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<body bgcolor="#FFEC93" text="#FFEC93"> <p>Sven</p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> EKPRO - Ingenieurdienstleistungen aus einer Hand. Wir verstärken Ihr Innovationspotential. Von der ersten Idee bis zu serientauglichen Prototypen unterstützen wir Ihre Produktentwicklung. Wir betrachten den Entwicklungsprozess ganzheitlich und interdisziplinär. Erstklassigen technischen Lösungen sind uns ebenso wichtig wie deren schnelle wirtschaftliche Umsetzung. Der vertrauliche Umgang mit allen Informationen wird von uns stets garantiert. Aus der Produktvision wird ein innovatives technisches Konzept zur Umsetzung entwickelt: 1. 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Sprechen Sie mit uns: Dr. Stefan Nettesheim EKPRO GmbH +49 30 740 719 02 +49 30 740 719 03 (fax) +173 99 31 341 (mobil) Dr. Sven Jakubith EKPRO GmbH +49 30 740 719 03 +49 30 740 719 03 (fax) + 173 610 617 6 (mobil) www.ekpro.de Themen und Schwerpunkte EKPRO ist spezialisiert auf komplexe Themen bei denen ein fundiertes Know-how aus Naturwissenschaft und Technik zusammenspielt. Je nach Anforderung werden über unser Partnernetzwerk Spezialisten aus Elektronik, Materialentwicklung, Software oder Rapid Prototyping eingebunden. Der fachliche Hintergrund übergreift: Lasertechnik, Oberflächenanalytik, Vakuumtechnik, Elektrochemie, Kryotechnik, Analogelektronik, Sensorik, Messtechnik, Kleinsteuerungen, CAD/CAE, CFD, Produktionstechnik, Verfahrenstechnik, Patentrecht, Projektmanagement, Qualitätswesen, Supply chain management Branchenerfahrung besteht mit Unternehmen aus: Automotive, Maschinenbau, Elektrotechnik, Konsumgüterindustrie und Energieversorgung Jakubith Stefan Nettesheim Brennstoffzelle fuel cell fuelcell ekpro Fuel Cell System for lightweight electric vehicles Stefan Nettesheim Abstract The main disadvantages of electric vehicles are the high battery weight, the low range and the long time needed for battery recharging. The combination of a battery with a fuel cell system presented in this paper allows to extend the range of operation at a reduced weight of the battery. Electric vehicles are often used in urban areas. This means a highly dynamic drive cycle with relatively low average power but high peak power needed for acceleration. The power unit proposed in this paper is based on a small 2kW PEM fuel cell which is fed with pure hydrogen. The main features of the fuel cell system are minimum parasitic power consumption, low maintenance and very short startup time. The fuel cell constantly charges an auxiliary NiCd battery that allows for high dynamic response, high peak power and brake energy regeneration. The system has been integrated and testes in the TWIKE easy, a high efficient lightweight electric vehicle. Keywords: PEM, fuel cell, hydrogen, electric vehicle, ZEV, NEV 1. Introduction In recent years fuel cells have gathered increasing attention in various field of energy provision. Although its roots last back to the first half of the 19th century only during the U.S. space program in the 1960s an acceptable maturity was reached and made the systems ready for technical application. Since then several classes of fuel cell were developed, but it is certainly due to the PEM (proton exchange membrane) fuel cell that a far wider interest is directed to fuel cell technology today. Some of the reasons for considering the PEM fuel cell technology as a potential "game changer" in mobile energy conversion systems are: high power density, dynamic response, efficiency, high conversion yields, low temperature operation, low system complexity, low noise, low emission level and that PEMFC´s are suited for mass production processes. However two problems still inhibit everyday use: - The costs of all fuel cell systems is still very high (compared to classical Sven Jakubith Stefan Nettesheim Brennstoffzelle fuel cell fuelcell ekpro combustion engines or battery systems) - A global hydrogen infrastructure is not available. Highly available fuels, such as hydrocarbons, have to be converted into hydrogen for efficient conversion into electric power. Only a low volumetric energy density can be realized by direct hydrogen storage. Unless the cost of fuel cell systems can not be reduced via serial production technologies a broad commercialization is not possible and hence the need to extend the fuel infrastructure is weak. This vicious circle can only be broken if attractive niche markets are carefully developed. One example for such a product could be a light electric vehicle with local zero emission properties. Therefore the fuel cell system has to be adapted to the needs of these customers. 2. System definition In order to define the targets of the technical development it is necessary to analyze the user profile for a classical car operated by an internal Sven Jakubith Stefan Nettesheim Brennstoffzelle fuel cell fuelcell ekpro combustion engine and a urban electric vehicle. ICE-Car User Profile Urban EV-User Profile Range Top Speed Infrastructure Power Accepted Costs/distance Accepted Costs/primary energy Accepted Costs/power Price limit Availability Convenience Duty cycle > 400 km > 150 km/h global > 50 kW 0.1 - 0.3 €/km 200-500 €/kW 0.01-0.05 €/kWh 10-100 k€ immediate high up to 12h/24h > 100 km 50-100 km/h local 1-20 kW < 0.1 €/km 1000-6000 €/kW 0.1-0.5 €/kWh < 15 k€ planned, seasonal medium > 1h/24h Table 1: Comparison of a typical user profile of a classical car an a user of a EV. Given the actual costs of a PEM fuel cell system of more than 1000€/kW a fast substitution of classical combustion engines by high power fuel cell systems seems technically ambitious and commercially risky. However the substitution of battery systems used in urban EV can develop into an attractive niche market in short terms. The driving forces can be local zero emission requirements but also the high energetic efficiency of such mobility concepts reflected by the low costs per traveled distance rather than low energy costs. This paradigm change can actually only be realized by a fuel cell system if it delivers electrical power in the range of several kW at high efficiency (> 50%) and has a weight that is considerably lower than that of battery systems of comparable capacity. Our target was to develop an electric energy system for a lightweight EV with an average power of 2 kW and Sven Jakubith Stefan Nettesheim Brennstoffzelle fuel cell fuelcell ekpro a peak power of 5 kW that combines classical batteries with fuel cell technology in an efficient way. An additional requirement was a high modularity of system so that it can be flexibly integrated into different types of EV of the same performance class. Practical tests have been performed with a TWIKE easy from Swiss LEM. 3. Fuel cell Our conclusion was to focus our development on fuel cell systems with a net stack power ranging from 1 to 10 kW. In the presented application the cell was designed to deliver a net electric power of 2 kW. For small fuel cell systems the reduction of parasitic power consumption (cooling, air circulation, electronics etc.) is of highest priority. Additionally the design of the system is restricted to low cost standard peripheral components such as pumps, valves and blowers. The stack (1) consists of 40 single cells and uses graphite bipolar plates from SGL Carbon and a commercially available membrane from Gore. The flow field of the cathode is optimized for low pressure drop (simple radial blower 5) and easy self-discharge of the product water. The product water can easily flow to the humidifier (2) where it is absorbed by a porous structure. A liquid coolant is pumped (3) through the bipolar plates and collects the reaction heat and dissipates it via a liquid/air cooler (4) vented by an axial fan (9). The thermal energy can be used to heat the vehicle cabinet or is blown outside. The anode is operated in "dead ended" mode resulting in a hydrogen conversion of 100%. At a given time interval a Sven Jakubith Stefan Nettesheim Brennstoffzelle fuel cell fuelcell ekpro short purge of the anode has to be performed to discharge some product condense water and to blow off the amount of inert gases that accumulate on the anode. The electrical output of the fuel cell is connected via a programmable DC/DC converter (6) to the power management of the vehicle permitting to load the batteries (8) under controlled conditions. The DC/DC module operates parallel to the battery bloc. For a commercial solution a higher level of integration of the fuel cell control system and the vehicle electronics would be advantageous to reduce the total costs and ton increase the system efficiency. If the battery shows full nominal tension the fuel cell operates "open loop" and no current is drawn. If on the other hand the battery tension drops due to a low state of charge or a high current drawn from the electric load, the DC/DC module "tries" to compensate for this tension drop. The current drawn from the fuel cell stack rises until the setpoint for the minimum stack-voltage is reached. This setpoint controlling the current of the primary circuit of the DC/DC module can be chosen in a way that the fuel cell operates either close to the maximum power point or at a high total system efficiency. The soft U/I curve typical for fuel cell systems, leading to a ratio of open loop to MPP Voltage of almost 2 turns to an advantage in this configuration since this self-regulated mechanism guarantees for a smooth power flow distribution. Furthermore the fuel cell is protected against current back flow or voltage spiking because of the high capacity of the battery. The battery block has its own temperature, charge control and safety circuit. At full state of charge no current is drawn Sven Jakubith Stefan Nettesheim Brennstoffzelle fuel cell fuelcell ekpro from the system. Net electrical power Parasitic power consumption Start up Fuel Humidification Cathode pressure drop Operation temperature Cooling Weight Stack Aggregates Hydrogen conversion Noise level 2 kW @ 24 V < 30 W < 30 s (90% power) independent from vehicle battery hydrogen passive, Cathode < 10 mbar -5 ... 50°C liquid 15 kg 10 kg 5 kg 100% < 30 dB Table 2: Technical description of the PEM fuel cell system Figure 1: Fuel cell system 4. Battery The battery module consists of 300 NiCd single cells with 3.2 Ah and a total nominal voltage of 360V. The module is protected against cell reversal by limiting the maximum current to 20A. This current, as well as the maximum charge current is automatically reduced if the temperature of the cells is exceedingly high. The result is a good cell performance and a optimized lifetime. 5. Hydrogen storage Hydrogen can be stored chemically in the form of hydrocarbons or metal hydrides. The chemical C-H bond is so strong that molecular hydrogen can only be liberated by using high temperature reforming processes. For small FC systems this thermocatalytic reforming is rather complex to control and expensive to realize. Hence, although hydrocarbons yield the highest storage density they will not be considered in this application. Alternatively hydrogen can be bound in the form of metal hydrides that allow for reversible adsorption/desorption cycles. Refueling of such a tank (adsorption) is an exothermic process and is promoted by cooling the metal-hydride structure. Desorption is a endothermic process and needs heat to proceed at a sufficient rate. For small metal-hydride storage systems the surface to volume ratio is favorable to allow a good heat transfer to the ambient air. Hence such systems can be charged and discharged in reasonable time without applying a complex heat management. An additional advantage is that for specific alloys charging and discharging proceeds in a pressure window between 0.1 and 10 bar. In all cases the desorption rate is limited and a high safety is guaranteed. Physical storage systems include pressurized hydrogen tanks and cryogenic storage systems. Cryogenic storage can be excluded for small FC-EV´s since it is expensive and a small recipient would exhibit a fast self discharge due to boil-off losses. Compressed hydrogen tanks up to 300 bar and of different size are state of the art. Higher pressures up to 700 bar are available Sven Jakubith Stefan Nettesheim Brennstoffzelle fuel cell fuelcell ekpro as prototypes. Compressed hydrogen is by far the cheapest solution and should be chosen if a small refueling compressor is available to charge the on-board tank to a constant pressure independently from the pressure of the stationary hydrogen reservoir. Metal hydride offers the highest safety and convenience of all systems that are actually available in the 0.1 to 10 kWh range. For practical investigation a small cylindric metal hydride tank (11, figure 1) with 2.6 Nm3 was mounted under the seat of the test vehicle. Roughly 10 Nm3 would be possible with 4 identical cylinders without exceeding the weight of the vehicle equipped with batteries only. An optimized geometry would yield a capacity of about 18 Nm3. The range extension is calculated to be 60, 240 or 430 km respectively. The result would be similar using commercial high pressure composite cylinders (450 bar). ?????????? Storage system Capacity kWh/l Capacity kWh/kg refueling GH2 (300 bar Metal) 0.6 2.15 + GH2 (700 bar Composite) 1.2 3.6 - LH2 1.2 3.5 - metal-hydride 2.2 0.3 ++ Table 3: hydrogen storage for small FC-EV Figure 2: Energy needed for isothermal compression of hydrogen compared to the energy for condensation of hydrogen. The volumetric storage density of some metal hydrides loaded at 20 bar is comparable to that of liquid hydrogen. 6. Costs and availability A hydrogen based fuel cell system can be realized at cost that are actually about 5.000 € per kW. The cost distribution is shown in figure 3. The highest reduction potential can be realized by using serial production technologies for the stack components (membrane and bipolar plates). Since a stack is a highly repetitive unit serial effects are Sven Jakubith Stefan Nettesheim Brennstoffzelle fuel cell fuelcell ekpro already considerable at low production numbers. This reduction for the stack shifts the distribution of costs towards electronics, auxiliary systems, housing and assembly. Hence only standard peripheral components (blowers, pumps, valves etc.) can be integrated in al low-cost fuel cell system. Small fuel cell systems will be available at a competitive price only when the stack is embedded in a system that is kept as simple as possible. One way to reach this goal is to combine a small fuel cell stack with a battery in a fuel-cell/battery hybrid electric vehicle. Similar effects can be observed for hydrogen compression and refueling technology. Large compressor units are state of the art and present in many chemical processes. Such plants are optimized for low operation costs and high durability. Scaling down to the hydrogen demand of a single FCEV does not make sense economically with the same technology. Especially for high pressure refueling (> 200 bar) no aggregates of convenient size are available on the market at this moment. For the type of vehicle described in this paper a compressor of 10 Nm3 throughput and a final pressure of 450 bar would be sufficient. Figure 3: Cost partition of small fuel cell systems today and in the near future. Whereas actually the system costs are dominated by the stack components this overweight will continuously decrease with serial production technologies. Figure 4: The costs for hydrogen compression depends strongly on the size of the compressor. 7. Conclusion A 2 kW fuel cell operated parallel to a battery of 5 kW peak power has been demonstrated in a EV application. The battery of reduced weight guarantees the dynamic response of the vehicle whereas the fuel cell extends the range of operation. The energy flow between the battery, the fuel cell and Sven Jakubith Stefan Nettesheim Brennstoffzelle fuel cell fuelcell ekpro the electric motor is regulated in a way that the system operates with a high efficiency. This choice seems to be promising to assure save and convenient operation and would be available to affordable prices in the near future. The main cost reduction stems from the fact, that the still rather expensive PEMFC is designed to yield the full power during vehicle acceleration or top speed intervals. However the issue of hydrogen storage and refueling remains the bottleneck for everyday use. This problem will only be solved if hydrogen refueling will be available parallel to the existing gasoline infrastructure. Complementary to the buildup of this global infrastructure individual solutions based on locally available hydrogen will satisfy the demand of the niche markets. Brennstoffzellen im Automobil: "Blockbuster oder Nischenprodukt" Dr. Stefan Nettesheim Die globale Entwicklung des weiter wachsender Verkehrsaufkommen verschärft die Besorgnis über die Ausbeutung der fossilen Treibstoffvorräte. Hinzu kommt die Erkenntnis, daß die CO2 induzierte Klimaerwärmung nur durch geschlossene Energiekreisläufe kontrollierbar ist. Die Nachhaltigkeit des Verkehrssektors hängt daher maßgeblich von der Einführung neuer Technologien ab. Das Potential die herkömmliche Verbrennungskraftmaschine weiter zu optimieren ist Sven Jakubith Stefan Nettesheim Brennstoffzelle fuel cell fuelcell ekpro trotz enormer Anstrengungen begrenzt. Brennstoffzellen werden vielfach als das Antriebskonzept der Zukunft angesehen. Wasserstoffversorgte Brennstoffzellen verursachen lokal keine Emissionen, arbeiten weitgehend geräuschlos und haben einen hohen Wirkungsgrad. Die Polymerelektrolyt Membran Brennstofzelle (Proton Excange Membrane) ist bezüglich Leistungsdichte, Dynamik und Betriebsbedingungen für die Anwendung im Fahrzeug prädestiniert. Praktisch alle großen Automobilkonzerne haben mit Konzeptfahrzeugen die prinzipielle technische Machbarkeit der Substitution des Verbrennungsmotors durch Brennstofzellenaggregate bewiesen. Der Weg zu einer erfolgreichen Markteinführung setzt indes vorraus, daß hinsichtlich des Betriebsverhaltens, des Anwendungskomforts, der Lebensdauer der geeigneten Treibstoffinfrastruktur und vor allem der Kosten entscheidende Fortschritte gemacht werden. Um diesen Aufgabenkomplex zu lösen sind enorme Investitionen der großen Konzerne aber auch eine neue industrielle Infrastruktur von Zulieferunternehmen nötig. Einerseits ist ein hohes Produktionsvolumen der Schlüssel zur Kostenreduktion, birgt aber andererseits ein hohes unternehmerisches Sven Jakubith Stefan Nettesheim Brennstoffzelle fuel cell fuelcell ekpro Risiko. Für ein mittelgroßes Unternehmen kann diese Risiko nur dadurch kalkulierbar gestaltet werden, indem die Produktpalette um die Brennstoffzellentechnologie diversifiziert bleibt und nicht vollständig von der Entwicklung im Automobilbereich abhängt oder eine enge Beziehung im Automobilbereich als OEM garantiert ist. Dieser Beitrag soll eine Überblick vermitteln mit welcher Strategie die Sachsenring AG auf diese Herausforderung reagiert. Kurzfristig ist es unwahrscheinlich, daß der Brennstoffzellenantrieb mit den Kosten, der Alltagstauglichkeit und Leistung eines modernen Verbrennungsmotor konkurrieren kann. Daher ist es aus Sicht der Sachsenring wahrscheinlicher, daß der unmittelbare Markteinstieg über Nischenprodukte erfolgt. Auch im Hausenergiesektor sind die Kostenvorgaben und technische Probleme (1000$/kW bei 3 kWel) weniger scharf als bei einem vollwertigen PKW-Traktionssystem (100$/kW bei 100 kWel). Sachsenring entwickelt daher Produkte im Leistungsbereich unterhalb von 10 kWel ohne den Fokus zu verlieren, der langfristig im Automobilsektor mit seinem hohen Marktvolumen liegt. Unser aktuellen Entwicklungsarbeiten zielen auf Nutzerfreundliche Produkte, bei denen das Brennstoffzellensystem durch einen hohen Gesamtwirkungsgrad ausgezeichnet ist und möglichst robust und einfach aufgebaut ist. Komplexität und Energieverbrauch der peripheren Aggregate werden konsequent minimiert. Die Kosten für das Stack-Subsystem werden stark sinken und damit wird der Kostendruck auf die Peripherie (Kühlung, Gasversorgung, Brennstoffaufbereitung etc.) stark ansteigen. Bei Brennstoffzellensystemen im Bereich unterhalb von Sven Jakubith Stefan Nettesheim Brennstoffzelle fuel cell fuelcell ekpro 10 kW wird die Einfachheit und der minimierte Verbrauch der Nebenaggregate letztlich über den Markterfolg entscheiden. Einige Beispiele für Produkte in die einfache und robuste Brennstoffzellensysteme integriert sein können sind: Autonome Energiequelle (APU), Portables Notstromaggregat, H2 - Speichersystem, Bordnetz, Sonderfahrzeuge, Citymobil, Boote, Gabelstapler, etc. Der besondere Reiz an diesen Nischenprodukten liegt unter anderem auch darin, daß die Funktion durch die aktuelle Wasserstoffinfrastruktur zu moderaten Kosten gewährleistet ist. Zur Zeit ist noch nicht absehbar welche Lösung sich im großen Maßstab zur Versorgung der Brennstoffzellen durchsetzen wird. In den USA wird zur Zeit der konventionelle Kraftstoff als H2-Träger bevorzugt. DaimlerChrysler setzt im PKW auf Methanol, doch auch andere Formen der Energieträger werden intensiv diskutiert und erprobt. Für eine Übergangszeit scheinen konventionelle Treibstoffe auf Erdöl/Erdgasbasis am ehesten geeignet die Zeit bis zu Praxisreife einer reinen Wasserstofftechnologie zu überbrücken. Ein Haupthindernis ist hier der hohe Investitionsaufwand für den Aufbau einer zu bestehenden System parallelen Infrastruktur. Hinzu kommt daß die effiziente und kompakte Speicherung des Wasserstoffes an Bord eines Fahrzeuges weiterhin ungelöst ist. Am Beispiel des Bedarfes an Platinkatalysator soll ein Szenario aufgezeigt werden, das mittelfristig problematisch werden könnte. Platin gehört zu den Metallen, die weltweit am seltensten vorkommen. Die Jahresproduktion beträgt ca. 4.5 Millionen Unzen (126 Tonnen) pro Jahr. Etwa die Hälfte dieser Produktion fließt in die Herstellung von Katalysatoren ein von denen der größte Anteil in der Automobilindustrie verwendet wird. Sollte ab ca. 2005 eine Serienfertigung von Brennstoffzellenfahrzeugen einsetzen ist mit einem zusätzlichen Bedarf von ca. 10-30 g Platin pro Fahrzeug zu rechnen. Innerhalb von wenigen Jahren würde die heutige Produktionskapazität der bestehenden Edelmetallminen gesprengt, was wiederum zu Verknappung und Kostensteigerungen führen würde. Insofern ist es hilfreich für eine rechtzeitige Kapazitätsanpassung und dem Ausbau der Edelmetallinfrastruktur (Recycling etc.), daß bereits ab 2001 eine stetige kalkulierbare Nachfrageerhöhung eintritt. Nischenprodukte können hier die Pufferfunktion übernehmen die einen stetigen Übergang ermöglichen. Analoge Überlegungen gelten für den Ausbau der Herstellungskapazität von Polymer-Elektrolyt-Membranen und Bipolarplatten und spezifisch angepaßten Nebenaggregaten. Insgesamt muß eine gesunde Sven Jakubith Stefan Nettesheim Brennstoffzelle fuel cell fuelcell ekpro Zulieferindustrie um die Brennstoffzellentechnik organisch wachsen, damit der enorme Bedarf der Automobilindutrie gedeckt werden kann. Die Sachsenring AG hat in diesem attraktiven Zukunftsfeld Position bezogen. Quellennachweis Internet: http://www.hyweb.de http://www.vda.de http://www.lbst.de Abschlußbericht: Innovationsprozeß vom Verbrennungsmotor zur Brennstoffzelle: Chancen und Risiken für die baden-württembergische Industrie; Fraunhoferinstitut für Systemtechnik und Innovationsforschung; Karlsruhe Abschlußbericht: Brennstoffzellen-Studie: Ganzheitliche Systemuntersuchung zur Energiewandlung durch Brennstoffzellen; Forschungsvereinigung Verbrennungskraftmaschinen e. V. ; Frankfurt am Main Konferenzbeitrag: PEM Fuel Cells in Stationary and Mobile Applications: Pathway to Commercialization; Reinhold Wuster; L-B-Systemtechnik GmbH; 6th Int. Technical Congress - Biel 99 Fuel Cells and their Applications, Karl Kordesch, Günther Simader, VCH, Weinheim Why Fuel Cells? Fuel Cells are a new highly efficient and environmentally benign power generation technology that can address the worlds energy conundrum namely its growing need for clean power coupled with a reduction of greenhouse gas emissions, a reduction of dependency on oil, and increased energy security without recourse to the nuclear option. They promise to create a paradigm shift in the way the world produces and uses electricity They have the potential to become cost competitive with conventional technologies for an astonishingly wide variety of applications and deliver a combination of benefits that are not available from conventional energy generation technologies. They could largely replace conventional combustion technologies in these applications and become the dominant energy conversion technology. They are the subject of intense development activity throughout the world. Major corporations and small and medium enterprises in the US, Japan, Europe and elsewhere are developing fuel cells for stationary and portable power generation, as a source for motive power, and as a replacement of or for performance enhancement of batteries in mobile telephones and laptops. Some governments recognising their benefits and keenly aware of the implications for quality of life competitiveness and employment that would follow failure to participate in this embryonic global industry are committed to supporting their rapid introduction and commercialisation. How do Fuel Cells work? Fuel Cells convert the energy produced when hydrogen and oxygen combine to form water directly into electricity and heat through a catalytically promoted electrochemical reaction. Unlike Sven Jakubith Stefan Nettesheim Brennstoffzelle fuel cell fuelcell ekpro conventional combustion technologies they do not rely on burning fuel to create heat which is then converted into electricity through a mechanical electricity generator. Their efficiency is thus not constrained by the second law of thermodynamics ("Carnots Law") which describes the efficiency limits of heat engines. What is a Fuel Cell System? The core of a fuel cell system is the Fuel Cell 'Stack'. Individual fuel cells are relatively small and limited in power production. They are therefore arranged in stacks to produce the level of power required by the application. To date fuel cell stacks have been built and arranged in systems from a few watts capacity to ten megawatts. Higher capacities are envisaged. Although hydrogen, the fuel, the fuel cell requires, is the most common element in the universe on earth hydrogen is not readily available. It has to be extracted from another source. Hydrogen can be sourced by passing electricity through water in a process called electrolysis which is incidentally the exact reverse of the fuel cell reaction. The process of extracting the hydrogen from another fuel such as natural gas or gasoline is called reformation. Hydrogen production can and does take place outside the fuel cell system. Hydrogen is today an industrial gas used in many processes. However many Fuel Cell systems include this capability either as a separate reformer attached to the stack or in some cases this reaction can be built in to the stack or even take place at the anode of the Fuel Cell itself. The source of the other fuel needed, oxygen, is usually the air The electricity produced by the Fuel Cell stack is direct current (DC) electricity. Many fuel cell systems also contain an inverter or power conditioner to convert the output to alternating current (AC) for use with as a substitute for the grid or with asynchronous motors. Types of fuel Cell There are a number of different types of fuel cell. They are known mostly by their different types of electrolyte. The main categories are Phosphoric Acid Fuel Cells (PAFC), Proton Exchange Membrane (PEM) Fuel Cells, Molten Carbonate Fuel Cells (MCFC), Solid Oxide Fuel Cells, Direct Methanol Fuel Cells (DMFC), Alkaline Fuel Cells (AFC). Each type has different operating characteristics. Operating temperatures and thus available heat vary considerably. Start up time varies Some have the ability to reform fuel at the anode or in the stack. System efficiency varies Sven Jakubith Stefan Nettesheim Brennstoffzelle fuel cell fuelcell ekpro depending on the fuel supplied. Some are more miniaturisable than others and so on. However it is these different characteristics that ensure that fuel cell technology is applicable for such a wide variety of applications. What applications are suitable for Fuel Cells Some of the applications for which Fuel Cell Systems are being developed are as follows:- Stationary Applications Distributed Power Industrial onsite power Onsite Power for hospitals Unintrerruptible power for Banks Domestic Household on site power Transport Applications (motive power) Buses Cars Trains Delivery vans Bicycles and scooters Boats Ships and Submarines Transport Applications (Auxiliary power) Trucks Cars Ships Aircraft Spacecraft Portable and microgeneration Portable generators Laptop computers Mobile phonee Power systems for Soldiers Do Fuel Cells impact energy security and energy market liberalisation? Fuel Cell Systems can be adapted to produce their hydrogen from wide variety of fuel including natural gas (methane), gasoline, diesel, naphtha, ammonia, methanol, ethanol. Hydrogen can also be produced from renewable sources such as biomass (e.g. methane methanol and ethanol) as well as via electrolysis from wind and photovoltaic energy. Because of this wide variety of possible fuels. Fuel Cells could make a major contribution to increased energy security and a reduction of dependency on oil. Likewise because of their efficiency and fuel flexibility fuel cells could help maximise the energy cost benefits of energy market liberalisation What is the environmental impact of Fuel Cells? A fuel cell system fuelled with hydrogen produces no toxic emissions (NOX, SOx, HC, CO, particulates) it Sven Jakubith Stefan Nettesheim Brennstoffzelle fuel cell fuelcell ekpro also produces no CO2. Of course if the hydrogen is sourced from a renewable source the applies to the whole ("Well to Wheel") fuel cycle However we do not have to wait for the hydrogen economy. Fuel cell systems using natural gas or other conventional fuels now produce virtually none of the pollutants NOX, HC, CO and Particulates and deliver reduced CO2 emissions because of their inherent superior efficiency. Less fuel for the same amount of energy means less CO2. What about Fuel Cells and a possible hydrogen economy? Many experts including some major oil companies such as BP and Shell think that at sometime in the future the energy economy will be based on hydrogen. They point out that not only does the world need to reduce its use of carbon fuels to reduce the production of greenhouse gasses but in the last few hundred years there has been a trend away from carbon from wood charcoal and coal to oil on to natural gas. There has been a trend shifting the hydrogen to carbon ratio in favour of hydrogen. They think the next logical step will be to move to hydrogen itself. They see hydrogen as a so called energy vector which would enable the contribution of renewable sources to the energy mix to be maximised. Renewable the availability of such renewable sources of energy such as wind, photovoltaic electricity, hydropower and biomass is not synchronous with demand in terms of time and location of availability. Some form of storage and distribution is needed. The production of hydrogen from wind power and photovoltaic power ar by reforming biomass fuel such as ethanol or methane or mehanol is one suggestion. For many decades to come the world will still use carbon and fossil fuels as the changeover will occur gradually. Indeed these fuels too will become part of the hydrogen economy. As mentioned above many Fuel Cell Systems now produce their own hydrogen within the system. Thus they could introduce and facilitate the adoption of a hydrogen economy and form an integral part of it. It is possible to configure Fuel Cell systems so that their reforming function produces hydrogen surplus to their own requirements and so could become themselves a source for hydrogen production. There is no more efficient way to convert hydrogen to electricity than through a Fuel Cell. How efficient are different sizes of Fuel Cells? A characteristic of conventional combustion technologies is the larger the system the more efficient. This has lead for example to the creation of ever larger conventional central power generation facilities. This does not apply to fuel Cells. This means that already fuel cell systems of a few kilowatts are not only vastly more efficient than their conventional equivalent but can compete with the efficiency of much larger conventional systems especially when distribution losses are taken in to account. Distribution losses do not occur for small highly efficient fuel cell systems located at the sight of the demand. Location of fuel cell systems at the point of energy demand makes it attractive to use by-product heat for space Sven Jakubith Stefan Nettesheim Brennstoffzelle fuel cell fuelcell ekpro heating or commercial and industrial processes. Highly efficient fuel cell systems are being developed for a wide variety of onsite power generation applications such as factories , hospitals, offices, and even the home. What could fuel cells mean for the grid? Fuel cell power could lead in the future to a very different grid system. The current system is essentially a top down system distributing power produced by gigawatt sized central electricity power station across large distances by familiar and unsightly hight tension cable. The voltage is reduced in stages until it is delivered at 110v, 230v, or 300v for local use. The grid is supported by smaller power stations to help cope with varying local demand differences ,peak demand and ensure grid stability. The efficiency of small size fuel cells could lead to a very different grid one where power is shuffled from point to point as one producer/consumer produces more than is required at the home location makes up for and supplies another consumer/producer. The grid of the future could be made up of local power production/consumer units backing each other up in a more bottom up grid. Modern power control communication technologies could make this possible. Replacement of large central electricity power stations as they come to the end of their life by small efficient local fuel cell could lead to the atrophy of those unsightly transmission lines and a very significant reduction in grid losses and costs. If Fuel Cells become the dominant means of providing motive power for cars (see below) it has been noted by a former Chairman of Texaco that there would be five times the current stationary generating capacity on wheels if each car had its own fuel cell generator on board to provide motive power. The fact that today an average car spends 96% of its life idle has prompted even more radical speculation of the possible shape of the power generating industry. They suggest in the future homes and offices will be supplied by vehicles owned by those who live and work in them when the car is normally idle. How do Fuel Cells perform over their operational power range? For maximum efficiency conventional combustion systems must operate at constant full load. Fuel cell systems reach maximum efficiency at roughly half load and maintain this to full load. This characteristic makes them particularly attractive for application in cars as a source of motive power or as a source of power to meet the ever increasing on board demands for electricity. Most cars do not operate at full load throughout the drive cycle particularly in the urban context. Even early fuel cell car prototypes are already showing a 50% improvement in efficiency over conventional engines in these applications with over one hundred years of continual improvement behind the conventional combustion engine. Large conventional car engines being used to power air conditioning and the other multitude of electrical systems when the vehicle is standing still do so with very low efficiency. The requirement for onboard electricity is Sven Jakubith Stefan Nettesheim Brennstoffzelle fuel cell fuelcell ekpro increasing as motor car manufacturers seek to move to electrical breaking and power steering to improve reliability response and reduce cost. Small efficient auxiliary fuel cell systems are being developed to cover these requirements. How noisy are Fuel Cell Systems? There is none of the noise associated with combustion engines and fuel cell systems contain far fewer moving parts than conventional systems. Because of this fuel cell systems are in development for such noise sensitive applications as location lighting for the film industry (where constant power output and lack of colour temperature variations associated with batteries is an additional fuel cell benefit), use in noise sensitive outdoor locations, and recreational applications. Are Fuel Cell systems reliable? With fewer moving parts than conventional systems some fuel cell systems are already proving more reliable than their conventional equivalent in some early stationary applications and fuel cells systems have already been installed as part of an uninterruptible power system (UPS) at the largest credit card clearing house in the US where the supplier claims 99.9999% availability for the UPS system What do Fuel Cells Cost? Fuel cells are not yet reached a cost at which they would be competitive for mass application. However spectacular progress is being made, with the car companies in the forefront, in designing cost out of Fuel Cell systems. Nevertheless for the benefits to the environment and energy security to be achieved cost must be reduced significantly for mass application. Fuel Cells the only energy conversion technology in the future? Their inherent simplicity compared to conventional alternatives, their wide applicability, range of benefits, and potential for low cost suggests that if not the only terrestrial energy conversion technology in the future conventional technology similar to the horse and steam will be confined to the realm of small niche Sven Jakubith Stefan Nettesheim Brennstoffzelle fuel cell fuelcell ekpro applications. What do Fuel Cells mean for competitiveness and employment? In the light of all this not surprisingly many large corporations as well as small and medium sized and specialist enterprises are involved in a massive effort to commercialise Fuel Cells. These include: Alstom Nissan Ballard Nuvera Buderous OMG Chevron Texaco Osaka Gas DaimlerChrysler PSA Dupont Renault Ebara Corporation Rolls Royce Engelhard Corporation RWE Ford Siemens Westinghouse General Motors Tokyo Gas Johnson Matthey Toshiba Mitsubishi Matsushita Toyota Mitsubishi Electric UTC Mitsubishi Heavy Industry Vaillant ......and many others A unique characteristic is the number of global alliances being structured even before commercialisation partners in these alliances involve companies supplying materials and components, stack manufacturers. system manufacturers, system integrators, installers, and users multinational in nature or located in different parts of the world. Multinationals are very flexible in locating facilities in areas of market and cost advantage. Having said that it is worth noting that Juergen Schempp said in Berlin when presenting the DaimlerChrysler Necar4 to the German Chancellor Gerhard Schroeder that fuel cells although still in development accounted then for over 10,000 jobs in Germany The issue facing National and regional governments is no longer if they can develop their own complete domestic fuel cell industry but can they ensure participation in this paradigm shift. Failure to participate in and support this developing industry and the market s for this technology could have catastrophic effects on regional and industrial competitiveness but risk putting in danger the millions of jobs in and dependant on the power equipment manufacturing and motor vehicle manufacturing industries. Not to mention the opportunity to create export driven new employment as the developing word looks to adopt this technology as it becomes competitive to leapfrog their way in to the future environmentally friendly and efficient diverse and liberalised global energy economy . How can government help? The risks and investment associated with the introduction are enormous especially for a technology as potentially disruptive such as Fuel Cells. Nevertheless it seem some governments are taking up the challenge and taking very significant measures to accelerate their introduction for stationary and automotive applications. In the lead is the US and in particular California. Japan seems to be catching up. Germany is probably third and is making significant efforts. The key way which government can help are work with the burgeoning fuel cell industry to :- 1. The support of large scale demonstration project to prove and build confidence in Fuel Cell technology. These need to be of sufficient size to cover the different types of fuel cells x different manufacturers x applications x different operating conditions. 2. Support the development of Globally compatible codes and standards to promote not inhibit intentional trade in fuel cells. 3. Breakdown regulatory Sven Jakubith Stefan Nettesheim Brennstoffzelle fuel cell fuelcell ekpro and market barriers that were developed with conventional technology in mind but inhibit the development of fuel cells. 4. Support the development of the necessary fuel infrastructure particularly for vehicles 5. Set an example by purchasing significant numbers of fuel cell equipment an vehicles for government use. 6. Develop appropriate temporary financial and fiscal incentives to facilitate the uptake of necessarily high cost early commercial systems to help fuel cells down the learning curve and up the production curve to high volume low cost systems competitive with conventional systems. 7. Introduce in schools and universities the necessary courses to ensure that a rapidly expanding demand for a qualified workforce can be met The benefits in terms of the environment, energy security, quality of life, competitiveness, and employment justify this. </p> </body>