Ludwig Scheitle

Stepping on the gas!

Rapidly increasing petrol and diesel prices have directed attention to alternative fuels, especially gas. The number of cars using natural gas on Europe's roads is growing steadily and there are also more and more gas filling stations. And the next trend is already on the horizon: natural gas could be supplemented and in some cases replaced by biogas.

Driving should be clean and cheap. Options for the future include vehicles running on hydrogen, electricity, or solar energy. However, hydrogen-powered drive systems are unlikely to be suitable for installation in mass-produced cars before 2020, and the other alternatives are not yet technically mature or economically viable. For this reason, the only new system to have attained widespread use in recent times is gas propulsion.

For a long time, it had to struggle with the chicken and egg problem. Since there were too few natural gas filling stations, very few gaspowered vehicles were sold, with the result that no additional gas filling stations were built. Even so, at the time of writing (early 2006), Germany already has more than 650 natural gas filling stations, and by 2007 there should be around 1,000 covering the whole country.

The natural gas infrastructure for motor vehicles is also expanding rapidly in Italy, Austria, Switzerland, Sweden, and France. Today's models can drive 400 to 500 km without refuelling — and even further with an additional tank full of conventional petrol.

Two different gas propulsion systems have been developed. One uses liquefied petroleum gas (LPG). This is a mixture of propane and butane and is supplied in liquid form at a pressure of roughly 8 bar. The other uses compressed natural gas (CNG), which is available from filling stations at a charging pressure of roughly 200 bar.

450,000 gas-powered cars on Italian roads

At the beginning of 2006, there were more than 35,000 natural gas cars in Germany. This bears no comparison to the 450,000 on Italian roads, where they have been a common sight for the last 40 years. They are served by 530 filling stations. Experts estimate that 400,000 such vehicles could also be registered in Germany by 2010.

Demand is rising, not only from private drivers, but also among industrial corporations and in the public sector, such as for refuse disposal. Buses powered by natural gas have been on the road for over ten years.

The public transport system in the Bavarian city of Augsburg uses more than 50 of them, and the plan is to have the entire fleet running on natural gas soon. Large fleet operators like DHL and Deutsche Telekom are also gradually converting their vehicles.

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Gas propulsion: standard feature

Many manufacturers build vehicles with gas propulsion as a standard feature. Owing to the additional space needed for the extra tanks, these are mostly estate cars, vans, and light commercial vehicles. They all have a combined (bivalent) drive system which accepts either natural gas or petrol.

The difference in price between a factory-made gas car and a diesel car is roughly the same as between a diesel car and a petrol car. Gas offers distinct operating advantages: the fuel costs only about half as much as conventional petrol and roughly 30% less than diesel.

The advantage is essentially due to the fact that natural gas fuel is subject to a lower rate of mineral oil tax. This ruling will remain in force until at least 2020. Also, gas car drivers do not have to worry that the price will be tied to the price of oil as in the case of town gas, because natural gas used in motor vehicles is not priced and taxed in the same way as natural gas used for heating. It is based on the prices of the other fuels, which are determined above all by supply and demand.

Gas cars are better for the environment in many ways: their pollutant load is roughly one-fifth as high as that of petrol cars, and there are no emissions of particulates like soot or dust. These vehicles could even make a name for themselves as "renewable energy cars" as they run on both natural gas and biogas.

Farmers produce biogas in fermentation processes, e.g. from such organic wastes as manure, silage, and abattoir waste. The gas is purified and mainly used in engines to generate electricity, but it can also be used to drive motor cars. The first biogas refuelling site in Germany opened in spring 2006; it will not be the last.

Gas from the fields

According to the Biogas Association, biogas could replace at least 10 and possibly even 16 billion cubic metres of natural gas by 2020. To achieve this, energy crops for biogas production would have to be planted on 10% of Germany's arable land.

Mono-cropping is not necessary: mixed cropping, crop rotation, grasslands, and fallow land are equally suitable. Based on the current volume of natural gas imports, it would mean that almost €7bn could be invested at home every year — in, among other things, jobs in the agricultural sector.

Risks and Chances

Most vehicles running on LPG have been converted from petrol to gas in a car workshop. Natural gas vehicles are normally built as such on the production line, where the quality and safety standards are higher.

There are no particular risks typically associated with gas propulsion systems. According to the ADAC, Germany's largest automobile association, and the TÜV, Germany's Technical Inspection Agency, gas cars are just as safe as petrol or diesel cars.

In fact, as crash tests have demonstrated, the risk of fire and explosion is even lower. Gas vehicles have been allowed to use underground parking facilities since 1993. Motor insurers have supported the spread of this new generation of vehicles in Germany from the very outset.

Since the advertising campaign for natural gas vehicles was launched in 2001, they have been insured under the same terms and conditions as petrol cars (despite the higher value insured) in the German motor insurers' rating catalogue. Some motor insurers also grant an extra green bonus with a promotional discount of up to 20%.

As these vehicles become more widespread, the cost of insurance will be increasingly based on the claims expenditure of natural gas models. It is the buyers who will ultimately prove decisive: are they private or commercial buyers, with high or low mileage?

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