The Goal is to Achieve Sustainable Mobility

It is no secret that the earth’s petroleum reserves are finite. But even long before the main source of energy which feeds mobility and keeps the global economy oiled is depleted, production will first decline amidst a continually increasing rate of consumption. In fact, the so-called depletion mid-point, i.e. the point in time at which half of all global petroleum deposits will be used up, could be reached within a matter of only a few years. The situation is further exacerbated by the growing cost of mining those resources which still remain at our disposal. As a consequence, the price of crude oil products will rise noticeably for us all. It is all only a matter of time.

According to IEA figures, total oil demand in 2005 was four gigatons p.a. That makes petroleum the energy source most in demand around the world – and this will continue to be the case over the foreseeable future. Yet petroleum combustion generates around ten billion tons of carbon dioxide (CO2), making it a major contributor to the mounting greenhouse effect. In 2005, that was the equivalent of around 38 per cent of global CO2 emissions. With the existence of three quarters of a billion cars around the world, it is clear that we will need an alternative to petroleum-based fuels very soon and that such an alternative will need to be available in vast quantities.

This is one of the reasons why the EU has decreed that at least 5.75 per cent of fuel (calculated on the basis of energy content) must be of biogenic origin by 2010. And this will only be an interim target, with plans afoot to introduce a target share of energetic biofuel of at least 10% in the European Union by 2010.

Evolution over revolution
The Volkswagen Fuel and Powertrain Strategy illustrates a path to sustainable mobility – the kind of mobility we have already embarked on and which can now be gradually further developed. This strategy has been extensively adopted by Germany’s federal government and by the EU in their own fuel strategies. Volkswagen wishes to actively help to reduce global emissions of climate-relevant CO2, to reduce local emissions such as nitrogen oxide or particulate matter and, not least, to limit our dependency on petroleum.

Secure sustained energy supplies require improved efficiency as well as the use of alternative sources of energy over the medium and long term. That includes, most notably, renewable, CO2-neutral sources of energy. However, Volkswagen’s fuel strategy also incorporates conventional petroleum-based fuels. We expect that such fuels will continue to be indispensable for some time yet, making it all the more important to keep working on optimising their properties so that they too will contribute towards emissions reduction. It is particularly important to reduce the share of sulphur and aromatic compounds. Such optimisation efforts must not, however, be limited to the fuels used in Europe, but must be applied around the globe to enable use everywhere of the newest and most efficient engines.

The future belongs to SunFuel®
We consider electric drive technology to have the greatest amount of potential for sustainable mobility over the long term, albeit that there is no telling right now whether the electricity used will be generated in a fuel cell using renewably generated hydrogen or classically stored using a battery. That is why Volkswagen is vigorously pursuing both technologies. Volkswagen has already developed its own fuel cell, one which has a significantly higher operating temperature. This cell, with a high-temperature polymer electrolyte membrane (HT PEM), runs at an operating temperature of up to 160°C (versus the conventional temperature of 80°C), which means it uses significantly less catalyst material, has a significantly longer life and is more compact.

A considerable amount of research still needs to be done on battery technology. State-of-the-art accumulators do not yet offer the kind of energy storage density and charging times needed to ensure uncomplicated vehicle drivetrain technology. Further improvements have yet to be made to the level of energy and power density as well as to the safety, cost and longevity of the batteries. Volkswagen has therefore joined forces with Degussa and Chemetall, two companies specialising in the field, to establish a supported Chair of Applied Material Sciences on Energy Storage and Conversion at the Westfälische Wilhelms University in Münster, Germany.

Volkswagen believes that the challenges associated with electric drive technology need to be tackled today and that several years of research will still be required. Indeed, it will probably take another ten years until these new technologies have secured a big enough share of the market to actually produce a significant degree of change. It is vital, therefore, that we supplement the distant goal of electric drive with a strategy for the near future – i.e. a strategy which involves effective and realistic phased evolutionary development aimed at achieving the revolutionary objective of sustainable mobility.

One of the crucial steps in this development is the electrification of powertrains. We are convinced that the share of drive performance produced by electric powertrain technology will gradually increase in future, eventually ending in an all-electric-powered vehicle. Hybrid technology as we know it today represents nothing more than an interim phase. This evolutionary path is very much dependent on the further development of battery storage capacity.

The development of second-generation liquid biofuels made from renewable resources (i.e. SunFuels®) as well as the significant further optimisation of first-generation biofuels are also crucial steps on the road to sustainable mobility. Whereas liquid fuels will continue to be the backbone of long-distance mobility, we believe that the future of short-distance mobility lies in electric-drive vehicles.

SunFuels® can be produced using numerous different types of renewable biomass and residual biomass material. One of the major benefits of such fuels is that they are sustainable – a quality determined by the fact that they satisfy the following criteria: compatibility with the existing infrastructure of filling stations and the vehicles on the market today, being practically CO2 neutral, not standing in competition with food production and clear technical potential for mineral oil substitution of around 20%. The advantage of first-generation biofuels such as biodiesel and ethanol made from food crops (e.g. wheat) is that these resources are widely available today. The production methods do, however, need to be improved if these fuels are to make any significant contribution towards easing the CO2 burden. We take the view that the goal of sustainable mobility can only be achieved through the inclusion of SunFuels® in a broader strategy. It is important, therefore, that we pave the way today for the use of SunFuels® in future.

The other main second-generation biofuel which meets our stringent demands, aside from SunDiesel® made of biomass (a SunFuel® product designed specifically for diesel engines), is ethanol made using straw. This SunEthanol® is particularly suitable as a component in petrol fuels. The status of vehicle technology today means all cars are already able to use up to five per cent by volume of ethanol in petrol.

Volkswagen has taken things one crucial step further, however. With only a few exceptions, Volkswagen-brand vehicles are designed to run on the standardised E10 (10% vol. Ethanol blend) fuels.

Turning engine and fuel technology into a homogeneous overall strategy
The Volkswagen Fuel and Powertrain Strategy endorses the use of different sources of energy rather than a wide range of energy mediums (i.e. fuels). Diversification of energy sources means a variety of raw material is used to produce alternative fuels. Synthetic diesel fuels offer particularly interesting prospects. These so-called synfuels are manufactured using the Fischer-Tropsch technique or similar processes. The first step in this technique involves reducing the raw material to synthesis gas. The next-in-line synthesis processing step then converts it into synthetic diesel. Syngas can be based on a whole array of different renewable or fossil resources such as wood, straw, natural gas or coal. Volkswagen promotes mainly the use of CO2-neutral biomass, e.g. wood, straw and energy plants, for the production of SunDiesel®, a non-sulphuric diesel fuel devoid of any aromatic compounds and which, when combusted, generates a much lower amount of pollutants and only emits as much CO2 into the atmosphere as was previously absorbed by the plants during photosynthesis.

Another important point is that the quality of synthetic fuels is largely independent of the actual raw material used! SunDiesel® made of biomass and synfuels made of natural gas or coal all possess the same premium fuel quality. The technology used to manufacture synthetic fuels constitutes a key element in the pursuit, at once, of independence from petroleum and better fuel quality (and thus reduced local emissions).

SynFuels and SunDiesel® are an ideal supplement to the petroleum-based fuels currently in use, because they can be mixed in any desired blend. And it is easier at this stage to define the specific chemical and physical attributes of synthetic fuels than it is to define those of conventional fuels. That is why we often refer to synfuels and SunDiesel® as designer fuels which can be used as a constructive element in engine development. They allow us to work simultaneously on developing a fuel and an engine. One prime example of this is the CCS® combustion process which combines the low emissions of a petrol engine and the efficient level of fuel consumption associated with diesel engines. This technology illustrates how a fuel strategy can become a fuel and powertrain strategy.

The hydrogen era
The path to sustainable mobility does, however, hold greater challenges in store. We will need to make use of other renewable sources of energy in addition to biomass to produce SunFuel®. This path is marked by the necessity to change how we think. We need to replace our “either/or” mentality with one that accommodates parallel solutions. We will need other renewable sources of energy in addition to biomass. Solar energy has a key role to play here. Nigh-but sustainable mobility has a real chance of being accomplished if other forms of efficiency enhancement in the area of vehicle technology and in the area of energy provision and storage are brought into play.

Future electricity-storage technology will play a vital role when it comes to the direct use of solar energy through the application of photovoltaic technology. Another way of producing renewably generated electricity is by using fuel-cell technology. This technology uses electricity to generate hydrogen. The fact that fuel-cell vehicles have a longer fuel range than electric-powered vehicles comes at a price, namely that of a complicated and costly hydrogen infrastructure. In contrast to hydrogen filling stations, power sockets are readily available everywhere. The only thing we can be clear about right now is that it is not a matter of primary importance whether or not sustainable mobility is hydrogen and fuel-cell based or electricity and battery based, since what is important is that both forms of energy be generated from renewable energy sources in the long term. If they are not, our innovative automotive technology will not result in any significant reduction of burden on the environment.

We can, and must, move ahead now and set an incisive course that will lead us towards sustainable mobility. The Volkswagen Fuel and Powertrain Strategy describes such a course – a course defined by the revolutionary objective of sustainable mobility coupled with an evolutionary approach to achieving that goal.