Pictures of the Future    Fall 2007

Road to a Lighter Future

The Scandinavian Mountains extend into the polar regions like an endless spine. Above them, the sky is a mass of heavy clouds driven in from the Atlantic by westerly winds. Here in Norway, there is obviously no shortage of water. Perhaps that’s why the Norwegians don’t just use it for drinking but also for power generation. They will proudly tell you that 99 % of their electricity comes from hydro-electric sources. Even the Oslo Metro runs on this clean form of electricity. However, in an attempt to make the Metro even more environmentally friendly, AS Oslo Sporveier, the city transport company, went looking for a new train four years ago. The search ended at Siemens Transportation Systems (TS). TS had already provided very economical trains for Vienna’s Metro system. Although the Norwegians wanted to base their Metro on the Vienna version, they were also determined to make it even greener.

In the meantime, the first MX trains have entered service in Oslo. Altogether, 63 units have been ordered. In addition to using one third less electricity than their predecessors, they contain no toxic substances. What’s more, it will be possible to recycle over 94 % of their components in 30 years when the trains are retired.

It’s clear from this example that high-technology can contribute a great deal to environmental performance. This applies to all types of transportation, be it subways, inter-city trains, aircraft or shipping. Various Siemens Groups have been working for a long time to perfect vehicles—for example, by reducing weight, improving drive systems, and introducing new materials. These days, they don’t just look at the final product, but assess the total product life cycle—from manufacturing and operation to disposal. Product developers at TS applied this kind of life cycle assessment (LCA) to the Oslo Metro, working with experts from the Ecodesign study program at Vienna Technical University (TU Wien). "In order to identify key potential savings, we first had to identify which phase used the most energy," says Dr. Joachim Pargfrieder, who is responsible for LCA at TS in Vienna.

The university staff take thousands of details into consideration for their eco-audits— thing like the energy consumed during bauxite mining and aluminum production or the heating requirements for a subway train on cold winter days. "For this type of analysis, sophisticated software—such as that developed at the TU—is required," says Pargfrieder. It quickly became clear that the main task was to achieve the highest possible energy savings at the lowest possible cost. It was obvious that weight could be saved by using aluminum. However, aluminum doesn’t have the good insulation properties needed to cope with chilly Oslo. To solve this problem in relation to the railcar body, experts at TS developed a hollow aluminum chamber profile with air pockets and glued-on insulation. The subway also saves energy through a sophisticated brake and drive management system that feeds the power generated during braking back into the network as electricity.

Pargfrieder and his colleagues have taken particular care to ensure that recyclable materials such as wood, plastics, metals, and ceramics make up 84 % of the total materials used. An additional ten per cent can be harmlessly incinerated to generate electricity, bringing the total of recyclable material to 94 %. "It’s hard to reach 100 % because fire safety makes it necessary to use certain composites that can’t really be split up," Pargfrieder explains. His goal is to further reduce this component and cut energy consumption even further.

Energy-Saving Direct Drive. The new Syntegra bogies developed by Pargfrieder’s colleagues at Siemens Transportation Systems in Erlangen, Germany, and Graz, Austria, might help him achieve his goal. (see Pictures of the Future, Spring 2006, The Competitive Drive). Syntegra is a highly integrated rail drive system in which the drive technology is attached under the floor of the vehicle. Unlike traditional systems, where the engine’s power is transferred to the axles via a gearbox—which causes noise, wear, and reduced efficiency—the Syntegra system employs motors mounted directly on the bogies.

To be more precise, a cylindrical electric motor sits directly on the drive axle like a ring on a finger, but without touching it. The motor uses a permanent magnetic field produced by rare-earth magnetic materials to rotate the axle. "These high-performance materials are the heart of the drive," says Dr. Lars Löwenstein, Syntegra’s project leader. "Until just a few years ago they would have been much too expensive." However, the price of rare-earth magnets capable of achieving the required quality has fallen. And because the new concept dispenses with the need for a gearbox, a Syntegra bogie is around a meter shorter than traditional models. The result: a weight savings of around two tons, while energy is reduced by 20 %.

The Syntegra prototype is currently being tested by Munich’s Municipal Transport Services—for the moment at night and without passengers. During the test, 200 sensors monitor how well the new technology is working. In a few months the train is due to carry its first passengers. On the basis of the 10,000 km the train has already run up on the Siemens test track in Wegberg-Wildenrath, Germany, it is already clear that Syntegra is fulfilling its promise. Energy consumption has dropped significantly.

But there is still room for improvement before the production model is scheduled for market launch in around three years. In particular, the production model will be leaner and lighter than the prototype, which was initially designed to be very robust. The energy density of the rare-earth materials is also to be increased to boost drive performance.

Lower Temperatures Boost Performance. Syntegra’s developers weren’t the only ones who had to wait a long time for their materials. So do did experts at Siemens Automation and Drives (A&D) in Nuremberg, who specialize in another type of material: superconductors. These materials are made from compounds that suddenly lose their electrical resistance when they are cooled to very low temperatures. The catch, at least initially, was that in most cases this type of cooling required the use of liquid helium at minus 269 °:C—an expensive product. But in 1987 researchers discovered substances that become superconducting at much higher temperatures. Unfortunately, these high-temperature superconductors (HTS) were still too expensive for most applications.

However, about five years ago these substances became significantly cheaper. In response, A&D decided in 2003 to develop its first HTS generator. Its rotor is fitted not with the usual copper coils, but with HTS windings that can carry around 100 times more current. The 400-kW machine was designed to be a third smaller and lighter than traditional units with the same capacity (Pictures of the Future, Spring 2006, Superconducting Generators).

This type of equipment is particularly suitable for power generation on ships since it saves space in a narrow hull. In the meantime, A&D has developed a prototype 4-MW machine that has been tested for a year in the System Test Center in Nuremberg, operating both as a generator and as a motor. The next step is a slowly rotating 4 MW HTS engine for the direct drive of a ship’s propeller. "We’re still in the development phase," says project leader Dr. Klemens Kahlen. "Assembly starts in 2008." The new motor will be tested in 2009. The first commercial motors could then hit the market as early as 2011. U.S. superconductor expert Alan Lauder has calculated that this type of HTS motor could reduce a ship’s annual fuel costs by up to $100,000.

Significant Savings. Fuel cost savings, particularly through weight reduction, are important in aviation. Every kilogram of mass saved represents a fuel savings of several tons over an aircraft’s lifetime. Alongside aluminum, aircraft engineers are therefore increasingly turning to carbon fiber composites (CFRP), which can reduce a plane’s weight by up to 30 %.

More CFRP parts—such as, for example, the 120-m² tail fin—are used in the new Airbus A380 than in any other aircraft. Toho Tenax Europe is the largest producer of carbon fibers in Europe and a global leader in carbon fiber technology. Over the last year the company’s Japanese parent company has built a new CFRP production line in Oberbruch, Germany. Siemens provided process control technology and other products and services for the plant.

"Because of our expertise in a number of business areas we were able to offer a total solution," says Klaus Vierbuchen, sales engineer at A&D in Cologne. Acting as a single-source provider, Siemens has delivered basic and detailed engineering, assembly monitoring, coordinated safety measures, and provided process measuring and control units, drive systems, motor switchgear, uninterruptible power supplies, and transformers for the plant.

In a complex process at the plant, kilometer-long fiber blanks are baked to produce finished products. Several hundred fibers run in parallel over rollers through individual stages of the automated process. A large number of parameters—oven temperature, speed of transportation, and dwell times—are processed by a Simatic PCS 7 process control system to ensure that the fibers meet the quality requirements stipulated by aircraft engineers.

The single-source solution was not only less costly than those offered by competitors, but also quicker to assemble. "The manufacturer was able to start production weeks before the actual deadline," says Vierbuchen. The new carbon fiber manufacturing plant illustrates that you can help make transportation sustainable in a variety of ways. For example, you can build an environmentally friendly subway or provide expertise to help operators build production plants for environmentally friendly high-tech products.
                                                                                                               Tim Schröder