27_dg02aThe Kyoto Outcome

The Kyoto-Protocol was passed at the end of the year 1997 at Kyoto. It foresees the obligatory reduction of industrial nations emissions by approximately 5,2 % compared to the year 1990 in the time among 2008 to 2012. The European Union has the aim to achieve 8% reduction of the climate relevant emissions in opposite to 1990. The Austrian quota to reduce the greenhouse gases emission is 13% (CO2, CH4, N2, FKW). Without doing any urgent measures the CO2 – emissions, caused by traffic, will further rise according to the nowadays trend until 2010 (in the opposite of the year 1990). While searching for new innovative technologies research workers always strike on alternative fuels.Auf der Suche nach neuen innovativen Technologien, stoßen Forscher immer wieder auf alternative Kraftstoffe.

Alternative fuel or alternative drive commonly are alternatives to traditional benzin or diesel, e.g. natural gas or liquid gas, but also bio diesel or electrical power by traditional battery or by fuel cells count to alternative power drives. Around the year 1900 electric energy and ethanol have been the leaders of the future hit lists.

Alternative Fuels

The vehicle of tomorrow will have to work very efficient and the CO2 emission will have to be as low as possible but reduction of power will not support selling. That means benzin and diesel will have to share their hegemony as fuel with alternative energy carriers. At the present worldwide more than 95% of motor vehicles are still powered by benzin or diesel. But the market for alternative fuel is growing. Car manufacturers, from Mercedes Benz with its fuel cells project up to the PSA-group with its electric powered vehicles, are dealing with this themes intensively.

463_tankstelle2At present bio diesel, liquid gas, natural gas and electric power are practically tested or actually used in Austria. In the meantime an intensive research after low cost manufacturing of fuel cells for mobile applications keeps on going. In search of low emission power drives one always strike to natural gas. It contents of almost clear methane (CH4). In many countries of this earth automobiles are powered with natural gas for a long time. Big automobile fleets get their power from natural gas, e.g. in the U.S.A., Argentina, Italy and Russia. The use of compressed natural gas shows the step between the age of mineral oil and the age of solar hydrogen.

The liquid storage of natural gas – LNG (liquefied natural gas) at minus 162°C is the following technical quantum jump. Up to now compressed natural gas is stored in steel tanks at 200 bar. This is technical more extensive compared to the storage of inflammable liquids and even involved with higher risks.

In the opposite to that one can see clear environmental advantages. The emission value of natural gas engines for several pollutants can not be reached with traditional benzin or diesel technology. Natural gas power is even more advantageous regarding climate protection despite of its higher consumption in opposite to a diesel engine, because natural gas has a very low part of carbon and therefore result low CO2 emissions.

For some time natural gas powered vehicles have been used by energy supply enterprises and public transport in Austria. Many known car manufacturers offer vehicles which can be powered either with natural gas or bezin.

 

The question is: Are there other advantages or disadvantages for drivers besides the environmental advantages?

Liechtenstein has the densest net of natural gas stations in Europe, with an average distance of 9 km in between them. In Austria there are at present six public natural gas pumps: three in Vienna and one in Graz, Linz and Dornbirn. The OMV enterprise plans to open 20 natural gas stations until 2004. Information about the petrol station network in Austria and in foreign countries you may get at:

www.omv.co.at/erdgas and www.erdgasfahrzeuge.de .

To make up for the deficit of natural gas supply-development, additional benzin tanks are foreseen in the vehicles. Like other manufacturers e.g. the Opel Zafira CNG utilizes this solution.

There is no loss of space in the inside area caused by this solution. With a switch one can choose the fuel, either benzin or natural gas, injected into the 1,6-l-engine. The maximum power of 71 kW (97 PS) is affected with gas power. The operational range with gas is approximately 300 kilometres. The benzin tank takes 15 litres that is sufficient for further 170 kilometres. Depending on the price of the day a reduction of cost by 2.– EURO each 100 kilometres in operation with gas can be assumed. In case of calculating the purchase costs against this advantage of fuel costs the absolute saving results after 70.000 driven kilometres.

 

The natural gas-station techniques:

There is no change for the driver during the fuelling process, the nozzle of the gasoline pump is fitted at the filler neck and the fuelling process is closed after 3 minutes. The nozzle looks different and the fuel is gaseous. With a strictly look at details a lot of techniques is behind it. Natural gas-stations are maintained via pipelines not by tank trucks, the pressure in the pipe line is low but the pressure in tanks of the vehicles lies at 200 bar, therefore it is necessary to compress the gas. There are different refuelling dispositions that vary not only in aspects of cost but also in safety aspects. This is important for the operator of gas stations.

 

1-Bank Method:

A fast-refuelling station consists of compressor, intermediate storage tank and fuel dispenser. When a vehicle is refuelled gas flows from the intermediate storage tank into the vehicle’s tank, powered by the pressure difference. For that reason one need only less and simple components. The disadvantage of this system is that the capacity of the intermediate storage tank can be used by a third only. The compressor runs often and let so increase the operating expenses.

 

3-Bank Method:

At this method the intermediate storage tank is separated into three parts. When refuelling the storage tanks will be switched automatically to the vehicle according to the difference of pressure. By that smaller storage tanks can be used which reduces the investment.

 

Mannesmann Method:

Mannesmann has developed this solution works with hydraulic compressors. In the first stage of the compressor the gas is compressed to a set value in the intermediate storage tank. When fuelling the fuel is directed to the vehicle with a booster compressor. This method allows a 75 % use of the intermediate storage tank volume.

 

Developing a sense of safety:

The tank of a natural gas powered vehicle and the stationary facilities in the area of a refuelling station are protected by a number of safety precautions. In case of fire pressure control valves and other safety devices avoid the gas tank is breaking or exploding. In case of natural gas overflow (natural gas is lighter than air) it will come to a fast reduction of concentration, there is even no concentration rise next the ground. The inflammation temperature of more than 560°C is clear higher than at benzin or diesel oil (220°C). Nevertheless: The interior space of the fuel dispenser is potentially explosive (zone 1). The inside installed devices must meet these requirements.

The supply of refuelling stations via pipelines replaces the fuel-transport on the road or rail which reduces the risks evident.

To ensure safety of natural gas stations on the same level TUV Austria has developed a catalogue of requirements, based on the technical experiences (VdTUV-code of practice) and on a therefore valid European standard. This catalogue of requirements allows to the constructor and the operator of natural gas stations to structure their technical documentation for a design approval procedure. After examination of this documentation by TUV Austria a report will be issued which can be the basis for an official approval procedure.

During the construction TUV Austria carries out the acceptance tests and at a positive result the award “TUV-examined natural gas-station” will be granted. Enterprises signed with this award ensure that their plants have been constructed regarding the state of art and that methodical maintenance is carried out. These plants are inspected regularly by TUV Austria in regard to safety.