Luxury German car manufacturing group Daimler is increasing its work on energy-efficient automobiles. Chief executive Dieter Zetsche said at the North American International Auto Show in Detroit this week that the company planned to roll out at least one new hybrid vehicle per year.

"Despite the enormous pressures that our entire industry is under these days, we are facing the year 2009 with measured confidence," Zetsche said.

The first hybrid -- which combines electric and internal combustion engines -- will be the top-of-the-line S400 BlueHybrid executive sedan in 2009. It is reported to be the first mainstream hybrid car to use a lithium-ion battery pack.

According to the German economic news weekly magazine Wirtschaftswoche, Daimler aims to have reduced its cars' exhaust emissions by 2012 to 136-138 milligrams of carbon dioxide per kilometer by using hybrid models, as well as smaller and more efficient engines. This would nearly achieve the European Union Commission target of 130 mg/kilometer.

In late 2007, Daimler's Mercedes and Smart cars' average carbon dioxide emissions were at 180 mg/kilometer, the Dusseldorf-based magazine said.

Taking advantage of a growth opportunity

"From 2012, we will offer our customers all standard series from the C-Class up with optional hybrid technology," Thomas Weber, Daimler's director of research and development, told the business daily Handelsblatt earlier this month.

This also included the popular full-size model E-Class, which was re-launched this year and unveiled at the Detroit show. It will be available with a hybrid engine starting in 2011, Wirtschaftswoche said. The next generation of the S-Class Mercedes, due to be introduced in 2013, is to be exclusively hybrid-powered, it said.

"Whoever doesn't invest in alternative engines is missing a growth opportunity," Weber said.

Affordable electric cars pose a challenge

Daimler also introduced the prototype for an electric vehicle called BlueZero at the Detroit auto show. The three BlueZero versions are based on the sandwich-floor architecture which the carmaker initially introduced for the A-Class.

The vehicles will utilize lithium-ion batteries, which are already widely used in consumer electronics but are being adapted to meet automotive requirements. The car will be able to drive 200 kilometers (124 miles) on a single charge, or 400 kilometers for a hybrid version that relies on a small combustion engine to recharge its battery. All three variants accelerate from 0 to 100 km/h in less than 11 seconds. The top speed is electronically limited to 150 km/h.

But mass production is "a few years" away, said Weber. Daimler still faced two challenges in manufacturing electric vehicles: making it affordable, and building up public infrastructure to charge the car's batteries.

Daimler last month took a 49 percent stake in the lithium-ion battery unit of Essen-based industrial group Evonik.