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

17 December 2014

Bclass1
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.

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.

—Professor Dr. Herbert Kohler, Chief Environmental Officer at Daimler AG

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.

December 17, 2014 in Electric (Battery), Emissions, Lifecycle analysis | Permalink | Comments (8) | TrackBack (0)

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Out of curiosity, I wonder how much the CO2 is increased when you burn peat to make electricity.

I'd like to see this analysis for different types of electric buses. My guess would be that the use phase is considerably higher since buses can run over 1 million km in a lifetime, with rather poor l/100km (typically around 50 l/100km).

Bogus numbers. As admitted in the quote below, the CO2 savings are at best 24%, not 64%.

Even the 24% number is exaggerated, because the *marginal* CO2/kWh (from incremental demand) for European grid mix is guaranteed to be higher than the average CO2/kWh, due to the additional demand being filled by fossile sources (coal, natgas).

QUOTE: 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. ENDQUOTE.

At least this Mercedes is not quite as dishonest about the true CO2 emissions of their car as BMW was about their model i8 in another article:


http://www.greencarcongress.com/2014/03/20140311-i8.html

BMW just completely ignored the CO2 from the electricity production altogether in their press release. Just complete lies all around.

For newbies or others that will now claim that I am against saving CO2, let me make it clear.

EFFICIENT hybrids are the answer. Buy a Prius or any other hybrid that gets 50mpg or better. They have lower CO2/mile than most "electric" cars. A Tesla model S is about a 35mpg equivalent in terms of CO2/mile. A Nissan Leaf is slighly worse than the bigger prius. Mercedes and BMW are not even close with their latest offerings.

Assuming Hydro power is not realistic, even in Norway (97% hydro power production) it would be misleading since Norway is part of the Nordic power system (i.e. ca 200g/kWh).

How would this graph look like if you compared a modern Volvo V70 D4 181hp with Tesla S 85KWh 385hp? They are similar in interior size, but not in power or range.

    A V70 D4 has 4.5 litres/100km combined consumption. This is diesel, but in total the CO2 emission should be less than the Mercedes B180.

    The battery and accessories for Tesla and B Electric weights ca 700kg and 300kg respectively. Assuming 50% of the CO2 emission in car production is related to battery, the Tesla CO2 emission from this stage is 17 ton/veh (5 x 700/300 + 5). If we assume the energy consumption is proportional with weight, the Tesla uses 27% more energy than B Electric (2100kg/1650kg), i.e. the Electricity Generation phase emission is 15 t/veh (11.9 x 1.27).

Based on these rough estimates and with the EU electricity grid mix the Tesla S 85kWh emits ca 33 tons CO2 versus the V70 emits ca 30 tons CO2.

So, are we actually reducing the global CO2 emissions or not? What about the subsidies on electric cars?

EVs can charge preferentially using low-CO2/low marginal cost sources (wind, solar and nuclear).

Cars these days are computers on wheels, and EVs even more so. They can easily charge when power prices are very low, which is when low-CO2/low marginal cost sources are producing the most.

This will both make driving low-CO2, and raise demand and power prices at these times thus helping incentivize low-CO2/low marginal cost sources.

EVs and low-CO2 power have a marvelous synergy.

Right on, nickg. Other posters above might do better to criticise governments which are failing to phase out dirty Coal fired power plants, than trying to pick holes in the claims of EV makers.There is no escaping the fact that, in actual daily use, these will be the answer to our majority emissions problems.Getting them an equally clean energy supply is clearly a parallel task, alongside getting ICEVs replaced by EVs.So please, people, stop knocking them.

The anti EV crowd are always quick to use the "long tailpipe" argument but fail to note cars with a "short" tailpipe also have a long one. If you are going to factor in the emissions from the power plant for the EV you should also add the emissions of the refinery and oil field to CO2 the ICE car already produces.

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