid will be more efficient, and less damaging than the oil that would otherwise be burnt by its petrol engine. “If you have a million of these cars, you will have more generation capacity than the grid has,” said Sergey Brin, 33, the co-founder of Google, who is worth an estimated $17 billion. “That’s really valuable.”

The $1 million investment in the so-called “vehicle-to-grid” technology was masterminded by Google’s philanthropic division, Google.org, and will ultimately include a 100-strong fleet of plug-in hybrids operated by Enterprise Rent-A-Car.

When Google’s initial fleet of hybrids is plugged in, it will be charged by Google’s new 1.6megawatt solar power facility – the largest such system in the United States – which is part of the company’s pledge of becoming “carbon neutral” by next year.

By selling their excess electricity to the grid owners of plug-in hybrids will be able to earn up to $3,000 a year. Such savings are likely to be offset by the higher initial retail price of hybrid cars.

At a press event on Monday Google executives joined an official of the Pacific Gas & Electric company to demonstrate how a plug-in Toyota Prius could actually make Google’s electricity meter run in reverse.

“There’s an awful lot of good for the environment to be done,” Dan Richer, director of climate change and energy initiatives at Google.org, said.