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Renewable raw materials improve the environmental balance sheet
Natural gas is a comparatively clean energy source. A modern natural gas vehicle such as the Passat TSI EcoFuel cuts down environmental pollution with CO2 emissions by about a quarter compared to a similar vehicle with conventional petrol drive. The environmental balance sheet of the vehicle becomes even better if the volatile propulsion fuel is produced from renewable raw materials. In that case, it is cut from the field – often in the form of maize, grass fodder or catch crops – and is processed to make biogas. In the subsequent cleaning procedure, the raw biogas is refined to natural gas quality, at which point it earns the right to be called biomethane, or in general parlance, bio natural gas and is 100% compatible with the current natural gas quality. At Volkswagen, the term SunGas® is also used, thereby emulating other biofuels with the appropriate prefix, "sun". After all, what is behind all these renewable fuels is the power of the sun. The special advantage of biomethane: In terms of area efficiency – that is the amount of energy produced per unit area – SunGas® is among the leaders in comparison to other biofuels.
High quota delivers environmental advantages
Expanding bio natural gas production and utilisation is a declared objective of the German Federal Government. By 2020, about six billion cubic metres of this renewable energy "raw material" should be fed into the natural gas pipeline network annually. This represents approximately seven percent of the current consumption in Germany. And by 2030, indeed, the annual feed-in is projected to rise to ten billion cubic metres.
It is a straightforward correlation: the greater the amount of bio natural gas that is added, the better it is for the environment. Of course, the whole thing is ideal in terms of the environmental balance sheet of the Passat TSI EcoFuel and other natural gas cars if it is possible to refuel with pure bio natural gas at a service station. This is possible in the Wendland region of Lower Saxony. In the vicinity of the towns of Lüchow and Dannenberg, the Raiffeisen cooperative society of Jameln has already been operating a filling station since 2006 at which the largely CO2 neutral fuel is available as a pilot project.
Taking account of the overall conversion chain from biomass production in the field through to utilisation of the fuel in the vehicle, it is apparent that the properties of bio natural gas are significantly positive from an environmental perspective. According to calculations by the European Commission, there is a greenhouse gas reduction potential of 70 percent for such a "well-to-wheel" balance sheet. The production process is still relatively new and should undergo further optimisations soon. In view of this, the EU considers even a reduction potential of 85 percent to be realistic in the long term.
Engine development keeping pace
It is no wonder that Volkswagen assigns great importance to the subject of SunGas® as part of its engine development. "We are working to overcome three major challenges," says Prof. Jürgen Leohold, the head of Group Research into the fields of fuel and drive strategy. "Locally, emissions should be reduced, while CO2 emissions in general must be lowered in order to protect the global climate and, at the same time, we have to tackle the task of securing the long-term supply of energy for future mobility. Complex challenges of this kind can only be met by taking a holistic approach. As a result, we are pushing ahead with the further development of our drives, always against the background of the enormous progress being made in the field of innovative, environmentally friendly fuels. In this regard, bio natural gas or SunGas® offers an extraordinarily great potential."