MUNICH (Bloomberg) -- BMW plans to offer plug-in hybrid versions of all its main models, including the best-selling 3-series sedan, as the world’s largest maker of luxury vehicles reacts to tighter emissions regulations.

Carmakers are adding electric motors to improve fuel efficiency and make their vehicles viable in cities like London, which has set up a low-emission zone to improve air quality. Plug-in hybrids have batteries that can be recharged from electrical outlets and can drive emission-free for longer distances than conventional hybrids.

BMW is presenting a prototype of a plug-in hybrid 3-series today in Miramas, France, the company said in a statement . The car combines a four-cylinder gasoline engine with an electric motor and can drive about 22 miles on battery power.

The German carmaker also plans to roll out a plug-in hybrid version of its X5 SUV and other core-brand models, according to the statement. Electric versions from the Mini and Rolls-Royce brands are also “a possibility,” said Manfred Poschenrieder, a spokesman for BMW.

BMW created the “i” sub-brand for showcasing its clean-car technology and safeguarding its image as a maker of sporty vehicles. The first cars from the BMW i unit were the i3 battery-powered city car and the i8 plug-in hybrid super car. The company didn’t specify a timeframe for rolling out plug-in hybrid versions of its models.

“Our accumulated expertise guarantees us a competitive edge,” Harald Krueger, BMW’s production chief, said in the statement.