CNG is a fuel which is emerging from the niche it has occupied up to now, and represents an excellent technology for the future for at least five reasons. Let’s take a look at them together.
1. CNG is ready for everyday use
For many decades, natural gas has been a central component of our energy supply, most notably for heating and cooking. And CNG has been ensuring momentum on the road for a long time as well: In 1863, Belgian inventor Etienne Lenoir test-drove the first natural gas-powered vehicle in the world – more than 20 years before Carl Benz puttered off in his gasoline-powered car. A slow maturation process has finally borne fruit: “CNG cars are ready for everyday use. The relationship between driving performance and overall maintenance costs are at least as efficient as with diesels”, says Dr. Jens Andersen, Head of Group Technology Strategy and Group Representative for CNG mobility at Volkswagen AG, which launched its first natural gas vehicle in 2002. Now the company’s CNG portfolio encompasses 17 different models. Additional models, such as the SEAT Arona1, will follow later this year. There are suitable CNG engines for all segments – from the 68 HP three-cylinder engine for city cars like the Volkswagen eco up!2, to the high-tech four-cylinder engine with 170 HP that powers the Audi A5 Sportback g-tron3. The CNG engines from Volkswagen feature bivalent, i.e. double, drive systems. Once the natural gas is used up, the system switches to gasoline. This allows natural gas vehicles to achieve ranges similar to those of gasoline and diesel vehicles. “But we will have to bring even more quasi-monovalent vehicles to the market in the future”, says Dr. Wolfgang Demmelbauer-Ebner, Head of Volkswagen Petrol Engine Development. “Quasi-monovalent means that one only tanks up with natural gas, but that there’s a small emergency tank for gasoline on board”. This frees up more space for the natural gas tank, and the engine is then also optimised for natural gas operation.
2. CNG is ready for the future
The typical natural gas cocktail consists mainly of methane, is deposited deep below the earth’s surface – and is packed with oodles of energy. But the conversation about CNG mobility today is not just about fossil natural gas. Biogas from agricultural production is also a component. Natural gas can also be produced synthetically – from renewable electricity: for example, in power-to-gas plants where wind power is converted into natural gas through a chemical process. These three types of natural gas create no compatibility problems, and natural gas vehicles can be operated with any one of, or any mix of the three, without the slightest technical modification.
CNG vehicles can therefore be powered entirely from renewable resources. Today, many CNG automobiles already drive with an (ad)mixture from renewable sources – and the numbers are rising. “It will be favourable to the success of CNG mobility to steadily increase the share of biogas or synthetic natural gas generated from natural materials”, says Dr. Andersen. “In the long run, the focus is therefore on renewable rather than fossil natural gas. CNG mobility offers plenty of options”.
And they are being used: SEAT in Jerez, Spain, extracts green-gas fuel from waste water. Audi operates a power-to-gas plant in Werlte, Lower Saxony – and is thereby playing its part in the energy transition. Integrated energy is the new catchphrase. Integrated energy refers to the integration of the areas of electricity, heat, industry and transportation through innovative technologies. For example, through power-to-gas technology, whereby renewable energy is converted into fuel.
3. CNG is reliably available
The existing supply network for natural gas mobility is more tightly meshed than for any other alternative drive technology. The supply is secured in Germany alone through an extensive natural gas grid that is over 500,000 kilometres long. There are also 50 enormous natural gas storage facilities. Logistically, CNG enjoys an advantage over, for example, e-mobility, which is still searching for effective storage solutions. “The immediate availability of natural gas makes it an important building block in our overall strategy for environmentally friendly mobility in the future”, says Dr. Ulrich Eichhorn, Head of Group Research and Development at Volkswagen.
In terms of the filling station network, Italy, the Netherlands, Germany, Sweden and Switzerland are among the role models in Europe. With the expansion of natural gas mobility, however, the corresponding infrastructure must also continue to grow. The Volkswagen Group has therefore joined forces with partners from the fields of natural gas supply, grid and filling station operations to create the “CNG-Mobilität” (or “CNG Mobility”) action alliance. One of the alliance’s goals is to raise the current number of roughly 860 natural gas filling stations in Germany to 2,000 in the years to come.
4. CNG is cost-effective
CNG is cheaper than either gasoline or diesel. Those who wish to compare prices, however, have to have a knack for conversion as well as calculation. That’s because CNG is sold in kilograms rather than litres. And the different energy contents of the fuels also have to be taken into account. A kilogram of CNG packs roughly 13.2 kilowatt hours (kWh), while diesel has 9.9 and gasoline 8.8 kWh per litre. If that seems a bit too complicated, here’s a practical example: If someone drives 100 kilometres in their Audi A5 Sportback3, the amount of gasoline needed will cost €8.80, diesel €5.30 and CNG a mere €4.50. This is also due to the fact that CNG generally attracts lower duties than gasoline and diesel, and is therefore more economical.
5. CNG is sustainable
Natural gas burns cleaner than conventional energy sources: the exhaust emissions of CNG vehicles contain 25 percent less CO2 than gasoline exhaust. If we are talking about biogas, then the CO2 balance is even more favourable and can even reach carbon neutrality, which means no CO2 emissions in the atmosphere. According to a study commissioned by the European Natural Gas Vehicle Association (NGVA), greenhouse gas emissions can be particularly sharply reduced, especially in the countries of Central Europe, if CNG is used as a fuel for automobiles. “If done properly, natural gas vehicles can be used to cut CO2 emissions by up to 80 percent”, declared German Chancellor Angela Merkel at the IAA International Motor Show in Frankfurt last year.
Moreover, CNG vehicles are virtually clean with regard to other emissions as well: they emit no soot particles from the exhaust and produce practically no harmful nitrogen oxides either. And since natural gas burns more slowly and thus “softer,” noise emissions are lower as well. CNG vehicles drive considerably more quietly than diesels.
Efficient CNG drive technologies will continue to play an important role in the global transport sector. Renewable energy sources can be used in part or in full as fuel components without requiring modifications to the vehicles. CNG mobility combines the experience and expertise of proven concepts with innovative and sustainable technologies. The Volkswagen Group aims to increase the number of registered CNG vehicles in Germany to roughly one million by 2025. And all that at an affordable price.
Sounds like a real alternative.
Source: Volkswagen AG
1 SEAT Arona CNG - This vehicle is not yet on sale or type approved and is therefore not subject to Directive 1999/94/EC. 2 Volkswagen eco up! – CNG consumption kg/100 km: urban 3.7 / extra urban 2.5 / combined 2.9; CO2 emissions combined in g/km: 82; efficiency class: A 3 Audi A5 Sportback (petrol engine models) – fuel consumption in l/100 km: urban 8.3-7.1 / extra urban 5.7-4.6 / combined 6.5-5.5; CO2 emissions combined in g/km: 149–106; efficiency class: C-A Audi A5 Sportback (diesel engine models) – fuel consumption in l/100 km: urban 6.5-4.8 / extra urban 5.2-3.7 / combined 5.7-4.1; CO2 emissions combined in g/km: 148–106; efficiency class: B-A Audi A5 Sportback g-tron - CNG consumption urban: CNG 5.5-5.0 kg/100 km | fuel 8.0-7.2 l/km / extra urban: CNG 3.4-3.1 kg/100 km | fuel 5.2-4.6 l/100km / combined: 4.2–3.8 kg/100 km | fuel 6.3–5.6 l/100 km; CO2 emissions combines: CNG 114–102 g/km | fuel 143–126 g/km; efficiency class: A+