What is the presence of the drive

bd | stvo.de - 13.11.2015

Source: © Stefan Koerber -fotolia.com

Against the background of increasing global warming, among other things, the car drivers come again and again into the focus of the climate protection activists. In order to reduce the emission of greenhouse gases, especially carbon dioxide (C02) and other climate-damaging substances, climate-friendly vehicle drives are becoming increasingly important. However, none of the alternative drive technologies can claim the final breakthrough. In the following, conventional and innovative drive technologies are compared with one another in terms of their advantages, disadvantages and risks.


1) Internal Combustion Engines - The most common type of drive


a) Gasoline - A never-ending success story?

i) Advantages of a gasoline engine

Of all the drive technologies available on the market, the classic combustion engines continue to sell best. It can be said that in the field of drive technologies, even with conventional internal combustion engines, great advances have been made for years. Particularly in terms of fuel consumption, positive values ​​are now being achieved compared to the last five to ten years, and the buyer is also on board with the choice of displacement, engine performance and driving style.

Furthermore, combustion engines have a (significantly) greater range compared to alternative drives, which means greater safety, for example compared to a purely electric car.


ii) Disadvantages and risks of a gasoline engine

Compared to all other types of drive, the pollutant values ​​are greatest in gasoline engines. Since the calculation of the vehicle tax for new cars in this country has for a number of years also been dependent on the level of fuel consumption, owners of new vehicles that emit more CO2 are financially more heavily burdened. In addition, the maintenance and repair costs for a gasoline engine are higher than for alternative drives.


b) Diesel vehicles - high driving comfort, low fuel consumption

i) Advantages of a diesel engine

Vehicles with a diesel drive have lower fuel consumption compared to gasoline engines with the same performance, they also achieve better efficiency and emit less CO2 than gasoline engines. The more economical drive does not have a negative effect on driving dynamics. With the same cubic capacity, a diesel vehicle has a higher torque than a gasoline engine, which is particularly noticeable when accelerating.

Some automobile manufacturers offer vehicles with a combinable technology, in which case the engine can burn both natural gas and conventional fuel and convert it into power. This technology combines the cheaper and more environmentally friendly refueling with natural gas, the supply of gasoline enables a longer range.


ii) Disadvantages of a diesel engine

On the one hand, a diesel vehicle is in most cases more expensive to buy than a gasoline engine. On the other hand, the higher purchase prices are offset by the still lower fuel price for diesel and the lower fuel consumption, but this is particularly noticeable on long journeys. However, since a diesel does not warm up as quickly as a gasoline engine on short journeys, this can have a negative impact on fuel consumption.



Regardless of the recent scandal about manipulated exhaust gas values ​​at the German automobile manufacturer Volkswagen, low-emission combustion engines are still a key technology for being able to permanently reduce carbon dioxide emissions in traffic. However, conventional drives are not a technology of the future; sooner or later their potential will be fully exhausted.


2) Alternative car drives - The different types of electric cars


a) Hybrid electric cars

i) Advantages of this drive technology

Two different types of drive are used in a hybrid drive. Hybrid drives, which combine gasoline and electric motors, are very popular with the world's leading automobile manufacturers, and this technology has long been ready for the market. A distinction must be made between different forms: In a mild hybrid, an electric motor supports the combustion engine when accelerating, a full hybrid uses only an electric motor.

There are also plug-in hybrids that have both an electric and a conventional combustion engine. As a result of the combined technology, a hybrid drive vehicle generally emits less C02 and other climate-damaging substances than a vehicle with a pure combustion engine. In addition, the hybrids are quieter. What drivers appreciate about this drive technology is that they can cover short distances emission-free and therefore environmentally friendly; on longer distances they have the range of a classic combustion engine. The Center of Automotive Management (CAM) from Bergisch Gladbach selected the 100 best innovations in the automotive industry over the past ten years (2005-2015) in a study. According to the study, German automobile manufacturers are among the most innovative companies in the industry, but there is still some catching up to do (in some cases significant) in the area of ​​alternative drive technologies.


ii) Disadvantages and risks of this drive technology

Critics complain that a hybrid vehicle is an electric car with a superfluous internal combustion engine. Because it can be charged at any conventional socket, the additional motor only leads to an unnecessary increase in weight. Added to this is the sometimes long charging time of the battery, which is empty relatively quickly compared to a purely electric car. Since the electric motor is primarily intended to cover the short distances with the plug-in hybrid, which consume a lot of fuel and therefore cause a lot of emissions, the weak battery power due to the comparatively long range is accepted.


b) Electric cars with a purely electric drive

i) Advantages of this drive technology

The federal government has set the target that one million electric cars (e-cars) should be on the roads in this country by 2020. Germany is currently still a long way from this goal, however, and there are more and more doubts about the attainability of this high goal, as Udo Lambrecht, head of the Transport and Environment Department at the Institute for Energy and Environmental Research Heidelberg (Ifeu), explains in this interview .

Electric cars have a number of advantages, which the consumer and comparison portal Verivox explains in an article. In addition, the different types of electric cars are listed under the link provided. On the one hand, it is an environmentally friendly drive technology, no exhaust gases and therefore no climate-damaging emissions are emitted when driving. On the other hand, the electrically powered vehicles are significantly quieter than a vehicle with a combustion engine. An electric car accelerates almost silently, there are no loud exhaust noises, and there is no gasoline or diesel smell in the air.

In addition, there are lower operating costs with an electric vehicle. On the one hand, there is significantly less wear on an electric motor, and on the other hand, there is no need to change the oil in an electric vehicle. In general, electric motors require less maintenance than conventional motors. If the vehicle owner uses the technology in accordance with the specifications, it is not necessary to visit a workshop over a longer period of time. One reason for this is the gentle braking technology: Compared to a vehicle with a conventional drive, the foot brake does not have to be operated as often. With an electric motor, the speed can be decelerated using what is known as recuperation. This significantly relieves the load on the brake pads and brake discs during operation.

The term recuperation describes processes for the recovery of energies (heat, electrical energy) that would otherwise remain unused. In the case of hybrid vehicles, recuperation means the following process: When braking, the electric motor acts as a generator, which is how electrical energy is generated. Part of this generated energy is stored in the vehicle battery.

In financial terms, there are currently fewer taxes on an electric car and insurance premiums are also lower. A state bonus as an incentive to buy an electric car is repeatedly called for and is still under discussion. In addition, there should be further incentives to buy electric cars, e.g. free parking spaces or the use of bus lanes. In March 2015, the German Bundestag passed a law that created the legal basis for this, but the actual implementation of the privileges for drivers of electric cars lies with the cities and municipalities.


ii) Disadvantages and risks of this drive technology

The advantages shown are offset by a number of disadvantages, risks and obstacles that make purchasing a purely electric car less attractive at the moment.

High purchase price

The pure electric cars are significantly more expensive than their counterparts with combustion engines. An example: The Volkswagen Golf with electric drive costs around 35,000 euros in the basic configuration. A Golf with comparable equipment with a combustion engine is available from around 24,000 euros. According to a current study by the P3 Group, electric vehicles should become competitive in terms of purchase price from 2018, and even have an advantage depending on technological progress. The engineering firm's forecasts are based on the progress made to date and the progress expected in battery technology.


Disadvantages in terms of range

Compared to the combustion engine and hybrid drive technology, the range of an electric car is still (significantly) shorter. Without charging, a pure electric vehicle has an average range of around 150 kilometers, depending on the manufacturer. If the speed is reduced, this increases the range on the one hand, and leads to a longer journey time on the other. According to the Bundesverband eMobilität e.V. (BEM), the coming generations of vehicles will achieve significant improvements here. The basis for this is the great technological progress in the development of vehicle batteries. In the next few years, significantly better values ​​are expected to stimulate purchases, experts speak of a range of 250 to 300 kilometers, and up to 400 km in the premium segment.


Different loading speeds

The vast majority of electric car owners charge their vehicle at home. How fast the charging process goes depends on the charging technology of the vehicle in question. There are clear differences until the memory is full again - the loading times range from one hour to eight to ten hours, depending on the vehicle model. Long charging times severely limit the everyday use of e-cars.

The charging power, specified in kilowatts (kW), is the decisive value when comparing the charging time. In many cases, however, the prerequisite for the charging capacity to be achieved is the purchase of a special device with integrated software control. Charging at a normal household socket takes significantly longer. In addition, some e-cars with a pure battery drive cannot access the full charging power of the household connection or the majority of the public electricity columns - usually 22 kW. In many cases, a higher charging capacity can only be achieved if the vehicle owner is willing to pay a surcharge when purchasing the vehicle.


Expansion of the public charging infrastructure required

Another reason for the small number of electric cars is the expandable infrastructure. In rural regions in particular, there is a lack of charging stations (“charging stations”). In its 2014 progress report, the National Electromobility Platform states that there were around 4,800 publicly accessible charging points at 2,400 locations across Germany in mid-2014. With these numbers, the Federal Republic is in the middle in an international comparison. For comparison: According to the ADAC, the number of conventional filling stations in 2015 was 14,209.



With the exception of plug-in hybrid technology, current electric cars are not yet suitable for the mass market. Many buyers cite either their enthusiasm for vehicle technology and / or climate protection as the main reasons for buying. In the next few years it will be decisive whether the currently rather unfavorable relationship between purchase price and practicality will change, making electric cars increasingly attractive not only for companies and fleet operators, but also for private consumers.


c) Electric cars with fuel cell drives

i) Advantages of this drive technology

From a technical point of view, a fuel cell car is a vehicle with an electric motor. The chemical reaction of hydrogen with the oxygen in the air produces electricity in the fuel cell. Electric motors powered by this technology have a significantly longer range than a vehicle with a purely electric drive, and they do not need to be charged for hours. In addition, fuel cell cars are emission-free and quiet in operation.

As with electric cars, East Asian automobile manufacturers are leaders in fuel cell drives. While Nissan is concentrating on electric cars, Toyota and Honda have presented their new models at this year's Tokyo Motor Show, which have smaller engines and more powerful drives and are even cheaper to buy. The background to this development is the state funding for alternative drives in Japan. The government subsidizes the expansion of the infrastructure for both electric and fuel cell cars.


ii) Disadvantages and risks of this drive technology

In relation to the other innovative types of propulsion explained, the framework conditions for hydrogen propulsion are the most complicated. Automobile experts rate the market chances for fuel cell technology as very low, in this decade the technology will no longer be ready for series production. Another reason for this is that the production of pure hydrogen is an energy-intensive process. This must be made from the chemical compound H with high energy input²0 or dissolved out of the hydrocarbons. Despite the high efficiency described, the energy balance of a fuel cell is very negative. Not even half of the energy used can be used.



Compared to electric cars, fuel cell cars have, on average, shorter charging times and a significantly longer range. What many models of these two alternative drive technologies have in common is the high purchase price. Hydrogen is considered to be the fuel of the future, but it will be some time before this alternative drive technology breaks through.


3) Alternative car drives - natural gas and ethanol


a) Natural gas drive - will the complete breakthrough on the market be achieved?

i) Advantages of this drive technology

Despite the persistently low gasoline price, switching to a car powered by natural gas can be profitable. This is also politically wanted, according to the will of the European Commission, every tenth vehicle in Europe is to run on natural gas by 2020. Natural gas vehicles are often equated with LPG vehicles, but this is a mistake. While autogas vehicles run on liquefied petroleum gas (LPG), natural gas vehicles need compressed natural gas (CNG) to drive, which is still gaseous when supplied. CNG is the technical term for natural gas, a combustible natural gas that can be found in underground storage facilities. Although it is a fossil fuel just like oil, natural gas is much more environmentally friendly than gasoline and diesel.

In the case of a vehicle with natural gas drive, a distinction must be made between the bivalent and the monovalent form. In the bivalent variant, an additional petrol tank is installed in addition to the natural gas tank, which increases the range when driving. Monovalent vehicles only have the natural gas tank, but have a better climate balance.


ii) Disadvantages and risks of this drive technology

If you want to fill up your vehicle with CNG, you don't necessarily have to wait to buy the next car. Every vehicle with a conventional gasoline engine can be technically retrofitted; this process costs between 3000 and 4500 euros, depending on the vehicle type. Here, some hoses and valves have to be modified or replaced, and a tank has to be installed. The latter usually takes place in the trunk and results in a loss of cargo space. Before converting, it should be ensured that the conversion is profitable due to the savings achieved. The amount of savings depends on the one hand on the type of vehicle and on the other hand on fuel consumption.

Another aspect to consider before buying a car with natural gas drive or before retrofitting is the still low, but increasing use of natural gas filling stations. There are currently around 1000 of these filling stations across Germany.



Vehicles powered by natural gas will receive tax subsidies until 2018. Depending on the vehicle type, the purchase orthe conversion is profitable. The biggest disadvantage is certainly the expandable infrastructure. The advantages and disadvantages of natural gas propulsion are presented in more detail at this point.


b) Flex fuel - driving with alcohol in the tank

i) Advantages of this drive technology

In principle, ethanol is suitable as a gasoline mixture for use in engines; in racing, for example, bio-fuel has been used for many years. The Coburg University of Applied Sciences is currently testing what benefits this alternative fuel could have in a large-scale experiment aimed at further developing the diesel fuel "R33". According to this website, 280 vehicles (cars and buses) have been running on diesel fuel with a renewable share of 33 percent since mid-2013. In addition to the seven percent bio-fuel used with conventional diesel, the test vehicles also contain a quarter of vegetable oil treated with hydrogen.

In the case of biofuel tunnels, the alternatives to conventional fuels are rapeseed methyl ester (RME, also known as biodiesel) and bioethanol, which is obtained from crops such as rapeseed, corn and wheat. Supporters and advocates of biofuel argue that greenhouse gases can be saved by using it on a large scale. The background to this is the requirement of the European Union (EU) that by 2020 one tenth of energy consumption in the transport sector should come from renewable sources. The so-called Biofuel Sustainability Ordinance specifies that with sustainable biofuels in the entire production and supply chain compared to fossil fuels, initially 35 percent and in the second step 50 percent (from 2017) greenhouse gases must be saved. Biofuels are only considered sustainable if they meet certain requirements in terms of environmental protection and sustainable agriculture. In the course of the introduction of the bio-fuel E10, a debate arose in this context that is characterized by misunderstandings and a lack of transparency, as shown below.


ii) Disadvantages and risks of this drive technology

At the beginning of 2011, the introduction of the biofuel E10 was decided by politicians. The biofuel E10, to which ten percent ethanol from agricultural products is added, is still controversial among some scientists and environmental organizations, the acceptance in the population is almost non-existent. The reasons for the widespread skepticism are diverse, as explained in detail in this article.

Vehicle manufacturers and automobile associations warned against the consumption of E10, as the biofuel allegedly damages the engines. So far, there is no reliable evidence that the intake of E10 is actually harmful to the engine and transmission. The debate has meanwhile led to the fact that bio-fuel hardly plays a role in the daily lives of most consumers in Germany. Despite the price advantage of E10 of around two cents per liter compared to conventional premium gasoline, which has an ethanol content of five percent. Due to the persistently lower oil price, the price advantage has almost halved since the introduction of E10. The reason for this is also the increased price of ethanol; due to the lack of economic incentive, bio-fuel will not be more popular with motorists.

Another point of criticism is the alleged lack of sustainability in the production of biofuels: environmental and consumer advocates argue in this connection with the clearing of arable land that would be omitted for the cultivation of staple foods. The EU reacted to this criticism, and in April of this year the EU Parliament decided to lower the proportion of biofuels from ten to seven percent. The above-mentioned goal of covering ten percent of energy consumption in the transport sector with bio-fuels continues to apply. However, the proportion of first-generation bio-fuel (e.g. May, rapeseed) is limited to seven percent.



Even four years after the introduction of E10, the fundamental discussion about the carbon footprint and sustainability of biofuels has not changed significantly. The fronts between supporters and opponents are still hardened. Both sides are relying on the next generation of biofuels and the one after that, but these new gasoline mixtures are not yet available on the scale to be used across the board in road traffic.


4) Conclusion - which drive technology does the future belong to?

There is no clear answer to this question: On the one hand, the vehicle manufacturers set different priorities; on the other hand, clear differences can be identified with regard to state funding for alternative drive technologies. There are many alternatives to conventional gasoline and diesel engines, but even with conventional drive technologies, the innovation potential has not yet been exhausted. It is currently not foreseeable which technology will ultimately prevail.