The fuel cell:A technical report.

Energy moving into the future

Managing global energy supplies is increasingly becoming a

key issue for the future of mankind. If present usage levels are

sustained, fossil energy resources created over several hundred

millions of years will be used up within just a few generations.

The future of energy supply lies in opening up renewable energy

sources and developing new technologies such as the fuel cell.

The fuel cells potentialFor decades, the internal-combustion engine has been a hallmark in the history of the automotive industry and of stand-alone energy supply. To most users, it hasso far been the only appropriate solution to drive cars or generate power at remote sites. Fuel cells offer, for thefirst time, the chance to replace the combustion enginein a number of applications and thereby avoid harmfulemissions.

For the energy industry, they open up the option ofsustainable, resource-saving supply, and thanks totheir ecological soundness many diverse applications.This includes applications in the mobile sector and allareas of the energy industry.

The fuel cell looks back on a long track record. As early as 1839, an Englishman, Sir William Robert Grove(1811 1896), constructed the first fuel cell. Its furtherdevelopment proved such an arduous task that Grovesconcept was only used in isolated applications for nearly100 years. His fuel cells featured electrodes made of platinum sitting in a glass tube with their lower endimmersed in dilute sulfuric acid as an electrolyte andtheir upper part exposed to hydrogen and oxygen insidethe tube. This was sufficient to produce a voltage of 1 volt. To turn the fuel cell into a really efficient sourceof power, substantial technical efforts had to be made.

Over 160 years have lapsed since the fuel cell was in-vented. Its true potential as the energy converter of thefuture has only recently manifested itself. Today, it is onthe point of commercial use.

Sir William Grove

(1811 1896) constructed

the first fuel cell

Groves historic fuel cell (1839)

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New prospectscreated by an old idea.

Fuel cells can revolutionize the energy sector

Fuel cells generate electricity from hydrogen and oxygen without any harmful

emissions and therefore in an extremely environmentally friendly way. Heat is

produced in varying amounts and, as a by-product, water.

The fuel cellprinciple.

A powerful concept for resource-saving harnessing of energy

Operating principle of the fuel cellA proton exchange membrane iscoated with a thin platinum cata-lyzer layer and a gas-permeableelectrode made of graphite paper.Hydrogen fed to the anode side ionizes into protons and electrons

at the catalyzer. The protons pass thecatalyzer layer, while the electronsremaining behind give a negativecharge to the hydrogen-side elec-trode. During the proton migration,a voltage difference builds up be-tween the electrodes. When theseare connected, this difference pro-duces a direct current that can drivean engine, for example. Finally, theprotons recombine with the elec-trons and the oxygen into water atthe cathode.

Besides the recovered electricenergy, the only reaction product iswater. Additionally, heat is producedby the electrochemical reactions andthe contact resistances in the fuelcell, which can be used for space orservice water heating.

The voltage of a single non-oper-ated cell is about 1.23 V (volts). Inoperation, this level falls to about0.6 to 0.7 V under load. As this level

is too low for practical applications,a sufficient number of cells is con-nected in series to obtain a usablevoltage. They may add up to 800cells in larger-sized plants.

The line-up of cells is equivalentto a stack, and this word has becomea technical term generally used forthis arrangement.

It is characteristic of fuel cells thatthey generate a DC voltage. To allowpractical use, it has to be transformedinto an AC signal. This is done bydownstream DC/AC converters.

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Hydrogen Oxygen

Excessoxygen

Excesshydrogen

Electrolyte

Reaction water

CathodeAnode

Electricalload

How a fuel cell works

Benefits of fuel cellsFuel cells convert hydrogen and oxygen intoelectric energy. At the same time, heat is pro-duced that lends itself to supplying processheat, producing hot water and delivering heatto buildings. If operated as co-generation units(combined heat and power generation CHP),fuel cells reach energy conversion rates of up to 80 percent and can therefore make a sus-tainable contribution to energy saving.

Compared with conventional techniques, the use of fuel cells holds additional promise.This includes high efficiencies even whereplant capacity is small, constant efficiencyunder part load, simple and modular design,low maintenance expenses and a level of hazardous substance emissions so low that itcannot be achieved with any other technique.

As hydrogen is directly converted by electro-chemical reactions, the efficiency of fuel cells is

unlike traditional energy conversion processes not limited. Fuel cells can therefore reach muchhigher efficiencies than internal-combustionengines.

Fuel cells are also effective under part load.Unlike in conventional systems, the efficiencyremains largely constant until 50 percent fullload. This has merits for plants which are fre-quently operated under part load (e.g. motorvehicles in inner-city traffic).

Carbon dioxide emissions (CO2) result fromuse of carbonaceous fuels. These include all fossil energies such as coal, oil and natural gas.As fuel cells will in the medium and long termuse fossil resources (natural gas) as an auxiliaryfuel, their use also leads to carbon dioxide emissions. But thanks to combined heat andpower generation and the high efficiencies, CO2 emissions will be lower than in conven-tional systems.

50 percent part load

Coal-fired plant

Efficiency

Gas turbine

Fuel cell

Full load

Practically

Theoretically

NOx CO CHx

BHPP FC

50

100

150

200

0

250

300

350

mg/Nm3 (mg / standard cubic meter) Source: HEW

Comparison of emissions

Compared with established technologies block heat and

power plants (BHPP) or other power plants fuel cells (FC)

boast very low emission levels.

Part-load efficiencies of fuel cells

The operating parameters of fuel

cells look favorable even under part

load. As opposed to conventional

plants, efficiency remains constant.

This qualifies fuel cells for use in

units frequently run on part load

(e.g. vehicles in inner-city traffic).

Five fuel cell technologies are at present being developed.They differ in

their electrolyte structure, working temperature and fuel requirements.

Their designations refer to the electrolyte used.

The fuel cell technique is on the point of commercial use in many areas

Fuel cell types and applications.

Type Electrolyte Special features Applications

SOFC Solid Oxide Solid zirconia Direct power production Central and stand-aloneFuel Cell from natural gas, ceramics CHP generation

MCFC Molton Carbonate Molten Complex process control, Central and stand-aloneFuel Cell carbonates corrosion problems CHP generation

AFC Alkaline Fuel Cell Aqueous High efficiency, Space operations,potash lye pure H2 and O2 only defense

PAFC Phosphoric Acid Phosphoric acid Limited efficiency, Stand-alone CHPFuel Cell corrosion problems generation

PEMFC Proton Exchange Proton exchange High flexibility in operation, Vehicles, stand-alone Membrane Fuel Cell polymer high power density CHP generation

membrane (small-scale)

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Solid Oxide Fuel Cell (SOFC)Solid oxide fuel cells are designed for usein all areas of electricity supply. At workingtemperatures up to 1000 C, they havepotential for highly efficient energy sup-ply. In particular if combined with mod-erately priced gas turbines, SOFC cellscan in future also be used to constructsmall-scale generation plants with effi-ciencies comparable to those of naturalgas fired combined-cycle power plants.Mini-plants for residential and small com-mercial applications are being developedby Swiss Sulzer Hexis AG, and larger-sizedplants with capacities between 250 kW(kilowatts) and 20 MW (megawatts) bySiemens Westinghouse.

SOFC fuel cell with gas turbine

Replacing the gas turbine combustion chamber

by a fuel cell leads to a hybrid process, raising the

gas turbines efficiency from less than 30 percent

to over 60 percent.

Fuel cell

Natural gasWaste heatexchanger

Compressor

Generator

Turbine

0.1 1 10

10

20

30

40

0

50

60

70

80

0.01 100 300 1,000

Gas turbineGas engine

PEFC PAFC

SOFC, MCFC

SOFC-, MCFC-Combined-cycle power plant

Combined-cycle power plant

Future: upper valuesPresent: lower values

Electric power output in MW

Electrical efficiency in percent

Fuel cell efficiency

The efficiency of fuel cells is not limited by the Carnot process as hydrogen

is directly converted by electrochemical reactions. Fuel cells can therefore

attain considerably higher efficiencies than comparable internal-combustion

engines.

Fuel cell types

N2, unconverted O2and reaction gas

Load

O2

CathodeAnode

Electrolyte

Fuel gas

Unconverted fuel gasand reaction gas

900 1,000 C

600 650 C

160 220 C20 120 C

60 120 CAFC

OH

PEMFC

H+

MCFC

CO32

O2

SOFC

PAFC

H+

O2

O2

CO2

O2

H2O

O2

H2O

H2

H2O

H2

H2

CO2

H2O

COH2

CO2

H2O

COH2

160 220 C20 120 C

N2, unconverted O2and reaction gas

Molten Carbonate Fuel Cell (MCFC)Molten carbonate fuel cells working attemperatures between 500 C and 600 Care being developed for industrial appli-cations. They permit electricity genera-tion with high efficiencies (approx. 55percent) and simultaneous production of process steam, offering excellentpotential for industrial combined heatand power generation. In Germany, aprominent developer of this technology is MTU, and in America, Fuel Cell Energy is foremost.

Alkaline Fuel Cell (AFC)Alkaline fuel cells are distinguished by a combination of low working temper-atures and high efficiencies. They arefavored for niche applications in thespace industry or the maritime sector, e. g. to drive submarines. The demandsthis cell type makes on the purity ofhydrogen and oxygen clearly limit thepractical scope of use. This fuel cell typeis developed by ZeVco (Zero EmissionVehicle Corporation) and others in Germany; worldwide, IFC (InternationalFuel Cell) and Fuji work on it.

Phosphoric Acid Fuel Cell (PAFC)Opportunities for phosphoric acid fuelcells working at temperatures around 200 C are in combined heat and powerproduction. Administrative buildings,hospitals, indoor pools but also large resi-dential estates are potential applications.Over 180 plants supplied by Americanmanufacturers ONSI are operated world-wide and have in part already beendecommissioned after reaching theirexpected service life. They are proof of the vast interest in using the fuel celltechnology. Still, experience with thistechnique has given rise to some doubtsabout its further success. They concernthe limited potential for saving manu-facturing costs, and technical restrictionsresulting from the need to constantlymaintain temperatures. Besides ONSI,Japanese companies Fuji and Toshibawork on this method.

Proton Exchange Membrane Fuel Cell(PEMFC)Employing fuel cells in the end user mar-ket is seen as a particularly interestingopportunity. About 25 percent of primaryenergy consumption in Germany areaccounted for by space heating and hotwater supply, so that use of fuel cells asCHP plants would contribute to energysaving. That temperature levels are rela-tively low in the supply of hot water forspace and service water heating opens up a range of applications for low-temperature cells with proton exchangemembranes.

PEM fuel cells are used in the Berlindemonstration project. With an electricpower output of 250 kWel , this is their firstcommercial-scale application in Europe.The success of this project will be animportant prerequisite for marketingplanned from 2004 onwards.

Energy consumed in Germany to supply heat

About 25 percent of the primary energy con-

sumption of 492 x 106 tons of hard-coal equiva-

lent were used in 1998 to meet space heating

and hot water needs.

Chemical reactions in each fuel cell type

9 %

34 %

57 %

Processheat

Hotwater

Spaceheating

89

Water vapor

Shift converter Fuel cell

Shift reactionReformer reaction Total

Product water

Water vapor

Anode off-gas (H2)

Making hydrogen availableIndustrial sources are, for example, che-mical industry operations. The excessH2 produced in synthesis gas manufac-ture has already found its way into theenergy supply sector, and can in futurebe used more widely. The same appliesto electric energy that is freely avail-

able in low-load periods. Electrolyzeroutfits can be employed to producehydrogen out of it and use it in peakload periods to cover electricity needsor supply vehicles with H2.

Recovering hydrogen from renewableenergies is today still seen as a futureoption. Economic reasons will continue

to reduce it to niche applications forsome time. Fossil energy sources suchas natural gas and mineral oil appearto be the most promising sources forhydrogen production in the mediumterm. This requires treatment so-called reformation processes to beinstalled upstream of the fuel cell.

Natural gas reformation

The futures nameis hydrogen.

Hydrogen stores renewable energies

Hydrogen is not freely available in nature. Chemical and

electrochemical processes will therefore long have to be used

to recover it.

Fuel cell

H2storage

Electrolyzer outfit Electrolyzer outfit Reformer

Renewable energy Excess electricity Industrial sources Natural gas reformation

Hydrogen production through reformationReformation is a multi-stage process trans-forming hydrogen-containing energysources into hydrogen-rich gases. As thisprocess consumes energy, it results indrawbacks to the energetic overall effi-ciency of a fuel cell process.

In a first step, natural gas is split in areformation reaction into a gas mix con-sisting of three parts hydrogen (H2) andone part carbon monoxide (CO). In addi-tion to process heat (+205.8 kJ/mol, i. e.kilojoules per mol), this requires feedingof water vapor as a coreactant. In a sec-ond step, the remaining CO is, with thehelp of steam, oxidized to carbon dioxide(CO2) in a shift reaction. It releases a fur-ther free hydrogen molecule. The finalproduct is a gas mix consisting of fourparts H2 and one part CO2 which can bedirectly used in the fuel cell.

The shift reaction is exothermic, i.e.connected with a release of energy ( 42.3 kJ/mol). This energy can be employedto partly cover the energy demand of refor-mation. PEM fuel cells are normally highlysensitive to CO contained in the fuel gas.Carbon monoxide is regarded as a catalyzerpoison. These fuel cells therefore necessi-

tate removing residual CO in a third oreven fourth treatment stage, which isdone in a process called selective oxi-dation.

The entire gas treatment process in-volves a 20 to 30 percent loss of energy,which detracts from the efficiency of thefuel cell process. Losses are lower whenhigh-temperature fuel cells are used.They permit internal reformation of thefuel inside the fuel cell, which leads tohardware savings and efficiency advan-tages. But the price paid for these bene-fits is that expensive materials with high temperature resistance have to be used.

State of the artFuel cells have reached a maturity todaythat allows building complete plants incommercially usable sizes. They serve asdemonstration units for their manufac-turers to test and optimize their plantconfigurations, and help their operators mainly energy utilities gain initial ex-perience with this new technology. Thisis also the purpose of the Berlin fuel cellproject. Demonstration projects shouldnot be confused with commercial fuel cellapplications. This needs further years ofdevelopment and operating experience.With a view to mobile applications, thismeans in particular that a decision has to be made which energy resource will infuture be needed either hydrogen isdirectly used, or methanol serves as anintermediate solution. For stationaryapplications, efficient and compactreformers will have to be developed thatallow low-cost conversion of natural gasinto hydrogen-rich gas.

Many companies have committed toworking intensively on development.Even well-renowned manufacturers nev-ertheless assume that both mobile andstationary serial products will not becommercially available until after 2004.

Methods of

hydrogen recovery

Design of a PEM fuel cell

A fluorine-containing polymer

membrane is the outstanding

feature of the PEM fuel cell design.

Vaporized with a catalytic precious

metal and covered by a gas-

permeable graphite electrode, it is

enclosed by two bipolar plates.

PEM fuel cells boast simple design

and uncomplicated manufacture.

1 Flow field plate (fuel supply)

2 Hydrogen supply3 Membrane electrode

assembly4 Air supply5 One fuel cell

pulled apart6 Stack consisting of

several cells

6

1 3

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5

Simple and low-costA fluorine-containing foil, vaporized with a catalyticprecious metal and coated with a gas-permeableelectrode made of graphite paper, is enclosed by twobipolar plates made of metal or graphite. Groovesmilled or pressed into the plates allow feeding ofhydrogen and oxygen or air to the anode and cathode.The simple design of the PEM fuel cell suggests thatmanufacture will in future be low-cost, permittingmass production as usual e. g. in the automotiveindustry.

Merits of PEM fuel cellsPEM fuel cells outperform competing technologiesin a number of ways that speak in favor of their goodmarketing potential. The following aspects are coreto its superiority:

PEM fuel cells are appropriate for mobile and sta-tionary use.Their versatility in application suggestssynergies, with cost benefits lying with stationaryapplications.

PEM fuel cells have the highest power density com-pared with competing technologies, with potentialfor further development.This allows building small,space-saving systems as required for remote-siteapplications.

PEM fuel cell applications in power supply rangefrom mini-systems generating a few watts via stand-alone units in combined heat and power to applica-tions in stand-by power supply a universally usabletechnology.

Description of the PEM fuel cell.

A variety of applications

200

400

600

800

0

1,000

1,200

Watts / liter

1995 1997199319911989

Development of

the power density

of PEM fuel cells

Project venture and project costsFive energy utilities participate in the Berlin fuel cell project: Bewag as the projectleader, lectricit de France (EdF) Paris,Hamburgische Electricittswerke AG (HEW) Hamburg, Hanover-based PreussenElektraAktiengesellschaft (now E.ON Energie AG,Munich) and Vereinigte Energiewerke Aktien-gesellschaft (VEAG) Berlin. Canadian manu-facturers Ballard Generation System (BGS)supplied the plant, and ALSTOM deliveredthe complete system.

ALSTOM regards the Berlin project as animportant step towards commercial-scaleintroduction of fuel cells. The company has plans for the future to jointly producecomparable plants in series with its partner Ballard in a new Europe-based company.They will hinge on successful completion of the Berlin demonstration project.

Project costs amount to an approximate 3.8 million. The innovative character of the project and its expected favorable impacton the European economy persuaded theEuropean Commission to financially assistthis project. It contributes 40 percent of theproject costs. The remainder is taken byALSTOM (around 10 percent) and the powersuppliers in charge (around 50 percent).

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The Berlin 250 kW PEM demonstration project.

The Berlin fuel cell project managed by Bewag is the first of its kind in

Europe.The project is the first to employ the PEM technology in the

200kW class in Europe.Three further plants are being installed as part of

a field test one plant in Switzerland was commissioned in fall 2000,

another plant in Belgium in spring 2001, and a fourth unit will take up

operation in the Netherlands in the second half of 2001.

A proud European cooperation venture

Project descriptionNatural-gas based PEM fuel cells consistof three partial systems: Gas treatment toconvert natural gas into hydrogen, the fuelcell stack, and the downstream AC/DCconverter generating an AC voltage.

The system applied in Berlin follows thisbasic design. If compared with competingsystems, however, it differs not only in thefuel cell type. The complete fuel cell systemincluding the upstream gas treatment unitworks under pressure. The four bar opera-ting pressure allows compact plant designwith reduced volumes of building materials.For the stack, this means a boost in powerand efficiency compared with atmosphericoperation.

After entering the plant, the natural gasis stripped of sulfur, reformed, and thenstripped of carbon monoxide (CO) by wayof oxidation to carbon dioxide (CO2) in theshift reactor and the following conversionstages. Subsequently, the gas mix fourparts hydrogen (H2) and one part carbondioxide (CO2) is fed to the fuel cell. AnyH2 not utilized in the fuel cell serves toheat the reformer. The steam additionallyneeded for reformation comes from con-densate recovered from the off-gas of thefuel cell. Under part load, demineralizedwater from the neighboring heat plant is used to balance any potential watershortage.

Pressurized operation requires compres-sion of natural gas and process air neededin the fuel cell. It is particularly the energyrequired to compress the air that triggersa distinct increase in station service needs.Utilizing the energy contained in the off-

gas with a turbo-supercharger helps to largely avoid this additional station servicerequirement.

The process design provides for outputof heat for heating purposes. Cooling waterruns through the cell in a primary coolingcycle which transfers its energy via a heatexchanger to the connected district heat-ing network. In the absence of any heatload, a stand-by cooler is used to ensuresufficient re-cooling of the primary coolingcycle.

An AC/DC converter sits downstream ofthe fuel cell. It transforms the DC outputsignal of the fuel cell into an AC voltagesignal utilizable for mains feeding.

The plant has a package design, with thecontainer housing all modules needed forthe process: gas treatment, fuel cell andinverter. Operation additionally requiresthe natural gas service connection, thehook-up to the district heating system, thepiping for process gases such as nitrogenand compressed air, and the demineralizedwater supply.

The fuel cell plant functions as an integralpart of the existing Berlin-Treptow heatplant of Bewag. This heat plant with itstwo 12.7MW steam boilers and an 18.7MWhot water boiler supplies to a local heatingsystem with a maximum demand of 25 MW.Minimum demand in summer is 500 kW.A bypass allows to connect the fuel cellwith the existing district heating system. A heat exchanger is used for heat removalto the return flow. Part of the return flow isthis way heated by about 10 K, usuallyfrom 65 to 75 C. The temperature level ofthe return flow that is low throughout theyear is, in connection with the high heatdemand, the prerequisite for fully reclaim-ing the heat rejected by the fuel cell.

The fuel cell is dimensioned for an elec-tric power output up to 250 kW. This is sufficient to cover the entire electricityneeds of the heat plant. The demand isoccasioned by the pumps recirculating the heating water, the driving gear of theburner ventilators and other loads neces-sary to ensure operation of the heat plant.

Air

Off-gas

Naturalgas

Anode/cathode off-gas

Reaction water

Air cooler

Start-up air

4 H2 + CO2

250 kWel

400 V 3~

Return flow districtheating network 230 kWth

H2 from electrolyzer outfit

Make-up water

Fuel cellReformer ShiftconverterCO

converter

Gas treatment

Turbo-supercharger

Process of the 250 kW PEM fuel cell plant

Besides use of the PEM fuel cell, the typical feature

of the plant is that the process is pressurized.

It allows compact design but requires increased

maintenance input.

Flow85 C

Return flow75 C

65 C

75 C

Flow: max 70 CAverage temperature: 58 C

Steamboiler

12.7 MWth

Steamboiler

12.7 MWth

Hot-waterboiler

18.7 MWth

Fuelcell

230 kWth

Maxheat

demand25 MWth

Return flow temperature in C

3,094 5,279 7,500

30

60

90

00 hrs p.a.

Project goalsWith this project, the partners pursue the goal of testing all qualities of the system in a comprehensivemeasuring program. In addition to the usual measur-ing devices for temperature, flow and electric para-meters, a gas chromatograph is used that allows tojudge the reformation and conversion rates of eachgas treatment step. These are some central functionsof the measuring program:

Evidencing operational safetyElectric efficiency (approx. 35 percent), evidencing that the course is constant Efficiency of each component reformer, stack and inverterAging behavior and voltage dropPart load behaviorTheoretical degradation (conversion of all existingenergies into heat) after 40,000 hoursEvidencing long-term functional security of thestack and plant Review availability and reliabilityTransient and start-up behavior Optimum linkage into power and heat supply systems

The measurement program will take approximatelytwelve months. This phase will be followed by three-year continuous operation to allow conclusions onlong-term operating behavior.

Approval procedureThe technical review by the German Technical ControlAssociation TV Rhineland/Berlin-Brandenburg wascore to the approval process. The reviews comprisedindividual testing of components and groups, safetychecks and functional testing. Tests are being carriedout in compliance with both the new European direc-tive for pressure devices and the Canadian CSA (Cana-dian Standards Association) directive. Their aim is toconduct, if possible, all tests that will later be requiredfor the ultimate serial product.

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Berlin-Treptow heat plant

The fuel cell is run as an

integral part of the heat plant.

A bypass ties it into the district

heating system.

Cooling compartment

Fuel cell stack

Humidifier module

Shift reactor module

Electrical compartment

Steam reformer

DC/AC converter

Fuel cell container

All components needed to operate the fuel cell

are housed in a container. What must be added

are the connections to natural gas, heating,

demineralized water, nitrogen and compressed-

air pipes.

Solutions for tomorrows world.

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Stand-alone, demand-guided power supply has ceased to be a utopia

Liberalization of the European power market has for many

companies thrown up the question whether energy supplies

in their usual form still tally with market developments.

Will investments in large-scale generation plant and extensive

distribution networks continue to pay back in future?

Future prospectsLarge power plants, not always loca-ted close to customers, have so farbeen the hallmark of power supply.Energy has been transported to usersover cost-intensive transmission anddistribution systems.

In addition, inner-city power plantshave been used in big cities such asBerlin or Hamburg. Besides producingpower, they have also served to provideheating services. This has created dis-trict heating systems with large groundcoverage.

Alternatives are now emerging forcommercial clients with the advent of stand-alone facilities such as windturbines, micro-turbines and blockheat and power plants. If linked to a modern communication system,

a complementary energy supply net-work with a focus on stand-alonefacilities can in future be installed.These facilities will evolve in responseto demand, clearly reducing invest-ment risks. Plans provide for numer-ous small generating plants operatedin an interconnected system of stand-alone service. Experts call them virtu-al power plants, or micro-grids. Fuelcells will be an essential componentof such stand-alone structures. Theywill be deployed close to the point ofuse for direct heat and power supply,with natural gas used as the predom-inant energy source in the initialphase. A precondition of this will bethat appropriate fuel cells can be easily integrated into existing supplysystems without detracting from the

well-being and living quality of con-sumers.

For large-scale uses such as satellitetowns or big residential buildings,mainly large generating units of thesize of the Berlin demonstration plantwill be employed, while small facilitiesare predestined for inner-city applica-tions where height limitations need to be respected. The plants will backup one another, and be linked throughthe existing public system or local distribution networks. An efficientcommunication system will monitoroperation of the individual compo-nents.

Fuel cellHeat

Electricity Natural gas

Fuel cellHeat

250 kWel 1 to 5 kWel

Fuel cell

Fuel cells for stand-alone energy supply

For larger-scale loads, plants with larger-sized

capacities are used. Where served facilities

are small, it is recommendable to deploy units

with their output limited to the demand of

the respective facility.

An important contribution towardpractical applicationFuel cells will play a key role as anelement of a future, sustainable ener-gy supply infrastructure because theyare energy-efficient and environmen-tally friendly. Their successful marketlaunch will largely depend on theavailability of products suitable forpractical use. Besides further devel-opment work, this will require practi-cal testing. The Berlin demonstrationproject has made an important con-tribution in this respect. It is open forvisits on the grounds of the fuel cellexhibition.

The Hessian fuel cell a demonstra-tion project 1993 1998The project of Hessische Elektrizitts-AG (HEAG), Darmstadt, and the Insti-tute of Chemical Technology of theDarmstadt Technical Universityenjoyed financial assistance from theHessian Ministry of Environment,Energy, Youth, Family and Health:During the project term between 29June 1993 and 28 April 1998, the fuelcell generated an electric power out-put of 5,462,951kWhel and a thermaloutput of 6,866,506 kWhth.

Pay a visit to Bewags fuel cell exhibitionEichenstrasse 7/corner of Puschkinallee12435 Berlin-TreptowS-Bahn station: Treptower ParkSubway station: Schlesisches Tor/ Bus 265Open Mondays through Fridays 10:00 to 18:00 hours,Saturdays and Sundays 13:00 to 17:00 hoursPhone +49 30-267-111 38Fax +49 30-267-1 03 13

The changed energy market environments

and availability of new, efficient generation

systems suggest that the structures of energy

supply will shift.

A rsum.

Fuel cells make an important contribution to energy supply in the 21st century

The history of the fuel cell

Fuel cell first described by Sir William Grove

First U.S. fuel cell patent (Vergnes)

Nernst for the first time applies yttri-um-doped zirconium for a bulb

Reid for the first time describes analkaline fuel cell

W. Schottky delivers a theoreticaltreatise on SOFCs

Baur and Preis for the first time publish SOFC experience

F. T. Bacon presents a 150W fuel cell

6 kW high-pressure fuel cell of F. T. Bacon

The Westinghouse SOFC programstarts

The Allis Charmers ManufacturingCompany uses a 15 kW fuel cell todrive a tractor

Fuel cell development for the Apollomission starts (1.4 kW, 200 C, potashlye, 3.5 bar)

1 kW PEMFC plant for the Geminispace program

Double electrode concept for alkalinefuel cells by Justl

United Technology Corp. (UTC) produces a 12.5 kW PAFC

UTC in New York produces a 4.8 MW plant

Westinghouse manufactures a 5 kW SOFC stack

11 MW PAFC plant in Japan

Westinghouse manufactures a 25 kW SOFC plant

Energy Research Corp. (ERC) manufactures a 2 MW MCFC plant

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Fuel cellexhibition

Eichenstrasse /Puschkinallee 52

Puschkinallee

Schlesisches Tor

Treptower Park

E-mail

Internet

Bewag Aktiengesellschaft

Puschkinallee 52

D 12435 Berlin

bewag@bewag.com

www.bewag.de

Phone

Fax

E-mail

Internet

Fuel cell exhibition

Eichenstrasse 7/corner of Puschkinallee

12435 Berlin-Treptow

S-Bahn station:Treptower Park

Subway station: Schlesisches Tor / Bus 265

Open Mondays through Fridays

10:00 to 18:00 hours,

Saturdays and Sundays

13:00 to 17:00 hours

Information:

+49 30-267-111 38

+49 30-267-1 03 13

innovationspark@bewag.com

www.innovation-brennstoffzelle.de

www.fuelcellpark.com May

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