First high-temperature fuel cell in industrial service

• HotModule in service at Michelin, Karlsruhe
• Series production run-up planned for 2006
• Record efficiency results
• Technology with high market potential
• New perspectives for power generation
• Technical data of the HotModule

Karlsruhe - On 7 February, at the Michelin tire works in Karlsruhe, the first high-temperature fuel cell for industrial service was put into operation. Under the brand name of, "HotModule" the fuel cell will undergo field-testing at Michelin under everyday operating conditions.

The HotModule is a technology developed with a decentralized and small power station in mind and now, after more than ten years of development, is presently in the testing in practice phase. This includes putting plants of this type into various areas of application to test their suitability for everyday service.

The HotModule is especially environmentally friendly because it emits almost no harmful substances. In addition, it is very easy on resources because it uses notably less fuel than comparative conventional power stations in order to produce the same amount of electrical power. The plant is also eminently suitable as a small decentralized power station because it produces not only electrical power but high-temperature heat. This heat is needed for a number of industrial purposes, at Michelin, for example, for producing process steam for vulcanizing tires. Normally, the HotModule will be operated with natural gas, but it can accept other fuels.

The Michelin location was very well suited for years of fuel -cell testing because the tire works operate a three-shift system and continually need steam. The potential inherent in the simultaneous production of heat and electrical energy, the so-called co-generation method, can therefore be used to its best advantage and the fuel cell operated at base load.

Series production run-up planned for 2006

The HotModule is full on schedule for series production. Up to the present, ten plants have been installed at field-test locations of which eight are presently being subjected to normal operating conditions. Two plants have completed their test cycles. Further plants are to be delivered in 2003 to customers in Europe, USA and Asia. In comparison with other fuel-cell technologies, the HotModule is already comparatively mature in design and construction and relatively cheaper to manufacture; reasons that, not least, bring the HotModule's series production within sight. Every new plant means increased experience that is absorbed into further development and preparation for the series production. Presently, the planned target for the series production run-up is the year 2006.

Record efficiency results

For over two years, the first HotModule was in field-test operation for a customer - the university of Bielefeld. It produced electrical energy for the municipal network and supplied the university with heat and steam. Important experience was won under continuous operation conditions that led to further optimization of the technology. During its total run time of 16,000 hours, the plant achieved record results. It ran for longer than any other carbonate fuel cell before and achieved an electrical efficiency of 47%, a value not reached by any other conventional technology in the 250-kW class. As a comparison, modern gas engines of the same performance class work with a mechanical efficiency of maximum 41%, not including the conversion of the mechanical energy into electrical power.

In 2001, the first high-temperature fuel cell in the clinical world was put into operation in the Rhön-Klinikum (clinic) in Bad Neustadt/Saale, supplying electrical power and heat for a part of the clinic. Apart from the power, the medical section uses the high-pressure steam (generated with the used air) for air-conditioning and sterilization purposes.

Up to now, two mtu-HotModules have been put in operation in the USA in the automobile industry and power-supply sectors. They were delivered as complete plants by Fuel Cell Energy Inc. (Danbury, Connecticut), an American co-operation partner in which mtu is the largest single shareholder. The HotModule cells, central components of the plants, originate from FCE.

Technology with high market potential

The results from the first HotModule field tests have generated a great deal of interest from possible users. Five further plants were put into operation in 2002, which was an important step towards series production. The plants were installed at, among others, De Te-Immobilien in Munchen, IPF in Magdeburg, RWE in Essen und IZAR Cartagena, Spain.

The stationary fuel-cell markets result from the possibilities opened up by this technology within the existing infrastructure. The fuel is mainly natural gas although other gases can also be used. In comparison to the usual co-generation plants, the HotModule has a much higher degree of efficiency and is much more cleaner. Presently the electrical mains output of 230 kW at a cell-block output of 270 kW, plus about 180 kW thermal energy. Overall, the HotModule can therefore achieve total utilization efficiency of over 90%. The amounts of pollutants from the HotModule are so low that, in keeping with the TA Luft (German clean-air standard), it is easier to speak of "used air" rather than exhaust. This air consists mainly of hot air and steam. Nitric and sulfur oxides are produced by the plant in concentrations that cannot be registered. Carbon dioxide is also in a much lower concentration than from conventional power stations. Michelin is striving with this plant for decidedly environment-friendly and carbon-dioxide-poor power generation in view of the tire work's location in the middle of the Karlsruhe town area.

New perspectives for power generation

Another technical feature of the HotModule is destined to take this fuel cell into other markets beyond those already known. In contrast to other fuel cells, the HotModule can be operated not only with natural gas but other fuels containing hydrocarbons such as biogas, methyl alcohol, sewer gas, landfill gas and residual gases from industry. This opens up completely new horizons for us. Today, many of these gases in industry and agriculture are unused and lost to us or, at best, used for heating purposes. The HotModule offers a highly efficient possibility of using these gases for electrical power generation.

Technical data of the HotModule

Fuel	Natural gas, biogas, sewer gas, landfill gas, residual gases (from industry), methyl alcohol
Electrical output of cell block	270 kW
Electrical mains output	Approx. 230 kW
Thermal output	180 kW
Electrical efficiency of cell block	Approx. 56 %
Total utilization efficiency	> 90 %
Number of cells	Approx. 350
Used-air temperature for heating purposes	Approx. 400° C