BMW's chief executive officer, Norbert Reithofer, has confirmed that the company's ActiveHybrid 5 sedan will go on sale as early as next year.

Reithofer told shareholders yesterday at BMW's annual meeting that the car it showed at the Geneva Motor Show in March as the BMW Concept 5-Series ActiveHybrid will be built.

He also committed the company to adding a hybrid version of its iconic 3-Series line, most likely when that car is next redesigned in 2012.

The 2012 BMW ActiveHybrid 5 will use a radical evolution of the mild-hybrid system already on sale in the 2010 ActiveHybrid 7 full-size sedan.

In the new model, a lithium-ion battery pack (of unspecified capacity) near the rear axle powers a 40-kilowatt (54-horsepower) electric motor mounted between its twin-turbo straight-six engine and an eight-speed automatic transmission.

The hybrid 5-Series will be able to run on electricity alone, just as the Toyota Prius and other hybrids do. In most driving, however, the motor will just add torque to assist the gasoline engine.

The smaller 15-kW (20-hp) electric motor in the hybrid 7-Series, by contrast, can only add torque to the output of that car's 440-hp twin-turbo V-8 engine.

As in most hybrids, the hybrid 5's engine will switch off when the car stops or even runs under light load, to take advantage of the electric running. It also recharges the battery via regenerative braking.

The goal is to reduce the overall carbon emissions of BMW's entire fleet by 25 percent or more by 2020, compared to 2008 levels.

BMW already has a full hybrid on sale; it's the the 2010 ActiveHybrid X6 "sport activity vehicle," which uses the Two-Mode Hybrid system it developed with General Motors, Daimler, and Chrysler.

But the joint development center for that project was closed last year, leaving GM the sole company to carry it forward. With Reithofer's confirmation of the evolutionary hybrid 5-Series and 3-Series models, it's clear that BMW is placing all its hybrid eggs in the basket it holds with Mercedes-Benz.

[Automotive News (subscription required) via Motor Authority]