A national laboratory of the U.S. Department of Energy 

Office of Energy Efficiency & Renewable Energy 

National Renewable Energy Laboratory 

Innovation for Our Energy Future 

Cost Analysis of PEM Fuel Cell Subcontract Report 

NREL/SR-560-39104 Systems for Transportation December 2005 

September 30, 2005 

E.J. Carlson, P. Kopf, J. Sinha, S. Sriramulu, 

and Y. Yang 

TIAX LLC 

Cambridge, Massachusetts 

NREL is operated by Midwest Research Institute ● Battelle Contract No. DE-AC36-99-GO10337 
Cost Analysis of PEM Fuel Cell 

Systems for Transportation 

September 30, 2005 

E.J. Carlson, P. Kopf, J. Sinha, S. Sriramulu, 

and Y. Yang 

TIAX LLC 

Cambridge, Massachusetts 

NREL Technical Monitor: K. Wipke 

Prepared under Subcontract No. KACX-5-44452-01 

Subcontract Report 

NREL/SR-560-39104 

December 2005 

National Renewable Energy Laboratory 

1617 Cole Boulevard, Golden, Colorado 80401-3393 

303-275-3000 • www.nrel.gov 

Operated for the U.S. Department of Energy 

Office of Energy Efficiency and Renewable Energy 

by Midwest Research Institute • Battelle 

Contract No. DE-AC36-99-GO10337
This publication was reproduced from the best available copy 

Submitted by the subcontractor and received no editorial review at NREL

NOTICE

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iii

Table of Contents 

TABLE OF CONTENTS...........................................................................................................................III

LIST OF TABLES........................................................................................................................................V

LIST OF FIGURES.................................................................................................................................. VII

1. ABSTRACT......................................................................................................................................... 1

2. SUMMARY ......................................................................................................................................... 2

3. INTRODUCTION............................................................................................................................. 10

4. SUMMARY OF COST PROJECT RESULTS (1998-2004) ......................................................... 11

4.1. REFORMER BASED SYSTEM (2001) ............................................................................................ 11

4.2. SUMMARY OF KEY COST DRIVERS (2001 – 2004)...................................................................... 22

5. PROJECT OBJECTIVE, SCOPE, AND APPROACH................................................................. 23

5.1. OBJECTIVE ................................................................................................................................. 23

5.2. SCOPE ........................................................................................................................................ 23

5.3. APPROACH ................................................................................................................................. 24

6. MANUFACTURING COST MODEL DESCRIPTION................................................................ 25

6.1. TECHNOLOGY-BASED COSTING METHODOLOGY ....................................................................... 25

6.2. PEM FUEL CELL MANUFACTURING COST MODEL..................................................................... 26

6.2.1. Overview............................................................................................................................... 26

6.2.2. Cost Definition...................................................................................................................... 27

6.2.3. Baseline Cost Model Description ......................................................................................... 27

6.2.3.1. Definition of System Operating Parameters............................................................................... 28

6.2.3.2. Development of Subsystem and Component Design ................................................................. 28

6.2.3.3. Cost Analysis ............................................................................................................................. 29

6.2.4. Sensitivity Analyses............................................................................................................... 29

6.2.5. Supply Chain Analysis .......................................................................................................... 31

7. DOE FUEL CELL SYSTEM TARGETS ....................................................................................... 33

8. SYSTEM ANALYSIS....................................................................................................................... 34

8.1. INTRODUCTION........................................................................................................................... 34

8.2. SYSTEM DESCRIPTION................................................................................................................ 34

8.3. SYSTEM PERFORMANCE RESULTS .............................................................................................. 36

8.3.1. Stack Efficiency..................................................................................................................... 36

8.3.2. System Parasitic Power Consumption.................................................................................. 38

8.4. SYSTEM EFFICIENCY .................................................................................................................. 39

8.5. SYSTEM COMPONENT SIZING ..................................................................................................... 39

8.5.1. PEMFC Stack ....................................................................................................................... 39

8.5.2. Power Density Assessment ................................................................................................... 39

9. COST ANALYSIS ............................................................................................................................ 41

9.1. INTRODUCTION........................................................................................................................... 41

9.2. STACK........................................................................................................................................ 41

9.2.1. Membrane............................................................................................................................. 43

9.2.1.1. Description................................................................................................................................. 43

9.2.1.2. Manufacturing Process............................................................................................................... 45

9.2.1.3. Membrane Costing..................................................................................................................... 49
iv

9.2.2. Gas Diffusion Layer (GDL).................................................................................................. 52

9.2.2.1. Description................................................................................................................................. 52

9.2.2.2. Manufacturing Process............................................................................................................... 52

9.2.2.3. Costing....................................................................................................................................... 53

9.2.3. Bipolar plates ....................................................................................................................... 54

9.2.3.1. Description................................................................................................................................. 54

9.2.3.2. Manufacturing Process............................................................................................................... 55

9.2.3.3. Costing....................................................................................................................................... 58

9.2.4. MEA...................................................................................................................................... 60

9.2.4.1. Description................................................................................................................................. 60

9.2.4.2. Manufacturing Process............................................................................................................... 61

9.2.4.3. Costing....................................................................................................................................... 63

9.2.5. Gasket................................................................................................................................... 64

9.2.5.1. Description................................................................................................................................. 64

9.2.5.2. Manufacturing Process............................................................................................................... 65

9.2.5.3. Costing....................................................................................................................................... 66

9.2.6. Stack Assembly ..................................................................................................................... 66

9.2.7. Stack Cost ............................................................................................................................. 67

9.2.7.1. Baseline Cost ............................................................................................................................. 67

9.2.7.2. Single Variable Sensitivity Analysis.......................................................................................... 67

9.2.7.3. Monte Carlo Simulation............................................................................................................. 69

9.2.7.4. Stack Cost Comparison – 2004 vs. 2005.................................................................................... 70

9.3. QC AND STACK BURN-IN ........................................................................................................... 71

9.4. BOP ........................................................................................................................................... 72

9.4.1. Air Management ................................................................................................................... 72

9.4.1.1. Air Filtration .............................................................................................................................. 72

9.4.1.2. Compressor-Expander................................................................................................................ 73

9.4.2. Water Management............................................................................................................... 74

9.4.2.1. Enthalpy Wheel Humidifier ....................................................................................................... 75

9.4.2.2. Membrane Humidifier................................................................................................................ 76

9.4.3. Thermal Management........................................................................................................... 78

9.4.4. Fuel Management................................................................................................................. 81

9.5. SYSTEM COST ............................................................................................................................ 85

9.6. SCENARIOS................................................................................................................................. 88

9.6.1. Lower Platinum Price........................................................................................................... 88

9.6.2. Inclusion of Value Chain Costs ............................................................................................ 88

9.7. STUDY RESULTS RELATIVE TO DOE TARGETS .......................................................................... 89

10. CONCLUSIONS AND RECOMMENDATIONS ..................................................................... 91

10.1. KEY DRIVERS............................................................................................................................. 91

10.2. OTHER FACTORS ........................................................................................................................ 92

10.3. RECOMMENDATIONS .................................................................................................................. 92

11. ACKNOWLEDGEMENTS......................................................................................................... 94

12. APPENDIX ................................................................................................................................... 95

12.1. $450/TROZ BASELINE COST SCENARIO ...................................................................................... 95

13. REFERENCES............................................................................................................................. 98
v

List of Tables 

Table 1. Key Model Parameters......................................................................................... 4 

Table 2. Changes in Stack Materials Cost on an Area Basis from 2004 to 2005 ............... 7 

Table 3. System Metrics Relative to DOE 2005 Targets................................................... 8 

Table 4. Component List and Allocation to Subsystems................................................. 12 

Table 5. 2001 Assumptions for the Reformer and Fuel Cell Stack ................................. 13 

Table 6. Comparison of Hybridization Scenarios with a 120 kW ICE Base Case .......... 17 

Table 7. 2004 Stack Parameters Compared to 2001 Values............................................ 18 

Table 8. Comparison of Cost of Reformate and Direct Hydrogen Systems.................... 19 

Table 9. Comparison of 50 kW and 80 kW Costs for the 2004 Systems ........................ 19 

Table 10. DOE Targets .................................................................................................... 33 

Table 11. Summary of the Stack Operating Conditions that Influence the System Design 

and Configuration of the 80 kWe PEMFC System........................................................... 34 

Table 12. Parameters Influencing the Stack Efficiency Estimation ................................ 37 

Table 13. Parasitic Power Consumption in the System ................................................... 38 

Table 14. Stack Specifications and Performance Assumptions....................................... 42 

Table 15. Stack Material Assumptions ............................................................................ 42 

Table 16. Stack Component Weight and Dimensions ..................................................... 43 

Table 17. Membrane Material Parameters....................................................................... 48 

Table 18. Membrane Process Parameters ........................................................................ 48 

Table 19. Membrane Material and Process Cost (on an active area basis)...................... 49 

Table 20. Membrane Single Variable Sensitivity Analysis Data Range Table ............... 50 

Table 21. GDL Material Parameters................................................................................ 52 

Table 22. GDL Process Parameters ................................................................................. 53 

Table 23. Material and Process Costs (on an active area basis) ...................................... 54 

Table 24. Bipolar Plate Material and Process Comparisons............................................ 54 

Table 25. Graphite Foil Bipolar Plate Material Parameters............................................. 58 

Table 26. Graphite Foil Bipolar Plate Process Parameters.............................................. 58 

Table 27. Graphite Foil Bipolar Plate Cost Break Down ................................................ 59 

Table 28. Compression Molded Bipolar Plate Cost......................................................... 60 

Table 29. Anode Material Parameters ............................................................................. 63 

Table 30. Cathode Material Parameters........................................................................... 63 

Table 31. MEA Process Parameters................................................................................. 63 

Table 32. MEA Cost Break Down................................................................................... 64 

Table 33. Seal Material Parameters ................................................................................. 66 

Table 34. Gasket Molding Process Parameters................................................................ 66 

Table 35. Gasket Cost Break Down................................................................................. 66 

Table 36. Stack Sensitivity Analysis Variable Ranges.................................................... 68 

Table 37. Stack Cost Comparison 2004 vs. 2005 ($/m2

)................................................. 70 

Table 38. Stack Cost Comparison 2004 vs. 2005 ($/kW)................................................ 71 

Table 39. Conditioning & QC Cost ................................................................................. 71 

Table 40. Key Characteristics of Honeywell CEM ......................................................... 73 

Table 41. Comparison between Honeywell and TIAX Estimates for CEM Cost ........... 74 

Table 42. Weight/Volume Parameters of Enthalpy Wheel Humidifier........................... 76 

Table 43. Materials, Processes, and Costs for Humidicore Enthalpy Wheel .................. 76 
vi

Table 44. Weight/Volume Parameters for Membrane Humidifier .................................. 77 

Table 45. Comparison of TIAX and PermaPure Cost Estimate for Membrane 

Humidifier......................................................................................................................... 78 

Table 46. Key Characteristics of Thermal Management System .................................... 79 

Table 47. Technical Specifications of High-Temperature Radiators............................... 80 

Table 48. Cost of High-Temperature Radiators for 40°C Ambient Temperature ........... 80 

Table 49. Characteristics of H2 Ejector............................................................................ 83 

Table 50. Characteristics of Recirculating Blower Assembly......................................... 84 

Table 51. Comparison Between 2004 and 2005 System Costs ....................................... 85 

Table 52. Parameter Values for the System Cost Sensitivity Analysis ........................... 86 

Table 53. Low Platinum Price Scenario .......................................................................... 88 

Table 54. Value Chain Cost Calculation.......................................................................... 89 

Table 55. Summary of 2005 PEMFC System Results..................................................... 90 
vii

List of Figures 

Figure 1. Overall System Configuration with Major Components.................................... 4 

Figure 2. Breakdown of System Cost for an 80 kW Direct Hydrogen Fuel Cell System 

($108/kW, $8,640) Produced at 500,000 Units per Year ................................................... 5 

Figure 3. Breakdown in Stack and BOP Component Cost Contributions for an 80 kW 

Direct Hydrogen Fuel Cell System ($108/kW, $8,640) ..................................................... 5 

Figure 4. Cost Breakdown for a 2005 80 kW Direct Hydrogen Stack ($67/kW, $5,360). 6 

Figure 5. Range in System Cost due to Uncertainty in Input Parameters.......................... 7 

Figure 6. System Configuration Used in 2001 Reformer – Fuel Cell System Cost 

Projection .......................................................................................................................... 11 

Figure 7. Thermally integrated reformer design used to cost the fuel processor including 

ATR, high and low temperature shift beds, burner and steam generation tubes .............. 12 

Figure 8. 2001 Reformer Based System Cost Breakdown (system cost of $324/kW) .... 14 

Figure 9. 2001 Fuel Cell System Cost Breakdown.......................................................... 15 

Figure 10. Stack and MEA Cost Breakdown for the 2001 System Configuration........... 15 

Figure 11. Direct Hydrogen System for 2004 Cost Update............................................. 16 

Figure 12. Cost of Compressed Hydrogen Storage Scenarios......................................... 17 

Figure 13. Stack Cost Versus Platinum Loading for Reformate and Direct Hydrogen 

Stacks ................................................................................................................................ 21 

Figure 14. Stack Cost versus Ohmic Resistance.............................................................. 22 

Figure 15. Scope of 2005 PEMFC Costing ..................................................................... 24 

Figure 16. 2005 Cost Project Approach........................................................................... 24 

Figure 17. Manufacturing Cost Model Schematic........................................................... 26 

Figure 18. Cost Elements of Detailed Cost Build-up ...................................................... 27 

Figure 19. Approach to PEMFC System Cost Model...................................................... 28 

Figure 20. Graphite Foil Bipolar Plate Manufacturing Flow Chart................................. 29 

Figure 21. Example of Single Variable Sensitivity Analysis .......................................... 30 

Figure 22. Example of Monte Carlo Sensitivity Analysis ............................................... 31 

Figure 23. Illustrative Automotive PEMFC Supply Chain.............................................. 32 

Figure 24. PEMFC System Layout.................................................................................. 35 

Figure 25. Comparison of the Required Flow from the Ejector versus the Actual Flow 

Estimated for the Chosen Ejector Design ......................................................................... 36 

Figure 26. Stack Efficiency as a function of the purge rate from the anode recycle loop 

for single cell operating voltage of 0.7 V. Comparable results are obtained for 0.65 V 

operation. .......................................................................................................................... 37 

Figure 27. Nitrogen concentration in the anode stream as a function of the stack power 

output (which is given as a fraction of the rated power). S1 corresponds to 0.7 V single 

cell voltage and S3 to 0.65 V............................................................................................ 38 

Figure 28. Efficiency of the 80 kW PEMFC system as a function of the rated power. S1 

corresponds to 0.7 V single cell voltage, S2 to 0.65 V (base case) and S3 to 0.6 V. ....... 39 

Figure 29. 2005 Stack Design.......................................................................................... 43 

Figure 30. Nafion Membranes Structure ......................................................................... 46 

Figure 31. Membrane Manufacturing Process Flow........................................................ 47 

Figure 32. Membrane Cost Breakdown Pie Chart........................................................... 49 

Figure 33. Membrane Single Variable Sensitivity Analysis Tornado Chart ................... 50 

Figure 34. DuPont, GM, and TIAX Membrane Cost Comparison.................................. 51 

Figure 35. GDL Manufacturing Process Flow Chart....................................................... 52 
viii

Figure 36. Grafcell® Production Process from GrafTech Website.................................. 55 

Figure 37. U.S. Patent 3,404,061 Flexible Graphite Web Process .................................. 56 

Figure 38. Embossing a Sheet of Flexible Graphite Material.......................................... 56 

Figure 39. Graphite Foil Bipolar Plate Process Flow ...................................................... 57 

Figure 40. Graphite Foil Process Cost Bar Chart ............................................................ 59 

Figure 41. Compression Molded Bipolar Plate Process Flow ......................................... 60 

Figure 42. Framing Seal Structure (U.S. Patent No. 6,716,550) ..................................... 61 

Figure 43. Framing Seals Layout (U.S. Patent No. 6,716,550) ....................................... 61 

Figure 44. MEA Structure................................................................................................ 61 

Figure 45. MEA with Frame Seals Manufacturing Process Flow ................................... 62 

Figure 46. U.S. Patent 5,284,718, A Top View of Gasket Grooves in Bipolar Plate...... 65 

Figure 47. U.S. Patent 5,284,718, A Top View of a Sealing Gasket............................... 65 

Figure 48. Stack Assembly Flow Chart ........................................................................... 67 

Figure 49. Stack Baseline Cost ($/kW)............................................................................ 67 

Figure 50. Single Variable Sensitivity Analysis Tornado Chart...................................... 68 

Figure 51. Stack Cost Monte Carlo Simulation Sensitivity Chart................................... 69 

Figure 52. Stack Cost Monte Carlo Simulation Frequency Chart ................................... 69 

Figure 53. Fuel Cell Stack and BOP................................................................................ 72 

Figure 54. (a) Honeywell Fuel Cell Turbo-Compressor with Mixed-Flow Compressor 

and VNT® Variable Nozzle Turbine, (b) Honeywell Fuel Cell Turbo-Compressor Motor 

Controller .......................................................................................................................... 73 

Figure 55. Humidicore Enthalpy Wheel Humidifier from Emprise ................................ 75 

Figure 56. Membrane Humidifier from PermaPure......................................................... 77 

Figure 57. Typical Arrangement of Radiators in Fuel Cell Vehicle................................ 79 

Figure 58. Fuel Management System .............................................................................. 81 

Figure 59. Zones of Operation of the Blower and Ejector............................................... 81 

Figure 60. Optimum Purge Rate for Cell Voltage of 0.7 V............................................. 82 

Figure 61. Ejector-Venturi Operating Principle............................................................... 83 

Figure 62. (a) Croll-Reynolds’ Schematic of Multiple Ejectors in Series, (b) Ejector from 

Elmridge............................................................................................................................ 83 

Figure 63. Hydrogen Recirculating Blower from H2 Systems, Inc. ................................ 84 

Figure 64. Stack and BOP Contributions to System Cost ............................................... 85 

Figure 65. Detailed Breakout of System Cost ................................................................. 86 

Figure 66. Parametric Studies on System Cost................................................................ 87 

Figure 67. Monte Carlo Analysis on System Cost........................................................... 87 

Figure 68. Illustrative Automotive PEMFC Supply Chain.............................................. 89 

Figure 69. Breakdown of System Cost for an 80 kW Direct Hydrogen Fuel Cell System 

(88 $/kW, $450/troz platinum price) Produced at 500,000 Units per Year...................... 95 

Figure 70. Breakdown in Stack and BOP Component Cost Contributions for an 80 kW 

Direct Hydrogen Fuel Cell System ($88/kW, $450/troz platinum price)......................... 95 

Figure 71. Cost Breakdown for 2005 80 kW Direct Hydrogen Stack ($48/kW, $450/troz 

platinum price).................................................................................................................. 96 

Figure 72. Range in Stack Cost due to Uncertainty in Input Parameters ($450/troz 

platinum price).................................................................................................................. 96 

Figure 73. Range in System Cost due to Uncertainty in Input Parameters ($450/troz 

platinum price).................................................................................................................. 97 
1

1. Abstract 

The successful commercialization of PEM fuel cells in transportation markets requires 

that the technology be competitive with internal combustion engine powertrains with 

regard to performance and cost, while meeting efficiency and emissions targets. TIAX 

has been working with the U.S. Department of Energy (DOE) since the late 1990s to 

assess the cost of PEM fuel cell systems using near-term technology as a basis, but cost 

modeled at high-production volumes. Integral to this effort has been the development of a 

system configuration in conjunction with Argonne National Laboratories (ANL), the 

specification of performance parameters and catalyst requirements, the development of 

representative component designs and manufacturing processes for these components, 

and the development of a comprehensive bill of materials and list of purchased 

components. The model, data, component designs, and results have been refined on the 

basis of comments from the FreedomCAR Technical Team and fuel cell system and 

component developers. 

In 2005, the cost of an 80 kW direct hydrogen fuel cell system was assessed relative to 

the DOE 2005 target of $125/kW. This system includes the fuel cell stack and balanceof-plant (BOP) components for water, thermal, and fuel management. Hydrogen storage 

is not included in this target. In this report, we provide a comprehensive description of 

the assumptions, approach, and final results of the 2005 PEMFC costing effort. The 

results of sensitivity and Monte Carlo analyses on components and the overall system are 

presented including the most important cost factors and the uncertainty in the fuel cell 

system cost projection given the model assumptions. The effects of selected scenarios on 

the fuel cell system cost ($/kW) were assessed, including the effect of platinum price and 

the effect of individual component markups on overall system cost. The results of these 

analyses are presented and their implications discussed. 
2

2. Summary 

Background 

The critical role that performance and cost play in the commercialization of fuel cell 

powertrains led DOE to initiate several studies beginning in 1998 to develop projections 

of fuel cell technology costs at high production volumes. The results of these assessments 

would provide DOE with: 

• Metrics to track the status of current technology and project the impact of future 

developments on system cost 

• A quantitative cost and technology framework supported by well documented 

design, performance, and material cost assumptions with which to conduct 

discussions with car makers and component developers on cost and performance 

targets 

• Insights into gaps in available technology and into areas in need of cost reduction 

for R&D portfolio planning 

This report presents the 2005 results and provides a high-level summary of TIAX’s 

findings since the project inception. 

Objective 

In 2005, the focus of the project was to update the cost projection and compare it with the 

DOE target of $125/kW for the fuel cell subsystem and BOP systems for air, water, 

thermal, and fuel management. Hydrogen storage, power electronics, electric drive 

motor, and hybrid batteries were excluded from the scope of this project. 

Approach 

The approach starts with a technology assessment of the system configuration and 

component technologies, leading to a bill-of-materials (BOM) for the system. For the 

stack components, bottom-up, activities-based costing methods were used to develop 

high-level cost projections for the material and process costs. For the BOP components, 

we worked with suppliers to obtain cost projections, which were then calibrated against 

our experience with similar technologies. Our preliminary estimates for the cost and 

system configuration, along with key design, cost, and process assumptions, were then 

presented to the car companies and material developers for their feedback. Sensitivity and 

Monte Carlo methods were used to identify key cost drivers and estimate the uncertainty 

in the results. 

Critical Factors 

Cell Voltage 

As in any analysis with a large number of parameters and design options, the assessment 

involved a number of design decisions relative to tradeoffs among performance, cost, and 

efficiency. For purposes of cost reduction and integration of the fuel cell system into the 

vehicle, the designer needs to minimize the size, weight, and cost of the system, while for 

fuel conservation one needs to maximize efficiency. Unfortunately, these goals are in 

conflict. Increasing the cell voltage at rated power, e.g., to 0.8 volts, increases efficiency 

but also increases the stack size, weight, and cost. Designing for long life may also 

increase system cost through increased loadings of valuable materials such as platinum. 
3

In the 2005 project, the Fuel Cell Tech Team recommended the use of 0.65 volts for the 

cell voltage at rated power to reduce stack size and cost. 

Platinum Price 

We were also faced with the selection of a platinum price for the baseline analysis. A 

dilemma arises from the current high in platinum prices ($900/troz) relative to the 

historically constant price of $450/troz. Use of the lower value allows easier comparison 

with the results of previous projections, while use of the current price allows one to see 

the impact of high prices. We have used today’s price for the baseline case while using 

the sensitivity analysis to capture the impact of uncertainty in these values. 

Power Density and Platinum Loading 

Power density on an active area basis and platinum loading are additional key parameters 

that drive the cost and size of the stack. We searched the literature and approached the 

industry for comments to identify the most likely values for the baseline case and 

reasonable upper and lower limits. The literature provides single cell results but little 

information on values for current stack designs with reasonable lifer, for example, power 

density without platinum loading. For the baseline costs, we assumed a total platinum 

loading of 0.75 mg/cm2 and a power density of 600 mW/cm2

 at 0.65 volts. 

Vertically Integrated Process vs. Outsourcing of Stack Components 

We continued to use a vertically integrated process for the manufacture of the stack 

components; however because the component markups over manufacturing cost in the 

value chain are not captured in this approach it led to a minimum cost estimate. In the 

case of the stack, with the integrator purchasing most of the components (membrane 

electrode assemblies (MEAs), gas diffusion layers, and bipolar plates), the markup could 

increase the projected cost of the stack by 20 percent to 50 percent. In our model, we treat 

the BOP components as purchased items and include markups in their cost contribution. 

Quality Control 

We have not included the cost of quality control into the current projection, partly 

because effective QC metrics are still under development and because current 

manufacturing processes are highly proprietary. High-level estimates were made for the 

impact of stack burn-in and performance characterization. For example, a 2 hour burn-in 

could raise the stack cost by 3%. 

All these factors will clearly increase the manufacturing cost of the system. As 

production volumes increase and component manufacturers accumulate experience, the 

cost of items, such as quality control, will decline. 

System Description 

When this project started in 1998 the baseline system was a 50 kW net electric PEMFC 

system with a fuel flexible reformer. With the transition from the Partnership for a New 

Generation of Vehicles (PNGV) to the FreedomCAR program, the focus shifted to direct 

hydrogen fueled systems and the rated power of the fuel cell system increased to 80 kW 

to better reflect the current practice of car companies. The peak and transient power of 

this system may be further enhanced by hybridization with batteries. Similar to earlier 
4

work, a PEMFC stack operating at 80o

C and 2.5 atm at rated power is used. In addition 

to the stack, the system includes components to humidify the anode and cathode streams, 

heat exchangers to cool the stack, and a blower to recirculate hydrogen in the anode loop. 

Figure 1 shows the overall system. Unlike earlier work, our cost assessment of the system 

does not include any fuel storage or fuel generation components. 

Source: Dr. Rajesh Ahluwalia of ANL

HT/LT Radiators

Demister

Electric 

Motor

PEFC

Stack

Air

Exhaust

Humidified Air

HT Coolant

Enthalpy 

Wheel

LT Coolant

Purge Valve

Recirculation 

Pump

LT Coolant 

Pump

HT Coolant 

Pump

Fan

Ejector

Pressure Membrane Regulator Humidifier

Dilution 

Mixer

Air 

Filtration

Hydrogen

Tank

Air 

Bypass

Not included 

in the fuel 

cell 

subsystem

Source: Dr. Rajesh Ahluwalia of ANL

HT/LT Radiators

Demister

Electric 

Motor

PEFC

Stack

Air

Exhaust

Humidified Air

HT Coolant

Enthalpy 

Wheel

LT Coolant

Purge Valve

Recirculation 

Pump

LT Coolant 

Pump

HT Coolant 

Pump

Fan

Ejector

Pressure Membrane Regulator Humidifier

Dilution 

Mixer

Air 

Filtration

Hydrogen

Tank

Air 

Bypass

HT/LT Radiators

Demister

Electric 

Motor

PEFC

Stack

Air

Exhaust

Humidified Air

HT Coolant

Enthalpy 

Wheel

LT Coolant

Purge Valve

Recirculation 

Pump

LT Coolant 

Pump

HT Coolant 

Pump

Fan

Ejector

Pressure Membrane Regulator Humidifier

Dilution 

Mixer

Air 

Filtration

Hydrogen

Tank

Air 

Bypass

Demister

Electric 

Motor

PEFC

Stack

Air

Exhaust

Humidified Air

HT Coolant

Enthalpy 

Wheel

LT Coolant

Purge Valve

Recirculation 

Pump

LT Coolant 

Pump

HT Coolant 

Pump

Fan

Ejector

Pressure Membrane Regulator Humidifier

Dilution 

Mixer

Air 

Filtration

Hydrogen

Tank

Air 

Bypass

Not included 

in the fuel 

cell 

subsystem

Figure 1. Overall System Configuration with Major Components 

Key Findings 

A PEMFC for transportation produced at high volume but based on today’s technology 

has a projected manufactured cost below the $125/kW target. Figure 2 shows the 

breakdown of the total cost of $108/kW between the stack, BOP, and assembly. All 

$/kW costs are given on a dollar per net power basis. Key assumptions in this projection 

are summarized in Table 1. 

Table 1. Key Model Parameters 

Parameter Units 2005 2004 

Power Density mW/cm2

 600 350 

Cell Voltage Volts 0.65 0.7 

Net Power kW 80 80 

Gross Power kW 90 88 

Production Volume Units/year 500,000 500,000 

Platinum Loading mg/cm2

 0.75 0.3 

Platinum Cost $/troz 900 450 
5

Significant changes in parameter values included an increase in power density due to 

performance improvements and a decrease in the design cell voltage, an increase in 

platinum loading to represent current practice in stacks, and an increase in platinum cost 

to reflect current pricing. 

Stack

63%

BOP

34%

Assembly

3%

Figure 2. Breakdown of System Cost for an 80 kW Direct Hydrogen Fuel Cell System 

($108/kW, $8,640) Produced at 500,000 Units per Year 

Figure 3 shows the split between the stack and BOP costs with the stack contributing 

approximately 63 percent. After the stack, the compressor-expander module (CEM), 

membrane humidifier, and carbon materials are the most important cost contributors. 

Stack

63%

HX, Coolant 

Pumps, and Fan

4%

CEM and Air 

Filtration

13%

Enthalpy Wheel 

Humidifier

3%

Membrane 

Humidifier

4%

H2 Blower and 

Ejector

4%

Misc (Valves, 

Sensors, and 

Piping)

6% Assembly

3%

Figure 3. Breakdown in Stack and BOP Component Cost Contributions for an 80 kW 

Direct Hydrogen Fuel Cell System ($108/kW, $8,640) 
6

Figure 4 shows the breakdown in the stack costs for 2005. The electrode contribution 

dominates because of the increased platinum loading and price, while the other 

components decreased in percent contribution and in cost per area because of reductions 

in material costs and the amount of material (thinner layers). The report details these 

changes. The top three cost drivers for the stack and the system are: 

• Power density 

• Platinum cost 

• Platinum loading 

Power density drives the size of the overall stack, while the product of platinum cost and 

loading determines the cost of the electrodes, the largest stack cost. Single cell power 

densities in the literature are higher than the selected value, but these values are derated 

in the stack to minimize hot spots and degradation. Increases in platinum cost and loading 

offset the decreases in other cell components and the increase in power density. 

Electrode

77%

GDL

5%

Bipolar 

Plate

5%

Membrane

6%

Seal

2%

BOS

2% Final 

Assembly

3%

Figure 4. Cost Breakdown for a 2005 80 kW Direct Hydrogen Stack ($67/kW, $5,360) 
7

A number of factors contribute to the system cost and Figure 5 shows the results of a 

Monte Carlo simulation to assess the effect of uncertainty in these parameters. The 

minimum, maximum, and most likely values are contained in the body of the report. For 

the range of input parameters considered, the analysis shows 98% certainty that the mean 

system cost is below the DOE target of $125/kW. 

108

12

97

$/kW

Mean

Std. Dev.

TIAX 

Baseline

Cost

108

12

97

$/kW

Mean

Std. Dev.

TIAX 

Baseline

Cost

2σ Mean $97/kW 2σ

Frequency Chart

Certainty is 98.02% from -Infinity to $125.00

.000

.005

.011

.016

.021

0

26.75

53.49

80.25

107

$60.00 $80.00 $100.00 $120.00 $140.00

5,000 Trials 4 Outliers

Forecast: System Cost ($/kW)

TIAX Baseline 

$108/kW

DOE 

Target 

$125/kW

Figure 5. Range in System Cost due to Uncertainty in Input Parameters 

Table 2 summarizes the key changes in stack material cost for 2005. A high-level 

assessment of the membrane cost resulted in a lowering of the perfluoro-sulfonic acid 

membrane cost. A decrease in thickness and cost of the gas diffusion layer and bipolar 

plate lowered these stack component costs. To achieve the thinner bipolar plates, this 

component was changed from a molded graphite resin composite to a molded/stamped 

expanded graphite part. 

Table 2. Changes in Stack Materials Cost on an Area Basis from 2004 to 2005 

Component 

2004 

Cost1

($/m2) 

2005 

Cost1

($/m2) 

% 

Change Cost Drivers / Comments 

Membrane 48.852

 23.38 -52% TIAX bottom-up costing, 2 mil unsupported 

membrane 

Electrode 67.19 279.02 315% 

Platinum cost increased from $450/troz to 

$900/troz, platinum loading increased from 

0.3 mg/cm2

 to 0.75 mg/cm2, platinum 

process markup is 20% which is same as 

2004 

GDL 32.00 18.40 -43% GDL thickness decreased from 350 μm to 

260 μm thickness ($8.50/m2

 on actual area) 

Bipolar plate 28.10 N/A N/A All plates have cooling channels 
8

Bipolar plate with 

cooling 27.45 17.38 -37% 

Material changed from molded graphite to 

expanded graphite. Every plate is a cooling 

plate. Thinner plate with less material 

Seal 7.25 6.08 -15% Increased amount of material, but switched 

from fluoropolymer to nitrile rubber ($5/lb) 

BOS 6.91 6.03 -13% Larger active area and same cost of 

components 

Final Assembly 8.14 10.53 29% 

Increased number of cells due to lower cell 

voltage. Does not include stack conditioning 

and QC 

Total 225.88 360.81 60% 

1

 m2 of active area 2

 $40/m2 membrane purchased, plus $8.85/m2 to condition membrane to fuel cell use 

For the system configuration used in the baseline assessment, Table 3 shows various 

system metrics relative to DOE targets for 2005. The stack cost is slightly higher than the 

target, due to the high assumed platinum price and the high platinum loading. Decreasing 

the thickness of the bipolar plates and increasing the area power density led to stack 

power densities close to the DOE target, while on a system level both power densities 

satisfy the targets. The volumetric density does not include allowance for a packing factor 

and might not satisfy the target in product form. Both efficiencies (rated and 25 percent 

of rated power) are about 5 percent lower than the DOE targets as a result of designing at 

0.65 volts. The baseline system contains 1.4 grams platinum per kilowatt. FreedomCAR 

and DOE roadmaps show values of 1.1 and 1.3 g Pt/kW respectively for the 2004 stack 

status similar to the baseline value from this study. 

Table 3. System Metrics Relative to DOE 2005 Targets 

Metric Units Value DOE 2005 Target 

Stack volume L 51 

Stack weight kg 58 

Stack cost $/kWe 67 $65 

Stack power density We/L 1569 1500 

Stack specific power We/kg 1379 1500 

Fuel cell system (FCS) volume1 L 131 

FCS weight kg 138 

FCS cost $/kWe 108 $125 

FCS power density1 We/L 610 500 

FCS specific power We/kg 580 500 

FCS efficiency @ rated power % 46 50 

FCS efficiency @ 25% rated power % 55 60 

1 Does not include packing factor, which would lower system power density 
9

Technology has progressed relative to the systems used in earlier analyses, leading to the 

reduction in cost and increases in power density. Discussions with MEA developers 

revealed that single cell performance of new products are significantly better with much 

lower platinum loadings, while providing longer life. When these improvements are 

realized at the stack level, the costs are further reduced. 

The issue of platinum pricing has a significant effect on stack and system cost. However, 

reductions in platinum loading will reduce the impact if prices remain at high-levels. In 

the longer term, the balance between supply and demand will determine whether 

platinum prices return to historic values. 

With increasing stack performance, lower platinum loadings, and lower platinum prices, 

BOP components will become more important cost contributors. More attention to BOP 

components and simplification of the system will be necessary to satisfy longer term fuel 

cell subsystem targets. 
10

3. Introduction 

Every new technology faces substantial barriers to commercialization; however, 

transportation markets present unique challenges including the size of the market, cost 

drivers, consumer expectations, product requirements (e.g., performance, safety, and 

reliability), well-entrenched technologies and emerging alternative technologies, fuel 

infrastructure issues, OEM profits, and societal (government) requirements. The latter 

includes emissions of pollutants and greenhouse gases, efficiency goals, and energy 

policy. Within this array of challenges, developers and automotive companies are 

attempting to develop cost-effective electric fuel cell powertrains for passenger vehicles. 

The current DOE goal for a fuel cell powertrain cost is $30/kWe (2015). Starting in the 

mid-1970s, the battery electric vehicle (BEV) story vividly illustrates the significant 

hurdles that radical new powertrains face in passenger vehicles. Even though the most 

recent industry/government BEV initiative, the U.S. Automotive Battery Consortium 

(USABC), failed to produce a viable mass-market EV battery, it led to significant 

advances in powertrain components, including electric motors and power electronics, that 

have benefited the fuel cell and hybrid electric vehicle efforts. 

Fuel cells have the potential to provide a clean power source for powering automobiles of 

the future. While there are many technical challenges facing fuel cells (such as cold start, 

durability, etc.), there are also major challenges relating to the economic viability of the 

technologies in the marketplace. Fuel cells and the hydrogen fuel must be costcompetitive with current gasoline and internal combustion technologies for fuel cell 

powertrains to enter the market place. 

Starting in 1998, the Technology & Innovation group of Arthur D. Little, Inc. (now TIAX 

LLC) began a five-year program (1) to model and project fuel cell system costs for the 

DOE, Office of Advanced Automotive Technologies (now Hydrogen FCIT). The project 

started with the characterization of the status of fuel cell system technology, development 

of a system layout and thermodynamic model, and development of an activities-based 

cost model for production of this system at high production volumes. The initial cost 

results for an on-board, fuel-flexible, reformer-based fuel cell system were presented at 

the first Future Car Congress (2) and are summarized in Section 4, “Summary of Cost 

Projection Results,” along with the results of more recent analyses. The model and 

supporting databases have evolved. The efforts of this project were extended in 2005 

through a project with NREL. 
11

4. Summary of Cost Project Results (1998-2004) 

Earlier cost projections from this project are presented to provide a historical perspective 

on how the projected cost of fuel cell systems has changed as the technology and system 

specifications have evolved. We also provide the results of several analyses to address 

questions such as the trade-offs among efficiency, cost, and weight when operating at 

high and lower voltage and how stack cost might change as platinum loading is 

decreased. The earlier analyses provide insights into key cost drivers. The following 

results are summarized: 

• Cost projection for fuel flexible reformer based system (2001) 

• Impact of lowering platinum loading on fuel cell cost 

• Impact of cell voltage on weight, system efficiency, and cost 

• Cost projection for compressed hydrogen storage 

• Cost projection for direct hydrogen based system (2004) 

We will also provide a summary of critical assumptions and how these may have changed 

over time. 

4.1. Reformer Based System (2001) 

The reformer system configuration shown in Figure 6 was developed in concert with 

ANL using a thermally integrated auto-thermal reformer with shift beds. 

Figure 6. System Configuration Used in 2001 Reformer – Fuel Cell System Cost Projection 

When the program started, the system included both the hydrogen supply and the stack 

subsystems. The system in Figure 6 translates into the component list shown in Table 4 

with the allocation of components between subsystems dictated by the PNGV program 

definitions. 

air air

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radiat

air

radiat

fan

fc

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mx

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rad

proc

proc

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proc

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rad

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gt

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sp

t 308.00

p 1.0000

m 0.0677

t 478.06

p 3.2000

m 0.0677

t 478.06

p 3.2000

m 0.0514

t 478.06

p 3.2000

m 0.0163

t 900.00

p 3.2000

m 0.0163

t 457.80

p 11.000

m 0.0099

t 457.80

p 11.000

m 0.0099

t 457.80

p 11.000

m 0.0010

t 457.80

p 11.000

m 0.0008

t 457.80

p 11.000

m 0.0089

t 900.00

p 11.000

m 0.0089

t 308.00

p 1.0000

m 0.0032

t 308.10

p 3.2000

m 0.0032

t 420.00

p 3.2000

m 0.0032

t 1300.0

p 3.1000

m 0.0284

t 1157.7

p 3.1000

m 0.0284

t 989.00

p 3.1000

m 0.0284

t 314.98

p 1.0000

m 0.1000

t 315.09

p 11.000

m 0.1000

t 315.09

p 11.000

m 0.0045

t 700.00

p 3.1000

m 0.0329

t 764.32

p 3.1000

m 0.0329

t 764.32

p 3.1000

m 0.0329

t 480.00

p 3.1000

m 0.0329

t 315.09

p 11.000

m 0.0955

t 315.09

p 11.000

m 0.00e+000

t 480.00

p 3.1000

m 0.0329

t 497.57

p 3.1000

m 0.0329

t 420.00

p 3.1000

m 0.0329

t 478.06

p 3.2000

m 0.0002

t 431.46

p 3.1000

m 0.0330

t 478.06

p 3.2000

m 0.0512

t 315.09

p 11.000

m 0.0955

t 315.09

p 11.000

m 0.0099

t 400.00

p 11.000

m 0.0099

t 457.80

p 11.000

m 0.0099

t 373.92

p 3.1000

m 0.0330

t 353.00

p 3.1000

m 0.0330

t 353.00

p 3.1000

m 0.0265

t 315.09

p 11.000

m 0.0856

t 315.09

p 11.000

m 0.0027

t 353.00

p 3.2000

m 0.0539

t 353.00

p 3.0000

m 0.0558

t 308.00

p 1.0000

m 0.3808

t 308.58

p 1.0050

m 0.3808

t 333.00

p 1.0050

m 0.3808

t 328.80

p 3.0000

m 0.0558 t 328.80

p 3.0000

m 0.0460

t 330.00

p 1.0000

m 0.8409

t 330.03

p 3.2000

m 0.8409

t 334.51

p 3.2000

m 0.8409

t 348.00

p 3.2000

m 0.8409

t 308.00

p 1.0000

m 2.5239

t 308.58

p 1.0050

m 2.5239

t 330.00

p 3.2000

m 0.8409

t 333.00

p 1.0050

m 2.5239

t 328.80

p 3.0000

m 0.0098

t 353.00

p 3.1000

m 0.0065

t 338.48

p 3.0000

m 0.0163

t 315.09

p 11.000

m 0.0829

t 319.11

p 3.0000

m 0.0992

t 320.24

p 3.0000

m 0.1000 t 308.00

p 1.0000

m 0.4838

t 308.58

p 1.0050

m 0.4838

t 314.98

p 3.0000

m 0.1000

t 313.00

p 1.0050

m 0.4838

t 353.00

p 3.0000

m 0.0246

t 540.29

p 3.0000

m 0.0707

t 524.36

p 3.0000

m 0.0707

t 418.76

p 1.0000

m 0.0707

t 457.80

p 11.000

m 0.0002

50 kW Gasoline Reformate PEM System for Transportation 50 kW Gasoline Reformate PEM System for Transportation 

air air

cp

pox

sp

htr

air pox boiler

sd

sd

sp

proc2

mx

heat

super pox

fuel

fuel

pump

vap

fuel

pox htr

air

heat

super

hts

mx

proc

water

proc

pump

hts

sp

hts

mx

hts

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sulfur

boiler

lts

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hts

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lts

sp

lts

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lts

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sp

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ref

sph2o

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sp

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sp

humc

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pefc

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cond

fan

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sp

burner

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radiat

radiat

air

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t 308.00

p 1.0000

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t 478.06

p 3.2000

m 0.0677

t 478.06

p 3.2000

m 0.0514

t 478.06

p 3.2000

m 0.0163

t 900.00

p 3.2000

m 0.0163

t 457.80

p 11.000

m 0.0099

t 457.80

p 11.000

m 0.0099

t 457.80

p 11.000

m 0.0010

t 457.80

p 11.000

m 0.0008

t 457.80

p 11.000

m 0.0089

t 900.00

p 11.000

m 0.0089

t 308.00

p 1.0000

m 0.0032

t 308.10

p 3.2000

m 0.0032

t 420.00

p 3.2000

m 0.0032

t 1300.0

p 3.1000

m 0.0284

t 1157.7

p 3.1000

m 0.0284

t 989.00

p 3.1000

m 0.0284

t 314.98

p 1.0000

m 0.1000

t 315.09

p 11.000

m 0.1000

t 315.09

p 11.000

m 0.0045

t 700.00

p 3.1000

m 0.0329

t 764.32

p 3.1000

m 0.0329

t 764.32

p 3.1000

m 0.0329

t 480.00

p 3.1000

m 0.0329

t 315.09

p 11.000

m 0.0955

t 315.09

p 11.000

m 0.00e+000

t 480.00

p 3.1000

m 0.0329

t 497.57

p 3.1000

m 0.0329

t 420.00

p 3.1000

m 0.0329

t 478.06

p 3.2000

m 0.0002

t 431.46

p 3.1000

m 0.0330

t 478.06

p 3.2000

m 0.0512

t 315.09

p 11.000

m 0.0955

t 315.09

p 11.000

m 0.0099

t 400.00

p 11.000

m 0.0099

t 457.80

p 11.000

m 0.0099

t 373.92

p 3.1000

m 0.0330

t 353.00

p 3.1000

m 0.0330

t 353.00

p 3.1000

m 0.0265

t 315.09

p 11.000

m 0.0856

t 315.09

p 11.000

m 0.0027

t 353.00

p 3.2000

m 0.0539

t 353.00

p 3.0000

m 0.0558

t 308.00

p 1.0000

m 0.3808

t 308.58

p 1.0050

m 0.3808

t 333.00

p 1.0050

m 0.3808

t 328.80

p 3.0000

m 0.0558 t 328.80

p 3.0000

m 0.0460

t 330.00

p 1.0000

m 0.8409

t 330.03

p 3.2000

m 0.8409

t 334.51

p 3.2000

m 0.8409

t 348.00

p 3.2000

m 0.8409

t 308.00

p 1.0000

m 2.5239

t 308.58

p 1.0050

m 2.5239

t 330.00

p 3.2000

m 0.8409

t 333.00

p 1.0050

m 2.5239

t 328.80

p 3.0000

m 0.0098

t 353.00

p 3.1000

m 0.0065

t 338.48

p 3.0000

m 0.0163

t 315.09

p 11.000

m 0.0829

t 319.11

p 3.0000

m 0.0992

t 320.24

p 3.0000

m 0.1000 t 308.00

p 1.0000

m 0.4838

t 308.58

p 1.0050

m 0.4838

t 314.98

p 3.0000

m 0.1000

t 313.00

p 1.0050

m 0.4838

t 353.00

p 3.0000

m 0.0246

t 540.29

p 3.0000

m 0.0707

t 524.36

p 3.0000

m 0.0707

t 418.76

p 1.0000

m 0.0707

t 457.80

p 11.000

m 0.0002

50 kW Gasoline Reformate PEM System for Transportation 50 kW Gasoline Reformate PEM System for Transportation 
12

Table 4. Component List and Allocation to Subsystems 

Fuel Processor Sub-System Fuel Cell Sub Fuel Cell Sub-System Balance-of-Plant

 Reformate 

Generator

 ATR

 HTS

 Sulfur Removal

 LTS

 Steam Generator

 Air Preheater

 Steam Superheater

 Reformate Humidifier

 Reformate 

Conditioner

 NH3 Removal 

 PROX

 Anode Gas Cooler

 Economizers (2)

 Anode Inlet Knockout 

Drum

 Fuel Cell Stack (Unit 

Cells)

 Stack Hardware

 Fuel Cell Heat 

Exchanger

 Compressor/Expander

 Anode Tailgas Burner

 Sensors & Control 

Valves

 Startup Battery

 System Controller

 System Packaging

 Electrical

 Safety

 Fuel Supply

 Fuel Pump

 Fuel Vaporizer

 Sensors & Control Valves for each section

 Water Supply

 Water Separators (2)

 Heat Exchanger

 Steam Drum

 Process Water 

Reservoir

Fuel Processor Sub-System Fuel Cell Sub Fuel Cell Sub-System Balance-of-Plant

 Reformate 

Generator

 ATR

 HTS

 Sulfur Removal

 LTS

 Steam Generator

 Air Preheater

 Steam Superheater

 Reformate Humidifier

 Reformate 

Conditioner

 NH3 Removal 

 PROX

 Anode Gas Cooler

 Economizers (2)

 Anode Inlet Knockout 

Drum

 Fuel Cell Stack (Unit 

Cells)

 Stack Hardware

 Fuel Cell Heat 

Exchanger

 Compressor/Expander

 Anode Tailgas Burner

 Sensors & Control 

Valves

 Startup Battery

 System Controller

 System Packaging

 Electrical

 Safety

 Fuel Supply

 Fuel Pump

 Fuel Vaporizer

 Sensors & Control Valves for each section

 Water Supply

 Water Separators (2)

 Heat Exchanger

 Steam Drum

 Process Water 

Reservoir

The cost of the reformer was based on a design similar to one in the patent literature from 

Arthur D. Little as shown in Figure 7. 

Source: Arthur D. Little patent (US 6,126,908) 

Figure 7. Thermally integrated reformer design used to cost the fuel processor including 

ATR, high and low temperature shift beds, burner and steam generation tubes 
13

In 2001, the assumptions shown in Table 5 were used to scale the reformer beds and the 

stack. The selection of 0.8 volts for the fuel cell voltage at rated power was driven by 

overall system-efficiency targets rather than trying to minimize system size by operation 

of the stack at or near its high power point. 

Table 5. 2001 Assumptions for the Reformer and Fuel Cell Stack 

Reformer 

Catalyst Beds Clean-up Beds 

Parameter ATR HTS LTS PROX Sulfur 

Removal 

NH3

Removal 

Temperature (°C) 1030 430 230 205 490 80 

Catalyst Pt/Ni Fe3O4/ 

CrO3

Cu/ZnO Pt ZnO Activated 

Carbon 

Support Alumina Alumina Alumina Alumina None None 

GSHV (1/hours) 15,000 10,000 5,000 10,000 N/A None 
14

Fuel Cell Stack 

Fuel Cell Operating Assumption Units 2000/2001 Baseline 

Unit Cell Voltage Volts 0.81

Power Density mW/cm2

 2502

Fuel Utilization % 85 

Cathode Stoichiometry 1.0 

Operating Temperature °C 80 

Percent Anode Air Bleed % 1 

1

 This cell voltage was specified to satisfy overall system efficiency goals. 2

 A current density of 310 mA/cm2 at 0.8 volts (250 mW/cm2) was selected on the basis of 

near term projections of available stack and unit cell data. 

Figure 8 shows how the $324/kW cost of the 2001 system was allocated among the 

subsystems. The contributions to the fuel cell subsystem are broken down further in 

Figure 9 and Figure 10. At this time, the fuel cell stack cost was $180/kW with major 

contributions from the electrodes (high platinum loading of 0.8 mg/cm2

 total plus 0.2 

mg/cm2 ruthenium and low power density of 250 mW/cm2) and the membrane ($100/m2). 

Older electrode technology and reformate, rather than hydrogen fuel, resulted in the low 

power density. Bipolar plates and the gas diffusion layers represented approximately 20% 

of the stack cost. The fuel cell subsystem also included a tailgas burner to burn unused 

fuel and a high-temperature expander to recover this energy. The expander was integral 

to the turbo compressor-expander module. 

Yr 2001 Cost Breakdown by Sub Yr 2001 Cost Breakdown by Sub-System 

Fuel Cell

67%

Fuel Processor

24%

Balance of Plant

3%

Assembly & Indirect

6%

Yr 2001 Cost Breakdown by Sub Yr 2001 Cost Breakdown by Sub-System 

Fuel Cell

67%

Fuel Processor

24%

Balance of Plant

3%

Assembly & Indirect

6%

Figure 8. 2001 Reformer Based System Cost Breakdown (system cost of $324/kW) 
15

Factory Cost Factory Cost

Fuel Cell Fuel Cell 

Stack

Tailgas Tailgas 

Burner

Air Supply

Cooling Cooling 

System

Total

($)

9,035

358

992

587

11,000

($/kW)

181

7

20

12

220

Fuel Cell Sub Fuel Cell SubSystem

Yr 2001 Estimate* Yr 2001 Estimate*

Yr 2001 Fuel Cell Cost Breakdown Yr 2001 Fuel Cell Cost Breakdown

Fuel Cell Module

83%

Integrated Tailgas Burner

3%

Compressed Air Supply

9%

Stack Cooling System

5%

Fuel Cell Stack

Factory Cost Factory Cost

Fuel Cell Fuel Cell 

Stack

Tailgas Tailgas 

Burner

Air Supply

Cooling Cooling 

System

Total

($)

9,035

358

992

587

11,000

($/kW)

181

7

20

12

220

Fuel Cell Sub Fuel Cell SubSystem

Yr 2001 Estimate* Yr 2001 Estimate*

Yr 2001 Fuel Cell Cost Breakdown Yr 2001 Fuel Cell Cost Breakdown

Fuel Cell Module

83%

Integrated Tailgas Burner

3%

Compressed Air Supply

9%

Stack Cooling System

5%

Fuel Cell Stack

Figure 9. 2001 Fuel Cell System Cost Breakdown 

Yr 2001 Fuel Cell Stack Cost Breakdown Yr 2001 Fuel Cell Stack Cost Breakdown Yr 2001 MEA Cost Breakdown Yr 2001 MEA Cost Breakdown

MEA

84%

Gaskets

2%

Bipolar Interconnect

6%

Bipolar Coolant

6%

End Plates

1% Packaging

1%

Gas Diffusion Layer

9%

Membrane

37%

Cathode 

26%

Anode 

28%

Yr 2001 Fuel Cell Stack Cost Breakdown Yr 2001 Fuel Cell Stack Cost Breakdown Yr 2001 MEA Cost Breakdown Yr 2001 MEA Cost Breakdown

MEA

84%

Gaskets

2%

Bipolar Interconnect

6%

Bipolar Coolant

6%

End Plates

1% Packaging

1%

Gas Diffusion Layer

9%

Membrane

37%

Cathode 

26%

Anode 

28%

Figure 10. Stack and MEA Cost Breakdown for the 2001 System Configuration 

In 2001, the top four cost drivers for the stack were: 

• Power density 

• Nafion cost 

• Platinum loading 

• Platinum price 

Low power density and high platinum loadings combined to produce a high overall 

platinum content, 3.62 g Pt/kW in the stack and a total of 4 g PGM/kW for the system 

(reformer catalysts and ruthenium in the anode for CO tolerance). 
16

During this period, the impact of operation at a high power point, i.e., 0.65 volts, on cost, 

efficiency, and weight was evaluated. Consideration of the high power point operation 

yielded mixed results. Operation at 0.65 volts doubled the assumed power of the stack 

(500 mW/cm2

) and lowered the system cost by approximately 20%. However, system 

weight increased slightly because of larger heat exchange requirements and a larger 

reformer. At rated power, the overall system efficiency decreased from 37% to 29% 

(LHV). The efficiency for this powertrain would be higher if calculated on the basis of a 

typical driving cycle in which a vehicle operates much of the time at fractions of the rated 

power, i.e., 25% to 30%. 

2004 

In 2004, a bottom-up cost analysis of compressed hydrogen was conducted and then 

combined with an updated stack cost based on pure hydrogen. We again worked with 

ANL to develop a system configuration and specifications for sizing the hydrogen storage 

capacity. In this analysis the system configuration shown in Figure 11 was used as a basis 

for calculating the efficiency of various hybridization options for a mid-size sedan (e.g., 

Ford Taurus) with a 370 mile range on a combined urban/highway drive cycle. 

Source: Dr. Rajesh Ahluwalia of ANL

Demister

Electric 

Motor Hydrogen

Humidifier 

Heater

PEFC

Stack

Compressor/Motor/Expander

Air

Exhaust

HT Radiator

Water Tank

Process Water

Humidified Air

Humidified 

Hydrogen

Coolant

Condensate

Pump

LT Radiator

Condenser

Source: Dr. Rajesh Ahluwalia of ANL

Demister

Electric 

Motor Hydrogen

Humidifier 

Heater

PEFC

Stack

Compressor/Motor/Expander

Air

Exhaust

HT Radiator

Water Tank

Process Water

Humidified Air

Humidified 

Hydrogen

Coolant

Condensate

Pump

LT Radiator

Condenser

Demister

Electric 

Motor Hydrogen

Humidifier 

Heater

PEFC

Stack

Compressor/Motor/Expander

Air

Exhaust

HT Radiator

Water Tank

Process Water

Humidified Air

Humidified 

Hydrogen

Coolant

Condensate

Pump

LT Radiator

Condenser

Source: Dr. Rajesh Ahluwalia of ANL 

Figure 11. Direct Hydrogen System for 2004 Cost Update 

A peak power of approximately 120 kW was selected for the different hybridization 

scenarios. Analysis of the system by ANL (3, 4) led to an 80kW fuel cell with 40 kW 

battery (peak). As shown in Table 6, this 80/40 system had a fuel economy of 68 mpgge 

and a hydrogen requirement of 5.6 kg for a range of 370 miles in a combined 

urban/highway drive cycle. 
17

Table 6. Comparison of Hybridization Scenarios with a 120 kW ICE Base Case 

ANL Results ICEV 120 

kW 

FC EV 

120 kW 

FC HEV 

100 kW 

FC HEV 

80 kW 

FC HEV 

60 kW 

Engine/Fuel Cell Power, 

kW peak 114 120 100 80 60 

Battery Power, kW peak 0 0 20 40 55 

Fuel Economy, mpgge 23 59 65 68 69 

Hydrogen Required N/A 6.3 5.9 5.6 5.6 

A Type IV carbon fiber wound tank with a polymer liner was used as the basis of the 

hydrogen storage tank cost analysis. The tank had metal bosses at each end, an outer 

layer of damage-resistant glass fiber, and impact-resistant foam end domes. BOP 

components in the hydrogen supply subsystem included an internal regulator, pressure 

relief components, valves, sensors, fill port, and piping. Figure 12 shows the cost results 

for different scenarios, including 5,000 and 10,000 psi storage pressures, single versus 

multiple tanks, and two fiber types (strength and cost). M30S is higher tensile strength, 

higher tensile modulus and higher cost, aerospace grade carbon fiber compared to T700S. 

5,000 PSI

Baseline

10,000 PSI

Baseline

5,000 PSI

3 Tanks

10,000 PSI

2 Tanks

5,000 PSI

10,000 PSI

0

5

10

15

20

25

123456

Scenarios

CH2 Storage System Cost ($/kWh)

Misc

Inspections

Assembly

Pipe&Fitting

Sensors

Valves

Fill Port

Regulator

Foam

Glass Fiber

Carbon Fiber

Liner

T700S M30S

5,000 PSI

Baseline

10,000 PSI

Baseline

5,000 PSI

3 Tanks

10,000 PSI

2 Tanks

5,000 PSI

10,000 PSI

0

5

10

15

20

25

123456

Scenarios

CH2 Storage System Cost ($/kWh)

Misc

Inspections

Assembly

Pipe&Fitting

Sensors

Valves

Fill Port

Regulator

Foam

Glass Fiber

Carbon Fiber

Liner

T700S M30S

Figure 12. Cost of Compressed Hydrogen Storage Scenarios 

The leading cost drivers for the storage subsystem were the cost and weight of the carbon 

fiber followed by the fill port and regulator costs. Multiple tank scenarios were 

considered to lower the profile of the system for vehicle integration, while higher strength 

fibers were looked at to reduce system weight. The storage system was found to satisfy 

the DOE mid-term specific energy target, but failed to meet volume and cost targets. The 

results of this analysis were then used to estimate an overall system cost. 
18

Table 7 compares the fuel cell system design assumptions for the 2001 reformate system 

and the 2004 direct hydrogen case. Overall, changing to direct hydrogen increased the 

power density of the stack and fuel utilization leading to reductions in stack size and cost 

and increases in efficiency. Calculation of the system efficiency on a drive-cycle basis 

allowed the stack to be designed at a lower cell voltage (higher area power density) while 

satisfying efficiency targets. Presentations by DuPont (5) discussed pathways to lower 

membrane costs, i.e., on the order of $40/m2

. For these assumptions, Table 8 contains a 

comparison of the 2001 and 2004 system cost estimate metrics. The latter is reported on a 

50 kW basis for consistency with the reformate values. In the 2004 hydrogen system the 

fuel loop has a simple design and does not contain a provision for purging nitrogen, 

circulation to minimize transport limitations at high power, or a tailgas burner. The 

increases in power density, reduction in platinum loading, and decrease in membrane cost 

were the primary drivers in lowering the cost of the stack and the system. Changing to 

compressed hydrogen lowers the cost of the fuel source, but only incrementally reduces 

the overall system cost. 

Table 7. 2004 Stack Parameters Compared to 2001 Values 

Parameter Units 2001 2004 Comments 

System Power kW 50 80 Change to mid-size sedan with hybridization 

Cell Voltage V 0.8 0.69 Efficiency calculated on a drive-cycle basis 

Power Density mW/cm2

 250 450 Increase due to lower voltage and direct 

hydrogen 

Total Pt Loading mg/cm2

 0.8 0.3 Technology improvements and direct 

hydrogen 

Fuel Utilization % 85 100 Reformate to direct hydrogen 

Electrolyte Cost $/m2

 100 40 Industry feedback 
19

Table 8. Comparison of Cost of Reformate and Direct Hydrogen Systems 

Component 2001 Reformate System 

($50/kW basis) 

2004 Direct Hydrogen 

($50/kW basis) 

Fuel Cell SS 221 104 

Stack 181 73

TGB 7 0

Air Supply 20 20

Cooling 12 11

Fuel Supply 76 58 

BOP 10 5 

Assembly and Indirect 17 8 

Total 324 176 

For purposes of comparison with the 2005 assessment, Table 9 presents the 2004 results 

on an 80 kW basis. Increasing the power rating of the system decreases the $/kW value to 

$145/kW because a number of the components (i.e., controllers, sensors) do not change 

in scale with power and because we did not vary the size of the hydrogen storage system. 

As a result, the fuel cell system changed by approximately 5% while the fuel supply 

decreased by approximately 30%. 

Table 9. Comparison of 50 kW and 80 kW Costs for the 2004 Systems 

Component 50 kW Basis 80 kW Basis 

Fuel Cell SS 104 97 

Stack 73 72 

TGB 0 0

Air Supply 20 13 

Cooling 11 12 

Fuel Supply 58 38 

BOP 5 4 

Assembly and Indirect 8 6 

Total 176 145 

Platinum Loading Analysis 

Electrode cost is a major cost driver of the stack and the system. As part of our 2002 

effort, the factors influencing platinum loadings were assessed to develop an estimate of 

future fuel cell stack cost for reformate and hydrogen systems. Platinum loading per 

kilowatt is a critical issue as indicated by the cost contribution of the electrodes to the 

stack (Figure 10) and by the DOE funding resources allocated to platinum reduction and 

performance improvements. 

Projections of minimum platinum requirements were estimated based on an analysis that 

considered: 
20

• Impact of catalyst particle size and catalyst activity on kinetics 

• Impact of electrolyte anion adsorption on catalyst kinetics 

• Development of polarization curves based on electrochemical kinetics 

• Impact of ohmic resistance losses on polarization curve 

An overview of this work was presented at the Future Car Congress in 2002 (2). This 

analysis was based on the assumption that the fuel cell would be operating at relatively 

high unit cell voltages (e.g., 0.8 volts) to achieve overall system efficiency targets. 

However, analyses that consider overall vehicle efficiency and reward higher fuel cell 

system power density will allow some relaxation of this stack efficiency target. At high 

cell voltages, cathode kinetics control the current flow and Tafel kinetics can be used to 

assess the effect of operating conditions and cathode voltage losses. Voltage drops were 

then assigned to the anode and resistive components on the basis of experimental data. 

Analysis of a series of scenarios involving catalyst loadings, pressure, and temperature 

led to the conclusion that the stack would have to operate at high temperature (e.g., 

160o

C) and elevated pressure (e.g., 3 atm) to satisfy long–term DOE fuel cell power 

density (milliwatt/cm2

) goals. 

The polarization curves and functional relationships between platinum loading and 

performance were then combined with the stack cost model to assess the relationship 

between platinum loading and materials cost. Several overall assumptions are important 

to understanding the basis of the analysis. 

• First, we assumed the performance of the catalyst is not limited by diffusion, the 

structure of the electrode, or the dispersion of the catalyst. In the early days of 

PEM fuel cell development, significant performance gains were made while 

appreciably decreasing the catalyst loadings. In our analysis, reduction in 

platinum loading leads to lower power density. 

• Second, introduction of resistance losses to the analysis reduces the power 

density that can be achieved by increasing catalyst loading or by decreasing the 

cell voltage. Voltage losses across resistances (I2

R) in the system reduce the 

voltage available to perform useful work at the electrodes. 

• Third, in the baseline cost estimate, the fuel cell stack materials represent over 

90% of the stack cost. Consequently, in this following analysis, only material 

costs were considered (i.e., MEA, gas diffusion layer, and bipolar plate). 

Figure 13 shows the material cost ($/kWe) versus cathode platinum loading for stacks 

operating at 3 atm, 160o

C, and 0.8 volts with direct hydrogen and reformate. 

Assumptions in this analysis include the use of an alloy catalyst with kinetic activity two 

times that of platinum, a unit cell resistance of 0.1 ohm/cm2, and an anode catalyst 

loading of one half the cathode loading. 
21

20

40

60

0 0.1 0.2 0.3 0.4 0.5 0.6

Cathode Platinum Loading / mg cm-2

Fuel Cell Materials Cost / $ kW-1

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Power Density / W cm-2

Hydrogen

Cell voltage = 0.8 V

20

40

60

80

100

0 0.1 0.2 0.3 0.4 0.5 0.6

Cathode Platinum Loading / mg cm-2

Fuel Cell Materials Cost / $ kW-1

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Power Density / W cm-2

Reformate

Cell voltage = 0.8 V

Figure 13. Stack Cost Versus Platinum Loading for Reformate and Direct Hydrogen Stacks 

The analysis produced an “L” shaped curve where material costs rise sharply at low 

platinum loadings (low power density) and then show weak dependence with increasing 

platinum loading. Figure 14 shows the flat portion of the curve for various values of 

resistance. Independent of the resistance value, all the curves have a minimum cost in the 

platinum loading region of 0.1 to 0.3 mg/cm2

. Insights into the factors influencing 

minimum platinum loading in addition to the value (mg/cm2

) and the resulting “L” 

shaped curve include: 

• Reduction of platinum loadings beyond some minimum value negatively impacts 

cost. First, on an area basis, the non-platinum material cost increases relative to 

the catalyst cost. Second, more materials are used due to a larger stack resulting 

from lower power density. 

• Cost goes through a minimum with increasing platinum loading due to the 

negative impact of resistance on power density. The kinetic benefit of the 

increased platinum loading is not realized due to the voltage losses arising from 

ohmic losses. 

• This analysis shows the critical cost implications of high ohmic losses within the 

stack. 

Assumption of different material costs will shift the curves but not change their nature or 

general shape. 
22

10

30

50

70

90

110

0 0.2 0.4 0.6

Cathode Platinum Loading / mg cm-2

Stack Materials Cost / $ kW-1

0.2

0.15

0.1

0.05

Rtotal / Ω cm2

Cell voltage = 0.8 V

3 atm, 160oC, 3.5 nm dia.

Figure 14. Stack Cost versus Ohmic Resistance 

4.2. Summary of Key Cost Drivers (2001 – 2004) 

The stack contributes the largest percentage of cost to the fuel cell subsystem. In 

discussing the stack parameters that influence cost, one must consider performance 

metrics, material/component costs, material loadings, and the interaction between these 

factors. The following points highlight the key drivers and illustrate the interactions. 

• The cost and size of the stack scale inversely with power density. The power 

density of the stack will depend on the polarization (iV) curve of the MEA in the 

stack, the cell voltage selected for operation at rated power, and the ohmic losses 

within the stack. MEA developers provide single cell iV curves for their products, 

however, the need to avoid hotspots in the stack and the presence of ohmic losses 

between the bipolar plates and the MEA result in lower performance in the stack. 

• System designers must then make trade-offs between power density and 

efficiency when selecting a design cell voltage. For example, at this stage of 

development, the car companies may prefer to have smaller stacks rather than the 

highest efficiency for the sake of integrating the stack into the vehicle. 

• A key driver of power density will be platinum loading; however, the costs of 

other stack materials (i.e., membrane, bipolar plates, and GDLs) set lower limits 

on platinum loading while ohmic losses limit the benefits of increasing Pt loading. 

The potential improvements in power at high loadings are offset by the voltage 

losses from contact and electrolyte resistances at high currents. 

• At high production volumes, material costs represent 70% to 80% of the system 

cost. Consequently, reduction of the amount of material (kg/kW) and cost of 

materials ($/kg) is critical to lowering cost. The importance of the cost of BOP 

components will increase as the stack cost is reduced. Some of the BOP 

components are relatively mature technologies and the potential for cost reduction 

is less than the stack materials. 
23

5. Project Objective, Scope, and Approach 

5.1. Objective 

The cost projection developed from this effort will allow assessment of the current status 

of PEMFC technology relative to the 2005 DOE cost target of $125/kW for the fuel cell 

stack and supporting BOP components for air, water, thermal, and fuel management. This 

target does not include the cost of hydrogen storage. 

5.2. Scope 

In this project, the scope encompassed the status of PEMFC technology in 2005 with the 

cost estimated for high production volumes, i.e., 500,000 units per year. Figure 15 shows 

the scope of the system considered. The analysis is focused on the fuel cell stack 

subsystem; however we also considered BOP components. We performed bottom-up 

costing for the major components of the fuel cell stack: 

• Membrane 

• Gas Diffusion Layer (GDL) 

• Electrodes 

• Membrane Electrode Assembly (MEA) 

• Bipolar Plates 

• Seals 

We estimated costs for other components based on in-house expertise and discussions 

with vendors: 

• Compressor-Expander 

• Air Filtration 

• Membrane Humidifier for Anode Hydrogen 

• Enthalpy Wheel Humidifier for Cathode Air 

• H2 Recirculation Blower-Ejector 

• Heat Exchangers 

• Coolant Pumps 

• Controls & Sensors 
24

Packaging (Piping, Electrical, .....)

Start-up Power (Battery); Anode Tailgas 

Burner

Included in DOE PEMFC System Analyzed

Hydrogen

Storage

Power 

Conditioning

Electric Motor

Electric Drive 

Train

Regenerative 

Braking 

System 

(Battery)

Managers (Controllers and Sensors)

Air Thermal Water Sensors

Other:

AC/Heating

Driver 

Interface

Fuel Cell

Not included within this assessment

Figure 15. Scope of 2005 PEMFC Costing 

5.3. Approach 

This project builds on previous experience with cost analysis PEM fuel cell systems 

developed over the past six years and ongoing work in cost assessment of hydrogen 

storage technologies. 

In this project, we followed a 3-step process to develop the 2005 cost projection and 

produce the final report, as shown in Figure 16. 

Task 1

Baseline Analysis Baseline Analysis

Task 2

Developer Developer

Feedback Feedback

Task 3

Final

Report

• KOM with Fuel Cell Tech 

Team

• Update 2004 system 

specifications, manufacturing 

processes and material costs

• Develop baseline cost 

estimate

• Prepare an 

interview/discussion guide for 

use with developers 

• Interview key developers for 

feedback on performance and 

cost assumptions

• Perform sensitivity analysis to 

key parameters

• Assess impact of feedback on 

design parameters and 

potential technology 

breakthroughs on overall 

system costs

• Prepare final written report

• Prepare final presentation to 

DOE

Deliverables Deliverables

• KOM presentation and 

summary of Tech Team 

comments

• Interview guide for use in 

developer discussions

• Revised cost projection based • Final Report and Presentation

on inputs from the developers

• Meeting with Tech Team to 

discuss 2005 cost projection

Task 1

Baseline Analysis Baseline Analysis

Task 2

Developer Developer

Feedback Feedback

Task 3

Final

Report

• KOM with Fuel Cell Tech 

Team

• Update 2004 system 

specifications, manufacturing 

processes and material costs

• Develop baseline cost 

estimate

• Prepare an 

interview/discussion guide for 

use with developers 

• Interview key developers for 

feedback on performance and 

cost assumptions

• Perform sensitivity analysis to 

key parameters

• Assess impact of feedback on 

design parameters and 

potential technology 

breakthroughs on overall 

system costs

• Prepare final written report

• Prepare final presentation to 

DOE

Deliverables Deliverables

• KOM presentation and 

summary of Tech Team 

comments

• Interview guide for use in 

developer discussions

• Revised cost projection based • Final Report and Presentation

on inputs from the developers

• Meeting with Tech Team to 

discuss 2005 cost projection

Figure 16. 2005 Cost Project Approach 
25

6. Manufacturing Cost Model Description 

6.1. Technology-Based Costing Methodology 

We have applied an internally developed technology-costing methodology that uses a 

highly interdisciplinary approach drawing on extensive experience in the cost modeling 

of electrochemical and power technologies including batteries, fuel cells, and balance of 

plant. The model integrates a fundamental understanding of fuel cell component/system 

performance parameters and their interactions, with expertise in materials (e.g., polymers, 

inorganic materials), design, and manufacturing operations (e.g., coating, molding, 

automation), and extensive knowledge of process cost modeling. We used our 

knowledge of technology developments and our relationships with stack and subsystem 

developers to calibrate the cost model and perform sensitivity analyses to system 

operating parameters, material costs, component designs, and selection of manufacturing 

processes. A five-step approach for conducting manufacturing cost analysis was used. 

Step 1. Product and manufacturing process definition: We started by identifying 

detailed product design parameters and manufacturing process options. The key elements 

for each component are material type and quantity, process cycle time, production 

equipment specifications, and direct labor requirements. 

Step 2. Production process scenario definition: The production process scenario is 

critical for identifying realistic and credible manufacturing costs based on current 

manufacturing process capabilities. The key elements of a scenario include annual 

production volumes, plant size and location, internal and outsourced operations, and 

wage rates. 

Step 3. Cost model development: A cost model was constructed that provides 

product/process costs based on the variable inputs defined in Steps 1 and 2. Cost outputs 

from the model were categorized by materials, labor, utilities, equipment, tooling, 

building, overhead labor, maintenance, and cost of capital. The structure of the model 

permits frequent and complex analyses of multiple inputs. 

Step 4. Development of cost models for relevant competitive design options and 

manufacturing processes: In order to make cost comparisons of competing 

technologies, design options, and alternative manufacturing processes, additional 

models/scenarios derived from the initial customized model were developed. The 

structure and consistent approach of our manufacturing cost model permits accurate and 

rapid comparisons. 

Step 5. Sensitivity, scenarios, and Monte Carlo simulation: These analyses provide an 

in-depth understanding of the key cost drivers in each technology and design option, the 

critical manufacturing processes for cost-reduction initiatives, and the economic risks 

associated with selected development and commercialization strategies. Figure 17 is a 

schematic representation of our manufacturing cost model. 
26

Material

Database

Quantity

Density

...

8-step

Calculation

Sheets

Scenario

Table

Product

Design

Process

Database

Purchased

Component

Database

Production

Database

Material

Property

Database

Material

Cost

Database

Nafion

Graphite Flake

...

Process #

Description

Capital Cost

Cycle Time

Batch Size

Labor Cost

...

Component #

Description

Cost per unit

Weight

...

Working days / Year

Capital recovery rate

Working Capital Period

Depreciation Period

...

Material

Selection

Formulation

Layer Data

Process

Plan

Cost

Output

& Analysis

Cell Size

Net Voltage

Net Amperes

Power Density

...

Anode Mtl

Cathode Mtl

Electrolyte Mtl

Bipolar Plate Mtl

...

Layer Formulation

Layer Costs

Quantity per Cell

...

Process Flow

...

Cost per Process

Cost vs. Volume

Cost vs. Scenario

...

Material Cost

Direct Labor Cost

Maintenance Cost

Operation Capital

...

Performance

Model

Formulation

Database

Anode Layer

Cathode Layer

Electrolyte Layer

Bipolar Plate

GDL Layer

Capital

Equipment

Database

Name

Description

Capital Cost

Capacity

Tool cost

...

Figure 17. Manufacturing Cost Model Schematic 

6.2. PEM Fuel Cell Manufacturing Cost Model 

6.2.1. Overview 

Our PEM fuel cell cost model is based on a bottom-up analysis of process flowcharts 

developed for critical components, materials, and subsystems. For this project, we 

worked closely with ANL to develop a stack and system configuration that would 

represent current fuel cell vehicle technology. 

ANL then developed a model to determine the state parameters (temperature, pressure, 

and mass and molar flows) of the various streams and components by thermodynamic 

modeling. The individual reactor beds and the fuel cell stack were then scaled using 

available kinetic or polarization data for the assumed catalyst materials and their 

loadings. 

We performed a bottom-up costing on the major stack components. Our manufacturing 

group developed production process options for key subsystems and components, and 

obtained raw material costs from potential suppliers. Purchased components were listed 

separately and suppliers were contacted regarding the availability and cost of outsourced 

components. An activity-based process model in Microsoft® Excel was then developed 

to estimate manufacturing costs using capital equipment and raw material costs, labor 
27

rates, and throughput for 500,000 units per year. The model yields cost per kilowatt, cost 

by subsystems and components, and a breakdown of material and process costs. 

With additional software, sensitivity and Monte Carlo analyses were performed on the 

base model. Our cost model assumptions and results were calibrated with feedback from 

the DOE, the FreedomCAR Fuel Cell Tech Team, and fuel cell suppliers and component 

developers. We integrated the feedback on stack and system performance parameters, 

manufacturing processes, and material and cost assumptions into the final cost estimate. 

6.2.2. Cost Definition 

As shown in Figure 18, the estimated cost includes factory costs (e.g., direct materials 

and labor, factory expenses, capital equipment) but excludes corporate charges for profit, 

sales expenses, and general services and administration. 

Direct

labor

Direct

Materials

Factory

Expense

General

Expense

Sales

Expense

Profit

Automobile Automobile

OEM

Price

Fixed Costs 

• Equipment and Plant Depreciation

• Tooling Amortization

• Equipment Maintenance

• Utilities

• Indirect Labor

• Cost of capital

Variable Costs 

• Manufactured Materials

• Purchased Materials

• Fabrication Labor

• Assembly Labor

• Indirect Materials

DOE Cost Estimate (Factory Cost)

Corporate Expenses (example) 

• Research and Development

• Sales and Marketing

• General & Administration

• Warranty

• Taxes

Excluded from DOE Cost Estimate

Figure 18. Cost Elements of Detailed Cost Build-up 

6.2.3. Baseline Cost Model Description 

Figure 19 illustrates the three essential steps we followed in developing the PEMFC 

system cost estimate. 
28

Figure 19. Approach to PEMFC System Cost Model 

6.2.3.1. Definition of System Operating Parameters 

Information on the system operating parameters, material selection and costs, 

manufacturing process selection and production capabilities were entered into the main 

input sheet. Data on materials and manufacturing processes were collected and evaluated 

in the first phase of the program. We calibrated our internal evaluation through phone 

interviews with leading suppliers of materials, components, and subsystems to the fuel 

cell system integrators. This exchange of information permitted us to refine our analysis 

and present a more accurate picture of the cost of state-of-the-art fuel cell designs and 

manufacturing processes. 

6.2.3.2. Development of Subsystem and Component Design 

Subsequently, incremental costs for each manufacturing process in the subsystem module 

sheets were estimated. For example, Figure 20 shows a flow chart of a manufacturing 

process for a graphite foil bipolar plate. 

Component Component

Definition of

Subsystem &

System Operating

Parameters

Definition of

Subsystem &

System Operating

Parameters

Develop Subsystem

& Component

Design

Develop Subsystem

& Component

Design

Cost Analysis Cost Analysis

Fuel Cell Stack Fuel Cell Stock

e.g.,

• Temperature

• Pressure

• Power

• Density

e.g.,

• Temperature

• Pressure

• Power Density

Bottoms Up

Model

•Materials

•Manufacturing

Processes

Bottom-Up

Model

•Materials

•Manufacturing

Processes

Total

System

Cost

Total

System

Cost

Balance of Plant Balance of Plant

Water, Air, & Thermal

Management

Water, Air, & Thermal

Management

Control & Sensors Control & Sensors

e.g.,

• Flow Rates

• Fuel Purity

e.g.,

• Flow Rates

• Fuel Purity

System Specification/Design Cost Modeling

Fuel Cell Stock Define Baseline

Designs

e.g.,

• Flow Rates

• Fuel Purity

Specifications for

Components

e.g.,

• Flow Rates

• Fuel Purity

Industry 

Projected for

Available

Data

Component Component

Definition of

Subsystem &

System Operating

Parameters

Definition of

Subsystem &

System Operating

Parameters

Develop Subsystem

& Component

Design

Develop Subsystem

& Component

Design

Cost Analysis Cost Analysis

Fuel Cell Stack Fuel Cell Stock

e.g.,

• Temperature

• Pressure

• Power

• Density

e.g.,

• Temperature

• Pressure

• Power Density

Bottoms Up

Model

•Materials

•Manufacturing

Processes

Bottom-Up

Model

•Materials

•Manufacturing

Processes

Total

System

Cost

Total

System

Cost

Balance of Plant Balance of Plant

Water, Air, & Thermal

Management

Water, Air, & Thermal

Management

Control & Sensors Control & Sensors

e.g.,

• Flow Rates

• Fuel Purity

e.g.,

• Flow Rates

• Fuel Purity

System Specification/Design Cost Modeling

Fuel Cell Stock Define Baseline

Designs

e.g.,

• Flow Rates

• Fuel Purity

Specifications for

Components

e.g.,

• Flow Rates

• Fuel Purity

Industry 

Projected for

Available

Data
29

Treat

Flake

Water 

Rinse or

Leach

Expansion

Treated

Roll 

Pressed

into Foil

Resin

Impregnation

Calendar

Line

Emboss

Compression

Mold

Die

Cut

Curing

Oven

Oxidizing

Medium

H2SO4

HNO3

1250C

Soggy

Graphite

Particles

2500 F Flame

Mix with

Ceramic Fiber

Or Carbon

Fiber

2 wt%

Thickness

2mm

10% Phenolics

Resin

Foil Density

1.5g/cc

17%~19% 

Resin

Control 

Foil 

Thickness

90~120 0C

10 min

Capex

$800K 

Channels

Seal grooves

Holes

In-line process

Raw

Graphite

Flake

$1.2 /lbs

Assume

Expanded

Flake

$2 /lbs

Capex

$200K

Capex

$400K

Capex

$200K

Capex

$1 million

Capex

$150K

Foil Thickness: 2mm

Web Width: 42 mm

Line Speed: 20 ft/min

Processes

In Costing

Figure 20. Graphite Foil Bipolar Plate Manufacturing Flow Chart 

We defined the following assumptions for each subsystem module: 

• Plant capacity scaled to market size (unit demand) 

• Manufacturing process capabilities (machining, molding, coating, assembly, 

level of automation, etc.) 

• Process and component sourcing (internal or out-sourced) 

• Material volume projections for cost and availability determination 

• Yield and scrap 

6.2.3.3. Cost Analysis 

We used a plant capacity appropriate for commercialization of PEMFC technology in the 

context of automotive markets (i.e., 500,000 units per year). We searched for analogies 

with systems in Internal Combustion (IC) engine vehicles for long-term extrapolation of 

costs, e.g., control and monitoring systems. 

With completion of the baseline cost estimate, we visited major material and component 

suppliers, technology developers, and fuel cell system fabricators to present the results of 

our initial analysis. We used feedback from these critical interviews to refine our analysis 

and identify any imminent developments that would significantly impact our baseline 

cost estimates. 

6.2.4. Sensitivity Analyses 

We performed sensitivity analyses on the PEMFC system model to assess the impact of 

key material and manufacturing process parameters on the baseline fuel cell stack and 

system cost. The system cost model is a complex cost analysis tool that permits 
30

evaluation of multiple design and operating parameters by changing selected inputs. 

These changes are carried throughout the model to generate revised cost estimates of 

selected subsystem modules as appropriate. This permits rapid and accurate comparison 

between design concepts, material and manufacturing developments, and system 

configurations. Figure 21 shows a single-variable sensitivity analysis, which depicts the 

impact on membrane cost, of varying one variable while holding all others constant. 

Membrane Cost ($/m^2)

95%

60

5

20

88%

200

50

100

$5.00 $10.00 $15.00 $20.00 $25.00 $30.00 $35.00

Nafion Cost ($/lb)

Membrane Web

Speed (ft/min)

Membrane Web

Width (cm)

Membrane Yield (%)

80

20

Membrane Cost ($/m^2)

95%

60

5

20

88%

200

50

100

$5.00 $10.00 $15.00 $20.00 $25.00 $30.00 $35.00

Nafion Cost ($/lb)

Membrane Web

Speed (ft/min)

Membrane Web

Width (cm)

Membrane Yield (%)

80

20

Figure 21. Example of Single Variable Sensitivity Analysis 

Figure 22 shows an example of a Monte Carlo statistical analysis, in which several 

parameters are varied simultaneously over a specified number of trials to determine the 

probability distribution of the overall cost. 
31

67

12

57

$/kW

Mean

Std. Dev.

TIAX 

Baseline

Cost

67

12

57

$/kW

Mean

Std. Dev.

TIAX 

Baseline

Cost

TIAX Baseline 

$67/kW

DOE Target 

$65/kW

2σ Mean $57/kW 2σ

Frequency Chart

Certainty is 77.34% from -Infinity to $65.00 ($/kW)

.000

.009

.017

.026

.034

0

42.75

85.50

128.2

171

$20.00 $40.00 $60.00 $80.00 $100.00

5,000 Trials 5 Outliers

Forecast: 2005 Stack Cost ($/kW)

Figure 22. Example of Monte Carlo Sensitivity Analysis 

Finally, the baseline costs and sensitivity results were summarized in a table using 

standard financial cost categories, for example: materials, labor, utilities, equipment, and 

tooling. Our final results include a review of system performance assumptions, material 

selection and performance, process flow sheets, process cycle times, and a breakdown of 

cost projections. 

6.2.5. Supply Chain Analysis 

In this project, we assume that the stack is vertically integrated and that the BOP 

components are purchased from suppliers. Alternatively, an OEM could assemble 

purchased subsystems and accept the higher cost associated with outsourcing. One of the 

scenarios we considered in the cost model was that the OEM would assemble the fuel cell 

stack using purchased MEAs and bipolar plates. Margin estimates at various levels of the 

supply chain are based on our experience with automotive suppliers and OEMs and 

onpublicly available information. Figure 23 proposes a rudimentary supply chain 

scenario. Additionally, the MEA supplier could purchase its membrane material rather 

than buy the membrane or membrane precursor material (ionomer). 
32

Figure 23. Illustrative Automotive PEMFC Supply Chain 
33

7. DOE Fuel Cell System Targets 

Table 10 shows the DOE targets for 80 kWe (net) direct-hydrogen fuel cell systems for 

transportation applications. The cost projection developed from this effort will allow 

assessment of the status of PEMFC technology and cost relative to the 2005 DOE targets. 

Table 10. DOE Targets 

Direct Hydrogen Fuel Cell Power System Target 

Characteristic Units 2005 2010 2015 

System Cost $/kWe 125 45 30 

System Efficiency @ 25% Rated Power % 60 60 60 

System Efficiency @ Rated Power % 50 50 50 

System Power Density, Specific Power W/L, W/kg 500 650 650 

 

Stack Cost $/kWe 65 30 20 

Stack Efficiency @ 25% Rated Power % 65 65 65 

Stack Efficiency @ Rated Power % 55 55 55 

Stack Power Density, Specific Power W/L, W/kg 1500 2000 2000 

 

MEA Cost $/kWe 50 15 10 

MEA Performance @ Rated Power mW/cm2

 800 1280 1280 

MEA Degradation Rate % 10 10 10 

 

PGM Cost $/kWe 40 8 6 

PGM Content g/kWe(peak) 2.67 0.5 0.4 

PGM Loading (both electrodes) mg/cm2

 0.7 0.3 0.2 

 

Membrane Cost $/m2

 200 40 40 

Bipolar Plate Cost $/kWe 6 4 

 

CEM System Cost $ 600 400 200 

Source: DOE Fuel Cell RD&D Plan Technical Targets: 80 kWe (net) Direct-H2 Automotive Fuel Cell Systems 
34

8. System Analysis 

8.1. Introduction 

Estimating the cost of the complete system requires identifying various components, 

sizing the components, and estimating the parasitic loads (which affect the stack size). A 

thermodynamic analysis is necessary for these estimates. ANL performed the 

thermodynamic system analysis; similar studies by ANL are available in the public 

literature (6, 7). In this section we describe the system layout, explain the rationale for the 

various components, and summarize the key findings of the analysis. The stack operating 

conditions, which dictate the system configuration to a large extent, are provided in Table 

11. 

Table 11. Summary of the Stack Operating Conditions that Influence the System Design 

and Configuration of the 80 kWe PEMFC System 

Parameter Value 

Single cell voltage 0.65 V 

Hydrogen consumption per pass 70% 

Oxygen utilization 50% 

Inlet anode and cathode RH 60% 

Operating temperature 80oC 

System pressure at rated power 2.5 atm 

8.2. System Description 

Figure 24 shows the key components of the 80 kWe PEMFC system for transportation 

and the system flow schematic. The system is assumed to operate on hydrogen from a 

compressed hydrogen storage tank and atmospheric air. In the following sections, we 

briefly describe the key elements of the major subsystems. 

An alternative system approach, not assessed here, is to operate at near atmospheric 

pressure and use in-stack water management. This approach simplifies the system 

design. 
35

Source: Dr. Rajesh Ahluwalia of ANL

HT/LT Radiators

Demister

Electric 

Motor

PEFC

Stack

Air

Exhaust

Humidified Air

HT Coolant

Enthalpy 

Wheel

LT Coolant

Purge Valve

Recirculation 

Pump

LT Coolant 

Pump

HT Coolant 

Pump

Fan

Ejector

Pressure Membrane Regulator Humidifier

Dilution 

Mixer

Air 

Filtration

Hydrogen

Tank

Air 

Bypass

HT/LT Radiators

Demister

Electric 

Motor

PEFC

Stack

Air

Exhaust

Humidified Air

HT Coolant

Enthalpy 

Wheel

LT Coolant

Purge Valve

Recirculation 

Pump

LT Coolant 

Pump

HT Coolant 

Pump

Fan

Ejector

Pressure Membrane Regulator Humidifier

Dilution 

Mixer

Air 

Filtration

Hydrogen

Tank

Air 

Bypass

Demister

Electric 

Motor

PEFC

Stack

Air

Exhaust

Humidified Air

HT Coolant

Enthalpy 

Wheel

LT Coolant

Purge Valve

Recirculation 

Pump

LT Coolant 

Pump

HT Coolant 

Pump

Fan

Ejector

Pressure Membrane Regulator Humidifier

Dilution 

Mixer

Air 

Filtration

Hydrogen

Tank

Air 

Bypass

Figure 24. PEMFC System Layout 

Anode hydrogen feed

Hydrogen from the compressed hydrogen tank is fed to the anode of the fuel cell via a 

hybrid ejector-recirculation pump. The hydrogen is humidified by air exiting the cathode 

through a membrane humidification unit. The humidification level in the inlet air stream 

is maintained at 60%. 

A hybrid ejector-recirculation pump is required because of the turndown characteristics 

of the ejector and parasitic power requirements of the recycle blower as shown in Figure 

25. For flow rates higher than 25% of rated power, the ejector designed for this 

application is able to supply the flow rate required. However, at less than 25% of rated 

power, the flow requirement is much higher than what the ejector can supply requiring 

the use of an active blower. 
36

H2 Blower only Ejector + Bypass valve

(L/s)

0

2

4

6

8

10

0 0.2 0.4 0.6 0.8 1

Fraction of Rated Fuel Flow

Entrainment

Target 

Entrainment

Ejector Performance

Nozzle Diameter: 2.3 mm

Mixing-Section Diameter: 6.3 mm

H2 Blower only Ejector + Bypass valve

(L/s)

0

2

4

6

8

10

0 0.2 0.4 0.6 0.8 1

Fraction of Rated Fuel Flow

Entrainment

Target 

Entrainment

Ejector Performance

Nozzle Diameter: 2.3 mm

Mixing-Section Diameter: 6.3 mm

0

2

4

6

8

10

0 0.2 0.4 0.6 0.8 1

Fraction of Rated Fuel Flow

Entrainment

Target 

Entrainment

Ejector Performance

Nozzle Diameter: 2.3 mm

Mixing-Section Diameter: 6.3 mm

Source: Dr. Rajesh Ahluwalia of ANL 

Figure 25. Comparison of the Required Flow from the Ejector versus the Actual Flow 

Estimated for the Chosen Ejector Design 

Cathode air feed

Atmospheric air is filtered and compressed to 2.5 atm in the compressor-expander 

module and humidified to 60% RH at 80oC in the enthalpy wheel humidifier. The exhaust 

from the cathode is used for humidifying the inlet air. The pressurized air stream is 

expanded in the expander for energy recovery. 

Stack cooling

The efficiency of the fuel cell stack under the defined operating conditions is 51.7%, 

implying that nearly 90 kW of heat from the stack must be rejected to maintain a constant 

stack temperature. A separate coolant flow-loop, the HT coolant loop in Table 24, is 

utilized for this purpose. 

8.3. System Performance Results 

The overall system efficiency is determined by the stack efficiency and the parasitic 

losses in the system. 

8.3.1. Stack Efficiency 

The stack efficiency is defined as the stack power output divided by the lower heating 

value of the fresh hydrogen feed. The stack efficiency accounts for the hydrogen loss 

through the purge of the recycle stream, the hydrogen crossover from the anode to the 

cathode, and the oxygen crossover from the cathode to the anode. Table 12 summarizes 

these factors for the baseline case. In Table 12 the hydrogen crossover is expressed as a 
37

fraction of the fresh feed of hydrogen, and the crossover of oxygen and nitrogen are 

expressed as fractions of the fresh feed of the respective species to the cathode. The 

stack efficiency on a LHV basis was calculated as 51.7%. 

Table 12. Parameters Influencing the Stack Efficiency Estimation 

Parameter Value 

Hydrogen crossover1 (%) 0.2 

Purge fraction (%) 0.6 

Nitrogen crossover (%) 0.01 

Oxygen crossover (%) 0.020 

Hydrogen utilization (%) 99.5 

Stack efficiency (%, LHV) 51.7 1

 Percentage H2 crossover is expressed as % of fresh H2 fed to stack, at 100% of rated power. 

The purge fraction was chosen to result in optimum stack efficiency. While the crossover 

of the species is dictated by the properties of the membrane, the purge fraction is a 

parameter that is left to the designer. Figure 26 shows the impact of purge fraction on the 

stack efficiency. At purge fractions lower than 0.6%, the concentration of nitrogen in the 

anode compartment increases resulting in lower cell voltage and hence lower efficiency. 

At purge fractions greater than 0.6%, a greater fraction of the freshly fed hydrogen is 

purged out of the system without being electrochemically utilized and hence the 

efficiency decreases. 

51.5

51.6

51.7

51.8

51.9

52.0

52.1

52.2

52.3

52.4

52.5

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

Purge (%)

Stack Efficiency (%)

Purge Rate for Peak Efficiency 

51.5

51.6

51.7

51.8

51.9

52.0

52.1

52.2

52.3

52.4

52.5

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

Purge (%)

Stack Efficiency (%)

51.5

51.6

51.7

51.8

51.9

52.0

52.1

52.2

52.3

52.4

52.5

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

Purge (%)

Stack Efficiency (%)

Purge Rate for Peak Efficiency 

Figure 26. Stack Efficiency as a function of the purge rate from the anode recycle loop for 

single cell operating voltage of 0.7 V. Comparable results are obtained for 0.65 V 

operation. 
38

ANL used data reported by Mittelsteadt et al. (8) to develop a correlation for nitrogen 

crossover in the fuel cell stack. An interesting consequence of the crossover of nitrogen 

into the anode compartment is that a steady state is reached for nitrogen concentration in 

the anode compartment. Therefore, although pure hydrogen is fed to the system, over 

time, hydrogen in the anode becomes diluted with nitrogen. Figure 27 shows the average 

concentration of nitrogen in the anode as a fraction of the rated power in of the stack. The 

nitrogen concentration within the stack can be as high as 15% at the stack outlet 

depending on the operating voltage. An important implication is that while single cell 

tests are often conducted on pure hydrogen, the conditions in the stack could be vastly 

different. 

Figure 27. Nitrogen concentration in the anode stream as a function of the stack power 

output (which is given as a fraction of the rated power). S1 corresponds to 0.7 V single cell 

voltage and S3 to 0.65 V. 

8.3.2. System Parasitic Power Consumption 

The parasitic power consumed by the balance of plant components associated with fuel 

delivery, air delivery, water management, and heat management has to be supplied by the 

fuel cell stack, which detracts from the overall electrical power output of the stack. Table 

13 summarizes the power consumption in the system. Therefore, the gross power output 

from the stack must equal 80 kW + 9.5 kW = 89.5 kW. 

The power consumption in the compressor-expander module is the net power consumed 

in the module after accounting for the power recovery from the expander. At rated power, 

the compressor was assumed to be 78% efficient, the expander 82% efficient, the motor 

92% efficient, and the controller 92% efficient. The compressor-expander was assumed 

to be capable of a turndown ratio of 20. 

Table 13. Parasitic Power Consumption in the System 

Component Power consumption (W) 

CEM (net) 5500 

Enthalpy wheel motor 126 

Radiator fan 2200 

Coolant pump 1400 

0

5

10

15

20

25

30

35

0 10 20 30 40 50 60 70 80 90 100

FCS Power (%)

N2 Concentration (%)

S1 (Outlet)

S1 (Inlet)

S3 (Outlet)

S3 (Inlet)
39

H2 recirculation pump 256 

Total 9500 

8.4. System Efficiency 

For the baseline operating conditions, the system efficiency at rated power was estimated 

as 47% (LHV of hydrogen), as indicated in Figure 28. With decreasing power output, the 

system efficiency increases primarily owing to rise in the cell voltage. The peak system 

efficiency occurs at ~ 5% of the rated capacity or nearly 4 kW. 

40

42

44

46

48

50

52

54

56

58

60

0 10 20 30 40 50 60 70 80 90 100

FCS Power (%)

FCS Efficiency (%)

S1

S3

S2

Figure 28. Efficiency of the 80 kW PEMFC system as a function of the rated power. S1 

corresponds to 0.7 V single cell voltage, S2 to 0.65 V (base case) and S3 to 0.6 V. 

8.5. System Component Sizing 

BOP discussions, sizing, and cost are combined in Section 10.4 

8.5.1. PEMFC Stack 

The stack size is governed by the stack power density, which in turn is determined by the 

operating conditions (such as cell voltage, RH, temperature, and pressure) and the cell 

design parameters (such as catalyst loading and membrane thickness). The power density 

and cell design parameters are critical to determining the stack costs. 

8.5.2. Power Density Assessment 

We assumed the following for the stack power density: 

- Single cell in the stack operates at 0.65 V 

- Total platinum loading of 0.75 mg/cm2

- Single cell area power density of 600 mW/cm2 

Based on feedback from the FreedomCAR Tech Team, we assumed an operating voltage 

for the single cell in the stack of 0.65 V. Based on discussions with various developers, it 

became clear that in stacks being evaluated in vehicles today, the catalyst loading was 

~ 0.75 mg/cm2

 total platinum. 
40

Data available in the literature (9) indicate that it would be possible to achieve power 

densities of ~ 750 mW/cm2

 at these catalyst loadings and 2.5 atm operation. These 

measurements were made in a large single cell under idealized conditions in the 

laboratory. However, to translate the data to a practical stack, we assumed that the single 

cell lab power density would be reduced by 20%, resulting in 600 mW/cm2

 power density 

for the stack. 
41

9. Cost Analysis 

9.1. Introduction 

In Section 2 (Summary) key assumptions and system design decisions are described, 

including: 

• The trade-offs between designing for higher power versus efficiency are explored. 

Designing for higher power, e.g., 0.65 V versus 0.75 V, reduces size, weight, and 

cost of the stack, but decreases efficiency relative to DOE targets by 

approximately 5%. 

• Platinum price, because of the electrode contribution to cost, has a significant 

impact on cost. Recent platinum prices are at all time highs ($900/troz) while 

historic prices established over the last 100 years are half this value. We used the 

current price in the baseline analysis, but also present results for the lower price 

for reference. The latter is consistent with earlier cost projections. 

• Power density and platinum loading are key cost drivers. With the information 

provided in this report, the reader can calibrate the results to their values. The cost 

of stack materials are provided on an area basis so the cost can be estimated for 

other power densities, while the impact of higher or lower platinum loadings can 

be estimated by factors. 

• The impact of meeting life requirements has not been factored into cost, however, 

this was discussed with the Tech Team and developers. We did not have a 

relationship, i.e., between platinum loading and life, that allowed us to make this 

trade-off in design. For the moment, we assume that the developments that will 

increase the life of the stack will not involve increased platinum loadings. 

The goal of this assessment is to capture the major cost contributions to the system. 

Within the scope of a project of this type, one cannot solve all the technical issues facing 

developers today. For example, we did not include system features designed to address 

startup in freezing conditions. As solutions to low temperature startup become public 

knowledge, they can be factored into the cost. The question of hydrogen purity, i.e. CO 

concentration, has not been factored into the system components or the assumed power 

density. Related to BOP, components required for purification of recovered water and 

sensors are not included. These BOP components are not expected to make a significant 

contribution now, however they may represent a larger share of the system cost in the 

future, as stack costs are lowered. 

9.2. Stack 

Stack specifications and performance assumptions are key drivers of power density and 

cost. Table 14 lists the stack assumptions for 2005. 
42

Table 14. Stack Specifications and Performance Assumptions 

Parameters Units 2005 Direct-H2 S/C1 Comments 

Production volume per year 500,000 S Same as in prev. studies 

Fuel cell net power kWe 80 S FreedomCAR Spec. 

Fuel cell gross power kWe 90 C ANL 

Cell voltage @ rated power V 0.65 S Tech Team feedback 

Stack voltage @ rated power V 300 V @ 266 A S Tech Team feedback 

Stack efficiency @ rated power % 51.7% C ANL 

Number of stacks 2 S Same as in prev. studies 

Number of cells per stack 231 C Calculated 

Cell pitch cells/inch 

cells/cm 

9.55, 

3.76 C Calculated 

Total Pt loading mg/cm2

 0.75 S Tech team/developer 

feedback 

Power density @ 0.65 V mW/cm2

 600 S 

TIAX estimates based on 

literature data and developer 

feedback 

Active area per cell cm2

 323 C Calculated 

Active area to total area % 85 S Developer feedback 

1

 S – Specified, C – Calculated 

The following material assumptions were used for the 2005 stack material cost 

projection. Table 15 is a summary of the stack material assumptions. 

Table 15. Stack Material Assumptions 

Component Parameter Baseline 

Membrane Material 

Supported 

Sulfonated fluoro-polymer 

No 

Electrodes – Cathode & Anode Catalyst Platinum 

Gas Diffusion Layer Material 

Porosity 

Woven carbon fiber 

70% 

Bipolar Plate Type Expanded graphite foil 

Cell Pitch - 9.55/inch, 3.76/cm 

The gasket frame seal configuration is shown in Figure 29 while Table 16 lists the stack 

component weight and dimensions. 
43

Membrane

Anode / GDL

Cathode / GDL

Bipolar Plate

Gasket Frame Seal

Bipolar Plate

Figure 29. 2005 Stack Design 

Table 16. Stack Component Weight and Dimensions 

Component Thickness (�m) Weight (g/cell) Weight1 (g/m2) 

Membrane 51 3.24 100 

Anode 20 0.66 20 

Anode GDL 2602 7.67 237 

Cathode 20 0.55 17 

Cathode GDL 2602 7.67 237 

Bipolar plate (a pair) 2000 63.96 1988 

Frame seal 641 2.74 85 

Gasket 100 0.58 18 

Total 2611 87 2702 1

 m2 of active area which is 323 cm2 per cell 2

 Thickness at 7.3 PSI (275 μm at 1 psi) 

9.2.1. Membrane 

9.2.1.1. Description 

Introduction 

A process description for fabrication of 1-2 mil thickness non-reinforced Nafion® 

membranes was constructed on the basis of a review of patents and publicly available 

literature. This process description is the basis for modeling the costs associated with 

membrane manufacture for PEMFCs in 2005. 
44

Background and Information Sources 

DuPont’s Nafion® is the industry standard material for forming the ion permeable 

membranes used in PEMFCs. Nafion is composed of a highly ion-conductive 

polyfluorosulfonic acid (PFSA) polymer that functions as a cation exchange medium, 

selectively transporting protons from anode to cathode in the fuel cell. 

DuPont’s original patent on the Nafion material (U.S. No. 3,718,627) named Walther 

Grot as inventor. Following Grot’s patents through time provides information on the 

evolution of both the Nafion material itself and its incorporation into membranes. The 

most recent patents on the technology are assigned to Ion Power, a business formed by 

Grot’s son, Stephen Grot in 1999 to distribute Nafion-based products for fuel cell and 

electrolysis applications. 

A second source of information is DuPont’s 2002 Fuel Cell Seminar presentation (5). In 

this presentation, a road map was given describing the evolution of DuPont’s membrane 

and dispersion products planned for 2002 to 2005. 

Finally, technical bulletins available at both DuPont’s and Ion Power’s websites give 

specifications and descriptions of current Nafion products, including membranes. 

The above information, along with TIAX knowledge of film and coating manufacturing 

processes, has been used to construct a Nafion membrane fabrication process for cost 

modeling. 

Nafion Membranes 

Non-reinforced Nafion PFSA membrane products currently available from DuPont/Ion 

Power include extrusion cast and dispersion cast membranes. The extrusion cast 

membranes (DuPont N-112, -1135, -115, -117, -1110) are melt extruded from 

perfluorosulfonyl fluoride resins (e.g., DuPont R-1100) followed by hydrolysis and acid 

exchange steps. These films are available in 2, 3.5, 5, 7, and 10 mil membrane 

thicknesses (EW 1100). In 2003, DuPont announced the development of a new highvolume, low-cost process for manufacture of “second generation” dispersion cast 

membranes. Dispersion cast films are formed directly from solutions of PFSA in water 

and alcohol by a coating process onto an inert PTFE backing film. These membranes are 

available from DuPont in 1-mil and 2-mil thicknesses at EW 1100 (NRE-211, -212). 

Based on available information, this dispersion casting process is the current state of the 

art, enabling manufacture of thin membranes with high ion conductivity, and is used as 

the basis for the membrane cost model. A 2-mil membrane thickness is chosen for cost 

modeling to be comparable to the 1999 values, in which DuPont’s N-112 extruded 

membrane was the basis of the estimate. Further, thinner membranes (< 50 microns) 

need higher H2 purge rates, can suffer from anode flooding, and higher H2 cross-over 

rates. 
45

Nafion Dispersions 

Nafion Dispersions are available from both DuPont and Ion Power. The dispersions 

consist of PFSA polymer, water, and low-molecular weight alcohols. DuPont’s product 

line (e.g., DE 520, DE 1020, DE 2020) includes 5%, 10%, and 20% PFSA with 34% to 

90% water and 1% to 50% VOCs (n-propanol, ethanol, and mixed ethers) by weight. 

Dispersions are available from Ion Power in 5% and 15% wt. PFSA solutions (LiquionTM 

LQ-1105/1005 and LQ-1115/1015) containing 20% to 45% water and 40% to 75% 

isopropanol. Compared to the earlier dispersions (U.S. Patent No. 4,433,082, Grot), these 

dispersions (U.S. Patent No. 6,552,093, Curtin) have tighter particle size distributions and 

minimized VOCs in the dispersion medium. In 2003, DuPont claimed the increased 

uniformity in composition of these dispersions would enable more predictable coating 

formulations and consistent processing, contributing to improved fuel cell performance. 

We have based our membrane cost estimate on the use of a dispersion similar to the 

LiquionTM dispersion. A 40% solids content dispersion was chosen, although this is 

higher than the highest percentage PFSA, low VOC (40% isopropanol/45% water) 

dispersion available from Ion Power. The highest practical limit for polymeric colloidal 

dispersions with acceptable flow rheology is in the 40% to 50% solids content range. The 

higher weight percent PFSA dispersion is preferred for greater ease in film-forming, oven 

length needed and the low VOCs reduce costs involved in solvent disposal or recovery. 

9.2.1.2. Manufacturing Process 

Film-Forming Process 

A process for fabricating non-reinforced Nafion membranes similar to DuPont’s NRE212 (EW 1100, 2 mil) was derived from U.S. Patent No. 6,552,093 (second generation 

dispersions, DuPont), U.S. Patent No. 6,641,862 (dispersion cast membrane electrode 

assemblies, Ion Power), and product bulletins from both DuPont and Ion Power. 

U.S. Patent No. 6,552,093 describes a process for making films from the second 

generation PFSA dispersions. According to the patent, the casting of the dispersion is 

typically done on a polymer belt from which the film can be easily released (e.g., PTFE). 

A (fluorochemical) surfactant may be added to the liquid dispersion medium to lower the 

surface tension of the composition and promote the even distribution of the composition 

on the polymer belt. 

The liquid dispersion medium is evaporated to form a film by heating at a temperature 

below the coalescence temperature, i.e., less than 100°C. The film is cured by heating to 

above the coalescence temperature. The Liquion product bulletin specifies solvent 

should be removed at 50°C for 30 minutes, followed by a curing step at 100-120°C for 15 

minutes. According to the 6,552,093 patent, this two-step process is believed to fuse the 

polymer particles, forming a film with similar properties to those extruded in the sulfonyl 

fluoride (thermoplastic) form and then hydrolyzed and acid exchanged. 

U.S. Patent No. 6,641,862 provides further detail on the film-forming process. In this 

patent, a Nafion “Web” is formed as one component of a membrane electrode assembly. 

A coating of “high-viscosity” Nafion ionomer dispersion is applied at a wet layer 

thickness of about 8 mils on a silicon-coated film of biaxially oriented polyethylene 
46

terephthalate (PET) using a “knife over roll” wet-layer application tool. The solution was 

dried and cured by passing the web under infrared lamps of about 3 kW located 1 foot 

away and a blower moving air over the web for cooling. The web speed was about 0.25 

m/min (0.8 ft/min). The resulting film was 10 microns in thickness. (Two, 10-micron 

ionomer layers were laminated together in the finished membrane electrode assembly.) 

From DuPont’s product data bulletin, NRE-212 membranes are packaged as shown in 

Figure 30 below. The Nafion membrane is positioned between the two layers – a 

coversheet and a backing layer. The coversheet is a 0.7 mil polypropylene (PP) film, the 

backing sheet is a 2.0 mil silicone-treated polyester film. The composite is wound on a 6 

in. ID plastic core. Standard roll widths are 12 in. (305 mm) and 24 in. (610 mm); 

standard lengths are 100 m. 

Figure 30. Nafion Membranes Structure

Ref: DuPontTM Nafion PFSA Membranes Product Information (NAE201, 2004) 

The assumptions made about the cast dispersion film-forming process, based on 

DuPont/Ion Power information and TIAX expertise in similar processes are summarized 

as follows. 

• Nafion dispersion of 40% by weight solids in 30% water and 30% isopropanol 

(somewhat higher than the Ion Power LQ-1115) 

• Roll-coating process starts with 2.5 mil wet film thickness to produce 1.0 mil (25 

micron) dry film thickness. 

• Coating applied to a 2.0 mil silicone-treated PET (26 in. wide) backing film 

• Preferred coating arrangement is “knife over roll” 

• Drying process occurs in a 3-stage oven 

- Flash dry (solvent removal) is 30 minutes at 50°C 

- Full dry (curing) is 15 minutes at 110°C 

- Forced air cooling is 5 minutes at 20°C 

• Line rates are in the range of 10-20 ft/minute 

• 2.0 mil (50 μm) membrane is produced by a double pass (2 x 1.0 mil per pass) 

• Lamination with 0.7 mil polypropylene (PP) coversheet 

• Final product will be 24 in (0.61 m) wide by 328 ft (100 m) on a 6 in plastic roll 

core. 

• Quality control stage includes pin-hole detection/web inspection 

• Class 10,000 clean room environment required 
47

Based on the assumptions above and a schematic of a coater-laminator line (10), a 

process flow can be laid out as shown in Figure 31. 

START

Quality Control

STOP

Unwind 

PET Film

Splicer

Guide

Cartridge

Coater

Gauge Dryer

(45 Mins)

Cooling

(5 Mins)

Gauge Quality

Control

Laminating

Guide

Unwinding

PP Film

Winding 

With Roll 

Changer

Packaging

Splicer

Second Pass

Unwind 

PET Film

Splicer

Guide

Cartridge

Coater

Gauge Dryer

(45 Mins)

Cooling

(5 Mins)

Gauge Quality

Control

Laminating

Guide

Unwinding

PP Film

Winding 

With Roll 

Changer

Packaging

Splicer

Second Pass

Figure 31. Membrane Manufacturing Process Flow

Ref: Black Clawson

The carrier film is approximately 2 meters wide, which is the maximum practical for this 

type of coating line. The coating may be done by reverse roll coating or knife over roll. 

The capital costs for each are quite similar, and coating quality will depend on dispersion 

rheology and the solvent system used in the dispersion. The oven has three sections for 

controlled heat-up, bake-dry, and cool-down. Wet and dry film thicknesses are 

monitored using convention technologies such as beta gauges. Moisture gauges monitor 

the water content of the film exiting the oven. Precise control of the moisture content is 

required to control the “plasticity” of the Nafion polymer. A second pass through the 

process will be run when thicker coatings are required. A laminating station adds the 

coversheet to the product. The edges are trimmed and the film is wound up at the last 

station in the line. Products may be slit to measure in-line or off-line. Rolls are bagged 

with metallized polyester overwrap to control the internal atmosphere. 

Major Material and Process Parameters 

We estimate that the raw material ionomer costs $80/lb at high volume. Gebert et al.’s 

paper (11) has a lower ionomer cost of ~ $30-50/lb. One of the major industry 

manufacturers indicated that $80/lb is on the lower side. Table 17 lists the material 

parameters for the manufacture of the membrane. 
48

Table 17. Membrane Material Parameters 

Material 

List 

Density 

(g/cc) 

Cost 

($/kg) 

Nafion 1.97 176 

Isopropanol 0.78 1.5 

The process Capital Expenses (CapEx) are based on conversations with original 

equipment manufacturers and the cycle time is based on a line speed of 20ft/min. U.S. 

Patent No. 6,641,862 shows that the membrane coating line speed is about 1 ft/min, but 

we assumed 20 ft/min based on industry feedback. The production line is fully automated 

and not labor intensive. The overall yield for the membrane process line is about 95%, 

based on industry feedback. Table 18 lists the process parameters for the manufacture of 

the membrane. 

Table 18. Membrane Process Parameters 

Process Description CapEx 

($) 

Labor Per 

Station 

Unwinding 100,000 0.1 

Splicer 50,000 0.1 

Guiding 50,000 0.1 

Cartridge Coater 350,000 0.1 

Gauging 60,000 0.1 

Dryer with Solvent Burner 5,000,000 0.1 

Quality Control 150,000 0.1 

Laminating 250,000 0.1 

Winding with Roll Changer 100,000 0.1 

Packaging 100,000 0.1 
49

9.2.1.3. Membrane Costing 

Baseline Cost 

The estimated membrane cost is $23/m2, in which material cost represents about 90% of 

the total cost. Table 19 shows the membrane cost break down according to material and 

process. 

Table 19. Membrane Material and Process Cost (on an active area basis) 

Material Process 

Process 

($/m2) ($/kg) ($/m2) ($/kg) 

Film Handling 0.37 37.0 0.31 3.1 

Coating 19.14 191.4 .61 6.1 

Drying & Cooling 0.00 0.00 1.16 11.6 

Quality Control 0.00 0.00 0.09 0.9 

Laminating 0.00 0.00 0.07 0.7 

Packaging 1.56 15.6 0.07 0.7 

Subtotal 21.08 210.8 2.31 23.1 

Total 23.38 ($/m2

) 

233.8 ($/kg) 

Figure 32 illustrates that the material cost accounts for about 90% of the total membrane 

cost, while all other costs are about 10%. The capital cost and equipment and tooling 

cost are the second and third cost drivers. This process is not labor intensive, and labor 

cost is a minor fraction of total cost. 

Material Cost

90%

Labor Cost

1%

Others

1%

Capital Costs

5%

Equipment & 

Tooling

3%

Figure 32. Membrane Cost Breakdown Pie Chart 
50

Single Variable Sensitivity Analysis 

We varied the Nafion cost, membrane web width, web coating speed, and overall 

membrane process yield to run single variable sensitivity analysis. This method tests each 

variable independently; it freezes the other variables at their baseline values when 

analyzing one variable. This method is also known as “one-at-a-time perturbation” or 

“parametric analysis.” (12) 

We chose a minimum Nafion cost based on Gebert et al.’s paper (11) and a maximum 

cost based on industry feedback. The range of values for web width is based on TIAX 

experience. The minimum web speed is based on Ion Power’s patent (1ft/min) and 

industry feedback, while the maximum is from industry feedback. The minimum and 

maximum membrane yield is from industry feedback. Table 20 shows the range of 

values for the membrane cost sensitivity analysis. 

Table 20. Membrane Single Variable Sensitivity Analysis Data Range Table 

Specifications Minimum Most Likely Maximum 

Nafion Cost ($/lb) 20 80 100 

Web Width (cm) 60 200 200 

Web Speed (ft/min) 5 20 50 

Membrane Yield (%) 88% 95% 95% 

The Tornado chart in Figure 33 shows that the Nafion cost has the most effect on 

membrane cost, which could drop to about $10/m2 when Nafion cost is $20/lb. The 

membrane web speed, web width, and process yield have smaller impacts on the 

membrane cost for the parameter ranges assumed. 

Membrane Cost ($/m^2)

95%

60

5

20

88%

200

50

100

$5.00 $10.00 $15.00 $20.00 $25.00 $30.00 $35.00

Nafion Cost ($/lb)

Membrane Web

Speed (ft/min)

Membrane Web

Width (cm)

Membrane Yield (%)

80

20

Membrane Cost ($/m^2)

95%

60

5

20

88%

200

50

100

$5.00 $10.00 $15.00 $20.00 $25.00 $30.00 $35.00

Nafion Cost ($/lb)

Membrane Web

Speed (ft/min)

Membrane Web

Width (cm)

Membrane Yield (%)

80

20

Figure 33. Membrane Single Variable Sensitivity Analysis Tornado Chart 
51

Cost Comparison 

DuPont’s 2 mil non-reinforced membrane cost projection (5), GM’s 1 mil non-reinforced 

membrane cost projection (13), and TIAX’s membrane cost estimate are compared in 

Figure 34. DuPont’s data is not available at high volume (500,000 vehicle/year). But, we 

can still see that TIAX’s estimate is between DuPont’s and GM’s membrane cost 

projection. 

2

4

6

8

100

2

4

6

8

1000

2

4

6

Cost / $ kg -1

103 104 105 106 107

 Production Rate / kg yr-1

DuPont

GM

TIAX

2

4

6

8

100

2

4

6

8

1000

2

4

6

Cost / $ kg -1

103 104 105 106 107

 Production Rate / kg yr-1

DuPont

GM

TIAX

Figure 34. DuPont, GM, and TIAX Membrane Cost Comparison 

Mass Production 

High volume, (500,000 vehicles per year) would require 7.5 million square meters of 

membrane annually. A single coating line (2 mil membrane) is estimated to cost about $6 

million and a total of 3 lines would be required to meet this annual production. The total 

capital investment on membrane equipment is about $20 million to meet the requirement 

of 500,000 vehicles annual production. The following are the assumptions: 

• Stack – 90 kW gross power per stack 

• Stack power density = 600 mW/cm2

• Downtime ~ 20% 

• Yield assumption ~ 95% 

• Operating 3 shifts (20 hours)/day, 240 days/year and production rate is ~ 4,167 

stacks/day 
52

9.2.2. Gas Diffusion Layer (GDL) 

9.2.2.1. Description 

Background and Information Sources 

Carbon fiber-based diffusion media has high porosity and electric conductivity and is 

widely used as a gas diffusion layer. The woven carbon cloth and non-woven carbon 

paper are commercially available for fuel cell application. Woven carbon cloth does not 

need a binder because of its woven structure, whereas non-woven carbon paper is bonded 

by carbonized resin. Diffusion layers are normally made hydrophobic in order to avoid 

flooding. The typical treatment uses PTFE to increase hydrophobicity. 

From developer discussions, we learned that the woven carbon cloths have less defects, 

are easier to coat, and have higher coating web speeds, but are more expensive than nonwoven carbon paper. We picked woven carbon cloth-based GDLs for our baseline. The 

specification is based on E-TEK® GDL LT 1200-W, which has 275 micron thickness at 1 

psi. 

The above information, along with TIAX knowledge of carbon fiber and coating 

manufacturing processes, was used to construct a GDL fabrication process for cost 

modeling. 

9.2.2.2. Manufacturing Process 

We assume that the woven carbon cloth is available in un-coated rolls. The hydrophobic 

process starts with preparing the hydrophobic ink. The material parameters for the 

manufacture of the GDL are shown in Table 21. 

Table 21. GDL Material Parameters 

Material List Loading 

(mg/cm2) 

Cost 

($/kg) 

Woven Carbon Cloth N/A 30 

PTFE 1.75 20.75 

Carbon Powder 2 3.35 

Water 10 0.05 

Figure 35 is a process flow chart for the manufacture of the GDL. 

Prepare 

Hydrophobic

Mixture

Mix 

Hydrophobic

Mixture

Dry 

Hydrophobic

Mixture

Heat

Treat

Spray 

Hydrophobic

Mixture

Coat Sinter

Carbon

Figure 35. GDL Manufacturing Process Flow Chart 

The following specific conditions and parameters were assumed: 

• The hydrophobic solution, consisting primarily of PTFE and carbon powder, has a 

solids content of 27 wt%. 
53

• A three-stage heat treatment oven was used for sintering 

- The first stage was at 80o

C for 20 minutes to achieve uniform distribution 

of PTFE polymer. 

- The second stage was at 250oC for 10 minutes to allow PTFE 

emulsification. 

- In the third stage, the roll is heated to 350o

C for 10 minutes to fix PTFE to 

the surface. 

The process temperature and cycle time are for costing purpose only. In reality, the 

process step, cycle time, and firing temperature will vary. 

The woven carbon cloth cost is based on the carbon fiber cost and the process cost, which 

includes several process steps, such as stabilization, spun yarn formation, weaving and 

carbonization. We assume that the PTFE is DuPont Teflon® T-30 and the carbon powder 

material price is a quote from Cabot®. 

The CapEx process is based on conversations with industrial equipment manufacturers. 

The cycle time is based on a line speed of 50 ft/min. We assumed a 50% ink loss in the 

process of spraying the hydrophobic mixture. Table 22 lists the process parameters for 

the manufacture of the GDL. 

Table 22. GDL Process Parameters 

Process Description CapEx 

($) 

Cycle 

Time 

Labor Per 

Station 

Prepare Hydrophobic Material 20,000 30 Min 0.2 

Mix Hydrophobic Material 50,000 300 Min 0.2 

Spray Hydrophobic Material 100,000 50 Feet/Min 0.2 

Dry Hydrophobic Material 400,000 20 Min 0.2 

Heat Treatment 350,000 10 Min 0.2 

Sinter 400,000 10 Min 0.2 

9.2.2.3. Costing 

Our baseline cost for the GDL is $18.4/m2, which includes both the cathode and anode 

side GDL layers. The material cost is about 95% of total cost, primarily because of high 

woven carbon cloths cost. 

The developer cost estimates for a single layer GDL at high volume varies from $5/m2

 to 

$10/m2

 according to whether non-woven carbon paper or woven carbon cloth is used as 

the basis. Table 23 lists the material and process costs for the GDL. 
54

Table 23. Material and Process Costs (on an active area basis) 

GDL 

($/m2) 

Material 17.68 

Capital Costs 0.66 

Labor 0.19 

Tooling 0.23 

Other1 0.13 

Total 18.40 

1

 Other costs include utilities, maintenance and building. 

9.2.3. Bipolar plates 

9.2.3.1. Description 

Introduction 

The bipolar plates are the largest volume and weight contributor to the PEM fuel cell 

stack and have a significant effect on the stack cost. There are several different 

technologies available to make bipolar plates. Table 24 shows four major material 

options. 

Table 24. Bipolar Plate Material and Process Comparisons 

Material Processes Process Layout 

Graphite Polymer 

Composite 

Compression Molding, 

Injection Molding, Polishing Discrete 

Carbon-Carbon 

Composite 

Slurry Molding, Chemical 

Vapor Infiltration Discrete 

Flexible Graphite Foil Expanded Flake, Rolling, 

Emboss Impression Molding Roll-to-Roll Continues 

Sheet Metal Stamping, Joining, Coating Discrete 

Graphite polymer composite bipolar plates use inexpensive graphite material and 

acompression/injection molding process. Until this year, we used molded graphite plates 

as the baseline in the PEM fuel cell study. But, they may have limitations on thickness 

reduction and conductivity improvement. 

Carbon-Carbon composite bipolar plates were developed by Oak Ridge National 

Laboratory (ORNL) and are being commercialized by Porvair. The bipolar plates are 

made by a low-cost slurry molding process to produce a carbon fiber preform and are 

then made hermetic through chemical vapor infiltration (CVI) with carbon. The 

infiltrated carbon also increases conductivity. The estimated cost is about $26/m2 at high 

volume, in which the CVI process cost is about 70%. The high process cost limits the 

application of this approach. 
55

Metal bipolar plates can be made in thin sheets by traditional stamping processes and 

could be easily mass produced. But, proprietary coatings are needed for corrosion 

protection and stable conductivity. The coating process will be a major cost contributor. 

Flexible graphite foil bipolar plates are made from expanded natural graphite flakes. 

They can be made thin to reduce stack volume. Graphite foil also has high electrical 

conductivity, low contact resistance, and low specific density, and it can be manufactured 

in roll-to-roll continuous process using emboss compression molding. 

Figure 36 is an example process flow from the Graftech® company website. We selected 

flexible graphite foil bipolar plates as baseline in this cost study. We also assume that 

there are cooling channels in the middle of every bipolar plate. 

Figure 36. Grafcell® Production Process from GrafTech Website 

9.2.3.2. Manufacturing Process 

U.S. Patent No. 3,404,061 describes a process for making flexible graphite web using 

natural graphite flake. Figure 37 shows the process flow chart. According to the patent, 

the flake is cleaned by acid to remove metal impurities and then rinsed by water or leach. 

The cleaned flake is sintered at 1000oC to obtain expansion in the c-direction. In this 

process, the c-direction dimension of the expanded particles ranges from about 100 to 

about 300 times that of the original dimension. Next the expanded graphite particles are 

compressed by roll into flexible graphite web. 
56

Figure 37. U.S. Patent 3,404,061 Flexible Graphite Web Process 

U.S. Patent No. 6,663,807 provides further detail on the emboss compression molding 

process. In this patent, a flexible graphite sheet passes through a vessel and is 

impregnated with a resin system. Then, the foil is dried and calendared to dimension 

(0.075mm to 3.75 mm). Finally, the foil passes through the emboss roll press to form the 

final shape and is cured in a low temperature oven (90~120oC) for 3 to 30 min. Figure 38 

is a schematic representation of the emboss compression molding of flexible graphite. 

Figure 38. Embossing a Sheet of Flexible Graphite Material 

The assumptions made about the embossing compression molding process are based on 

the patent literature, feedback from Graftech, and TIAX expertise in similar processes. 

The process assumptions used can be summarized as follows: 
57

• Natural graphite flake raw material costs $1.2/lb. 

• Expanded graphite flake costs $2.0/lb. 

• Flexible graphite foil thickness is 1 mm. 

• Flexible graphite foil web width is 42 mm. 

• Line rates are about 20 ft/minute. 

• Drying oven will be on for 3 to 30 minutes at 90 to 120o

C. 

• Two graphite plates are in parallel layout in the foil. 

• Process line yield 95% and material scrap rate 10% (recyclable). 

Figure 39 shows the flexible graphite foil bipolar plate process flow used in the cost 

estimation. We assumed that the expanded graphite flake is $2/lb and we did not cost the 

first three process steps. Only the process steps within the dashed line frame are included 

in the cost model. Two plates are bonded together to form a cooling bipolar plate. 

Treat

Flake

Water 

Rinse or

Leach

Expansion

Treated

Roll 

Pressed

into Foil

Resin

Impregnation

Calender

Line

Emboss

Compression

Mold

Die

Cut

Curing

Oven

Oxidizing

Medium

H2SO4

HNO3

1250C

Soggy

Graphite

Particles

2500 F Flame

Mix with

Ceramic Fiber

Or Carbon

Fiber

2 wt%

Thickness

2mm

10% Phenolics

Resin

Foil Density

1.5g/cc

17%~19% 

Resin

Control 

Foil 

Thickness

90~120 0C

10 min

Capex

$800K 

100 ft long

Channels

Seal grooves

Holes

In-line process

Raw

Graphite

Flake

$1.2 /lbs

Assume

Expanded

Flake

$2 /lbs

Capex

$200K

Capex

$400K

Capex

$200K

Capex

$1 million

Capex

$150K

Foil Thickness: 1mm

Web Width: 42 mm

Line Speed: 20 ft/min

Processes

In Costing

Figure 39. Graphite Foil Bipolar Plate Process Flow 
58

Table 25 lists the material parameters and Table 26 lists the process parameters for the 

manufacture of the graphite foil bipolar plate. 

Table 25. Graphite Foil Bipolar Plate Material Parameters 

Material List Content Cost 

($/kg) 

Expanded Graphite Flake 81% 4.40 

Vinyl Ester 15% 3.73 

Carbon Fiber 2% 10.00 

Poly Dimethylsiloxane (SAG) 0.05% 18.50 

Methyl Ethyl Ketone Peroxide 1.0% 6.66 

Colbat Napthenate 0.3% 8.18 

Table 26. Graphite Foil Bipolar Plate Process Parameters 

Process Description CapEx 

($) 

Cycle 

Time 

Labor Per 

Station 

Oxidizing Graphite Flake 300,000 - - 

Water Rinse or Leach 300,000 - - 

Expansion Treatment 2,000,000 - - 

Roll Press 200,000 20 ft/min 0.2 

Resin Impregnation 400,000 20 ft/min 0.2 

Calender Foil 200,000 20 ft/min 0.2 

Emboss Compression Mold 1,000,000 20 ft/min 0.2 

Die Cut 150,000 1 

plates/sec 0.2 

Curing Oven 800,000 30 min 0.2 

9.2.3.3. Costing 

The graphite foil bipolar plate costs $17.35/m2 at high volume (500,000 vehicle/year). 

The material cost is about 60% and process cost is about 40% of total. Table 27 illustrates 

the cost breakdown. 
59

Table 27. Graphite Foil Bipolar Plate Cost Break Down 

Bipolar Plate Cost based on Active Area ($/m2) 

Material Process 

Roll Form 10.23 0.90 

Impregnation 1.00 

Calender 0.64 

Compression Molding 2.08 

Die cut 0.55 

Curing 1.95 

Subtotal 10.23 7.12 

Total 17.35 

In the process cost, the emboss compression and curing processes are the major cost 

contributors. Each of these steps is about 30% of the total process cost. High CapEx costs 

are one of the main reasons. Figure 40 shows the process cost comparison. 

Major Process Costs ($/m2) 

$0

$1

$2

$3

Roll Foil Impregnation Calendar Compression

Molding

Die Cut Curing

Process Cost ($/m2)

Figure 40. Graphite Foil Process Cost Bar Chart 

Compression Molded Graphite Bipolar Plates 

We also estimated the cost of compression molded synthetic graphite bipolar plates, 

which have the same geometry as the flexible graphite foil plate. The result shows the 

two different processes have very close costs. Figure 41 shows the compression molded 

plates’ process and Table 28 is the cost breakdown. 
60

Prepare 

BP Plate

Mix 

Plate

Compression 

Molding

Cure

BP Plate

Grinding

Polishing

4 Cavities

Figure 41. Compression Molded Bipolar Plate Process Flow 

Table 28. Compression Molded Bipolar Plate Cost 

Bipolar Plate 

$/m2

Material 8.65 

Capital Costs 3.42 

Labor 2.26 

Tooling 2.90 

Others 1.40 

Total 18.64 

9.2.4. MEA 

9.2.4.1. Description 

Introduction 

The MEA is the key stack component. A typical five-layer MEA includes anode side 

GDL, anode, membrane, cathode, and cathode side GDL. The platinum based catalyst 

can be deposited either on the GDL or the membrane. The catalyst layers are normally 3 

to 20 microns thick. The thick catalyst layer is typically deposited on the GDL, while 

thinner catalyst layers are typically deposited on the membrane because of the GDL’s 

rough surface. 

Platinum cost and loading are major cost drivers for MEA cost. The current platinum cost 

is about $850 ~ 900/troz, whereas historical prices have been about $450/troz (14). We 

used $900/troz platinum as a baseline to reflect the current price. The total platinum 

loading is 0.75 mg/cm2

 in baseline cost analysis based on feedback from the Tech Team 

and developers. The baseline power density is 600 mW/cm2

. 

U.S. Patent No. 6,716,550 B1 describes an MEA using edge seals to seal reactant fluid 

stream passages to prevent leaks or inter-mixing of fuel and oxidant fluid streams. 

According to the patent, a separate framing seal engages the edge of MEA. In Figure 42, 

framing seal 150 comprises two sealing portions 152 and a web portion 154. The two 

sealing portions and the web portion are of a unitary construction. MEA 110 fits into 

groove 156. Figure 43 illustrates a plan view of an MEA with framing seal 150 and 

MEA 110. Manifold seals (165) are formed together with framing seals. The patent also 

provides the framing seal material, which could be silicones, ethylene propylene diene 

monomer (EPDM), natural rubber, etc. 
61

Figure 42. Framing Seal Structure (U.S. Patent No. 6,716,550) 

Figure 43. Framing Seals Layout (U.S. Patent No. 6,716,550) 

Using the above information, along with TIAX knowledge of MEA design and analysis, 

we selected a baseline MEA design for cost modeling. Figure 44 illustrates the cross 

section of the MEA. The membrane is about 1mm larger than GDL at both sides. We 

have separate manifold seals for the air, fuel, and water channels. 

Membrane

Anode / GDL

Cathode / GDL

Frame Seal

Figure 44. MEA Structure 

9.2.4.2. Manufacturing Process 

Manufacturing Process 

The MEA manufacturing process starts with preparation of anode and cathode layer inks. 

We used a gravure printing process to deposit the electrodes onto the GDLs. After the 

drying process, anode/GDL and cathode/GDL layers are pre-cut to size, but still 

connected in roll. The reason for this is that the final size of the anode/GDL and 

cathode/GDL layers is slightly smaller than membrane size. 
62

Finished membrane, anode/GDL layer, and cathode /GDL layer are all in roll stock form. 

The five layers are assembled by hot press lamination. This roll-to-roll process improves 

throughput and reduces the manufacturing cost. After this, the MEA is die-cut into 

individual sheets. After this step, the process becomes a succession of discrete steps. 

Finally, the frame seals are cast into place. Figure 45 illustrates the whole MEA process. 

Platinum

Recovery

Membrane

(in Roll)

Hot Press

Laminate

Die Cut 

MEA 

(In Sheet)

Casting 

Mold Frame 

Seals

Mix

Anode Ink

Prepare

Anode Ink

Gravure

Printing

Drying

Anode

(In Roll)

Platinum

Recovery

Mix

Anode Ink

Prepare

Anode Ink

Gravure

Printing

Drying

Cathode

(In Roll)

Anode Side 

GDL

Cathode 

Side GDL

Figure 45. MEA with Frame Seals Manufacturing Process Flow 

Major Material and Process Parameters 

We assume that the anode catalyst loading is 0.25 mg/cm2, which is one third of the total 

platinum loading, and the cathode catalyst loading is 0.5 mg/cm2, which is two thirds of 

the total platinum loading. The assumed platinum cost is $900/troz ($28,936/kg). We 

assume there is an additional 20% of platinum cost to cover the catalyst preparation cost. 

The final platinum cost is $1,080/troz ($34,723/kg). Table 29 and Table 30 show the 

anode/cathode ink concentration and material costs. 
63

Table 29. Anode Material Parameters 

Material 

List 

Content 

(mg/cm2) 

Cost 

($/kg) 

Anode Nafion Loading 0.6 176 

Anode Catalyst Support Carbon 

Powder 

1.2 3.35 

Catalyst Platinum 0.25 34,723 

(added 20% process cost) 

Electrode Solvent Glycerol 24 2 

Nafion Solvent Alcohol 12 1.5 

Water 6 0.05 

Table 30. Cathode Material Parameters 

Material 

List 

Content 

(mg/cm2)

Cost 

($/kg) 

Cathode Nafion Loading 0.6 176 

Cathode Catalyst Support Carbon 

Powder 10.6 3.35 

Catalyst Platinum 0.5 34,723 (added 20% process 

cost) 

Electrode Solvent Glycerol 12 2 

Nafion Solvent Alcohol 12 1.5 

Water 6 0.05 

The fully automated roll-to-roll process has a 50 ft/min web speed and is not labor 

intensive. Table 31 illustrates the major process parameters. 

Table 31. MEA Process Parameters 

Process 

Description 

CapEx 

($) 

Cycle 

Time 

Labor Per 

Station 

Material Preparation (weigh) 20,000 30 min 0.2 

Mixing Material 50,000 300 min 0.2 

Gravure Printing 35,000 50 ft/min 0.2 

Drying 300,000 30 min 0.2 

Hot Press and Blank 150,000 0.17 min/cell 0.2 

Mold Framing Seal 300,000 0.5 min/4 cells 0.2 

9.2.4.3. Costing 

The MEA costs $325/m2 with platinum loading of 0.75mg/cm2. Material cost contributes 

about 96% and process cost contributes the balance. The electrodes dominate with about 

85% of the total cost, because of the high platinum loading and high platinum cost. Table 

32 shows the MEA cost breakdown. 
64

Table 32. MEA Cost Break Down 

MEA1 

($/m2) 

Frame Seal1 

($/m2) 

Material 310.22 1.08 

Membrane -21.17 

Electrode -271.86 

GDL -17.18 

Capita Recovery 8.70 1.04 

Labor 0.53 0.82 

Tooling & Equipment 0.91 0.97 

Other2 0.50 0.44 

Subtotal 320.86 4.35 

Total 325.21 

1 m2

 of active area 

2 Other costs include utilities, maintenance and building 

9.2.5. Gasket 

9.2.5.1. Description 

We assume that the MEA is sealed to the bipolar plate by an “O-ring” type gasket in a 

groove. The molded or form-in-place (FIP) gasket form seals around air, fuel, and water 

channels. 

U.S. Patent No. 5,284,718 describes a gasket structure for the air, fuel, and water 

channels. According to the patent, the gasket grooves are molded to the bipolar plate. A 

SANTOPRENE brand rubber is used as gasket material, and the gasket is punched out by 

a metal die. Figure 46 and Figure 47 show the gasket and gasket groove structure. 

We assume a similar gasket structure in our baseline model. We assume the gasket 

material is Nitrile Rubber (NBR) and a transfer molding process is used. 
65

Figure 46. U.S. Patent 5,284,718, A Top View of Gasket Grooves in Bipolar Plate 

Figure 47. U.S. Patent 5,284,718, A Top View of a Sealing Gasket 

9.2.5.2. Manufacturing Process 

Transfer molding has a shorter cycle time than compression molding, but longer than 

injection molding. The bipolar plate is used as part of the “die” and the NBR gasket can 

be formed in place. Transfer molding has a higher material scrap rate because of the nonutilized “transfer pad.” Table 33 and Table 34 show the major material and process 

parameters. 
66

Major Material and Process Parameters 

Table 33. Seal Material Parameters 

Material 

List 

Density 

(g/cc) 

Cost 

($/kg) 

NBR 1.5 11.00 

Table 34. Gasket Molding Process Parameters 

Process 

Description 

CapEx 

($) 

Cycle 

Time 

Labor Per 

Station 

Transfer Molding 280,000 5 min/ 16 

cavities 0.2 

9.2.5.3. Costing 

The gasket costs about $1.72/m2, in which material cost is about 30% and process cost is 

about 70%. The gasket cost is less than 1% of total stack cost. Table 35 illustrates the 

gasket cost break down. 

Table 35. Gasket Cost Break Down 

Seal1 ($/m2) 

Material 0.49 

Capital Costs 0.40 

Labor 0.26 

Tooling 0.39 

Other2 0.18 

Total 1.72 

1

m2 of active area 

2

Other costs include utilities, maintenance and building

9.2.6. Stack Assembly 

The final stack assembly integrates fully automated pick-and-place assembly robots and 

manual labor. 

• The bipolar plates with gaskets, the MEAs with framing seals, end plates, and tie 

bolts are assembled by a pick-and-place robot. 

• The current conductors, insulators, and outer wrap are mounted manually. 

• Final stack conditioning and QC are costed separately and not included in the 

baseline stack cost. Figure 48 illustrates the stack assembly process flow. 
67

Anode/GDL

(in Roll)

Membrane

(in Roll)

Hot Press

Laminate

Cathode/GDL

(in Roll)

Die Cut

MEA

Casting 

Mold Frame 

Seals

Compression 

Molding 

Bipolar Plate

Transfer 

Molding 

Gaskets

Stack

Assembly

Balance 

of Stack

Figure 48. Stack Assembly Flow Chart 

9.2.7. Stack Cost 

9.2.7.1. Baseline Cost 

The stack baseline cost is $67/kW (net electric power) or $5,360. The baseline power 

density assumption is 600 mW/cm2

. The electrodes represent approximately 77% of the 

fuel cell stack cost because of the increased platinum loading (0.75 mg/cm2

) and platinum 

cost ($900/troz). Figure 49 shows the stack cost breakdown pie chart. As a reference, 

the 2004 fuel cell stack cost estimate was $72/kW with a platinum loading of 0.30 

mg/cm2, a power density of 350 mW/cm2, and a platinum cost of $450/troz. 

Electrode

77%

GDL

5%

Bipolar 

Plate

5%

Membrane

6%

Seal

2%

BOS

2% Final 

Assembly

3%

Figure 49. Stack Baseline Cost ($/kW) 

9.2.7.2. Single Variable Sensitivity Analysis 

We varied the platinum cost, platinum loading, power density, membrane cost, GDL cost, 

and graphite material cost to perform a single variable sensitivity analysis in which each 

parameter is varied independently. 
68

The minimum platinum cost corresponds to the historical price (14) and the maximum is 

the current price. The minimum platinum loading is from the 2004 TIAX study (15) and 

the maximum platinum loading is based on DOE, Tech Team, and developer feedback. 

The minimum power density is from the TIAX 2004 study (15) and the maximum is from 

literature data. The minimum membrane cost is referenced from the GM paper (13) and 

the maximum is from developer feedback. The minimum and maximum of GDL and 

graphite material costs are both from developer feedback. 

Table 36. Stack Sensitivity Analysis Variable Ranges 

Sensitivity Analysis 

Process Description Units Min Baseline Max 

Platinum Cost $/troz 450 900 900 

Platinum Loading mg/cm2

 0.30 0.75 0.75 

Power Density mW/cm2

 350 600 800 

Membrane Cost $/m2

 10 23 50 

GDL Cost $/m2

 10.00 18.40 20.00 

Graphite Foil Material Cost $/lb 1.00 2.00 3.00 

The Tornado chart in Figure 50 shows that the power density has the largest effect on 

stack cost, which could vary from $50/kW to $110/kW. The platinum cost and platinum 

loading also have a significant impact on the stack cost. In the low platinum cost case, the 

stack cost can drop to $45/kW. The membrane cost, graphite material cost, and GDL cost 

have a smaller impact on stack cost. 

2005 Stack Cost ($/kW)

350

450

0.3

10

1

10

800

900

0.75

50

3

20

$20 $40 $60 $80 $100 $120

Power Density

(mW/cm^2)

Pt Cost ($/troz)

2005 Pt Loading

(mg/cm^2)

Membrane Cost

($/m2)

Graphite Material

Cost ($/lbs)

GDL Cost ($/m2)

Figure 50. Single Variable Sensitivity Analysis Tornado Chart 
69

9.2.7.3. Monte Carlo Simulation 

In the sensitivity chart, the horizontal bars show magnitude and direction of sensitivity. 

Figure 51 illustrates again that power density has the most powerful impact on stack cost, 

while platinum cost and loading are in second and third position consistent with the 

single variable sensitivity analysis. 

Target Forecast: 2005 Stack Cost ($/kW)

Power Density (mW/cm^2) -.70

Pt Cost ($/troz) .40

2005 Pt Loading (mg/cm^2) .33

Membrane Cost ($/m2) .14

Graphite Foil Web Speed -.05

Graphite Material Cost ($/lbs) .03

GDL Cost ($/m2) .03

NBR Cost -.00

-1 -0.5 0 0.5 1

Measured by Rank Correlation

Sensitivity Chart

Figure 51. Stack Cost Monte Carlo Simulation Sensitivity Chart 

The multi-variable sensitivity analysis in Figure 52 shows that the mean stack cost is 

$57/kW at a production volume of 500,000 units per year. For the input parameters used 

this analysis shows a 77% certainty that the mean stack cost will be below the DOE target 

of $65/kW. The TIAX baseline stack cost of $67/kW is based on typical parameters, 

while the mean stack cost of $57/kW is based on the whole set of parameters included in 

the sensitivity analysis. 

67

12

57

$/kW

Mean

Std. Dev.

TIAX 

Baseline

Cost

67

12

57

$/kW

Mean

Std. Dev.

TIAX 

Baseline

Cost

TIAX Baseline 

$67/kW

DOE Target 

$65/kW

2σ Mean $57/kW 2σ

Frequency Chart

Certainty is 77.34% from -Infinity to $65.00 ($/kW)

.000

.009

.017

.026

.034

0

42.75

85.50

128.2

171

$20.00 $40.00 $60.00 $80.00 $100.00

5,000 Trials 5 Outliers

Forecast: 2005 Stack Cost ($/kW)

Figure 52. Stack Cost Monte Carlo Simulation Frequency Chart 
70

9.2.7.4. Stack Cost Comparison – 2004 vs. 2005 

Table 37. Stack Cost Comparison 2004 vs. 2005 ($/m2) 

Component 2004 Cost1 

($/m2) 

2005 Cost1 

($/m2) % Change 

Membrane 48.852

 23.38 -52% 

Electrode 67.19 279.02 315% 

GDL 32.00 18.40 -43% 

Bipolar Plate 28.10 N/A N/A 

Bipolar Plate with Cooling 27.45 17.38 -37% 

Seal 7.25 6.08 -16% 

BOS 6.91 6.03 -13% 

Final Assembly 8.14 10.53 29% 

Total 225.88 360.81 60% 

The 2005 stack cost on an area basis is $361/m2

, which is 60% higher than the 2004 stack 

cost. The following factors contributed to the changes shown in Table 37: 

• Membrane: The TIAX bottom-up cost of 2 mil unsupported membranes in 2005 

is $23/m2

. In 2004, we assumed that the membrane was purchased at $40/m2, plus 

8.85 $/m2 to condition the membrane for fuel cell use. 

• Electrode: In 2005, Pt cost has increased from $450/troz (2004) to $900/troz. Pt 

loading has increased from 0.3 mg/cm2 (2004) to 0.75 mg/cm2 in 2005. The Pt 

process markup is 20%, which is the same as in 2004. 

• GDL: GDL thickness decreased from 350 mm in 2004 to 260 mm in 2005 

($8.50/m2

 on actual area). 

• Bipolar plate: The process and material changed from molded graphite (2004) to 

thinner expanded graphite foil in 2005. Every plate is a cooling plate and is 

thinner, with less material. 

• Seal/Gasket: The amount of material increased, but switched from fluoropolymer 

($30/lb) in 2004 to nitrile rubber ($5/lb) in 2005 
71

Table 38 illustrates the cost comparison on a net power base. 

Table 38. Stack Cost Comparison 2004 vs. 2005 ($/kW) 

Component 2004 Cost1 

($/kW2) 

2005 Cost1 

($/kW2) % Change 

2005 DOE 

Target 

($/kW) 

Membrane 15.62 4.36 -72% 

Electrode 21.48 52.08 142% 

GDL 10.23 3.43 -66% 

50 

Bipolar Plate 8.98 N/A N/A 

Bipolar Plate with Cooling 8.78 3.24 -63% 

6 (2010) 

Seal 2.32 1.13 -51% 

BOS 2.21 1.12 -49% 

Final Assembly 2.60 1.96 -24% 

Total 72.22 67.34 -7% 65 

9.3. QC and Stack Burn-in 

Stack conditioning and final quality checks, which could be significant cost contributors 

(e.g., 5% to 50% higher), were not included in this analysis at the recommendation of the 

Tech Team and DOE. Testing of the complete system with BOP would represent an 

additional cost. 

For purposes of this analysis we assumed burn-in could take from 2 to 24 hours. 

Developers did not provide feedback on their burn-in parameters. However, they did 

confirm the importance of this step. We estimated that it would cost $9.01/m2 for 2 hours 

stack conditioning & QC and $108.10/m2 for 24 hours. 

Table 39. Conditioning & QC Cost 

2 Hours Stack 

Conditioning & QC 

24 Hours Stack 

Conditioning & QC 

Number of Test Stations 521 6,250 

Number of Stacks per Day 4,168 4,168 

Total Equipment Cost $104M $1,250M 

Cost ($/m2) 9.01 108.10 

Our cost estimates are based on the following assumptions: 

– Capital cost for a test station is $200,000 

– Labor is 0.2 per station 

– Yield is 100% 

– Up-time is 80% 

– Consumables, such as H2 or credit for the power, are not included 

Table 39 shows the capital costs and additional stack costs. 
72

9.4. BOP 

The fuel cell BOP components have been categorized into four management systems: 

air, water, thermal and fuel. 

• The air management system includes air filtration and a compressor expander module 

(CEM) for air supply. 

• The water management system includes an enthalpy wheel humidifier for cathode air 

and a membrane humidifier for anode hydrogen. 

• The thermal management system includes high-temperature radiators and a hightemperature coolant pump. 

• The fuel management system includes a hydrogen recirculation blower and ejectors. 

BOP and ancillary components represent a significant weight/volume as well as cost 

contribution to the overall PEMFC system cost. As an example, Figure 53 shows a 

fuel cell system (16), in which the BOP appears to occupy as much as 60% of the 

total system volume. 

Figure 53. Fuel Cell Stack and BOP 

We had discussions with several component suppliers to develop high-volume estimates 

of BOP component costs. In cases where these components are not produced at high 

volumes, we calibrated supplier cost projections by developing internal estimates based 

on analogies with automotive components. 

9.4.1. Air Management 

9.4.1.1. Air Filtration 

As in IC engine vehicles, the PEMFC vehicle will require air filtration for removal of 

particulate matter, but will also require chemical filtration for removal of contaminants 

such as sulfur, salts, carbon monoxide, and hydrocarbons. We contacted Donaldson, Inc. 

for estimates of the air filtration systems required in PEMFC systems for transportation 
73

applications. At high volumes of 500,000 per year, such air filtration systems are 

expected to represent a negligible cost, approximately $3 per unit or less than $0.1/kW. 

The filters would be an ongoing maintenance item similar to current IC engine air and oil 

filters. 

9.4.1.2. Compressor-Expander 

A CEM was chosen to supply pressurized air for the PEMFC cathode stream. The 

expander is included in order to recover energy from the pressurized cathode exhaust 

stream and thus reduce compressor motor parasitic power requirements. Honeywell, Inc. 

has been developing turbo-CEM equipment under contract to the DOE and serves as the 

basis of our cost, weight, and volume estimate. We have also benchmarked its estimate 

with our own, based on analogies to the automotive industry. Figure 54 (a) and Figure 54 

(b) show a Honeywell CEM and motor controller (17). 

 (a) (b) 

Figure 54. (a) Honeywell Fuel Cell Turbo-Compressor with Mixed-Flow Compressor and 

VNT® Variable Nozzle Turbine, (b) Honeywell Fuel Cell Turbo-Compressor Motor 

Controller 

The CEM is a high-speed centrifugal machine, with a maximum speed of 110,000 rpm, 

and an idling speed of 36,000 rpm. It employs airfoil bearings, a mixed-flow axial 

compressor with 78% efficiency at rated flow, a radial inflow variable nozzle turbine 

with 82% maximum efficiency, and a liquid-cooled motor and motor controller with 

efficiency of 85%. The CEM is capable of a large turn-down ratio of 20:1. Table 40 lists 

some of the key parameters for the Honeywell CEM, as well as a comparison to estimates 

from ANL’s system model. 

Table 40. Key Characteristics of Honeywell CEM 

Parameter Units ANL1 Honeywell2 

Air flow rate g/s 98 90 

Input power w/ expander W 5.5 9.4 

Input power w/o expander W 15.7 

Volume L 16.3 15 

Weight kg 19 17.5 1

 Source: Dr. Rajesh Ahluwalia of ANL 

2

 Source: Dr. Mark Gee of Honeywell, DOE 2005 Hydrogen Program Review 
74

We assumed that ambient temperature is 40°C, stack temperature is 80°C, and 

compressor outlet pressure is 2.5 atm. Honeywell estimates the factory cost of the CEM 

to be $700 for a volume of 100,000 units per year. This figure includes the 

turbomachinery, motor and motor controller, but does not include labor, testing, or capital 

expenditure. By Honeywell estimates, the cost breakout is approximately 90% for the 

turbomachinery, 5.5% for the motor, and 4.5% for the motor controller. We assumed that 

process cost represents approximately 30% or $200 at high volumes. Finally, we 

included a markup of 20% to obtain an estimate of the OEM price of $1080. 

In contrast, our internal estimates, based on conventional automotive turbocharger 

technology, put the OEM cost of the turbomachinery at between $200 and $300 at large 

volumes. A 16 kW motor may cost between $200 and $250, and the motor controller 

another $100 at large production volumes. This results in a total of approximately $650, 

including material, process, labor, CapEx, and markup to OEM price. Table 41 compares 

these two cost estimates for the CEM. 

Table 41. Comparison between Honeywell and TIAX Estimates for CEM Cost 

Cost Contributor Honeywell Cost TIAX Calibrated OEM Price 

Turbomachinery $630 

 (90% of $700) $200-300 

Motor (16 kW) $38 

(5.5% of $700) ~ $200-250 

Motor controller $32 

(4.5% of $700) ~$100 

Total material cost $700 

Process cost, CapEx, 

other 

$200 

(assumed 30% process cost) 

OEM price $1080 

(assumed 20% markup) $650 

Another point of reference is a California Energy Commission (CEC) report (18) on the 

cost of hybrid-electric vehicles, which uses $(300+30 x kW) as a fit for its data on OEM 

motor and motor controller costs. Using a motor size of 16 kW, the CEC formula yields 

a motor and motor controller OEM cost of $780. Again, using an automotive analogy for 

turbo-compressor OEM costs of ~$300, we arrive at a total figure of $1080, which is the 

same as our cost projections based on Honeywell technology. Therefore, we chose 

$1080 as the baseline cost and used $650 as a lower bound in a sensitivity analysis. 

9.4.2. Water Management 

The water management system consists of an enthalpy wheel for cathode air 

humidification and a membrane humidifier for anode H2 humidification. An enthalpy 

wheel was chosen for cathode air humidification since it offers several advantages over a 

membrane humidifier, as listed below: 

• Lower pressure drop and hence parasitic power usage 

• Additional heat exchangers to cool the cathode air are not required 

• Expander has better power recovery (lower pressure drop) 
75

However, the enthalpy wheel humidifier was not considered for anode gas humidification 

since it would allow crossover of cathode exhaust gases into the hydrogen stream. We 

contacted Emprise for information on the enthalpy wheel technology and costs, and 

PermaPure for the membrane humidifier details. 

9.4.2.1. Enthalpy Wheel Humidifier 

The enthalpy wheel consists of a Cordierite (alumina) drum coated with a γ-alumina 

desiccant coating. Sensible and latent heat are exchanged between the two streams of air; 

warm, humid cathode exhaust air and cooler, drier inlet air. A face seal separates the 

exhaust and inlet air streams. Figure 55 shows a HumidicoreTM enthalpy wheel 

humidifier from Emprise. 

 

Figure 55. Humidicore Enthalpy Wheel Humidifier from Emprise 

The Cordierite material is the same as that used in automotive catalytic converter 

monoliths and is manufactured by: 

• Extrusion through a die to form the monolith 

• Drying in a microwave oven 

• Firing at 1200°C 

A wash coat of γ-alumina is applied to the core and then fired at 1200°C. Next, it is 

polished or lapped to a very tight tolerance so that the face seal has a good contact 

surface. The polymer face seal is an injection-molded part and may be made of Delrin or 

glass-filled Teflon. 

We used sizing data from ANL’s system performance model to determine weight and 

volume of the enthalpy wheel and to size/cost the motor. Table 42 lists the major weight 

and volume parameters of the enthalpy wheel humidifier. The cartridge includes the core 

and packaging, but not the manifolds. 
76

Table 42. Weight/Volume Parameters of Enthalpy Wheel Humidifier 

Units 0.65 V Case Comments 

Core inch 7 x 7.2 

Cartridge inch 8.3 x 9.2 

Desiccant γ -alumina coated 400 cpi 

Cordierite monolith, 4 mil thick walls, 

Emprise updated core to 8"D x 6"L 

Cartridge volume L 8.0 

Cartridge weight kg 6.8 

Motor power We 110 Emprise updated motor to 25 We 

Total volume L 13.0 Includes 5 L motor 

Total weight kg 11.8 Includes 5 kg motor 

Table 43 lists the key material costs and process costs of the Humidicore enthalpy wheel 

at low production volumes of 500 to 1000 per year. From discussions with Emprise, we 

estimate that the low-volume cost of $750 for the enthalpy wheel humidifier could be 

reduced to $260 at high volumes. At this time, the Humidicore enthalpy wheel 

production process is largely manual and therefore time consuming and labor intensive. 

Automation and use of injection molded parts could significantly lower the 

manufacturing cost of the humidifier. 

Table 43. Materials, Processes, and Costs for Humidicore Enthalpy Wheel 

Cost Contributor 

Emprise LowVolume Cost 

($) 

Comment 

Extruded cordierite core 40 

8”D x 6”L, similar size core for 

automotive catalytic converter 

monolith ~$10. 

Plates and Seals 75 High volumes would imply a molded 

part with much lower cost. 

Apply γ - alumina wash coat, fire 

@ 1200°C in oven 

22 

Polishing/lapping to very tight 

tolerance Not available Manual polishing, 4 min 

Face seal 6 Delrin, glass-filled Teflon, injectionmolded 

Manifolds 25 Injection-molded plastic, anodized Al 

Motor 125 

Merkle-Korff brushless DC, 

integrated gearbox, $60 at high 

volumes 

9.4.2.2. Membrane Humidifier 

Figure 56 shows a typical membrane humidifier from PermaPure. 
77

Figure 56. Membrane Humidifier from PermaPure 

The humidifier consists of extruded Nafion tubes mounted in headers at each end. The 

headers are made of a two-part polyurethane resin. The unit is molded from glass-filled 

polyphenylsulfone (PPS). 

We considered two PermaPure models of membrane humidifiers for the sizing and 

costing effort; the FC300 and the FC400 series. ANL sized a unit that is close to the 

FC200 series in terms of membrane area requirements. However, the unit is machined 

from polypropylene, which softens at temperatures above 80°C and at pressures above 12 

psig. The FC300-1660-10HP would provide a 10°C approach dew point with an outlet 

dewpoint of 70°C for the humidified fuel stream if the cathode stream entered the 

humidifier saturated at 80°C. The FC400-2500-10HP provides a higher outlet dew point 

of 74°C for the humidified fuel stream. 

We used the FC400-2500-10HP PermaPure humidifier as a basis for the cost estimation 

of this application. Table 44 summarizes the major weight and volume parameters for 

the membrane humidifier. 

Table 44. Weight/Volume Parameters for Membrane Humidifier 

Units 0.65 V Case Comments 

No. of Nafion tubes 1045 

Membrane area m2

 0.65 

ID = 1 mm, OD = 1.12 mm; used 

PermaPure FC400-2500-10HP unit for 

costing, which has 2500 tubes 

Core inch 3 x 7 

Housing inch 3.7 x 11.5 

Volume L 2 

Weight kg 3.0 

Source: Dr. Rajesh Ahluwalia of ANL 

The membrane humidifier costs were estimated from discussions with PermaPure and 

calibrated with Nafion monomer cost estimates. We assumed that Nafion represents the 

major contribution to the material cost and that polyurethane resin and glass-filled PPS 
78

(which make up the housing and headers) are minor contributors. Table 45 compares 

PermaPure and TIAX cost estimates for the FC300 and FC400 series humidifiers that 

were considered for this PEMFC system. 

Table 45. Comparison of TIAX and PermaPure Cost Estimate for Membrane Humidifier 

Units FC300-1660-10HP FC400-2500-10HP 

TIAX Estimate

Average Eq. Wt. of Nafion 1015 1015 

TT-040 tubing weight g/ft 0.154 0.154 

Number of Nafion tubes 1660 2500 

Active length of tubing inch 10 10 

Trapped length of Nafion in headers inch 3 3 

Total length of Nafion tubing inch 13 13 

Total weight of Nafion g 277 417 

Assumed cost of Nafion $/lb 150 150 

Material cost of Nafion tubes $ 92 138 

Assumed % process cost, other % 50% 50% 

Humidifier factory cost $ 183 276 

Assumed markup to OEM price % 150% 150% 

TIAX estimated OEM price $ 275 414 

PermaPure Price Estimate

PermaPure estimated price $ 350 370-400 

We estimated that a membrane humidifier would cost between $275 and $415, while 

PermaPure estimates were between $350 and $400. Since the FC400 series humidifier is 

more likely to achieve the desired humidification level in the hydrogen stream, we chose 

the FC400-2500-10HP as the cost basis. Therefore, we assumed $380 as the baseline 

cost of the membrane humidifier at production volumes of 500,000 units per year. 

9.4.3. Thermal Management 

We had detailed discussions with Modine, a major supplier of heat exchangers for 

conventional automotive and fuel cell applications. Figure 57 shows a PEMFC vehicle 

thermal management system consisting of three high-temperature (HT) radiators, an HT 

coolant pump, and a radiator fan. The main HT radiator is cooled by forced air through 

the radiator fan. The other two HT radiators are located in front of the wheels and are 

cooled by ram air. The HT main radiator looks like a conventional automotive radiator, 

but has enhanced heat transfer surfaces, while the HT wheelhouse radiators have a 

microchannel design. The HT radiators are used to cool the stack and the lowtemperature (LT) radiator is used to cool the electric motor and power electronics. The 

LT radiator, LT coolant pump and air-conditioning condenser are not included in the 

scope of this costing effort. 
79

HT Radiator

HT Wheelhouse 

Radiator (left)

LT Radiator

HT Wheelhouse 

Radiator (right)

AC Condenser

Wheelhouse Duct

HT Radiator

HT Wheelhouse 

Radiator (left)

LT Radiator

HT Wheelhouse 

Radiator (right)

AC Condenser

Wheelhouse Duct

Source: Mr. Mark Voss of Modine

Air flow

HT Radiator

HT Wheelhouse 

Radiator (left)

LT Radiator

HT Wheelhouse 

Radiator (right)

AC Condenser

Wheelhouse Duct

HT Radiator

HT Wheelhouse 

Radiator (left)

LT Radiator

HT Wheelhouse 

Radiator (right)

AC Condenser

Wheelhouse Duct

Source: Mr. Mark Voss of Modine

Air flow

Figure 57. Typical Arrangement of Radiators in Fuel Cell Vehicle 

We used a combination of ANL system performance specifications and industry input 

from Modine to size and cost the different components of the thermal management 

system. Table 46 lists some of the key characteristics of the thermal management system 

costed in this study. 

Table 46. Key Characteristics of Thermal Management System 

Units S2 (0.65 V) Comments 

Coolant Pump 

Flow rate kg/s 5 ∆P = 13 psi 

Power kW 1.4 

Volume L 7 

Weight kg 7 

34% combined pump and motor 

efficiency 

ANL estimate 

Radiator Fan 

Air flow rate kg/s 3.8 55 mph @ 6.5% grade 

Fan head Pa 425 

Fan power kWe 2.2 

72% combined fan and motor 

efficiency; ANL estimate 

Volume L 1.5 ANL estimate 

Weight kg 2.5 ANL estimate 

HT Radiators 

Heat duty kW 80 Modine data 

Surface area m2

 0.51 Modine data 

Volume L 17 Modine data 

Weight kg 11 Modine data 

Modine provided the technical information for sizing the heat exchangers at 25°C and 

40°C ambient temperature, while we used the latter for specifying the radiators. The HT 

main radiator air inlet temperature shows the effect of the heat rejection from the LT 
80

radiator and AC condenser. Table 47 lists these technical specifications. The coolant 

used is 40/60 ethylene glycol-water by volume. 

Table 47. Technical Specifications of High-Temperature Radiators 

General Units 

Ambient temperature °C 25 40 

Ambient pressure kPa 101.3 101.3 

HT Main Radiator

Air mass flow kg/s 3.09 2.92 

Air average inlet temperature °C 34.8 48.0 

Air pressure drop Pa 335 322 

Heat rejection kW 78.9 54.6 

Coolant mass flow kg/s 2.81 2.80 

Coolant pressure drop kPa 26 25 

Coolant inlet temperature °C 80 80 

HT Wheelhouse Radiators (combined) 

Air mass flow kg/s 0.62 0.58 

Air average inlet temperature °C 25 40 

Air pressure drop Pa 372 354 

Heat rejection kW 36.7 26.3 

Coolant mass flow kg/s 0.19 0.20 

Coolant pressure drop kPa 25 25 

Coolant inlet temperature °C 80 80 

By Modine estimates, the high-volume OEM cost of the high-temperature radiators plus 

the radiator fan would be $183 ± 20%, when the radiator fan costs $37. We have used 

$220 as the baseline cost for the radiator and fan ($183 + 20%), and performed a 

sensitivity analysis with $183 and $260 as the bounds. Table 48 summarizes the cost, 

weight, and volume of the HT radiators. 

Table 48. Cost of High-Temperature Radiators for 40°C Ambient Temperature 

Parameter HT Main Radiator HT Wheelhouse 

Radiator 

Total 

Core length (mm) 692 267 

Core width (mm) 538 264 

Core depth (mm) 28 45 

Max weight (kg) 6.3 2.3 10.9 

Volume (L) 10.4 6.3 23 

Cost ($) 62 42 146 
81

9.4.4. Fuel Management 

As shown in Figure 58, the fuel management system consists of a recirculating blower, 

venturi-ejector, fine pressure regulator, and purge valve. The hydrogen storage tank and 

its related cost, weight, and volume considerations are not included in the scope of this 

study. 

Demister

PEFC

Stack

Purge Valve

Recirculation 

Pump

Ejector

Pressure Membrane Regulator Humidifier

Hydrogen

Demister Tank

PEFC

Stack

Purge Valve

Recirculation 

Pump

Ejector

Pressure Membrane Regulator Humidifier

Hydrogen

Demister Tank

PEFC

Stack

Purge Valve

Recirculation 

Pump

Ejector

Pressure Membrane Regulator Humidifier

Hydrogen

Tank

Figure 58. Fuel Management System 

In this design, the ejector recirculates anode gases and entrains fresh H2 for 25% to 100% 

of the rated flow, while the blower is utilized at flow rates below 25% of rated flow. 

Figure 59 is a plot of the entrainment versus fraction of rated flow. The ejector 

performance does not meet the target entrainment rate for flow rates below 25% of rated 

flow, and hence the blower is used in this region. 

H2 Blower only Ejector + Bypass valve

(L/s)

0

2

4

6

8

10

0 0.2 0.4 0.6 0.8 1

Fraction of Rated Fuel Flow

Entrainment

Target 

Entrainment

Ejector Performance

Nozzle Diameter: 2.3 mm

Mixing-Section Diameter: 6.3 mm

H2 Blower only Ejector + Bypass valve

(L/s)

0

2

4

6

8

10

0 0.2 0.4 0.6 0.8 1

Fraction of Rated Fuel Flow

Entrainment

Target 

Entrainment

Ejector Performance

Nozzle Diameter: 2.3 mm

Mixing-Section Diameter: 6.3 mm

0

2

4

6

8

10

0 0.2 0.4 0.6 0.8 1

Fraction of Rated Fuel Flow

Entrainment

Target 

Entrainment

Ejector Performance

Nozzle Diameter: 2.3 mm

Mixing-Section Diameter: 6.3 mm

Source: Dr. Rajesh Ahluwalia of ANL 

Figure 59. Zones of Operation of the Blower and Ejector 
82

However, at flow rates greater than 25% of rated capacity, the ejector performance 

exceeds the target entrainment rate, and some H2 must bypass the ejector. The purge 

valve continuously vents the built-up H2, N2, and H2O stream to minimize the dilution 

effects of N2 crossover. The purged H2 is diluted by mixing with cathode exhaust air to 

percentages safe for discharge. From system efficiency modeling performed by ANL, the 

optimum purge rate is 0.6%. This assumes pure hydrogen feed and 70% hydrogen 

consumption per pass. At lower purge rates, the stack efficiency decreases because of 

lower cell voltage due to build-up of N2, while at higher purge rates, the stack efficiency 

decreases because of lower effective H2 utilization. Figure 60 shows this relationship 

between stack efficiency and purge rate for a cell voltage of 0.7 V. 

51.5

51.6

51.7

51.8

51.9

52.0

52.1

52.2

52.3

52.4

52.5

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

Purge (%)

Stack Efficiency (%)

Purge Rate for Peak Efficiency 

51.5

51.6

51.7

51.8

51.9

52.0

52.1

52.2

52.3

52.4

52.5

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

Purge (%)

Stack Efficiency (%)

51.5

51.6

51.7

51.8

51.9

52.0

52.1

52.2

52.3

52.4

52.5

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

Purge (%)

Stack Efficiency (%)

Purge Rate for Peak Efficiency 

Source: Dr. Rajesh Ahluwalia of ANL 

Figure 60. Optimum Purge Rate for Cell Voltage of 0.7 V 

The ejector design is based on the ejector-venturi principle and uses the pressure energy 

in the high-pressure hydrogen tank (regulated to a desired pressure below 5000 psi) as the 

motive force to recirculate anode gases, as well as deliver a fresh feed of hydrogen. The 

high-pressure hydrogen issuing through an expanding nozzle has its pressure energy 

converted to velocity energy. A vacuum is created, and the anode gases (H2, N2, H2O) are 

entrained. The mixture of gases enters the venturi diffuser where its velocity energy is 

converted into pressure sufficient to discharge against a predetermined back-pressure. 

Figure 61 below depicts the operating principle of the ejector-venturi. 
83

Motive H2 from 

storage tank, 

< 5000 psi

Entrainment of anode 

gases (H2, N2, H2O)

Discharge/Recirculation 

of anode gases (H2, N2, 

H2O)

Source: Croll-Reynolds website

Figure 61. Ejector-Venturi Operating Principle 

In some situations, more than one ejector with solenoid controls would be required to 

provide the necessary range of recirculation flows. Figure 62 (a) and Figure 62 (b) show 

some pictures of typical ejectors. 

Figure 62. (a) Croll-Reynolds’ Schematic of Multiple Ejectors in Series, (b) Ejector from 

Elmridge 

We have assumed that two ejectors would satisfy the range of flows between 25% and 

100% of rated flow. Discussions with Elmridge, a manufacturer of ejectors, indicate that 

current prices for such an ejector at low volumes would be approximately $300 per 

ejector. However, significant savings would be achieved with automated production 

lines and appropriate tooling, and we believe the cost of the ejector component could be 

approximately $20 at high-volume production. Table 49 lists key characteristics of the 

ejector. 

Table 49. Characteristics of H2 Ejector 

Units Value Comment 

Volume L 3.5 

Weight kg 1.8 

Includes air-cooled 

controller; (24 or 42 V) 

Cost $ 40 2 ejectors assumed 
84

We found only one supplier for the hydrogen recirculation blower, H2 Systems Inc., 

although others may exist. We used the drawing available on H2 Systems’ website as the 

basis to develop a high-volume cost estimate of such a blower. Figure 63 shows a 

schematic drawing of the HRB-L blower with dimensions in mm, while Table 50 lists 

key characteristics of the blower assembly. 

Source: Dr. Patrick Sterchi of H2 Systems, 

www.h2systems.net

Figure 63. Hydrogen Recirculating Blower from H2 Systems, Inc. 

TIAX internal estimates project a blower cost of $85 and motor and motor controller 

costs of $200, with a heat sink cost of $15 at high volumes. Therefore, the total cost of 

the unit would be approximately $300 at high volumes. The motor is expensive due to 

the fact that it is a high-rpm motor. H2 Systems provides a total weight estimate of 1.5 kg 

and a volume of 2.7 L for the blower. 

Table 50. Characteristics of Recirculating Blower Assembly 

Cost ($) Comments 

Blower assembly w/ seals 85 Thermoplastic impeller, 14% to 20% peak 

efficiency 

Motor 150 

4-5 A continuous current @ 24 V; 25,000-

30,000 rpm, 87% to 89% efficiency; TIAX cost 

estimate $50 to $100 

Motor controller 50 TIAX estimate $30 to $50 

Heat sink 15 Motor heat rejection, air cooled, finned 

Total 300 H2 Systems’ cost estimate $500
85

9.5. System Cost 

The overall cost of the PEM fuel cell system is $108/kW, with the stack contributing 63% 

($67/kW) and the BOP and assembly contributing 37% ($41/kW). Figure 64 shows the 

breakout between stack and BOP contribution to the 2005 PEMFC system cost. 

Stack

63%

BOP

34%

Assembly

3%

Figure 64. Stack and BOP Contributions to System Cost 

Relative to past analyses, the BOP cost represents a larger percentage of the system cost. 

In 2004, TIAX analyses estimated the stack cost to be $72/kW and the BOP cost to be 

$25/kW, resulting in a system cost of $97/kW. Table 51 is a comparison of 2005 system 

cost with 2004 system cost for an 80 kW net PEMFC system for transportation 

applications. 

Table 51. Comparison Between 2004 and 2005 System Costs 

Cost Contributor 2004 Cost ($/kW) 2005 Cost ($/kW) 2005 DOE Target 

($/kW) 

80 kWe Net Stack 72 67 65 

BOP & Assembly 25 41 60 

PEMFC System 97 108 125 

The air management system is the largest share of the BOP cost, with the CEM and air 

filtration representing $13.5/kW, or 13%, of the overall system cost. The water 

management systems comprised of the enthalpy wheel and membrane humidifier 

represent the next largest contributors to the BOP cost at $8/kW, or 7%, of the overall 

system cost. The fuel management system and thermal management system each 

contribute $4.3/kW, or 4%, of the overall system cost. Figure 65 shows a detailed 

breakout of the contributors to the system cost. 
86

Stack

63%

HX, Coolant 

Pumps, and Fan

4%

CEM and Air 

Filtration

13%

Enthalpy Wheel 

Humidifier

3%

Membrane 

Humidifier

4%

H2 Blower and 

Ejector

4%

Misc (Valves, 

Sensors, and 

Piping)

6% Assembly

3%

Figure 65. Detailed Breakout of System Cost 

A multi-variable sensitivity analysis was performed on the overall system cost. Power 

density, platinum cost, platinum loading, Nafion cost, graphite cost, carbon cloth cost, 

nitrile rubber cost, CEM cost, hydrogen blower cost, and radiator cost were varied 

simultaneously to obtain a mean system cost. Table 52 shows the parameter values 

selected for the system cost sensitivity analysis. 

Table 52. Parameter Values for the System Cost Sensitivity Analysis 

Parameter Units Minimum Baseline Maximum 

Power density mW/cm2

 350 600 800 

Pt cost $/troz 450 900 900 

Pt loading mg/cm2

 0.45 0.75 0.75 

Nafion cost $/kg 44 176 220 

Graphite cost $/lb 1 2 4 

Carbon cloth cost $/kg 15 30 60 

Nitrile rubber cost $/lb 3 5 8 

CEM cost $/unit 700 1080 1200 

H2 blower cost $/unit 200 300 500 

Radiator cost $/unit 183 220 260 

Figure 66 shows the relative impact of the different parameters on system cost. 

Consistent with the stack being the largest cost in the system, power density, platinum 

cost, and platinum loading are the top three drivers for the system cost. A group of seven 

parameters, including BOP component costs and stack material costs, are secondary 

drivers of system cost. 
87

Target Forecast: System Cost ($/kW)

Power Density (mW/cm^2) -. 71

Pt Cost ($/troz) .40

2005 Pt Loading (mg/cm^2) .32

Compressor/Expander .11

Nafion Cost ($/kg) .09

Graphite Material Cost ($/lbs) .07

Carbon Cloth Matl Cost .05

H2 Pump Cost .05

NBR Cost .04

HX Cost .03

-1 -0.5 0 0.5 1

Measured by Rank Correlation

Sensitivity Chart

Figure 66. Parametric Studies on System Cost 

Figure 67 shows the results of a Monte Carlo analysis for the same variation of input 

parameters with the mean system cost at $97/kW and with a standard deviation of 

$12/kW at a production volume of 500,000 units per year. For the chosen set of input 

parameters, there is a 98% probability that the mean system cost will be below the DOE 

target of $125/kW. 

108

12

97

$/kW

Mean

Std. Dev.

TIAX 

Baseline

Cost

108

12

97

$/kW

Mean

Std. Dev.

TIAX 

Baseline

Cost

2σ Mean $97/kW 2σ

Frequency Chart

Certainty is 98.02% from -Infinity to $125.00

.000

.005

.011

.016

.021

0

26.75

53.49

80.25

107

$60.00 $80.00 $100.00 $120.00 $140.00

5,000 Trials 4 Outliers

Forecast: System Cost ($/kW)

TIAX Baseline 

$108/kW

DOE 

Target 

$125/kW

Figure 67. Monte Carlo Analysis on System Cost 
88

9.6. Scenarios 

9.6.1. Lower Platinum Price 

We also costed a low platinum price scenario in which the platinum price is $450/troz 

with a 40% catalyst process mark-up. The analysis shows that the stack cost is $48/kW 

and the system cost is $88/kW. Compared with the baseline costs, the stack cost is about 

30% lower and the system cost is about 20% lower. The lower platinum cost only 

changes the electrode cost, which decreases by 40% from $52/kW to $32/kW. Table 53 

compares the $450/troz and $900/troz platinum price scenarios. 

Table 53. Low Platinum Price Scenario 

Platinum Price ($/troz) 

450 900 

Stack Cost ($/kW) 47.64 67.34 

System Cost ($/kW) 87.89 107.59 

Stack % of System Cost 54% 63% 

Electrode % of Stack Cost 68% 77% 

Catalyst Mark-up Over LME Platinum 

Price (%) 40% 20% 

9.6.2. Inclusion of Value Chain Costs 

In the baseline analysis, we assumed that the stack manufacture is vertically integrated, 

and the BOP components are purchased from suppliers. Alternatively, an OEM could 

also assemble purchased subsystems and accept the higher cost associated with 

outsourcing. One of the scenarios we considered in the cost model was that the OEM 

would assemble the fuel cell stack using purchased MEAs and bipolar plates. 

For the purpose of this analysis, we used margins of 30% on the various stack 

components. It should be noted that the BOP components are outsourced/purchased parts 

in the baseline analysis as well. If the OEM is assumed to be the stack integrator, the 

margin allocations may look as shown in Figure 68. 
89

Ionomer

Membrane

MEA

Assembly

Conditioning

Quality Control

Stack

Bipolar Plates

GDL

Catalyst

30%

20-40%

30%

Assembly

Quality Control

Powertrain

Vehicle Integration

System

30%

CEM HX Fuel 

mgmt.

Water 

mgmt.

%%% % Graphite

xx%

MEA

OEM

Figure 68. Illustrative Automotive PEMFC Supply Chain 

A sample calculation is outlined in Table 54 below. If value chain costs are included, our 

analyses show a 31% increase in the stack cost, from $67/kW to $88/kW, and a 19% 

increase in the system cost from $108/kW to $129/kW. 

Table 54. Value Chain Cost Calculation 

Component Vertically Integrated Stack Supply Chain Scenario 

Cost ($/kW) % margin Cost ($/kW) 

Stack 

Membrane 4.36 - 4.36 

Electrodes 52.08 - 52.08 

GDL 3.43 30% 4.46 

Seals 1.13 - 1.13 

MEA sub-total 61 30% 81 

 

Bipolar Plates 3.24 30% 4.21 

Balance-of-Stack 1.12 - 1.12 

Stack Assembly 1.96 - 1.96 

Stack sub-total 67 - 88 

System 

Balance-of-Plant 41 - 41 

System total 108 - 129 

9.7. Study Results Relative to DOE Targets 

The 2005 PEM fuel cell system meets the DOE targets for cost and specific power, but 

falls short of the DOE efficiency targets by five percentage points. The latter results from 

the decision to use a cell design voltage of 0.65V rather than 0.7 V. Table 55 summarizes 
90

the volume, weight, and cost of the various fuel cell subsystems and compares them to 

relevant DOE targets. 

Table 55. Summary of 2005 PEMFC System Results 

Subsystem Volume 

(L) 

Weight 

(kg) 

Cost 

($/kW) 

DOE 2005 

Target 

Stack 51 58 67 65 $/kW 

Stack power density (We/L) 1569 1500 We/L 

Stack specific power (We/kg) 1379 1500 We/kg 

Air management system (CEM, air filter) 15 17.5 13.5 

Fuel management system (blower, ejectors) 5.1 6.2 4.25 

Thermal management system (HT radiators, 

fan, coolant pump) 

25.5 20.5 4.25 

Water management system (enthalpy wheel, 

membrane humidifier) 

15 15 8 

Other components& Assembly 19 21 11 

BOP Subtotal 80 80 41 

Total 131 138 108 125 $/kW 

FC system power density (We/L) 610 500 We/L 

FC system specific power (We/kg) 580 500 We/kg 

FC system efficiency @ rated power 46% 50% 

FC system efficiency @ 25% rated power 55% 60% 

It should be noted that the volume estimates do not include a packing factor, which would 

lower the volumetric power density. If a packing factor is included, the 2005 system will 

not meet the DOE targets for fuel cell system power density. 

At the stack level, the stack cost is slightly higher than the DOE target of $65/kW. 

However, the stack meets the DOE target of 1500 We/kg for specific power and is close 

to the DOE target of 1500 We/L for stack power density. Decreased bipolar plate 

thickness and higher power density were the main drivers for increased stack power 

density. 

The fuel cell system efficiency falls short of the DOE system efficiency target of 46% at 

rated power. This is primarily because of the choice of cell voltage of 0.65 V, which 

results in a stack efficiency of 51.7% at rated power. For a cell voltage of 0.7 V, the 

stack efficiency is 55.3% at rated power, and fuel cell system efficiency is 49.8% at rated 

power. 

The baseline system contains 1.4 grams platinum per kilowatt. FreedomCAR and DOE 

roadmaps show values of 1.1 and 1.3 g Pt/kW respectively for the 2004 stack status 

similar to the baseline value from this study. 
91

10. Conclusions and Recommendations 

10.1. Key Drivers 

The summary at the front of the report provides an overview of the key findings. 

Additional discussion on the key drivers (power density, platinum price, and platinum 

loading) and BOP follows. 

The question of stack performance and platinum loading are key technical inputs into the 

cost projection and are also closely held data within the industry. We have provided the 

basis for our selection of parameters and tried to account for the impact of the uncertainty 

in these values on cost with the sensitivity analyses. Consideration of single cell currentvoltage data, performance degradation of the MEA, de-rating of the single cell 

performance in the stack to avoid hot-spots, and life are factors in selecting operating 

points and platinum loading. Additional industry input is needed to strengthen the basis 

for selection of these parameters. The ongoing Hydrogen Infrastructure and Fuel Cell 

vehicle technology validation effort between industry and the DOE may provide data on 

performance, life, and grams platinum per kW across a range of demonstration vehicles 

representative of current technology, however, low cost is probably a secondary 

consideration in this project. 

In this study, our primary focus was on technology advances such as power density, 

platinum loading, component design parameters (e.g., dimensions, sizing parameters), 

and material costs. Our projections for these parameters have been calibrated against 

industry estimates. However, of all the materials considered, the already high price of 

platinum ($/kg) is very sensitive to the existing supply/demand relationship and 

econometric factors including political events and growth in emerging economies such as 

China and India. The current high price of platinum is largely driven by strong demand 

from emerging economies (both for vehicle emissions control and jewelry) and the 

difficulties with expanding mining output in South Africa. We have tried to address the 

issue of platinum pricing by assuming today’s high cost for the baseline projection while 

using the historic price ($450/troz) as the minimum in the sensitivity analysis. In 

comparing the 2005 projection with earlier values, the reader should separate the changes 

in performance metrics (i.e., power density and platinum loading) from the econometric 

factors (i.e., platinum price). Historical data suggest the latter will come down, however, 

this will be an ongoing concern. 
92

10.2. Other Factors 

We started the cost project in 1998/1999 using a vertically integrated production process 

to project the stack manufacturing cost. This provides a minimum cost projection, but 

may not represent the reality of a fuel cell powertrain manufacturing value chain. We 

have included a value chain scenario to illustrate the potential impact of including 

supplier margins on the stack cost. Of course the assumed margins will be highly 

dependent on the competitive intensity for that component, the state of the technology of 

each developer, premiums for performance, and component demand relative to 

production capacity. The impact of value chain margins on stack cost could be on the 

order of 20% to 50% depending on these factors. 

Quality control technology, its implementation in production lines, and its reliability will 

have a significant impact on the yield of the stack process and product reliability. Fuel 

cells with their bipolar design, have many cells (hundreds) in series, consequently 

performance and reliability will be highly dependent on obtaining uniform material 

properties and eliminating point defects. Existing techniques (electrostatic, dielectric, and 

optical) may be used to monitor pinholes and thickness of the membrane, however, 

measuring the uniformity of electrochemical performance using methods that depend on 

many parameters including uniformity of catalyst loading and surface treatments, 

thickness of electrode layers, porosity, and pore size distribution of layers require 

development. At this time, these processes are proprietary and we have not included them 

in the stack cost. 

The cost of burn-in was considered as part of quality control on the stack. The cost of 

burn-in will depend on the time and equipment required for this step. This is also a 

proprietary topic and we were not able to obtain direction on which parameters to use. 

Currently, burn-in processes are not well understood, and developers indicated that this 

should be an area of research because it will impact manufacturing cost and product 

reliability of stacks. Engine tests are currently used to reduce product warranty costs in 

cars. 

Use of advanced hydrogen storage technologies will add hardware for thermal integration 

of the stack with the storage system. On a total system basis, this could lower cost, but it 

might make the stack subsystem more expensive. 

10.3. Recommendations 

As a result of our discussions with developers and our analysis the following areas may 

be the subject of future assessments: 

• A more in-depth look at BOP components including humidification and fuel 

management might be needed. The level of product design, manufacturing 

methods, and number of developer options were found to be at a much earlier 

stage of development than the stack. 
93

• What technology, material, design, and manufacturing advances are required in 

stack and BOP components to achieve the 2015 target of $30/kW for the fuel cell 

subsystem? In a materials intensive technology, increases in performance (kW/kg) 

and reductions in material cost ($/kg) are required to lower overall cost. 

Simultaneously, simplification of design will reduce components. 

• We have only considered a high-production volume scenario (500,000 units per 

year), while the cost as production volume ramps up to achieve economies of 

scale will be important to the commercialization process. Assessment of cost at 

lower production volumes will be important to estimating the incentives needed to 

introduce early products. 

• A more detailed look at the Quality Control requirements and technologies 

needed for high yields and reliable products would be important to the success of 

fuel cell powertrains. 
94

11. Acknowledgements 

We appreciated the support from NREL and the DOE in conducting this project. As in 

previous analyses, ANL’s system modeling support and experience in specification of 

fuel cell systems has been valuable in developing our results. 

Furthermore, the input and feedback from the FreedomCAR Fuel Cell Technical Team, 

stack component developers, stack developers, and BOP component developers has been 

very important to the development of input assumptions and designs that are 

representative of 2005 technology, while still protecting proprietary information. 

The Principal Investigator’s name appears on project reports and summaries, however, 

this report represents the efforts of a dedicated project team including Yong Yang 

(manufacturing cost model), Suresh Sriramulu (fuel cell technology), Jayanti Sinha 

(BOP), Peter Kopf (polymer processing), and Cathryn Firenze (administration and report 

preparation). 
95

12. Appendix 

12.1. $450/troz Baseline Cost Scenario 

The following figures provide cost breakdowns for the low-priced platinum scenario. 

Stack

54%

BOP

42%

Assembly

4%

Figure 69. Breakdown of System Cost for an 80 kW Direct Hydrogen Fuel Cell System (88 

$/kW, $450/troz platinum price) Produced at 500,000 Units per Year 

Stack

54%

HX, Coolant 

Pumps, and Fan

5%

CEM and Air 

Filtration

15%

Enthalpy Wheel 

Humidifier

4%

Membrane 

Humidifier

5%

H2 Blower and 

Ejector

5%

Misc (Valves, 

Sensors, and 

Piping)

8% Assembly

4%

Figure 70. Breakdown in Stack and BOP Component Cost Contributions for an 80 kW 

Direct Hydrogen Fuel Cell System ($88/kW, $450/troz platinum price) 
96

Membrane

9%

Electrode

69%

GDL

7%

Bipolar Plate

7%

Seal

2%

BOS

2%

Final Assembly

4%

Figure 71. Cost Breakdown for 2005 80 kW Direct Hydrogen Stack ($48/kW, $450/troz 

platinum price) 

48

13

56

$/kW

Mean

Std. Dev.

TIAX 

Baseline

Cost

48

13

56

$/kW

Mean

Std. Dev.

TIAX 

Baseline

Cost

TIAX Baseline 

$48/kW

DOE Target 

$65/kW

2σ Mean $56/kW 2σ

Frequency Chart

Certainty is 78.38% from -Infinity to $65.00 ($/kW)

.000

.009

.018

.026

.035

0

44.00

88.00

132

176

$30.00 $52.50 $75.00 $97.50 $120.00

5,000 Trials 0 Outliers

Forecast: 2005 Stack Cost ($/kW)

Figure 72. Range in Stack Cost due to Uncertainty in Input Parameters ($450/troz platinum 

price) 
97

88

13

95

$/kW

Mean

Std. Dev.

TIAX 

Baseline

Cost

88

13

95

$/kW

Mean

Std. Dev.

TIAX 

Baseline

Cost

Frequency Chart

Certainty is 97.62% from -Infinity to $125.00

.000

.008

.016

.025

.033

0

41

82

123

164

$60.00 $80.00 $100.00 $120.00 $140.00

5,000 Trials 16 Outliers

Forecast: System Cost ($/kW)

TIAX Baseline 

$88/kW

DOE 

Target 

$125/kW

2σ Mean $95/kW 2σ

Figure 73. Range in System Cost due to Uncertainty in Input Parameters ($450/troz 

platinum price) 
98

13. References 

1. Carlson, E., “Cost Analyses of Fuel Cell Stacks/Systems,” for the Department of 

Energy, DOE Program Manager –Garland, N.; Prime Contract No. DE-FC02-

99EE50587. 

2. Carlson, E.; Thijssen, J.; Lasher, S.; Sriramulu, S.; Stevens, G.; Garland, N., 

“Cost Modeling of PEM Fuel Cell Systems for Automobiles”, Future Car 

Congress, Paper 2002-01-1930, Society of Automotive Engineers (2002). 

3. Ahluwalia, R.K. and Wang, X., “Direct Hydrogen Fuel Cell Systems for Hybrid 

Vehicles,” Journal of Power Sources, in print now. 

4. Ahluwalia, R.K.; Wang, X. and Rousseau, A., “Fuel Economy of Hybrid Fuel 

Cell Vehicles,” 2004 Fuel Cell Seminar, San Antonio, TX, Nov. 2-5, 2004. 

5. Curtin, D.E. and Watkins, M.A., “High Volume, Low Cost Manufacturing 

Process for Nafion® Membranes,” 2002 Fuel Cell Seminar, Palm Springs 

(November 2002)

6. Ahluwalia, R.K.; Wang, X.; Doss, E.D.; and Kumar, R., "Fuel Cell Systems 

Analysis." 2005 USDOE Hydrogen, Fuel Cells & Infrastructure Technologies 

Program Review, Crystal City VA, May 2005. 

7. Ahluwalia, R.K.; Wang, X.; Doss, E.D.; and Kumar, R., “Transportation Systems 

and Balance of Plant Components,” DOE Hydrogen Program, FY 2004 Progress 

Report, pp. 511-515. 

8. Mittelsteadt, C. and Umbrell, M. of Giner Electrochem, “Gas Permeability in 

Perfluorinated Sulfonic Acid Polymer Electrolyte Membranes,” 207th ECS 

Meeting, Quebec City, CA, May 2005. 

9. Cleghorn, S. of DuPont, "A Portfolio of Cost Effective MEA Products," Grove 

Seminar Presentation, London, September 2003. 

10. http://www.bcconverting.com/content/2prodline/coatingtapelbl.htm

11. Gebert, M.; Hohlein, B. et al., "Benchmark Cost Analysis of Main PEFC-Ionomer 

Membrane Solutions." Trans. of the ASME, Journal of Fuel Cell Science and 

Technology, Vol. 1, pp. 56-60, Nov. 2004. 

12. “Crystal Ball User’s Manual,” Version 4.0, Decisioneering, Inc., 1999. 
99

13. Mathias, M.; Gasteiger, H., et al. of General Motors Corp., "Can Available 

Membranes and Catalysts Meet Automotive Polymer Electrolyte Fuel Cell 

Requirements?" Am. Chem. Soc. Preprints, Div. Fuel Chem., 49 (2), 471, 2004. 

14. Carlson, E; Huang, Y.; and Noordzij, M., “Precious Metal Availability and 

Economic Analysis for PEMFC Vehicle Commercialization,” 2003 Fuel Cell 

Seminar, Miami Beach (November 2003). 

Carlson, E., “Precious Metal Availability and Cost Analysis for PEMFC,” 

Commercialization Project for the Department of Energy, DOE Program Manager 

–Anderson, A., Prime Contract No. DE-FC04-01AL67601 

Final report reference DOE web-site: 

http://www.eere.energy.gov/hydrogenandfuelcells/pdfs/tiax_platinum.pdf 

15. Carlson, E., “DOE Hydrogen Program FY2004 Progress Report, V.I.4 Cost 

Analyses of Fuel Cell Stacks/Systems, Discussion of Cost Assessment of 

Compressed Hydrogen Storage Tank Costs,” DOE Program Manager – Garland, 

N., Prime Contract No. DE-FC02-99EE50587. 

16. Gangi, J., "Fuel Cells in Transportation Applications," Fuel Cells 2000, Hydrogen 

Technology Forum, Washington DC, June 2004 

17. Gee, M. of Honeywell, "Cost and Performance Enhancements for a PEM Fuel 

Cell System," DOE Hydrogen Program, FY 2004 Progress Report, pp. 531-533. 

18. Energy & Environmental Analysis Inc., “Analysis and Forecast of the 

Performance and Cost of Conventional and Electric-Hybrid Vehicles,” Prepared 

for the California Energy Commission (CEC), P600-02-13CR, March 2002. 
F1146-E(12/2004) 

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1. REPORT DATE (DD-MM-YYYY)

December 2005 

2. REPORT TYPE

Subcontract Report 

3. DATES COVERED (From - To)

through September 30, 2005 

4. TITLE AND SUBTITLE

Cost Analysis of PEM Fuel Cell Systems for Transportation 

5a. CONTRACT NUMBER

DE-AC36-99-GO10337 

5b. GRANT NUMBER

5c. PROGRAM ELEMENT NUMBER

6. AUTHOR(S)

E.J. Carlson, P. Kopf, J. Sinha, S. Sriramulu, and Y. Yang 

5d. PROJECT NUMBER

NREL/SR-560-39104 

5e. TASK NUMBER

HF55.8100 

5f. WORK UNIT NUMBER

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

TIAX LLC 

15 Acorn Park 

Cambridge, Massachusetts 02140-2390 

8. PERFORMING ORGANIZATION 

REPORT NUMBER

KACX-5-44452-00 

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

National Renewable Energy Laboratory 

1617 Cole Blvd. 

Golden, CO 80401-3393 

10. SPONSOR/MONITOR'S ACRONYM(S)

NREL 

11. SPONSORING/MONITORING 

AGENCY REPORT NUMBER

NREL/SR-560-39104 

12. DISTRIBUTION AVAILABILITY STATEMENT

National Technical Information Service 

U.S. Department of Commerce 

5285 Port Royal Road 

Springfield, VA 22161 

13. SUPPLEMENTARY NOTES

NREL Technical Monitor: Keith Wipke 

14. ABSTRACT (Maximum 200 Words)

The results of sensitivity and Monte Carlo analyses on PEM fuel cell components and the overall system are 

presented including the most important cost factors and the effects of selected scenarios. 

15. SUBJECT TERMS

PEMFC; fuel cell; cost analyses 

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OF ABSTRACT

UL 

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