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The Warsaw Voice » Other » November 19, 2008
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Taming Hydrogen
November 19, 2008   
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Prof. Jerzy Kaleta, director of the Material Science
and Technical Mechanics Institute (IMiMT) at the Wrocław University of Technology in southwestern Poland, talks to Maciej Wełyczko.

Tell us about the beginnings of your love affair with hydrogen.

Over 10 years ago we started research on composite cylinders for methane as a gaseous fuel for motor vehicles. We had already made successful attempts to construct light composite cylinders for Polish helicopters to be used to rapidly fill up pontoons in the event of an emergency landing on water. But the methane cylinders were of key importance. We designed a fourth-generation carbon-fiber cylinder with a thermoplastic liner. We produced the whole cylinder independently at the institute and then launched its production in a Polish company. As we were looking for a European supplier of equipment the company needed for high-volume cylinder production, we met many European university researchers and manufacturers. They invited us to take part in a really big European project associated with high-pressure composite hydrogen cylinders. It was a challenge to us because the cylinders were supposed to hold gas at a pressure of 700 bars. Meanwhile, methane cylinders work at a pressure of only 200 bars. And this is how we joined the consortium working on the StorHy (Storage of Hydrogen) program with a budget exceeding 18 million euros. We are the only participant from a new EU member country.

Where can your technology be used?

First of all, it can be used to store hydrogen. And one should remember that hydrogen is a quite "whimsical" gas. It is very light, which is a drawback because one needs a large volume of hydrogen to get an energy equivalent of, say, 1 kilogram of gasoline. But it also has advantages-it can be compressed to a very high pressure.

Generally, hydrogen has the potential to alter the face of our transport system within a short time. At present, two technologies are used. Hydrogen can be mixed with air and burned in a combustion engine. This kind of propulsion is very clean environmentally. But the target technology is the fuel cell. It will be powered from two sources, hydrogen and oxygen. The fuel cell generates electricity to power engines. It is assumed that such cars will have no mechanical transmission. Their engines will be mounted directly on wheels and controlled through electronic systems. As a result, the cars will be much simpler in mechanical terms.

Cylinders can also be used to store other gases-for any application where we need a large amount of energy stored at a low weight. One example are aviation applications. In the future, gas cylinders could also be used in stationary fuel cells for emergency power supply to hospitals and telecommunications facilities, for example.

The key element of all these ideas is to eliminate oil as a source of energy. Europe is dependent on liquid fuel imports. Over 70 percent of the oil it consumes has to be imported-in many cases from regions that are politically unstable. Hydrogen may help us ensure energy security for Europe and achieve environmental effects. The only waste product from fuel cells-if one can use the word waste in this case at all-is water. If we learn to produce hydrogen cheaply the energy problem will be solved.

Why has progress in this area been so slow? Where are the bottlenecks?

There are two kinds of constraints. A cylinder prototype is expensive. At present, a cylinder with which a car could cover a distance of 500-600 kilometers costs 15,000 euros. Ultimately-and this is another phase of the project we will be carrying out under the EU's 7th Framework Program-such a cylinder should cost 2,000-3,000 euros. This price level offers an opportunity for the cylinders to be mounted in cars on a mass scale.

Is the cylinder the most expensive part of this technology?

Cell fuel is also expensive. A cylinder has to ensure a high level of safety and this pushes the price up. But hydrogen storage in cylinders is still the cheapest technology of the three currently available. Hydrogen can also be stored in liquid form by cooling it. But the cooling process requires a lot of energy. The third option is to store hydrogen as a component of solid chemical compounds and then recover it. This technology is the most expensive. One kilogram of hydrogen in gaseous or liquid form costs 4 euros and can be bought, for example, at an Aral gas station in Berlin, one of several stations in Germany that sell hydrogen fuel. Meanwhile, 1 kilogram of hydrogen stored in solid compounds, which is the most promising technology for the future, costs thousands of euros.

The problem of hydrogen storage will be solved very quickly. A greater problem will be to develop the whole hydrogen infrastructure, which will enable us to refuel our cars with hydrogen in a convenient way and close to our homes. How should hydrogen be supplied to fuel stations? Should it be transported by pipelines or tank trucks? I think it will take us around 20 years to build the necessary hydrogen infrastructure.

A system of vehicles powered by compressed natural gas (CNG) will come into use on a mass scale much sooner. In Germany, this fuel, which should not be confused with LPG, is already quite popular, and the country has around 1,300 stations selling CNG, which is mainly composed of methane. Methane is also of great interest to Poland. At present, the most cost-effective way to produce hydrogen is to derive it from methane. Hydrogen can also be derived from hard or brown coal. This technology may be of great importance for Poland, considering the large coal deposits in the vicinity of Legnica in the southwest of the country and elsewhere.

Of what use is 1 kilogram of hydrogen given the efficiency of today's engines?

In energy terms, 1 kilogram of hydrogen is equivalent to around 2.9 kilograms of gasoline. It is assumed that in 2010 this amount will be sufficient for a small passenger car to travel 100 kilometers. At present, around 1.5 kilograms of hydrogen is needed to do so.

What is the main focus of your research?

We make strength, static and fatigue tests. Another area of our research is work on developing an intelligent cylinder, that is a cylinder with a system to monitor its condition throughout its life span.

As regards strength research, we simply conduct tests in which cylinders are destroyed. We have to check what maximum pressure a cylinder is able to withstand. A cylinder normally working at a pressure of 700 bars should survive 1,650 bars. We also have to simulate a cylinder's 10-year-long work period by loading it 15,000 times, which is equivalent to the same amount of charging and discharging cycles. The number of cycles in such tests is often increased by three times, in which case a cylinder is loaded and unloaded 45,000 times. The tests take many weeks and are performed with a frequency of two cycles per minute. We make them at room temperature but also at a temperature of minus 40 degrees Celsius because the cylinder has to meet certain parameters even in such harsh "Siberian" conditions. We have a special laboratory, one of three of its kind in Europe, where we conduct such research. For safety reasons the cylinders are loaded with hydrogen on special exercise sites. In the laboratory, the gas is replaced with oil. Our cylinders have a carbon-fiber layer that is 2 centimeters thick. We have to use such sophisticated materials if we want the cylinder to weigh 40 rather than 200 kilograms. No one would like to carry a large steel cylinder in the car. The strength-to-weight ratio is very important in such designs. This ratio is very high for our cylinders.

An intelligent cylinder, that is one equipped with an onboard monitoring system, as it is called in our project, is provided with sensors at the production stage. The system comes with appropriate software and a processor that provides information about the cylinder's condition throughout its 10-year life span. The system communicates with the driver, who may be advised, for example, to go to a service station. The system contains only fiber-optic sensors so there is no risk of ignition.

What about industrial production of your cylinders?

A limited series of cylinders has already been manufactured so the cylinder exists physically. The same goes for the sensor system. The cylinders are mounted in experimental vehicles made by Daimler-small Mercedes A-Class cars. As I have said, another stage in the project will be aimed at reducing the cylinder's price to enable its high-volume production. We are making tests on cylinders produced by three global manufacturers, who are our partners in the program. One of them is Dynetek, a Canadian group that has a large plant near Düsseldorf. The second one is the Ullit company of France, the largest producer of cylinders for methane storage. And the third one is Faber of Italy. We are testing the strength of these cylinders and checking how to mount sensors on them. In the future, our cylinders may be installed in cars such as Mercedes, Renault, Citroen, Ford, Volvo and Opel.

Aren't you worried that people's fear of the risk of explosion may be the greatest obstacle to the development of hydrogen technology?

This explains why large European projects such as ours carefully examine the psychological aspect. A good example is experience with methane stored in cylinders at a pressure of 200 bars. Such a pressure is also very high and may be no less dangerous for people than 700 bars. In countries where high-pressure cylinders are used as holding tanks for gaseous fuel it has been clearly demonstrated that these products are safe. The number of accidents with these cylinders is much smaller than the number of accidents with gasoline tanks in traditional cars. The level of safety is so high that methane is used in the United States to power school buses and vehicles used by airport services, for example.

New things always cause some level of fear. We have to show people clearly that the cylinders are safe. We check them for safety quite "brutally." During the tests, the cylinders are shot at with ordinary and incendiary bullets, and grenades are set off next to them. They are thrown down from a height, or notched to simulate various disastrous events. The fact that the research program is so strenuous and the regulations so strict has an impact on the cylinders' price. Why are the cylinders so expensive? One of the most important reasons is that they have to meet very stringent safety regulations. Now, we have to make them cheaper without undermining their safety.
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