Mercedes-Benz B-Class Electric Drive reduces lifecycle CO2 emissions by as much as 64% compared to B 180 gasoline model

17 December 2014

CO₂ emissions of the B-Class Electric Drive compared with the B 180 gasoline-engine variant [t/car]. Click to enlarge.

The Mercedes-Benz B-Class Electric Drive (earlier post) delivers up to 64% lower CO₂ emissions than the equivalent B 180 gasoline model (when charged with hydroelectricity), according to Mercedes-Benz and TÜV Süd. The 132 kW B Class Electric Drive has a range of some 200 km (124 miles). TÜV Süd has awarded the electric-drive Sports Tourer the environmental certificate in accordance with ISO standard TR 14062 based on a comprehensive life-cycle assessment of the B-Class Electric Drive.

Over its entire life cycle, comprising production, use over 160,000 kilometers (99,419 miles) and recycling, the B-Class Electric Drive produces emissions of CO₂ that are 24% (7.2 tonnes – EU electricity mix) or 64% (19 tonnes – hydroelectricity) lower than those of the B 180, despite the higher emissions generated during the production process.

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This is due primarily to the efficiency of the electric motor, which gives rise to significant advantages during the use phase. One key factor here is the energy management system: the optional radar-based regenerative braking system, for example, ensures the optimal recuperation of braking energy back into the battery. This further enhances the efficiency of the drive system and enables even greater ranges.

CO₂ emissions during the use phase depend upon the method used to generate electricity. In 160,000 kilometers of driving use, the new B-Class Electric Drive (NEDC combined consumption from 16.6 kWh/100 km) produces 11.9 tonnes of CO₂, assuming use of the EU electricity mix. When electricity generated by hydroelectric means is used to power the electric vehicle, the other environmental impacts relating to electricity generation are also almost entirely avoided.

For CO₂ emissions, and likewise for primary energy requirements, the use phase represents a share of 53% and 59% respectively.

As a comparison, the B 180 (NEDC combined consumption 5.4 l/100 km) emits 23.8 tonnes of CO₂ during the use phase.

The fact that we are able to integrate the electric motor and batteries into a perfectly normal B-Class does not only mean that we can assemble the Electric Drive alongside the other B-Class vehicles on one production line, but almost more importantly means that our customers do not have to make any compromises at all in terms of spaciousness, safety or comfort. The B-Class Electric Drive is an important milestone along our journey towards emission-free driving.

B-Class Electric Drive. The electric B-Class was developed by Mercedes-Benz in collaboration with Tesla Motors; the car uses a Tesla drive system. (The battery for the predecessor model of the smart fortwo electric drive, for instance, also comes from Tesla.)

The electric motor delivers maximum torque of more than 340 N·m (251 lb-ft)—approximately equivalent to the torque from a modern, naturally aspirated three-liter gasoline engine. The B-class takes 7.9 seconds to accelerate from 0 to 100 km/h. In the interests of optimizing the range, the top speed is electronically limited to 160 km/h (99 mph).

Steel/ferrous materials account for around half of the vehicle weight (51.4%) in the new B-Class Electric Drive, followed by polymer materials with around 17% and light alloys (12.8%) as the third-largest group. The shares of other materials (primarily glass and graphite) and non-ferrous metals stand at 5.9% and 5% respectively. Precious metals make up around 4%. Service fluids comprise around 2.4%. The remaining materials—process polymers and electronics—contribute about 1.5% to the weight of the vehicle.

The polymers are divided into thermoplastics, elastomers, duromers and non-specific plastics, with thermoplastics accounting for the largest proportion, at 11%. Elastomers (predominantly tires) are the second-largest group of polymers, at 3.6%.

The material mix is markedly different that the gasoline version of the B Class. As a result of the alternative drive components, the proportion of steel in the B-Class Electric Drive is around 8% lower, for example, while the shares of light alloys and non-ferrous metals are each approx. 3% higher and the share of precious metals is approx. 4% higher than for the gasoline variant. The share of service fluids is almost 2% lower, due to the absence of fuel.