Technical Report

NREL/TP-560-46267

September 2009

Analyzing the Levelized Cost of 

Centralized and Distributed 

Hydrogen Production Using the 

H2A Production Model, Version 2

T. Ramsden and D. Steward

National Renewable Energy Laboratory

J. Zuboy

Independent Contractor
National Renewable Energy Laboratory

1617 Cole Boulevard, Golden, Colorado 80401-3393

303-275-3000 • www.nrel.gov

NREL is a national laboratory of the U.S. Department of Energy

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Operated by the Alliance for Sustainable Energy, LLC

Contract No. DE-AC36-08-GO28308

Technical Report

NREL/TP-560-46267

September 2009

Analyzing the Levelized Cost of 

Centralized and Distributed 

Hydrogen Production Using the 

H2A Production Model, Version 2

T. Ramsden and D. Steward

National Renewable Energy Laboratory

J. Zuboy

Independent Contractor

Prepared under Task No. H278.3100
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iii

Executive Summary

The U.S. Department of Energy’s (DOE) Hydrogen, Fuel Cells, and Infrastructure Technologies 

Program is exploring the necessary hydrogen production, delivery, storage, and fuel cell 

technologies needed to commercialize fuel cell vehicles and hydrogen fuel infrastructure. A key 

component of the DOE Hydrogen Program’s R&D effort is investigation of the potential costs of 

these hydrogen technologies, including the cost of hydrogen production. 

This report presents an analysis of the levelized cost of producing hydrogen via different 

pathways using the National Renewable Energy Laboratory’s (NREL) H2A Hydrogen 

Production Model, Version 2. NREL developed the H2A Production Model in 2002 to help

DOE’s Hydrogen Program understand the cost of producing hydrogen for the transportation 

market. The model enables technical and economic analysis of central and distributed (i.e., at the 

fueling station, or “forecourt”) hydrogen production technologies. Using a standard discounted 

cash flow rate of return methodology, it determines the levelized hydrogen cost, including a 

specified after-tax internal rate of return on investments. The cost calculation is based on a wide 

variety of inputs that characterize financial assumptions as well as capital, operating, maintenance, 

feedstock, utility, and replacement costs. The recently released Version 2 of the model features 

enhanced usability and functionality. Input fields are consolidated and simplified. New capabilities 

include performing sensitivity analyses and scaling analyses to various plant sizes.

To enhance long-term energy security, DOE envisions that hydrogen will be produced from 

various energy sources using a range of processing methods, including large-scale centralized 

and small-scale distributed production. Although the cost of producing hydrogen from these 

different pathways will vary from region to region based on feedstock availability and cost, a 

consistent analysis methodology is important for understanding and comparing costs associated 

with each pathway. With input from a team of hydrogen experts, NREL developed 19 

standardized H2A production technology cases, enabling analysis of levelized hydrogen 

production costs from centralized and distributed facilities using eight general production 

pathways:

• Central biomass gasification

• Central grid electrolysis

• Central coal gasification (with and without carbon sequestration)

• Central natural gas reforming (with and without carbon sequestration)

• Central nuclear-based high-temperature electrolysis

• Distributed natural gas reforming

• Distributed grid electrolysis

• Distributed ethanol reforming.

For each pathway, currently available and expected future technologies were analyzed (except 

for the central nuclear case, which only includes a future case). Figure ES - 1 shows the 

calculated hydrogen production cost (per kilogram of hydrogen produced) for each technology 
iv

case and timeframe. The values represent the levelized production cost of hydrogen (in 2005$), 

including a 10% after-tax internal rate of return on investments (this cost can also be thought of 

as the minimum selling price of hydrogen, although the actual hydrogen price will be driven by 

the market). 

The levelized hydrogen production cost ranges from approximately $1.30 to $4.50 per kilogram, 

with the lowest production costs associated with traditional fossil fuel pathways such as coal and 

natural gas. However, once the costs associated with carbon capture and sequestration are 

included, production of hydrogen from renewable biomass resources becomes one of the most 

cost-competitive pathways. 

$0.00

$0.50

$1.00

$1.50

$2.00

$2.50

$3.00

$3.50

$4.00

$4.50

$5.00

Natural Gas

Coal

Natural Gas

w/Seq

Biomass

Coal w/Seq

Nuclear

Electrolysis

Natural Gas

Ethanol

Electrolysis

Cost per kg of Hydrogen Produced (2005$)

Current

Future

Central Forecourt

Costs are for hydrogen production and carbon sequestration only; delivery, compression, storage, and dispensing costs are not

included.

Figure ES - 1. Levelized Hydrogen Production Cost: All Technology Cases.

DOE’s goal is to reduce the untaxed levelized cost of hydrogen to $2.00 to $3.00 per gasoline 

gallon equivalent (GGE) delivered at the pump, regardless of the technology pathway used. (A 

kilogram of hydrogen has about the same energy content as a gallon of gasoline, i.e., it is about 1 

GGE.) The H2A Production Model does not address delivery and dispensing costs for central 

cases, but it does analyze levelized hydrogen compression, storage, and dispensing (CSD) costs 

for forecourt cases because these functions will be included at the same fueling station site as the 

hydrogen production operations. Overall, CSD costs are expected to total about $1.90 per 

kilogram of hydrogen dispensed. Given these costs, which are not included in Figure ES - 1, the 

total levelized cost of dispensed hydrogen for the forecourt pathways ranges from about $3.50 

per kilogram for onsite natural gas reformation to about $6.00 per kilogram for onsite 
v

electrolysis ($5.00/kg in the future). This cost might be improved in the future as better CSD

technologies are developed and modeled.

This report also presents analyses of process energy efficiency—the ratio of process energy 

output to input—for the various hydrogen production pathways. Process energy efficiency 

indicates the quantity of resources needed to produce hydrogen and is therefore an important 

indicator of the efficient use of domestic resources. The future nuclear case has the highest 

process energy efficiency at 83%; the current biomass case has the lowest at 46% (Figure ES -

2).

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Natural Gas

Coal

Natural Gas

w/Seq

Biomass

Coal w/Seq

Nuclear

Electrolysis

Natural Gas

Ethanol

Electrolysis

Production Process Energy Efficiency 

(energy outputs divided by energy inputs)

Current

Future

Central Forecourt

Energy inputs and outputs are for hydrogen production and carbon sequestration only; compression, storage, and dispensing 

energy is not included. All values were calculated using LHVs.

Figure ES - 2. Process Energy Efficiency: All Technology Cases
vi

Table of Contents

Executive Summary....................................................................................................................... iii

Table of Contents........................................................................................................................... vi

List of Figures............................................................................................................................... vii

List of Tables ............................................................................................................................... viii

Introduction......................................................................................................................................1

H2A Hydrogen Production Model...................................................................................................1

H2A Production Model Functions.............................................................................................2

H2A Production Technology Cases...........................................................................................3

Overview of Levelized Hydrogen Production Cost and Energy Use ..............................................6

Levelized Hydrogen Production Cost........................................................................................7

Process Energy.........................................................................................................................12

Sensitivity Analysis .................................................................................................................15

Detailed Levelized Hydrogen Production Cost Results.................................................................16

Common Input Parameters and Processes.....................................................................................16

Central Cases .................................................................................................................................19

Biomass Gasification ...............................................................................................................19

Process Description............................................................................................................19

H2A Model Inputs.............................................................................................................22

H2A Model Results............................................................................................................24

Grid Electrolysis......................................................................................................................27

Process Description............................................................................................................27

H2A Model Inputs.............................................................................................................30

H2A Model Results............................................................................................................31

Coal without CO2 Sequestration ..............................................................................................35

Process Description............................................................................................................35

H2A Model Inputs.............................................................................................................37

H2A Model Results............................................................................................................39

Coal with CO2 Sequestration ...................................................................................................42

Process Description............................................................................................................42

H2A Model Inputs.............................................................................................................44

H2A Model Results............................................................................................................46

Natural Gas without CO2 Sequestration ..................................................................................49

Process Description............................................................................................................49

H2A Model Inputs.............................................................................................................49

H2A Model Results............................................................................................................51

Natural Gas with CO2 Sequestration........................................................................................54

Process Description............................................................................................................54

H2A Model Inputs.............................................................................................................55

H2A Model Results............................................................................................................57

Nuclear Energy via High-Temperature Electrolysis................................................................60

Process Description............................................................................................................60

H2A Model Inputs.............................................................................................................60

H2A Model Results............................................................................................................62

Forecourt Cases..............................................................................................................................64
vii

Grid Electrolysis......................................................................................................................65

Process Description............................................................................................................65

H2A Model Inputs.............................................................................................................67

H2A Model Results............................................................................................................69

Natural Gas..............................................................................................................................73

Process Description............................................................................................................73

H2A Model Inputs.............................................................................................................76

H2A Model Results............................................................................................................77

Ethanol.....................................................................................................................................80

Process Description..................................................................................................................80

H2A Model Inputs...................................................................................................................84

H2A Model Results..................................................................................................................85

Sources...........................................................................................................................................89

List of Figures

Figure ES - 1. Levelized Hydrogen Production Cost: All Technology Cases............................... iv

Figure ES - 2. Process Energy Efficiency: All Technology Cases..................................................v

Figure 1. Schematic of Data Flow Among H2A Worksheets..........................................................3

Figure 2. Hydrogen Production Design Capacity: All Technology Cases ......................................6

Figure 3. Levelized Hydrogen Production Cost: All Technology Cases.........................................8

Figure 4. Contributions to Levelized Hydrogen Production Cost: Current Technology Cases.....10

Figure 5. Contributions to Levelized Hydrogen Production Cost: Future Technology Cases ......11

Figure 6. Capital Investment Relative to Production Design Capacity: All Technology Cases....11

Figure 7. Contributions to Delivered Levelized Hydrogen Cost: Forecourt Technology Cases...12

Figure 8. Process Energy Inputs and Outputs: Current Technology Cases...................................13

Figure 9. Process Energy Inputs and Outputs: Future Technology Cases.....................................14

Figure 10. Process Energy Efficiency: All Technology Cases......................................................14

Figure 11. Example "Tornado Chart" (Current Coal without CO2 Sequestration Case)...............15

Figure 12. Variables Producing the Largest Effects in Sensitivity Analyses................................16

Figure 13. Process Flow Diagram—Current Biomass Gasification ..............................................21

Figure 14. Process Flow Diagram—Future Biomass Gasification................................................22

Figure 15. Central Current Biomass: Sensitivity Analysis Results...............................................26

Figure 16. Central Future Biomass: Sensitivity Analysis Results.................................................27

Figure 17. Process Flow Diagram—Grid Electrolysis ..................................................................29

Figure 18. Central Current Grid Electrolysis: Sensitivity Analysis Results..................................34

Figure 19. Central Future Grid Electrolysis: Sensitivity Analysis Results....................................34

Figure 20. Process Flow Diagram—Current Coal without CO2 Sequestration.............................36

Figure 21. Process Flow Diagram—Future Coal without CO2 Sequestration...............................36

Figure 22. Central Current Coal without CO2 Sequestration: Sensitivity Analysis Results..........41

Figure 23. Central Future Coal without CO2 Sequestration: Sensitivity Analysis Results ...........42

Figure 24. Process Flow Diagram—Current Coal with CO2 Sequestration ..................................43

Figure 25. Process Flow Diagram—Future Coal with CO2 Sequestration....................................44

Figure 26. Central Current Coal with CO2 Sequestration: Sensitivity Analysis Results...............48

Figure 27. Central Future Coal with CO2 Sequestration: Sensitivity Analysis Results.................48
viii

Figure 28. Process Flow Diagram—Natural Gas without CO2 Sequestration...............................49

Figure 29. Central Current Natural Gas without CO2 Sequestration: Sensitivity Analysis Results53

Figure 30. Central Future Natural Gas without CO2 Sequestration: Sensitivity Analysis Results54

Figure 31. Process Flow Diagram—Natural Gas with CO2 Sequestration....................................55

Figure 32. Central Current Natural Gas with CO2 Sequestration: Sensitivity Analysis Results...59

Figure 33. Central Future Natural Gas with CO2 Sequestration: Sensitivity Analysis Results.....59

Figure 34. Process Flow Diagram—Nuclear Energy via High-Temperature Electrolysis............60

Figure 35. Central Nuclear Energy via High-Temperature Electrolysis: Sensitivity Analysis 

Results......................................................................................................................................64

Figure 36. Process Flow Diagram—Grid Electrolysis ..................................................................66

Figure 37. Forecourt Current Grid Electrolysis: Sensitivity Analysis Results..............................71

Figure 38. Forecourt Future Grid Electrolysis: Sensitivity Analysis Results................................72

Figure 39. Process Flow Diagram—Current Natural Gas.............................................................74

Figure 40. Process Flow Diagram—Future Natural Gas...............................................................75

Figure 41. Forecourt Current Natural Gas: Sensitivity Analysis Results......................................79

Figure 42. Forecourt Future Natural Gas: Sensitivity Analysis Results........................................80

Figure 43. Process Flow Diagram—Current Ethanol....................................................................82

Figure 44. Process Flow Diagram—Future Ethanol......................................................................83

Figure 45. Forecourt Current Ethanol: Sensitivity Analysis Results.............................................87

Figure 46. Forecourt Future Ethanol: Sensitivity Analysis Results...............................................88

List of Tables

Table 1. Highlights of H2A Production Model, Version 2..............................................................2

Table 2. H2A Hydrogen Production Technology Cases..................................................................4

Table 3. Common Input Parameters and Processes for Production Technology Cases ................17

Table 4. Central Biomass: Technical Operating Parameters and Specifications...........................22

Table 5. Central Biomass: Cost Input Summary ...........................................................................23

Table 6. Central Biomass: Energy Input Summary .......................................................................24

Table 7. Central Biomass: Cost Results Summary ........................................................................24

Table 8. Central Biomass: Process Energy Results Summary.......................................................25

Table 9. Central Current Biomass: Sensitivity Analysis Values ...................................................26

Table 10. Central Future Biomass: Sensitivity Analysis Values...................................................27

Table 11. Central Grid Electrolysis: Technical Operating Parameters and Specifications ...........30

Table 12. Central Grid Electrolysis: Cost Input Summary............................................................31

Table 13. Central Grid Electrolysis: Energy Input Summary........................................................31

Table 14. Central Grid Electrolysis: Cost Results Summary.........................................................32

Table 15. Central Grid Electrolysis: Process Energy Results Summary .......................................33

Table 16. Central Current Grid Electrolysis: Sensitivity Analysis Values....................................33

Table 17. Central Future Grid Electrolysis: Sensitivity Analysis Values......................................33

Table 18. Central Coal without CO2 Sequestration: Technical Operating Parameters and 

Specifications...........................................................................................................................37

Table 19. Central Coal without CO2 Sequestration: Cost Input Summary....................................38

Table 20. Central Coal without CO2 Sequestration: Energy Input Summary ...............................39

Table 21. Central Coal without CO2 Sequestration: Cost Results Summary ................................39

Table 22. Central Coal without CO2 Sequestration: Process Energy Results Summary...............40
ix

Table 23. Central Current Coal without CO2 Sequestration: Sensitivity Analysis Values............41

Table 24. Central Future Coal without CO2 Sequestration: Sensitivity Analysis Values .............42

Table 25. Central Coal with CO2 Sequestration: Technical Operating Parameters and 

Specifications...........................................................................................................................44

Table 26. Central Coal with CO2 Sequestration: Cost Input Summary.........................................45

Table 27. Central Coal with CO2 Sequestration: Energy Input Summary.....................................46

Table 28. Central Coal with CO2 Sequestration: Cost Results Summary......................................46

Table 29. Central Coal with CO2 Sequestration: Process Energy Results Summary ....................47

Table 30. Central Current Coal with CO2 Sequestration: Sensitivity Analysis Values.................47

Table 31. Central Future Coal with CO2 Sequestration: Sensitivity Analysis Values...................47

Table 32. Central Natural Gas without CO2 Sequestration: Technical Operating Parameters and 

Specifications...........................................................................................................................50

Table 33. Central Natural Gas without CO2 Sequestration: Cost Input Summary ........................51

Table 34. Central Natural Gas without CO2 Sequestration: Energy Input Summary....................51

Table 35. Central Natural Gas without CO2 Sequestration: Cost Results Summary.....................52

Table 36. Central Natural Gas without CO2 Sequestration: Process Energy Results Summary ...52

Table 37. Central Current Natural Gas without CO2 Sequestration: Sensitivity Analysis Values53

Table 38. Central Future Natural Gas without CO2 Sequestration: Sensitivity Analysis Values..54

Table 39. Central Natural Gas with CO2 Sequestration: Technical Operating Parameters and 

Specifications...........................................................................................................................56

Table 40. Central Natural Gas with CO2 Sequestration: Cost Input Summary .............................56

Table 41. Central Natural Gas with CO2 Sequestration: Energy Input Summary.........................57

Table 42. Central Natural Gas with CO2 Sequestration: Cost Results Summary..........................57

Table 43. Central Natural Gas with CO2 Sequestration: Process Energy Results Summary ........58

Table 44. Central Current Natural Gas with CO2 Sequestration: Sensitivity Analysis Values.....58

Table 45. Central Future Natural Gas with CO2 Sequestration: Sensitivity Analysis Values.......58

Table 46. Central Nuclear Energy via High-Temperature Electrolysis: Technical Operating 

Parameters and Specifications.................................................................................................61

Table 47. Central Nuclear Energy via High-Temperature Electrolysis: Cost Input Summary .....62

Table 48. Central Nuclear Energy via High-Temperature Electrolysis: Energy Input Summary .62

Table 49. Central Nuclear Energy via High-Temperature Electrolysis: Cost Results Summary ..63

Table 50. Central Nuclear Energy via High-Temperature Electrolysis: Process Energy Results 

Summary..................................................................................................................................63

Table 51. Central Nuclear Energy via High-Temperature Electrolysis: Sensitivity Analysis 

Values ......................................................................................................................................64

Table 52. Forecourt Grid Electrolysis: Cost Input Summary ........................................................68

Table 53. Forecourt Grid Electrolysis: Energy Input Summary....................................................69

Table 54. Forecourt Grid Electrolysis: Cost Results Summary.....................................................69

Table 55. Forecourt Grid Electrolysis: Process Energy Results Summary ...................................70

Table 56. Forecourt Current Grid Electrolysis: Sensitivity Analysis Values................................71

Table 57. Forecourt Future Grid Electrolysis: Sensitivity Analysis Values..................................72

Table 58. Forecourt Natural Gas: Cost Input Summary ................................................................76

Table 59. Forecourt Natural Gas: Energy Input Summary............................................................77

Table 60. Forecourt Natural Gas: Cost Results Summary.............................................................78

Table 61. Forecourt Natural Gas: Process Energy Results Summary ...........................................78

Table 62. Forecourt Current Natural Gas: Sensitivity Analysis Values........................................79
x

Table 63. Forecourt Future Natural Gas: Sensitivity Analysis Values..........................................80

Table 64. Forecourt Ethanol: Cost Input Summary.......................................................................84

Table 65. Forecourt Ethanol: Energy Input Summary...................................................................85

Table 66. Forecourt Ethanol: Cost Results Summary....................................................................86

Table 67. Forecourt Ethanol: Process Energy Results Summary ..................................................86

Table 68. Forecourt Current Ethanol: Sensitivity Analysis Values...............................................87

Table 69. Forecourt Future Ethanol: Sensitivity Analysis Values.................................................88
1

Introduction

In 2003, President Bush announced the Hydrogen Fuel Initiative to promote the development of 

hydrogen and fuel cell technologies. The Initiative's goal is to reduce U.S. dependence on foreign 

oil while addressing the environmental impacts of the transportation sector by reducing air 

pollution and greenhouse gas emissions associated with climate change. The U.S. Department of 

Energy’s (DOE) Hydrogen, Fuel Cells, and Infrastructure Technologies Program is helping

develop the hydrogen production, delivery, storage, and fuel cell technologies needed to 

commercialize fuel cell vehicles and hydrogen fuel infrastructure. A key component of the 

Hydrogen Program’s R&D effort is investigation of the potential costs of these technologies, 

including the cost of hydrogen production. 

This report presents an analysis of the levelized cost of producing hydrogen via different 

pathways using the National Renewable Energy Laboratory’s (NREL) H2A Hydrogen 

Production Model, Version 2. NREL developed the H2A Production Model in 2002 to help the

Hydrogen Program understand the cost of producing hydrogen for the transportation market.

NREL recently completed a significant revision to the model. At the same time, with the input of 

a team of hydrogen experts, NREL developed 19 standardized hydrogen production technology 

cases, analyzing hydrogen production from centralized and distributed facilities. 

The first section of this report provides background on the H2A Production Model's purpose and 

functions. This is followed by a summary of modeling results for the 19 H2A production 

technology cases (page 6). The remainder of the report includes input parameters and processes

common to all H2A technology cases (page 16) as well as unique inputs and results for specific 

central (page 19) and forecourt (page 64) technology cases.

H2A Hydrogen Production Model

To enhance long-term energy security, DOE envisions hydrogen produced from various energy 

sources using a range of processing methods, including large-scale centralized and small-scale 

distributed production. Although the actual cost of producing hydrogen from these pathways will 

vary from region to region based on feedstock availability and cost, it is important to better 

understand current and potential costs of the range of hydrogen production technologies. The 

H2A Production Model is an analytical tool that provides a consistent analysis methodology and 

allows transparent understanding and reporting of hydrogen production costs.

The H2A Production Model enables the technical and economic analysis of central and 

distributed (i.e., fueling station or "forecourt") hydrogen production technologies. Using a 

standard discounted cash flow rate of return methodology1

 1 Short, W.; Packey, D. J.; Holt, T, A Manual for the Economic Evaluation of Energy Efficiency and Renewable 

Energy Technologies. NREL/TP-462-5173. Golden, CO: National Renewable Energy Laboratory, March 1995.

, it determines the levelized hydrogen 

cost (minimum selling price) to achieve a net present value (NPV) of zero, including a specified 

after-tax internal rate of return on investments. The cost calculation is based on a wide variety of 

inputs that characterize financial assumptions as well as capital, operating, maintenance, 

feedstock, utility, and replacement costs. Model users can provide their own inputs or can begin 

with any of the 19 standard technology case studies developed in conjunction with the H2A 
2

model. With these technology cases, users can accept default technology input values or enter

their own custom values. Users can also modify the model's financial inputs.

Version 2 of the H2A Production Model features enhanced usability and functionality. Input 

fields are consolidated and simplified. New capabilities include performing sensitivity analyses 

and scaling analyses to various plant sizes. Table 1 lists highlights of Version 2. Visit 

www.hydrogen.energy.gov/h2a_production.html to download Version 2 and its user guide.

Table 1. Highlights of H2A Production Model, Version 2

Enhanced usability

• Clarified definitions, assumptions, and default values

• Consolidated and simplified input fields

New functionality

• Flexible analysis capability

• Sensitivity analyses and tornado charts

• Easy plant scaling

• Upstream energy use and greenhouse gas emissions estimates (based on GREET Model2

• Process energy efficiency and greenhouse gas emissions estimates

)

• Carbon tax calculations based on feedstock carbon content and upstream energy use, credits for 

carbon sequestration

• Forecourt hydrogen compression, storage, and dispensing modeling (based on H2A Delivery

Analysis Scenario and Carrier Components Models3

• Central CO2 compression, transportation, and injection calculations

)

• Easy importing, exporting, and printing of data and results

New and updated technology cases

• Central production of hydrogen

o Biomass gasification

o Grid-based electrolysis

o Coal gasification (with and without carbon sequestration)

o Natural gas reforming (with and without carbon sequestration)

o Nuclear—high-temperature electrolysis

• Distributed production of hydrogen

o Electrolysis

o Natural gas reforming

o Ethanol reforming

H2A Production Model Functions

The H2A Production Model is actually two models: one Microsoft Excel workbook to analyze 

centralized hydrogen production technologies and another to analyze distributed/forecourt

hydrogen production technologies for use at fueling stations. The two models are very similar. 

The primary difference is that the central model ends at the plant gate, i.e., it accounts for 

production but not distribution of hydrogen, whereas the forecourt model performs fueling 

 2 Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) Model, 

www.transportation.anl.gov/software/GREET. 3 H2A Delivery Scenario Analysis and Delivery Carrier Components Models, 

www.hydrogen.energy.gov/h2a_delivery.html.
3

station compression, storage, and dispensing calculations adapted from the H2A Delivery 

Scenario Analysis and Delivery Carrier Components models. The central model performs carbon 

sequestration calculations.

The model workbooks are organized into 19 or more worksheets, which have tabs color coded 

according to their function. Figure 1 shows the data flow among worksheets. In general, users 

can select from the slate of standard production cases or can input their simulated hydrogen 

production facility's technical operating parameters and specifications; financial input values; 

energy feedstocks, utilities, and byproducts; capital costs; and fixed and variable operating costs. 

The model uses these inputs—along with price data and physical properties of process 

materials—to calculate projected levelized hydrogen cost and approximate process energy use 

and greenhouse gases emissions. For detailed information about the model, download its user 

guide at www.hydrogen.energy.gov/h2a_production.html.

Figure 1. Schematic of Data Flow Among H2A Worksheets

H2A Production Technology Cases

As part of the H2A Production Model development, NREL worked with a team of "key 

industrial collaborators" from hydrogen-related industries as well as numerous government, 

academic, and consulting experts to model 19 specific hydrogen production pathways reflecting 

eight general production methods (Table 2). Input parameters were defined by experts in the 
4

design and advancement of technologies for each production method. Seven of the production 

methods were modeled based on current technology (assumed to be available as of 2005, the 

year in which the technology cases were first published) and future technology (assumed to be 

available in the 2020–2030 timeframe). The central coal and natural gas pathways were also

modeled with and without carbon capture and sequestration. Hydrogen production from nuclear 

energy was modeled as a future case only (with an assumed startup in 2030). 

As the transportation market for hydrogen develops, it is likely that hydrogen initially will be 

produced in a distributed fashion at the fueling station. Distributed production will be 

accomplished via onsite reformation of natural gas and renewable ethanol and via onsite water 

electrolysis. Once the hydrogen market is more established, these distributed production facilities 

will be augmented with larger, centralized hydrogen production facilities that make hydrogen 

using fossil fuels (including coal and natural gas), nuclear power, and renewable energy sources

(including biomass and wind-generated electricity). Hydrogen produced at these central facilities 

will be delivered to fueling sites initially using trucks and, later, pipelines. The H2A technology 

cases were developed to reflect this full range of production techniques.

Table 2. H2A Hydrogen Production Technology Cases

Central production technologies

Biomass

1. Current biomass gasification (version 2.1.2)

2. Future biomass gasification (version 2.1.2)

Electrolysis

3. Current grid electrolysis (version 2.1.1)

4. Future grid electrolysis (version 2.1.1)

Coal

5. Current coal without carbon sequestration (version 2.1.1)

6. Future coal without carbon sequestration (version 2.1.1)

7. Current coal with carbon sequestration (version 2.1.1)

8. Future coal with carbon sequestration (version 2.1.1)

Natural gas

9. Current natural gas without carbon sequestration (version 2.1.1)

10.Future natural gas without carbon sequestration (version 2.1.1)

11.Current natural gas with carbon sequestration (version 2.1.1)

12.Future natural gas with carbon sequestration (version 2.1.1)

Nuclear

13.Future nuclear via high-temperature electrolysis (version 2.1.1)

Forecourt production technologies

Electrolysis

14.Current grid electrolysis (version 2.1.2)

15.Future grid electrolysis (version 2.1.2)

Natural gas

16.Current natural gas (version 2.1.1)

17.Future natural gas (version 2.1.1)

Ethanol

18.Current ethanol (version 2.1.2)

19.Future ethanol (version 2.1.2)

Figure 2 shows the wide variety of hydrogen production design capacities among the various 

H2A cases. The central cases were modeled to produce at least 50,000 kg of hydrogen per day, 
5

but the design capacities vary depending on the technology modeled. The current central cases 

have hydrogen production capacities ranging from approximately 52,000 to 820,000 kg of 

hydrogen per day, with each plant design optimized for its specific production capacity. At the 

high end, the minimum practical size requirements of a nuclear facility dictate that the 

production plant be designed to produce a very large amount of hydrogen. At the low end, for 

central electrolysis, multiple electrolyzers will need to be installed to attain 52,000 kg/day of 

production; the modular nature of the design could easily allow higher production rates, although 

the per-kilogram hydrogen cost is not expected to be lower. Biomass-based production facilities 

were modeled with a capacity of approximately 150,000 kg/day. This plant size is driven not by 

the biomass gasification technology but rather by the distance from which biomass feedstock can 

be delivered economically.

All the forecourt cases model facilities that produce 1,500 kg of hydrogen per day. In addition to 

their advantage of eliminating the need for an extensive hydrogen delivery infrastructure, 

distributed production facilities can be sized to match the hydrogen demand of the local area. To 

facilitate easy comparisons across technology pathways, the standard H2A cases are all based on 

a 1,500-kg/day production capacity.

The technology cases include not only the designed production capacity, discussed above, but 

also the potential plant output. Because of plant outages and scheduled maintenance, actual plant 

output will be less than design capacity. The default capacity factor—which is multiplied by the 

design capacity to calculate plant output—is 90% for central cases (with some exceptions) and 

about 85% for forecourt cases.

The capacity factor for the forecourt stations was calculated based on expected seasonal 

variations in demand and planned and unplanned hydrogen production equipment outages. The 

following calculations were used to derive the value (Source: Directed Technologies, Inc.).

CF = 100% – Rseason–Rplanned–Runplanned–Rextra

Where:

CF = Operating capacity factor

Rseason = CF reduction for seasonal loads (winter to summer) Assumption = 10%

Rplanned = CF reduction for planned shutdown

7 days per year for planned system shutdown (annual maintenance, etc.)

Rplanned = 7 day/year ÷ 365 day/year = 1.92%

Runplanned = CF reduction for unplanned shutdowns

6 "expected" unplanned system shutdowns per year (equipment failure, 

power outage, etc.)

14 hr system down for each unplanned shutdown (average):

2 hr to react to shutdown (also allows unit to cool)

6 hr to get repair personnel to site

4 hr to effect repairs (assumes replacement parts are in hand)

2 hr to bring unit back to full power and monitor for proper 

performance
6

Runplanned = 6 shutdowns/year × (14 hr/shutdown ÷ 8,760 hr/year) = 0.96%

Rextra = CF reduction for needing extra production capacity to refill storage tanks

after unplanned shutdowns

H2 storage for hourly/daily demand fluctuations determined by the 

Chevron supplied hourly demand load calculations in the HDSAM/H2A 

model

Chevron demand based on highest daily demand of highest weekly 

demand (Friday in summer)

1,500 kg/day maximum rating of forecourt production system

14 hr system down for each unplanned shutdown (average)

30 days of design time between unplanned shutdowns

Rextra = 14 hr/shutdown ÷ (30 days × 24 hr/day) = 1.94%

H2 storage for unplanned shutdowns = 14 hr/shutdown ÷ 24 hr/day × 

1,500 kg/day = 875 kg

CF = 100% – 10% –1.92% –0.96% –1.94% = 85.2%

0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

800,000

900,000

Natural Gas

Coal

Natural Gas

w/Seq

Biomass

Coal w/Seq

Nuclear

Electrolysis

Natural Gas

Ethanol

Electrolysis

Production Design Capacity (kg hydrogen/day)

Current

Future

Central Forecourt

All forecourt 

technologies have 

a design capacity 

of 1,500 kg 

hydrogen/day

Figure 2. Hydrogen Production Design Capacity: All Technology Cases

Overview of Levelized Hydrogen Production Cost and Energy 

Use

Using the standard H2A production technology cases, the levelized costs of producing hydrogen 

from eight typical production pathways were investigated. The results of this cost analysis, as 

well as an analysis of the process energy required for the various production pathways, are
7

presented below. The subsequent sections of this report describe the detailed inputs and results 

for each technology pathway. Visit www.hydrogen.energy.gov/h2a_prod_studies.html to 

download the cases.

Levelized Hydrogen Production Cost

DOE’s goal is to reduce the untaxed levelized cost of hydrogen to $2.00 to $3.00 per gasoline

gallon equivalent (GGE) delivered at the pump, regardless of the technology pathway used. (A

kilogram of hydrogen has about the same energy content on a lower heating value [LHV] basis 

as a gallon of gasoline, thus a kilogram of hydrogen is approximately equal to 1 GGE.) The H2A 

Production Model and associated technology cases help researchers to understand the levelized 

hydrogen production cost component of this DOE goal. The central cases show only the 

production cost component, with costs reflecting produced hydrogen available “at the plant 

gate." The full cost of this centrally-produced hydrogen also needs to include the cost of 

hydrogen delivery and dispensing, which can be determined using DOE’s Hydrogen Delivery 

Scenario Analysis Model.

4

Figure 3

The forecourt production cases include levelized hydrogen 

production costs by component and also provide the levelized cost of hydrogen compression, 

storage, and dispensing (CSD) because these functions will be included at the same fueling 

station site as the hydrogen production operations.

shows the calculated cost per kilogram of hydrogen produced for each technology case 

and timeframe. The values represent the levelized cost of hydrogen (in 2005$), including a 10% 

after-tax internal rate of return (this cost can also be thought of as the minimum hydrogen selling 

price, although the market will drive the actual hydrogen price). Although the model can 

accommodate a wide variety of financial strategies and assumptions, a standard set of financial 

assumptions was used for the cases to maintain consistency. Cost values are shown in 2005$ for 

all cases. To allow a consistent comparison of hydrogen production costs from central and 

forecourt technologies, CSD costs are not included in this figure; only production costs and 

carbon sequestration costs (for the two relevant central cases) are included. (See Figure 7 for the 

CSD costs of the three forecourt technology cases.)

The levelized hydrogen production cost ranges from approximately $1.30 to $4.50 per kg, with 

the lowest production costs associated with traditional fossil fuel pathways such as coal and 

natural gas. However, once the costs associated with carbon capture and sequestration are 

included, hydrogen production from renewable biomass resources becomes one of the most costcompetitive pathways. For most cases, the cost difference between current and future timeframes 

varies only slightly. The central and forecourt electrolysis cases realize a substantial price 

decrease in the future timeframe, primarily owing to a large expected decrease in the capital cost 

of the electrolyzer system. Overall, the costs of water electrolysis production are higher than 

other pathways. These costs are based on average U.S. electricity prices. Electrolysis production 

might be more cost competitive in regions with below-average electricity prices.

For most pathways, capital and feedstock costs are the dominant contributors to total cost, each 

typically contributing one-third to one-half—and up to more than three-quarters—of the total 

levelized production cost. Figure 4 and Figure 5 show the contribution of various cost 

components to hydrogen production cost. Feedstock costs are based primarily on energy cost 

 4 H2A Delivery Scenario Analysis Model, www.hydrogen.energy.gov/h2a_delivery.html.
8

projections from the Energy Information Administration’s Annual Energy Outlook (AEO).5 To 

maintain consistency among cases, the AEO price projections for the 2005 “High A Case” were 

used for most analyses. The total feedstock cost for the production pathway also depends on the 

amount of process energy used and the production process efficiency, which are discussed 

below. Estimates of total capital costs were developed by the H2A team as part of developing the 

H2A production technology cases. In general, the production pathways investigated represent the

use of pioneering technologies. To better represent the expected costs associated with capital 

investment in a commercialized market, the projected capital costs for central facilities were

based on the “nth plant,” where the technology has been proven on a large scale, the first-of-itskind cost penalties have been overcome, and costs have stabilized. Similarly, capital cost 

projections for forecourt technologies are based on a production level of 500 units per year.

$0.00

$0.50

$1.00

$1.50

$2.00

$2.50

$3.00

$3.50

$4.00

$4.50

$5.00

Natural Gas

Coal

Natural Gas

w/Seq

Biomass

Coal w/Seq

Nuclear

Electrolysis

Natural Gas

Ethanol

Electrolysis

Cost per kg of Hydrogen Produced (2005$)

Current

Future

Central Forecourt

Costs are for hydrogen production and carbon sequestration only; compression, storage, and dispensing (CSD) costs are not 

included. Figure 7 shows CSD costs for forecourt technology cases. The H2A Production Model, Version 2.0, calculates CSD costs 

for forecourt technology cases only; however, hydrogen produced from central technologies also would incur CSD costs in order for 

the hydrogen to be usable in vehicles.

Figure 3. Levelized Hydrogen Production Cost: All Technology Cases

Beyond capital and feedstock costs, operating and maintenance costs, raw material costs, and 

other variable costs can play a significant role. Sequestration costs can be significant for the 

natural gas and coal cases that include carbon capture and sequestration. The costs of carbon 

sequestration for the coal pathway in particular are large because of coal's higher CO2 emissions 

factor relative to natural gas. The total cost of hydrogen can be reduced as a result of revenue 

generated from the sale of material or energy byproducts of the hydrogen production process.

For example, several coal pathways produce excess electricity, which is sold to generate revenue.

 5 Energy Information Administration Annual Energy Outlook, http://www.eia.doe.gov/oiaf/aeo/aeoref_tab.html.
9

This is represented in the figure by the gray bar segments below the $0 line (the total hydrogen 

cost equals the segments above the $0 line minus the segment below the $0 line). Sale of 

byproducts other than electricity (e.g., oxygen from electrolysis) was not considered for these 

standardized cases.

To better understand the impact of capital investment on production cost, the amount of capital 

investment required can be compared to facility design capacity. Figure 6 shows the relative 

capital intensity of the technology cases, dividing total initial direct capital cost by hydrogen 

production design capacity. The coal-based technology cases are more capital intensive than 

most other cases; this is offset by the low cost of coal feedstock and the credit for byproduct 

electricity generated (see Figure 4 and Figure 5). Electrolysis is relatively capital intensive in the 

current timeframe, with a large reduction in capital cost in the future timeframe (owing to the 

lower-cost electrolyzer systems in the future).

The forecourt cases include the levelized cost of hydrogen production as well as the CSD costs at 

the fueling site, so these cases provide the full cost of delivered hydrogen, which can be 

compared to the DOE goal of $2.00 to $3.00 per GGE dispensed to the consumer (Figure 7).

CSD costs constitute approximately one-third to one-half of total delivered hydrogen costs, about 

$1.90 per kilogram of hydrogen dispensed. Because the forecourt cases have identical hydrogen 

production capacities and fueling station characteristics, their CSD costs are almost identical. 

The only difference is the lower electricity cost for electrolysis. It was assumed that, because of 

their high electricity consumption, these facilities would be able to purchase electricity at a lower 

industrial rate.

DOE expects forecourt hydrogen production at fueling stations to meet hydrogen demand during 

the early transition to hydrogen. As seen in Figure 7, the total levelized cost of dispensed 

hydrogen is expected to be about $3.50 per kilogram for onsite natural gas reformation (the 

lowest-cost pathway), which exceeds DOE’s target price.6

 6 Also see the 2006 systems integration independent review Distributed Hydrogen Production from Natural Gas, 

This total dispensed cost of onsite 

hydrogen might be improved in the future as better CSD technologies are developed and 

modeled. Currently, the H2A Model does not capture improved CSD technologies and lower 

CSD costs for future applications; thus, modeled current and future CSD costs are the same.

www.hydrogen.energy.gov/pdfs/40382.pdf, which used the H2A Production Model to project that the cost of 

distributed hydrogen production from natural gas at high volumes could meet the upper range of DOE's $2.00 to 

$3.00 per GGE cost target.
10

-$1.00

-$0.50

$0.00

$0.50

$1.00

$1.50

$2.00

$2.50

$3.00

$3.50

$4.00

$4.50

$5.00

Natural Gas

Coal

Natural Gas

w/Seq

Biomass

Coal w/Seq

Electrolysis

Natural Gas

Ethanol

Electrolysis

Contribution to Total Hydrogen Production Cost (2005$)

Carbon Sequestration

Other Variable

Other Raw Material

O&M

Feedstock

Capital

Byproduct Credit

Central Forecourt

Costs are for hydrogen production and carbon sequestration only; compression, storage, and dispensing costs are not included. The 

gray segment below the $0 line for coal represents a credit for byproduct electricity; the total cost of hydrogen from this technology 

equals the colored segments above the $0 line minus the gray segment below the $0 line.

Figure 4. Contributions to Levelized Hydrogen Production Cost: Current Technology Cases
11

-$1.00

-$0.50

$0.00

$0.50

$1.00

$1.50

$2.00

$2.50

$3.00

$3.50

$4.00

$4.50

$5.00

Natural Gas

Coal

Biomass

Natural Gas

w/Seq

Coal w/Seq

Nuclear

Electrolysis

Natural Gas

Ethanol

Electrolysis

Contribution to Total Hydrogen Production Cost (2005$)

Carbon Sequestration

Other Variable

Other Raw Material

O&M

Feedstock

Capital

Byproduct Credit

Central Forecourt

Costs are for hydrogen production and carbon sequestration only; compression, storage, and dispensing costs are not included. The 

gray segments below the $0 line for coal and coal with sequestration represent credits for byproduct electricity; the total cost of 

hydrogen from these technologies equals the colored segments above the $0 line minus the gray segment below the $0 line.

Figure 5. Contributions to Levelized Hydrogen Production Cost: Future Technology Cases

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

5.5

6

Natural Gas

Coal

Natural Gas

w/Seq

Biomass

Coal w/Seq

Nuclear

Electrolysis

Natural Gas

Ethanol

Electrolysis

Ratio of Total Direct Capital Cost to Annual 

Design Capacity ($ per kg hydrogen/year)

Current

Future

Central Forecourt

These are initial direct capital costs for hydrogen production and carbon sequestration only; compression, storage, and dispensing 

capital costs are not included, nor are replacement capital costs incurred over the production plants' lifetimes.

Figure 6. Capital Investment Relative to Production Design Capacity: All Technology Cases
12

$0.00

$0.50

$1.00

$1.50

$2.00

$2.50

$3.00

$3.50

$4.00

$4.50

$5.00

$5.50

$6.00

$6.50

$7.00

Current 

Natural Gas

Future 

Natural Gas

Current

Ethanol

Future 

Ethanol

Current

Electrolysis

Future

Electrolysis

Contribution to Delivered Hydrogen Cost (2005$)

CSD Other Variable

CSD O&M

CSD Capital

Hydrogen Production

This figure includes refueling station compression, storage, and dispensing (CSD) costs—unlike Figure 3, Figure 4, and Figure 5, 

which show hydrogen production costs only. The H2A Production Model, Version 2, calculates CSD costs for forecourt technology 

cases only; however, hydrogen produced from central technologies also would incur both delivery and CSD costs in order for the 

hydrogen to be made available for use by hydrogen fuel-cell vehicles.

Figure 7. Contributions to Delivered Levelized Hydrogen Cost: Forecourt Technology Cases

Process Energy

Hydrogen can be derived from a variety of domestic energy resources, including fossil, nuclear, 

and renewable sources. Process energy efficiency—the ratio of process energy output to input—

indicates the quantity of resources needed to produce hydrogen and is therefore an important 

indicator of the efficient use of domestic resources.

Figure 8 and Figure 9 show the process energy requirements for the different production 

pathways. The figures show the amount of input energy required (in the form of the energy 

contained in the feedstocks and the process energy used in the transformation) to produce one 

kilogram of hydrogen, which is shown as an output. For all cases, feedstocks constitute the vast 

majority of input energy. Byproduct energy flows are shown separately from the hydrogen 

output energy. The coal (current and future) and coal with carbon sequestration (future) cases 

produce excess electricity, which is another energy output for these cases. Energy used for 

carbon sequestration is identified separately from energy used for hydrogen production. The 

energy inputs shown do not include energy used upstream of the process—e.g., to extract fossil 

fuels and refine or produce feedstocks—or energy used for hydrogen delivery, compression, 

storage, and dispensing; thus they do not represent life-cycle or "well-to-wheel" energy use.

The future nuclear case has the highest ratio of process energy output to input (i.e., the highest 

process energy efficiency) at 83%. The current biomass case has the lowest process energy 

efficiency at 46%. Figure 10 shows the process energy efficiencies of all cases.
13

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

Natural Gas

Coal

Natural Gas

w/Seq

Biomass

Coal w/Seq

Electrolysis

Natural Gas

Ethanol

Electrolysis

Energy Inputs (positive) and Outputs (negative) 

(GJ/kg hydrogen)

Utility

Feedstock

Carbon Sequestration

Byproduct

Hydrogen

Central Forecourt

Energy inputs and outputs are for hydrogen production and carbon sequestration only; compression, storage, and dispensing 

energy is not included. The segments below the zero line represent the energy contained in the produced hydrogen and the energy 

in byproduct electricity. Net energy equals the segments below the zero line minus the segments above the zero line. All values 

were calculated using LHVs.

Figure 8. Process Energy Inputs and Outputs: Current Technology Cases
14

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

Natural Gas

Coal

Natural Gas

w/Seq

Biomass

Coal w/Seq

Nuclear

Electrolysis

Natural Gas

Ethanol

Electrolysis

Energy Inputs (positive) and Outputs (negative) 

(GJ/kg hydrogen)

Utility

Feedstock

Carbon Sequestration

Byproduct

Hydrogen

Central Forecourt

Energy inputs and outputs are for hydrogen production and carbon sequestration only; delivery, compression, storage, and 

dispensing energy are not included. The segments below the zero line represent the energy contained in the produced hydrogen 

and the energy in byproduct electricity. Net energy equals the segments below the zero line minus the segments above the zero 

line. All values were calculated using LHVs.

Figure 9. Process Energy Inputs and Outputs: Future Technology Cases

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Natural Gas

Coal

Natural Gas

w/Seq

Biomass

Coal w/Seq

Nuclear

Electrolysis

Natural Gas

Ethanol

Electrolysis

Production Process Energy Efficiency 

(energy outputs divided by energy inputs)

Current

Future

Central Forecourt

Energy inputs and outputs are for hydrogen production and carbon sequestration only; compression, storage, and dispensing 

energy is not included. All values were calculated using LHVs.

Figure 10. Process Energy Efficiency: All Technology Cases
15

Sensitivity Analysis

The H2A Production Model technology cases include sensitivity analyses to help users 

understand how the levelized hydrogen cost would change using different assumptions for key 

input parameters. For each case, key input variables were assigned three values: a likeliest value, 

a 10th-percentile value (i.e., the value at which 10% of the predicted inputs are at or below that 

value), and a 90th-percentile value (i.e., the value at which 90% of the predicted inputs are at or 

below that value). The variable values assigned were based on feedback from analysts consulted 

as part of the H2A development process and on ongoing DOE research into the uncertainties 

inherent to the various hydrogen production variables.

The likeliest, 10th-percentile, and 90th-percentile values for each single input variable were 

entered into the H2A Model while the other input variables were held constant at their likeliest 

values. The results of this analysis are ranges of levelized hydrogen production costs 

corresponding to the ranges of input variable values, which can be visualized in a "tornado 

chart." This indicates how much effect each input variable has on hydrogen cost when varied in 

isolation: the larger the range of hydrogen cost, the greater the effect of the variable. Figure 11 is 

an example tornado chart for the current coal without CO2 sequestration case. In this example, 

total direct capital cost has the largest effect on hydrogen cost: a total direct capital cost of $290 

million results in a hydrogen cost of about $1.35/kg, and a total direct capital cost of $430 

million results in a hydrogen cost of about $1.75/kg. 

1.3 1.35 1.4 1.45 1.5 1.55 1.6 1.65 1.7 1.75 1.8

Labor Cost ($/year) [range $7M -

$14M]

Plant Efficiency [range 45% - 65%]

Coal Price [range ± 30%]

Operating Capacity Factor [range

80% - 95%]

Total Direct Capital Cost [range

$290M - $430M]

Hydrogen Cost ($/kg)

Figure 11. Example "Tornado Chart" (Current Coal without CO2 Sequestration Case)
16

Figure 12 shows the input parameters that most frequently have the greatest effect on the 

modeled cost of hydrogen for all technology cases. Feedstock price has the greatest effect on 

hydrogen cost in 10 cases and the second-greatest effect in two cases. Capital costs have the 

greatest impact on hydrogen cost in seven cases and the second-greatest effect in four cases. For 

the forecourt cases, the amount of hydrogen storage has the greatest impact on hydrogen cost in 

two cases and the second-greatest impact in two cases. Operating capacity factor and feedstock 

conversion efficiency have the second-greatest impact in six and five cases, respectively.

0

2

4

6

8

10

12

14

Feedstock

Price

Capital Cost

ForecourtHydrogen

Storage

Capacity

Operating

Capacity

Factor

Feedstock

Conversion

Efficiency

Number of Technology Cases

Second-Largest Sensitivity Analysis

Effect on Hydrogen Cost

Largest Sensitivity Analysis Effect on

Hydrogen Cost

Sensitivity analyses include hydrogen production variables for all cases; compression, storage, and dispensing variables for 

forecourt technology cases; and carbon sequestration variables for central cases.

Figure 12. Variables Producing the Largest Effects in Sensitivity Analyses

Detailed Levelized Hydrogen Production Cost Results

The results presented above provide an overview of the full range of hydrogen production cases

developed using the H2A Production Model (Table 2 shows the cases studied). The sections 

below present additional details of these cases by production pathway, starting with the central 

cases and followed by the forecourt cases. Each case begins with a description of the hydrogen 

production process used, followed by a detailed accounting of the costs expected and the 

resulting levelized hydrogen cost. For full details, download the cases at 

www.hydrogen.energy.gov/h2a_prod_studies.html.

Common Input Parameters and Processes

The H2A technology cases have various default input parameters and processes, many of which 

are common to all or most of the cases. Table 3 lists these common values. Parameters and 

processes unique to each case are discussed in subsequent sections of this report.
17

Table 3. Common Input Parameters and Processes for Production Technology Cases

Analysis methodology Discounted cash flow (DCF) model that calculates a 

levelized hydrogen cost yielding a prescribed IRR

Analysis period 40 years for central cases; 20 years for forecourt cases

Average burdened labor rate for staff $50/hour for central cases; $10/hour for forecourt cases

Capacity factor 90% for central cases with exceptions; 85.2% for forecourt 

cases 

Capital expenditure schedule—central 25%–75% of capital spent in first year of construction; 25%–

75% in second year; 20%–30% in third year

Capital expenditure schedule—forecourt 100% of capital spent in first year of construction, with a 1-

year total construction period.

Central storage Optional buffer only as required for efficient operations

CO2 capture credit Not included in base cases (default value = 0)

CO2 production taxes Not included in base cases (default value = 0)

Construction period and cash flow 2–3 years for central cases; 1 year for forecourt cases

Co-produced and cogenerated electricity 

selling price

$30/MWh 

Decommissioning 10% of initial capital for central cases, with exceptions; 0% 

for forecourt cases

Depreciation type and schedule for initial 

depreciable capital cost

MACRS: 20 years for central cases with exceptions; 5 years 

for compressors, 7 years for remainder of plant for forecourt 

cases

Energy and emissions data From H2A Production Model HyARC Physical Property Data

worksheet; various original sources

Energy feed and utility prices (standard) Energy feed and utility prices vary over time based on values 

derived and extrapolated from AEO 2005 High A Case within 

H2A Production Model Energy Feed & Utility Prices

worksheet; sourced from U.S. Energy Information 

Administration AEO Reference Case 2005 modified for high 

projected oil prices

Facility life 40 years for central cases with exceptions; 20 years for 

forecourt cases with exceptions

Fixed operating costs during startup 75%–100% of total for central cases; 75% for forecourt 

cases

Forecourt compressed hydrogen storage 120% of maximum daily production

G&A rate 20% of labor costs

Hydrogen pressure at central gate 300 psig; if higher pressure is inherent to the process, apply 

pumping power credit for pressure > 300 psig
18

Hydrogen purity 98% minimum; CO < 10 ppm, sulfur < 10 ppm

Hydrogen storage pressure at forecourt 6,250 psig

Income taxes 35% federal; 6% state; 38.9% effective

Inflation rate 1.9%, but with resultant price of hydrogen in reference year 

constant dollars

Land cost $5,000/acre purchased for central cases; $0.3/sqft/month for 

long-term lease for forecourt cases

Location Production facilities are assumed to be located in the United 

States

Non-energy material prices From H2A Production Model Non-Energy Material Prices

worksheet

Process contingency % adjustment to the total initial capital cost such that the 

result incorporates the mean or expected overall 

performance. Process contingency was set at 0 for the H2A 

case studies

Project contingency % adjustment to the total initial capital cost such that the 

result represents the mean or expected cost value; periodic 

replacement capital includes project contingency. Project 

contingency was set at 15% of direct capital costs for the 

central H2A case studies and 5% of direct capital costs for 

the forecourt H2A case studies

Property taxes and business insurance 2%/year of the total initial capital cost

Reference financial structure 100% equity with 10% IRR; model allows debt financing

Reference year dollars 2005, to be adjusted at half-decade increments (e.g., 2005, 

2010)

Revenues during startup 50% of total

Sales tax Not included on basis that facilities and related purchases 

are wholesale and through a general contractor entity

Salvage value 10% of initial capital for central cases with exceptions; 0% for 

forecourt cases

Sensitivity variables and ranges Based on applying best judgment of 10% and 90% 

confidence limit extremes to the most significant baseline 

cost and performance parameters

Startup time 1–2 years for central cases; 0.5 years for forecourt cases

Startup year 2005 for current cases; 2025 for future cases (except central 

future nuclear case, for which it is 2030)

Technology development stage All central and forecourt case cost estimates are based on 

mature, commercial facilities

Variable operating costs during startup 75% of total for central cases (except nuclear, for which it is 

50%); 50% for forecourt cases

Working capital rate 15% of the annual change in total operating costs
19

Pressure swing adsorption (PSA) is used for hydrogen purification for all cases except 

electrolysis. The PSA unit separates the hydrogen from the other components in the shifted gas 

stream; mainly CO2, unreacted CO, CH4, and other hydrocarbons. The hydrogen purity achieved 

from a PSA unit can be greater than 99.99%. Based on past conversations with industrial gas 

producers, the shifted gas stream must contain at least 70 mol% hydrogen before it can be 

purified in the PSA unit. Purification of streams more dilute than this decreases the product 

purity and recovery of hydrogen. For these analyses, the concentration of hydrogen in the gas 

stream prior to the PSA may be less than 70 mol%. In these cases, part of the PSA hydrogen 

product stream is recycled back into the PSA feed. For a 70 mol% hydrogen PSA feed, a 

hydrogen recovery rate of 85% is typical with a product purity of 99.9 vol%. 

Costs for carbon (CO2) compression, transport to the sequestration site, and injection are 

calculated in a separate tab for the central production cases that include carbon sequestration.

Capital and operating costs for CO2 compression, installation, and maintenance of the pipeline 

for transporting the CO2 to the sequestration site and injection well costs are included. Capital 

and operating costs for carbon capture are assumed to be included in the capital and operating 

costs of the production facility. For H2A analysis of hydrogen production processes, it is 

assumed that only carbon contained in the process feedstock can be captured. Carbon contained 

in fuels such as natural gas used for steam generation (i.e., as a utility) cannot be captured.

However, emissions from fuels used as utilities are included in the total emissions from the 

process shown in the model's Results worksheet.

Central Cases

The following sections describe the processes, inputs, and results for the H2A central production 

technology cases (see Table 2 for a list of cases). Values that are common to all cases are not 

shown in these sections; see Common Input Parameters and Processes (above) for those values.

Biomass Gasification

Process Description

The central current (Figure 13) and future (Figure 14) biomass technology cases are based on the 

Battelle/FERCO indirectly heated biomass gasifier, conventional catalytic steam reforming, 

water gas shift, and PSA purification. The biomass feedstock is assumed to be a woody biomass, 

represented as hybrid poplar. Process energy sources include internally generated steam and 

electricity, industrial electricity, and commercial natural gas. Aspen Plus® was used to model the 

thermodynamics of the system.

The as-received wood is dried from 50 wt% moisture to 12 wt% with a rotary dryer. The dryer 

uses gas from the char combustor as the drying medium. Conveyors and hoppers feed the wood 

to the low-pressure, indirectly heated, entrained-flow gasifier. Heat for the endothermic 

gasification reactions is supplied by circulating hot synthetic olivine, which is a calcined 

magnesium silicate (primarily enstatite [MgSiO3], forsterite [Mg2SiO3], and hematite [Fe2O3]) 

used as a sand for various applications, between the gasifier and a char combustor vessel. A 

small amount of MgO is added to the fresh olivine to keep from forming glass-like bed 

agglomerations that would result from biomass potassium interacting with the silicate 
20

compounds. The gasification medium is steam. The char formed in the gasifier is burned in the 

combustor to reheat the olivine. Particulate removal is performed through cyclone separators. 

Ash and any sand particles that are carried over are landfilled.

Reforming (CnHm + nH2O ↔ (n+m/2)H2 + nCO) and water-gas shift (CO + H2O ↔ CO2 + H2) 

are the main reactions in the steam reformation process. The reformer is fueled by the PSA 

offgas, and a small amount of natural gas is added for burner control. The amount of natural gas 

added is equal to 10% of the heating value of the PSA offgas. The high-temperature shift (HTS) 

and low-temperature shift (LTS) reactors convert the majority of the CO into CO2 and H2

through the water-gas shift reaction. 

The steam cycle is integrated with the biomass-to-hydrogen production process and produces 

power in addition to providing steam for the gasifier and reformer operations. There is an 

extraction steam turbine/generator, and steam is supplied to the reformer and gasifier from the 

intermediate- and low-pressure turbine sections, respectively. Preheaters, steam generators, and 

superheaters are integrated within the process design. The condensate from the syngas 

compressor and the condensate from the cooled shifted gas stream prior to the PSA are sent to 

the steam cycle, de-gassed, and combined with the makeup water. A pinch analysis was 

performed to determine the heat integration of the system.

A cooling water system is also included in the Aspen Plus® model to determine the requirements 

of each cooling water heat exchanger within the hydrogen production system as well as the 

requirements of the cooling tower. 
21

Although hydrogen compression appears in this diagram, compression energy use and capital costs were removed from the 

analysis for consistency with other H2A cases.

Figure 13. Process Flow Diagram—Current Biomass Gasification

The design of the future biomass gasification process differs from the current process design in 

that the tar reformer consists of a reactor vessel and a catalyst regeneration vessel. Additionally, 

because the tar reformer in the future design reforms a significant amount of the syngas methane, 

the steam reformer is eliminated from the design. The tar reforming reactor/catalyst regenerator 

system operates isothermally. The heat required for the tar reforming reactor/catalyst regenerator 

system is supplied by burning the PSA offgas along with some natural gas. The steam-to-carbon 

ratio for the shift conversion step is set at 2 mol H2O/mol C. The biomass-to-hydrogen process is 

integrated with the steam cycle.
22

Although hydrogen compression appears in this diagram, compression energy use and capital costs were removed from the 

analysis for consistency with other H2A cases.

Figure 14. Process Flow Diagram—Future Biomass Gasification

H2A Model Inputs

The following tables show the H2A Model input values for the central current and future 

biomass technology cases. Default values that are common to all central cases are not shown in 

the tables below; see Common Input Parameters and Processes (page 16) for those values. 

Table 4 shows the technical operating parameters and specifications. The central current and 

future biomass cases produce approximately 140,000 kg of hydrogen per day. Table 5

summarizes the cost inputs, including capital, fixed operating, and variable operating costs. 

Table 6 summarizes the feedstock and utility energy inputs.

Table 4. Central Biomass: Technical Operating Parameters and Specifications

Current Future

Plant design capacity (kg hydrogen/day) 155,000 155,000

Plant output (kg hydrogen/day) 140,000 139,000

Plant output (kg hydrogen/year) 51,000,000 50,800,000
23

Table 5. Central Biomass: Cost Input Summary

Capital Costs (million 2005$) Current Future

Initial direct

Feed handling and drying 20.1 20.1

Gasification, tar reforming, quench 17.8 25.3

Compression and sulfur removal 16.6 17.1

Steam methane reforming, shift, PSA 32.1 —

Shift and PSA — 17.5

Steam system and power generation 15.3 15.1

Cooling water and other utilities 3.6 3.6

Buildings and structures 6.4 6.4

Total initial direct 111.9 105.0

Indirect depreciable

Site preparation 1.1 1.0

Engineering and design 14.5 13.6

Project contingency 16.8 15.7

Up-front permitting 10.1 9.4

Indirect non-depreciable Land cost 0.3 0.3

Total indirect 42.8 40.1

Total initial (initial direct + indirect) 154.6 145.1

Expected replacementa 5.9 8.1

Totalb 160.5 153.2

Fixed Operating Costs (million 2005$/year) Current Future

Labor 5.6 5.2

G&A 1.1 1.0

Property taxes and insurance 3.1 2.9

Material for maintenance and repairs 0.6 0.5

Totalb 10.4 9.7

Variable Operating Costs (million 2005$/year)c Current Future

Energy feedstocks, utilities, byproducts

Biomass feedstock 27.4 26.4

Commercial natural gas 2.9 1.4

Industrial electricity 2.8 2.7

Other materials and byproducts Cooling water 0.3 0.4

Process water 0.1 0.1

Other variable operating costs

Other variabled 0.1 0.1

Other materiale 7.4 5.0

Waste treatment 1.3 1.2

Solid waste disposal 0.8 0.7

Totalb 43.2 38.0

a

Sum of expected replacement capital costs over the 40-year plant life, adjusted to the year in which they are incurred using an NPV 

calculation.

b

Components might not add to total owing to rounding. c

These costs vary over time in accordance with H2A Model price tables; startup year costs are shown here. d

MgO, boiler chemicals, #2 diesel fuel, and cooling tower chemicals. e

Catalyst, olivine, and other materials.
24

Table 6. Central Biomass: Energy Input Summary

Feed Lower Heating Value Material Use (per kg hydrogen)

Current Future

Biomass feedstock 19.6 MJ/kg 12.8 kg 12.4 kg

Commercial natural gas 36.6 MJ/Nm3 0.2 Nm3 0.1 Nm3

Industrial electricity 3.6 MJ/kWh 1.0 kWh 0.9 kWh

H2A Model Results

The following tables and figures show the H2A Model results for the central current and future 

biomass technology cases. Table 7 summarizes the cost results. The central current biomass case 

produces hydrogen for $1.61/kg. The future case produces hydrogen for $1.47/kg. Capital costs 

and feedstock costs each account for approximately one-third of the hydrogen cost.

Table 7. Central Biomass: Cost Results Summary

Cost Component

Cost Contribution 

($/kg hydrogen)

Percentage of 

Hydrogen Costa

Current Future Current Future

Capital 0.53 0.50 33% 34%

Fixed O&M 0.21 0.20 13% 14%

Feedstock 0.55 0.53 34% 36%

Other raw material 0.15 0.10 9% 7%

Other variableb 0.16 0.13 10% 9%

Total hydrogen cost 1.61 1.47 100% 100% a

Total might not add to 100% owing to rounding. b

Including utilities.

Table 8 summarizes the process energy results. Most of the energy input is in the form of 

biomass feedstock. The only energy output is hydrogen. The process energy efficiency on a 

lower heating value basis (LHV energy output divided by energy input) is 46.1% for the current 

case and 48.3% for the future case. These are process energy inputs only and do not include 

energy used upstream of the process, e.g., to extract fossil fuels and refine feedstocks or to 

collect and transport biomass resources. The results also do not include energy used for hydrogen 

compression, storage, and dispensing or for consumption in vehicles; thus they do not represent 

life-cycle or "well-to-wheel" energy use.
25

Table 8. Central Biomass: Process Energy Results Summary

Energy Component

Energy Input 

(MJ per kg hydrogen)

Energy Output 

(MJ per kg hydrogen)

Current Future Current Future

Biomass feedstock 251 242 — —

Commercial natural gas 6 3 — —

Industrial electricity 4 3 — —

Hydrogen — — 120 120

Total 261 249 120 120

Process energy efficiency (LHV)a

Current = 46.1%

Future = 48.3% a

Process energy efficiency = hydrogen energy output ÷ all feedstock and process energy inputs.

Table 9 (current) and Table 10 (future) show the values used in the sensitivity analyses. See 

Sensitivity Analysis (page 15) to learn how these values were chosen. Figure 15 (current) and 

Figure 16 (future) show the sensitivity analysis results. For both cases, total capital cost has the 

largest effect on hydrogen price, followed by feedstock price and production process energy 

efficiency. Operating capacity factor, total fixed operating cost, and labor requirement have 

smaller effects on hydrogen cost.
26

Table 9. Central Current Biomass: Sensitivity Analysis Values

Variable Lower Value Nominal Value Upper Value

Labor requirement (FTE) 25 54 70

Total fixed operating cost (million $) 7.3 10.4 13.5

Operating capacity factor 0.95 0.90 0.80

Plant efficiency 55% 46% 35%

Biomass feedstock price ($/kg) 0.029 0.042 0.054

Total capital investment (million $) 100.0 154.6 220.0

1.3 1.4 1.5 1.6 1.7 1.8 1.9

Labor Requirement (FTE) [range 25

to 70]

Total Fixed Operating Cost [range ±

30%]

Operating Capacity Factor [range

80% - 95%]

Plant Efficiency [range 35% - 55%]

Biomass Feedstock Price [± 30%]

Total Capital Investment [range

$100M - $220M]

Hydrogen Cost ($/kg)

Figure 15. Central Current Biomass: Sensitivity Analysis Results
27

Table 10. Central Future Biomass: Sensitivity Analysis Values

Variable Lower Value Nominal Value Upper Value

Labor requirement (FTE) 20 50 60

Total fixed operating cost (million $) 6.8 9.7 12.6

Operating capacity factor 0.95 0.90 0.80

Plant efficiency 58% 48% 38%

Biomass feedstock price ($/kg) 0.029 0.042 0.054

Total capital investment (million $) 95.0 145.1 220.0

1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8

Total Labor Requirement, ranging

from 20-60 FTE

Total Fixed Operating Costs, with a

range of +/- 30%

Operating Capacity Factor, ranging

from 80% to 95%

Plant Efficiency, ranging from 38%

to 58% LHV

Woody Biomass Feedstock Cost,

ranging from about $25-50/ton (+/-

30%)

Total Capital Cost, ranging from

$95M to $220M

Hydrogen Cost ($/kg)

Figure 16. Central Future Biomass: Sensitivity Analysis Results

Grid Electrolysis

Process Description

The central current and future grid electrolysis technology cases (Figure 17) are based on a 

standalone grid-powered electrolyzer system with a total hydrogen production capacity of 52,000 

kg/day. The system is based on the Hydro bi-polar alkaline electrolyzer system (Atmospheric 

Type No.5040 - 5150 Amp DC); for the future case, improvements in cost and performance were 

determined in consultation with the H2A development group. The total electrolyzer system 

consists of 50 electrolyzer units, each capable of producing 485 Nm3 of hydrogen per hour. The 

electrolyzer units use high-purity process water for electrolysis. Potassium hydroxide (KOH) is 

needed for the electrolyte in the system. The system includes the following equipment: 

transformer, thyristor, electrolyzer unit, lye tank, feed water demineralizer, hydrogen scrubber, 

gas holder, two compressor units to 30 bar (435 psig), deoxidizer, and twin tower dryer.
28

The electrolyzer system receives AC grid electricity, which is converted via transformer and 

rectifier subsystems into DC electricity for use by the electrolyzer stack. The transformer 

subsystem is an oil-immersed, ambient air-cooled unit, manufactured to IEC-76. The rectifier 

subsystem converts the AC voltage to DC voltage using thyristors. Cooling is generally 

accomplished via forced air achieved by fans on the bottom of the rectifier cabinet but can also 

be accomplished with cooling water. The electrolyzer system uses 4.8 kWh (current case) or 4.0 

kWh (future case) of electricity per Nm3 of hydrogen produced, i.e., 53.4 kWh (current case) or 

44.7 kWh (future case) per kg of hydrogen produced.

The electrolyzer system requires high-purity water to avoid deterioration of electrolyzer 

performance. Process water is demineralized and softened to a specific resistance of 1–2 

megaohm/cm in the water demineralizer unit. The system requires 1 L/Nm3 (2.939 gal/kg) of 

hydrogen produced. 

The electrolyzer system produces hydrogen and oxygen from the electrolysis of feed water. The 

gas from each cell in the electrolyzer stack is collected in the hydrogen and oxygen flow 

channels and fed into the gas/lye (KOH) separators. The lye, separated from the produced gas, is 

recycled through the lye pump, through the lye cooler, and back into the lye tank. Excess heat in 

the electrolyzer is removed by the lye cooler. Oxygen is removed from the lye in the oxygen/lye 

separator. The system modeled does not capture the oxygen gas, but capture of the high-purity 

oxygen gas is a possibility. Saturated hydrogen gas from the hydrogen/lye separator is fed to the 

gas scrubber subsystem, which purifies the hydrogen. The hydrogen gas is held in a small gas 

holder unit and is compressed to 435 psig. Following compression, residual oxygen is removed 

from the hydrogen gas by the deoxidizer unit, and the hydrogen gas is dried in the twin tower 

dryer. The purity of the hydrogen gas coming off the electrolyzer stack is 99.9%. Following the 

gas purifier, deoxidizer, and dryer stages, the purity of hydrogen increases to 99.9998% (2 ppm).
29

Figure 17. Process Flow Diagram—Grid Electrolysis
30

H2A Model Inputs

The following tables show the H2A Model input values for the central current and future grid 

electrolysis technology cases. Default values that are common to all central cases are not shown 

in the tables below; see Common Input Parameters and Processes (page 16) for those values. 

Table 11 shows the technical operating parameters and specifications. The central current and 

future grid electrolysis cases produce approximately 51,000 kg of hydrogen per day. Table 12

summarizes the cost inputs, including capital, fixed operating, and variable operating costs. 

Table 13 summarizes the energy inputs.

Table 11. Central Grid Electrolysis: Technical Operating Parameters and Specifications

Current Future

Plant design capacity (kg hydrogen/day) 52,000 52,000

Plant output (kg hydrogen/day) 51,000 51,000

Plant output (kg hydrogen/year) 19,000,000 19,000,000
31

Table 12. Central Grid Electrolysis: Cost Input Summary

Capital Costs (million 2005$) Current Future

Initial direct

Electrolyzer units (50) 30.2 11.2 

Transformer/rectifier units (50) 5.7 2.1

Compressor units to 30 bar/435 psig (100) 27.4 10.2

Gas holders (50) 14.2 5.3

Balance of planta 17.0 6.3

Total initial direct 94.4 35.1

Indirect depreciable

Site preparation 0.9 0.4

Engineering and design 4.7 1.8

Project contingency 9.4 3.5

Up-front permitting 0.9 0.4

Indirect non-depreciable Land cost 0.03 0.03

Total indirect 16.1 6.0

Total initial (initial direct + indirect) 110.4 41.1

Expected replacementb 13.1 7.1

Totalc 123.5 48.2

Fixed Operating Costs (million 2005$/year) Current Future

Labor 0.3 0.3

G&A 0.1 0.1

Property taxes and insurance 2.2 0.8

Material for maintenance and repairs 2.8 1.1

Totalc 5.4 2.2

Variable Operating Costs (million 2005$/year)d Current Future

Energy feedstocks, utilities, byproducts Industrial electricity 54.9 46.8

Other materials and byproducts

Cooling water 0.4 0.4

Process water 0.1 0.1

Compressed inert gas 0.01 0.01

Other variable operating costs Other material

e 0.4 0.4

Totalc 55.9 47.8

a

Includes gas purifier (hydrogen scrubber), feed-water purifier/demineralizer, lye tank, deoxidizer, and twin tower drier. b

Sum of expected replacement capital costs over the 40-year plant life, adjusted to the year in which they are incurred using an NPV 

calculation.

c

Components might not add to total owing to rounding. d

These costs vary over time in accordance with H2A Model price tables; startup year costs are shown here. e

Electrolyte solution.

Table 13. Central Grid Electrolysis: Energy Input Summary

Feed Lower Heating Value Material Use (per kg hydrogen)

Current Future

Industrial electricity 3.6 MJ/kWh 53.4 kWh 44.7 kWh

H2A Model Results

The following tables and figures show the H2A Model results for the central current and future 

grid electrolysis technology cases. Table 14 summarizes the cost results. The central current grid 
32

electrolysis case produces hydrogen for $4.50/kg. The future case produces hydrogen for 

$3.24/kg. Feedstock (electricity) is the largest expense for both cases. Capital costs decrease 

substantially from the current to the future timeframe.

Hydrogen from the central electrolysis cases is more expensive than from the forecourt 

electrolysis cases ($4.23/kg for current and $3.10 for future) because the forecourt electrolyzer is 

assumed to be “skid mounted” and inexpensive to install, whereas the installation and 

coordination of multiple electrolyzers for the central cases are assumed to be more costly.

Table 14. Central Grid Electrolysis: Cost Results Summary

Cost Component

Cost Contribution 

($/kg hydrogen)

Percentage of 

Hydrogen Costa

Current Future Current Future

Capital 1.16 0.47 26% 15%

Fixed O&M 0.32 0.13 7% 4%

Feedstock 2.96 2.58 66% 80%

Other raw material 0.02 0.02 1% 1%

Other variableb 0.03 0.03 1% 1%

Total hydrogen cost 4.50 3.24 100% 100% a

Total might not add to 100% owing to rounding. b

Including utilities.

Table 15 summarizes the process energy results. All the energy input is in the form of electricity 

feedstock. The only energy output is hydrogen. Results are reported based on both the lower 

heating value (LHV) and higher heating value (HHV) of hydrogen. The HHV—which accounts 

for the latent and sensible heat of vaporization of the combustion products (i.e., water vapor) 

between 150°C and 25°C—represents the actual amount of energy required to electrolyze water

and is a more thermodynamically accurate measure for this production technology because liquid 

water (not water vapor) is produced. However, LHV—which assumes the latent and sensible 

heat of vaporization of the combustion products are not recovered between 150°C and 25°C—is 

also given because it is customary to use LHV to measure the performance of hydrogen 

production technologies. The HHV of hydrogen is 18% greater than the LHV. Only LHV results 

are given for the other hydrogen production technologies discussed in this report because LHV is

a more accurate measure for those higher-temperature processes.

The process energy efficiency (energy output divided by energy input) is 73.8% for the current 

case and 88.2% for the future case (HHV). These are process energy inputs only and do not 

include energy used upstream of the process. The results also do not include energy used for 

hydrogen compression, storage, and dispensing or for consumption in vehicles; thus they do not 

represent life-cycle or "well-to-wheel" energy use.
33

Table 15. Central Grid Electrolysis: Process Energy Results Summary

Energy Component

Energy Input 

(MJ per kg hydrogen)

Energy Output 

(MJ per kg hydrogen)

Current Future Current Future

Industrial electricity 192 161 — —

Hydrogen — — 120 120

Total 192 161 120 120

Process energy efficiency (LHV)a

Current = 62.4%

Future = 74.6%

Process energy efficiency (HHV)a

Current = 73.8%

Future = 88.2% a

Process energy efficiency = Hydrogen energy output ÷ all feedstock and process energy inputs.

Table 16 (current) and Table 17 (future) show the values used in the sensitivity analyses. See 

Sensitivity Analysis (page 15) to learn how these values were chosen. Figure 18 (current) and 

Figure 19 (future) show the sensitivity analysis results. For both cases, electricity price has the 

largest effect on hydrogen price.

Table 16. Central Current Grid Electrolysis: Sensitivity Analysis Values

Variable Lower Value Nominal Value Upper Value

Total fixed operating cost (million $) 3.8 5.4 7.0

Operating capacity factor 0.98 0.97 0.85

Electrolyzer system efficiency (HHV) 79% 74% 69%

Uninstalled electrolyzer cost ($/kW) 575 675 775

Industrial electricity price ($/kWh) 0.039 0.055 0.072

Table 17. Central Future Grid Electrolysis: Sensitivity Analysis Values

Variable Lower Value Nominal Value Upper Value

Total fixed operating cost (million $) 1.6 2.2 2.9

Operating capacity factor 0.98 0.97 0.85

Electrolyzer system efficiency (HHV) 90% 88% 76%

Uninstalled electrolyzer cost ($/kW) 240 300 450

Industrial electricity price ($/kWh) 0.039 0.055 0.073
34

3.6 4.1 4.6 5.1 5.6 6.1

Total Fixed Operating Costs, with a

range of +/- 30%

Operating Capacity Factor, ranging

from 85% to 98%

Electrolyzer System Efficiency,

ranging from 69% to 79% (HHV)

Uninstalled electrolyzer cost per kW,

ranging from $575/kW to $775/kW

Industrial Feedstock Electricity

Price, ranging from 4¢/kWh to

7¢/kWh (+/- 30% range)

Hydrogen Cost ($/kg)

Figure 18. Central Current Grid Electrolysis: Sensitivity Analysis Results

2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 4 4.2

Total Fixed Operating Costs, with a

range of +/- 30%

Operating Capacity Factor, ranging

from 85% to 98%

Uninstalled electrolyzer cost per kW,

ranging from $240/kW to $450/kW

Electrolyzer System Efficiency,

ranging from 76% to 90% (HHV)

Industrial Feedstock Electricity

Price, ranging from 4¢/kWh to

7¢/kWh (+/- 30% range)

Hydrogen Cost ($/kg)

Figure 19. Central Future Grid Electrolysis: Sensitivity Analysis Results 
35

Coal without CO2 Sequestration

Process Description

The central current coal without CO2 sequestration technology case is based on commercially 

available process technologies (Figure 20). The plant modeled uses a Wabash River–scale 

Conoco-Phillips (EGas) gasifier, conventional gas cooling, commercial shift conversion and acid 

gas cleanup, commercial sulfuric acid technology, and commercial PSA. The EGas gasifier is the 

gasifier of choice for this study because it has been operated on bituminous and sub-bituminous 

coals. The process design includes an air separation unit for supplying concentrated oxygen to 

the gasifier and an amine unit for separation of a CO2-rich stream (~ 93mol% CO2) from the 

hydrogen-rich stream. The up-front removal of nitrogen from the process and separation of a 

CO2-rich stream makes this process design amenable to carbon sequestration. The only 

additional process step required for CO2 sequestration would be compression and transport of 

the CO2 stream.

The future case is based on longer-term process technology (Figure 21). Hot raw gas from the 

transport gasifier is sent to the hot gas desulfurization process for desulfurization. Elemental 

sulfur is produced as a byproduct. The clean filtered hot gas then goes through a hydrogen 

separation membrane, where the shift reaction occurs and hydrogen is separated from CO2. A 

portion of the hydrogen is fired to heat compressed air entering the ITM oxygen separation unit.

Heat for the air is also extracted from the hot CO2 stream with a high-temperature heat 

exchanger. Additional hydrogen is used to produce power from a combined cycle solid oxide 

fuel cell (SOFC) and gas turbine. Pure oxygen produced from the ITM is cooled and compressed 

for use in the gasifier. The remaining hydrogen is compressed for product delivery. The CO2-rich 

stream is fired with oxygen and expanded to recover energy as power. Note that the CO2-rich 

stream shown as “CO2 Product” in Figure 21 is not captured for CO2 sequestration, and 

therefore it is a waste stream rather than a product stream.
43

Figure 20. Process Flow Diagram—Current Coal without CO2 Sequestration 

Figure 21. Process Flow Diagram—Future Coal without CO2 Sequestration 
37

H2A Model Inputs

The following tables show the H2A Model input values for the central current and future coal 

without CO2 sequestration technology cases. Default values that are common to all central cases 

are not shown in the tables below; see Common Input Parameters and Processes (page 16) for 

those values. 

Table 18 shows the technical operating parameters and specifications. The central coal without 

CO2 sequestration cases produce approximately 255,000 (current) and 222,000 (future) kg of 

hydrogen per day. Table 19 summarizes the cost inputs, including capital, fixed operating, and 

variable operating costs. Table 20 summarizes the energy inputs.

Table 18. Central Coal without CO2 Sequestration: Technical Operating Parameters and 

Specifications

Current Future

Plant design capacity (kg hydrogen/day) 284,000 246,000

Plant output (kg hydrogen/day) 255,000 222,000

Plant output (kg hydrogen/year) 93,000,000 81,000,000
38

Table 19. Central Coal without CO2 Sequestration: Cost Input Summary

Capital Costs (million 2005$) Current Future

Initial direct

Coal handling prep and feed 31.0 35.5

Feedwater and misc. BOP systems 5.3 9.4

Gasifier and accessories 84.2 69.7

Air separation unit 58.5 34.8

Hydrogen separation and gas cleanup 55.4 54.0

Expander/generators and SOFC/CT — 68.8

HRSG ducting and stack 18.8 —

HRSG and steam turbine generator — 15.1

Steam turbine generator 15.8 —

Cooling water system 6.4 2.3

Ash handling system 8.0 6.5

Accessory electric plant 12.2 26.5

I&C 10.6 12.9

Buildings and structures 6.0 6.3

Zinc oxide polisher 0.6 —

Total initial direct 312.8 341.9

Indirect depreciable

Site preparation 5.1 3.4

Engineering and design 31.3 34.2

Project contingency 46.9 85.5

Up-front permitting 38.3 34.2

Indirect non-depreciable Land cost 1.3 1.3

Total indirect 122.9 158.5

Total initial (initial direct + indirect) 435.7 500.5

Expected replacementa 14.8 24.8

Totalb 450.5 525.3

Fixed Operating Costs (million 2005$/year) Current Future

Labor 10.4 12.5

G&A 2.1 2.5

Property taxes and insurance 8.7 10.0

Material for maintenance and repairs 1.9 2.1

Totalb 23.1 27.0

Variable Operating Costs (million 2005$/year)c Current Future

Energy feedstocks, utilities, byproducts Coal feedstock 29.7 30.6

Industrial electricity byproductd (8.9) (36.4)

Other materials and byproducts Process water 0.5 0.4

Sulfuric acid byproductd (0.0) —

Other variable operating costs

Other variable 2.4 1.0

Waste treatment 0.1 0.1

Solid waste disposal 0.9 0.8

Totalb,d 24.7 (3.5)

a

Sum of expected replacement capital costs over the 40-year plant life, adjusted to the year in which they are incurred using an NPV 

calculation.

b

Components might not add to total owing to rounding. c

These costs vary over time in accordance with H2A Model price tables; startup year costs are shown here. d

Numbers in parentheses represent income.
39

Table 20. Central Coal without CO2 Sequestration: Energy Input Summary

Feed/(Byproduct) Lower Heating Value

Material Use/(Production)

(per kg hydrogen)

Current Future

Coal feedstock 27.7 MJ/kg 8.5 kg 9.8 kg

(Industrial electricity) 3.6 MJ/kWh (3.2 kWh) (15 kWh)

H2A Model Results

The following tables and figures show the H2A Model results for the central current and future 

coal without CO2 sequestration technology cases. Table 21 summarizes the cost results. The 

central current coal without CO2 sequestration case produces hydrogen for $1.41/kg. The future 

case produces hydrogen for $1.45/kg. Capital cost is the largest expense for both cases. Both 

cases partially offset costs with income from byproduct electricity generation.

Table 21. Central Coal without CO2 Sequestration: Cost Results Summary

Cost Component

Cost Contribution 

($/kg hydrogen)

Percentage of 

Hydrogen Costa

Current Future Current Future

Capital 0.88 1.14 62% 78%

Fixed O&M 0.26 0.35 18% 24%

Feedstock 0.33 0.41 24% 28%

Byproduct credits (0.10) (0.47) (7%) (33%)

Other variableb 0.04 0.03 3% 2%

Total hydrogen cost 1.41 1.45 100% 100% a

Total might not add to 100% owing to rounding. b

Including utilities.

Table 22 summarizes the process energy results. All the energy input is in the form of coal 

feedstock. The energy outputs are hydrogen and electricity. The process energy efficiency 

(energy output divided by energy input) is 55.8% for the current case and 64.1% for the future 

case. These are process energy inputs only and do not include energy used upstream of the 

process. The results also do not include energy used for hydrogen compression, storage, and 

dispensing or for consumption in vehicles; thus they do not represent life-cycle or "well-towheel" energy use.
40

Table 22. Central Coal without CO2 Sequestration: Process Energy Results Summary

Energy Component

Energy Input 

(MJ per kg hydrogen)

Energy Output 

(MJ per kg hydrogen)

Current Future Current Future

Coal feedstock 236 271 — —

Industrial electricity byproduct — — 11 54

Hydrogen — — 120 120

Total 236 271 131 174

Process energy efficiency (LHV)a

Current = 55.8%

Future = 64.1% a

Process energy efficiency = process energy output ÷ process energy input.

Table 23 (current) and Table 24 (future) show the values used in the sensitivity analyses. See 

Sensitivity Analysis (page 15) to learn how these values were chosen. Figure 22 (current) and 

Figure 23 (future) show the sensitivity analysis results. For both cases, total direct capital cost 

has the largest effect on hydrogen price.
41

Table 23. Central Current Coal without CO2 Sequestration: Sensitivity Analysis Values

Variable Lower Value Nominal Value Upper Value

Labor cost (million $/year) 7.0 10.4 14.0

Plant efficiency 65% 56% 45%

Coal price ($/kg) 0.026 0.037 0.049

Operating capacity factor 0.95 0.90 0.80

Total direct capital cost (million $) 290 313 430

1.3 1.35 1.4 1.45 1.5 1.55 1.6 1.65 1.7 1.75 1.8

Labor Cost ($/year) [range $7M -

$14M]

Plant Efficiency [range 45% - 65%]

Coal Price [range ± 30%]

Operating Capacity Factor [range

80% - 95%]

Total Direct Capital Cost [range

$290M - $430M]

Hydrogen Cost ($/kg)

Figure 22. Central Current Coal without CO2 Sequestration: Sensitivity Analysis Results
42

Table 24. Central Future Coal without CO2 Sequestration: Sensitivity Analysis Values

Variable Lower Value Nominal Value Upper Value

Labor cost (million $/year) 9.0 12.5 15.0

Plant efficiency 70% 64% 50%

Coal price ($/kg) 0.027 0.039 0.050

Operating capacity factor 0.95 0.9 0.8

Total direct capital cost (million $) 310 342 440

1.3 1.4 1.5 1.6 1.7 1.8

Labor Cost ($/year) [range $9M -

$15M]

Plant Efficiency [range 50% - 70%]

Coal Price [range ± 30%]

Operating Capacity Factor [range

80% - 95%]

Total Direct Capital Cost [range

$310M - $440M]

Hydrogen Cost ($/kg)

Figure 23. Central Future Coal without CO2 Sequestration: Sensitivity Analysis Results

Coal with CO2 Sequestration

Process Description

The central current coal with CO2 sequestration technology case is based on commercially 

available process technologies (Figure 24). The plant modeled includes a Wabash River–scale 

Destec (EGas) gasifier, conventional gas cooling, commercial shift conversion and acid gas 

cleanup, commercial sulfuric acid technology, and commercial PSA. Two-stage Selexol is used 

to remove CO2. CO2 is compressed to 2,200 psi for sequestration. The EGas gasifier is the 

gasifier of choice for this study because it has been operated on bituminous and sub-bituminous 

coals.

For the future case, hot raw gas from the transport gasifier is sent to the hot gas desulfurization 

process for desulfurization (Figure 25). Elemental sulfur is produced as a byproduct. The clean,
43

filtered hot gas then goes through a hydrogen separation membrane where the shift reaction 

occurs and hydrogen is separated from CO2. A portion of the hydrogen is fired to heat 

compressed air entering the ITM oxygen separation unit. Heat for the air is also extracted from 

the hot CO2 stream with a high-temperature heat exchanger. Additional hydrogen is used to 

produce power from a combined-cycle SOFC. Pure oxygen produced from the ITM is cooled 

and compressed for use in the gasifier. The remaining hydrogen is compressed for product 

delivery. The CO2-rich stream is fired with oxygen and expanded to recover energy as power.

The CO2 exhaust is compressed for pipeline delivery.

Figure 24. Process Flow Diagram—Current Coal with CO2 Sequestration
44

Figure 25. Process Flow Diagram—Future Coal with CO2 Sequestration

H2A Model Inputs

The following tables show the H2A Model input values for the central current and future coal 

with CO2 sequestration technology cases. Default values that are common to all central cases are 

not shown in the tables below; see Common Input Parameters and Processes (page 16) for those 

values. 

Table 25 shows the technical operating parameters and specifications. The central coal with CO2

sequestration cases produce approximately 277,000 (current) and 222,000 (future) kg of 

hydrogen per day. Table 26 summarizes the cost inputs, including capital, fixed operating, and 

variable operating costs. Table 27 summarizes the energy inputs.

Table 25. Central Coal with CO2 Sequestration: Technical Operating Parameters and 

Specifications 

Current Future

Plant design capacity (kg hydrogen/day) 308,000 246,000

Plant output (kg hydrogen/day) 277,000 222,000

Plant output (kg hydrogen/year) 101,000,000 81,000,000
45

Table 26. Central Coal with CO2 Sequestration: Cost Input Summary

Capital Costs (million 2005$) Current Future

Initial direct

Coal handling prep and feed 31.0 35.5 

Feedwater and misc. BOP systems 5.3 9.4

Gasifier and accessories 71.0 69.7

Air separation unit 77.5 34.8

Hydrogen separation and gas cleanup 106.3 54.0

Expander/generators and SOFC/CT — 68.8

HRSG ducting and stack 18.8 —

HRSG and steam turbine generator — 15.1

Steam turbine generator 13.6 —

Cooling water system 5.6 2.3

Ash handling system 8.0 6.5

Accessory electric plant 13.2 26.5

I&C 10.6 12.9

Buildings and structures 5.6 6.3

Zinc oxide polisher and CO2 comp. 24.4 —

CO2 compressor 35.7 35.7

CO2 injection (site and wells) 2.4 2.4

CO2 pipeline 78.6 78.6

Total initial direct 507.7 458.7

Indirect depreciable

Site preparation 6.5 4.6

Engineering and design 50.8 45.9

Project contingency 76.1 114.7

Up-front permitting 49.0 45.9

Indirect non-depreciable Land cost 1.3 1.3

Total indirect 183.7 212.2

Total initial (initial direct + indirect) 691.4 670.9

Expected replacementa 138.0 133.9

Totalb 829.4 804.8

Fixed Operating Costs (million 2005$/year) Current Future

Labor 10.4 12.5

G&A 2.1 2.5

Property taxes and insurance 13.8 13.4

Material for maintenance and repairs 2.3 2.2

Totalb 28.7 30.6

Variable Operating Costs (million 2005$/year)c Current Future

Energy feedstocks, 

utilities, byproducts

Coal feedstock 29.7 30.6

Industrial electricity (for CO2 sequestration) 9.6 9.8

Industrial electricity byproductd — (9.8)

Commercial electricity byproductd — (30.6)

Other materials and byproducts Process water 0.5 0.4

Other variable operating costs

Other variable 2.7 1.0

Waste treatment 0.1 0.1

Solid waste disposal 0.8 0.8

CO2 sequestration O&M 3.5 3.5

Totalb 46.9 5.8 a

Sum of expected replacement capital costs over the 40-year plant life, adjusted to the year they are incurred using an NPV calculation. b

Components might not add to total owing to rounding. c

These costs vary over time in accordance with H2A Model price tables; startup year costs are shown here. d

Numbers in parentheses represent income.
46

Table 27. Central Coal with CO2 Sequestration: Energy Input Summary

Feed/(Byproduct) Lower Heating Value

Material Use/(Production)

(per kg hydrogen)

Current Future

Coal feedstock 27.7 MJ/kg 7.8 kg 9.8 kg

Industrial electricitya 3.6 MJ/kWh 1.7 kWh 2.1 kWh

(Industrial electricity) 3.6 MJ/kWh — (2.2 kWh)

(Commercial electricity) 3.6 MJ/kWh — (12.6 kWh) a

Electricity used for CO2 sequestration.

H2A Model Results

The following tables and figures show the H2A Model results for the central current and future 

coal with CO2 sequestration technology cases. Table 28 summarizes the cost results. The central 

current coal with CO2 sequestration case produces hydrogen for $2.05/kg. The future case 

produces hydrogen for $2.00/kg. Capital cost is the largest expense for both cases. The future 

case partially offsets costs with income from byproduct electricity generation.

Table 28. Central Coal with CO2 Sequestration: Cost Results Summary

Cost Component

Cost Contribution 

($/kg hydrogen)

Percentage of 

Hydrogen Costa

Current Future Current Future

Production capitalb 1.06 1.23 52% 62%

CO2 sequestration capitalb 0.21 0.29 10% 14%

Production fixed O&Mc 0.27 0.36 13% 18%

CO2 sequestration O&Mc 0.03 0.04 1% 2%

Feedstock 0.31 0.41 15% 20%

Byproduct credits — (0.52) — (26%)

Other variabled 0.07 0.08 4% 4%

CO2 sequestration energy 0.10 0.12 5% 6%

Total hydrogen cost 2.05 2.00 100% 100% a

Total might not add to 100% owing to rounding. b

CO2 capture capital costs are included as part of production capital costs. CO2 sequestration capital costs 

include compression, injection, and pipeline costs.

c

CO2 capture O&M costs are included as part of production fixed O&M costs. CO2 sequestration O&M costs 

include compression, injection, and pipeline costs.

d

Including utilities.

Table 29 summarizes the process energy results. The energy inputs are in the form of coal 

feedstock and electricity used for CO2 sequestration. The energy outputs are hydrogen and 

electricity. The process energy efficiency (energy output divided by energy input) is 53.7% for 

the current case and 62.0% for the future case. These are process energy inputs only and do not 

include energy used upstream of the process. The results also do not include energy used for 

hydrogen compression, storage, and dispensing or for consumption in vehicles; thus they do not 

represent life-cycle or "well-to-wheel" energy use.
47

Table 29. Central Coal with CO2 Sequestration: Process Energy Results Summary

Energy Component

Energy Input 

(MJ per kg hydrogen)

Energy Output 

(MJ per kg hydrogen)

Current Future Current Future

Coal feedstock 217 271 — —

Industrial electricitya 6 8 — —

Industrial electricity byproduct — — — 8

Commercial electricity byproduct — — — 45

Hydrogen — — 120 120

Total 223 279 120 173

Process energy efficiency (LHV)b

Current = 53.7%

Future = 62.0%

a

Electricity used for CO2 sequestration. b

Process energy efficiency = process energy output ÷ process energy input.

Table 30 (current) and Table 31 (future) show the values used in the sensitivity analyses. See 

Sensitivity Analysis (page 15) to learn how these values were chosen. Figure 26 (current) and 

Figure 27 (future) show the sensitivity analysis results. For both cases, production process total 

direct capital cost has the largest effect on hydrogen price.

Table 30. Central Current Coal with CO2 Sequestration: Sensitivity Analysis Values

Variable Lower Value Nominal Value Upper Value

Labor cost (million $/year) 7.0 10.4 14.0

Plant efficiency 60% 54% 45%

Coal price ($/kg) 0.026 0.037 0.049

Operating capacity factor 0.95 0.9 0.8

CO2 sequestration capital cost (million $) 75 117 175

Production process total direct capital cost (million $) 350 391 500

Table 31. Central Future Coal with CO2 Sequestration: Sensitivity Analysis Values

Variable Lower Value Nominal Value Upper Value

Labor cost (million $/year) 9.0 12.5 15.0

Plant efficiency 65% 62% 50%

Coal price ($/kg) 0.027 0.039 0.050

Operating capacity factor 0.95 0.9 0.8

CO2 sequestration capital cost (million $) 70 117 170

Production process total direct capital cost (million $) 310 342 420
48

1.9 1.95 2 2.05 2.1 2.15 2.2 2.25 2.3 2.35

Labor Cost [range $7M/year -

$14M/year]

Plant Efficiency [range 45% - 60%]

Pittsburgh No 8 Coal Price [range

$24 - $44 per ton]

CO2 sequestration capital costs

[range $75M/year - $175M/year]

Operating Capacity Factor [range

80% - 90%]

Production Process Total Direct

Capital Cost [range $350M - $500M]

Hydrogen Cost ($/kg)

Figure 26. Central Current Coal with CO2 Sequestration: Sensitivity Analysis Results

1.8 1.85 1.9 1.95 2 2.05 2.1 2.15 2.2 2.25 2.3

Labor Cost [range $9M/year -

$15M/year]

Plant Efficiency [range 50% - 65%]

Pittsburgh No 8 Coal Price [range

$24 - $46 per ton]

Operating Capacity Factor [range

80% - 95%]

CO2 sequestration capital costs

[range $70M - $170M]

Production Process Total Direct

Capital Cost [range $310M - $420M]

Hydrogen Cost ($/kg)

Figure 27. Central Future Coal with CO2 Sequestration: Sensitivity Analysis Results
49

Natural Gas without CO2 Sequestration

Process Description

In the central natural gas without CO2 sequestration technology cases, natural gas is fed to the 

plant from the pipeline at a pressure of 450 psia (Figure 28). The gas is generally sulfur free, but 

odorizers with mercaptans must be cleaned from the gas to prevent contamination of the 

reformer catalyst. The desulfurized natural gas feedstock is mixed with process steam to be 

reacted over a nickel-based catalyst contained inside a system of high-alloy steel tubes. The 

reforming reaction is strongly endothermic, and the metallurgy of the tubes usually limits the 

reaction temperature to 1,400°–1,700°F. The flue gas path of the fired reformer is integrated with 

additional boiler surfaces to produce about 700,000 lb/hour steam. Of this, about 450,000 lb/hour 

is superheated to 450 psia and 750°F to be added to the incoming natural gas. Additional steam 

from the boiler is sent off site. After the reformer, the process gas mixture of CO and hydrogen 

passes through a heat-recovery step and is fed into a water gas shift reactor to produce additional 

hydrogen. 

The PSA process is used for hydrogen purification based on its ease of operation and ability to 

produce high-purity hydrogen and low amounts of CO and CO2. Shifted gas is fed directly to the 

PSA unit, where hydrogen is purified up to approximately 99.6%.

Figure 28. Process Flow Diagram—Natural Gas without CO2 Sequestration

H2A Model Inputs

The following tables show the H2A Model input values for the central current and future natural 

gas without CO2 sequestration technology cases. Default values that are common to all central 

cases are not shown in the tables below; see Common Input Parameters and Processes (page 16) 

for those values. 
50

Table 32 shows the technical operating parameters and specifications. The central natural gas

without CO2 sequestration cases produce approximately 341,000 kg of hydrogen per day. Table 

33 summarizes the cost inputs, including capital, fixed operating, and variable operating costs. 

Table 34 summarizes the energy inputs.

Table 32. Central Natural Gas without CO2 Sequestration: Technical Operating Parameters and 

Specifications

Current Future

Plant design capacity (kg hydrogen/day) 379,000 379,000

Plant output (kg hydrogen/day) 341,000 341,000

Plant output (kg hydrogen/year) 125,000,000 125,000,000
51

Table 33. Central Natural Gas without CO2 Sequestration: Cost Input Summary

Capital Costs (million 2005$) Current Future

Initial Direct

Process plant equipment 95.9 72.0 

Balance of plant and offsites 38.3 28.7

SCR NOx control on stack 0.6 0.4

Total Initial Direct 134.8 101.1

Indirect depreciable

Site preparation 1.4 1.1

Engineering and design 13.5 10.1

Project contingency 20.2 15.2

Up-front permitting 10.5 7.9

Indirect non-depreciable Land cost 0.1 0.1

Total Indirect 45.7 34.3

Totala 180.5 135.4

Fixed Operating Costs (million 2005$/year) Current Future

Labor 2.1 2.1

G&A 0.4 0.4

Property taxes and insurance 3.6 2.7

Material for maintenance and repairs 0.8 0.6

Totala 6.9 5.8

Variable Operating Costs (million 2005$/year)b Current Future

Energy feedstocks, 

utilities, byproducts

Natural gas feedstock 136.2 124.0

Industrial electricity 3.9 4.2

Other materials and byproducts Demineralized water 2.1 2.1

Cooling water 0.0 0.0

Other variable operating costs Other variablec 2.1 2.1

Totala 144.4 132.5 a

Components might not add to total owing to rounding. b

These costs vary over time in accordance with H2A Model price tables; startup year costs are shown here. c

SMR catalyst, SCR, PSA sorbent, and shift catalyst.

Table 34. Central Natural Gas without CO2 Sequestration: Energy Input Summary

Feed Lower Heating Value

Material Use

(per kg hydrogen)

Current Future

Natural gas feedstock 36.6 MJ/Nm3 4.5 Nm3 4.5 Nm3

Electricity 3.6 MJ/kWh 0.6 kWh 0.6 kWh

H2A Model Results

The following tables and figures show the H2A Model results for the central current and future 

natural gas without CO2 sequestration technology cases. Table 35 summarizes the cost results. 

The central current natural gas without CO2 sequestration case produces hydrogen for $1.32/kg. 

The future case produces hydrogen for $1.40/kg. Feedstock cost is the largest expense for both 

cases and accounts for the hydrogen cost increase in the future case. The AEO 2005 high oil case 

projected price of industrial natural gas increases only about 6% between 2005 and 2045, the 
52

timeframe for the current case, but increases nearly 41% during the timeframe for the future 

case. 

Table 35. Central Natural Gas without CO2 Sequestration: Cost Results Summary

Cost Component

Cost Contribution 

($/kg hydrogen)

Percentage of 

Hydrogen Costa

Current Future Current Future

Capital 0.25 0.20 19% 14%

Fixed O&M 0.06 0.05 4% 3%

Feedstock 0.95 1.08 72% 77%

Other variableb 0.07 0.07 5% 5%

Total hydrogen cost 1.32 1.40 100% 100% a

Total might not add to 100% owing to rounding. b

Including utilities.

Table 36 summarizes the process energy results. Energy inputs are in the form of natural gas 

feedstock and electricity. The energy output is hydrogen. The process energy efficiency (energy 

output divided by energy input) is 71.9% for the current case and 71.8% for the future case. 

These are process energy inputs only and do not include energy used upstream of the process. 

The results also do not include energy used for hydrogen compression, storage, and dispensing or 

for consumption in vehicles; thus they do not represent life-cycle or "well-to-wheel" energy use.

Table 36. Central Natural Gas without CO2 Sequestration: Process Energy Results Summary

Energy Component

Energy Input 

(MJ per kg hydrogen)

Energy Output 

(MJ per kg hydrogen)

Current Future Current Future

Natural gas feedstock 165 165 — —

Electricity 2 2 — —

Hydrogen — — 120 120

Total 167 167 120 120

Process energy efficiency (LHV)a

Current = 71.9%

Future = 71.8% a

Process energy efficiency = process energy output ÷ process energy input.

Table 37 (current) and Table 38 (future) show the values used in the sensitivity analyses. See 

Sensitivity Analysis (page 15) to learn how these values were chosen. Figure 29 (current) and 

Figure 30 (future) show the sensitivity analysis results. For both cases, natural gas feedstock 

price has the largest effect on hydrogen price.
53

Table 37. Central Current Natural Gas without CO2 Sequestration: Sensitivity Analysis Values

Variable Lower Value Nominal Value Upper Value

Fixed operating cost (million $/year) 4.8 6.9 9.0

Operating capacity factor 0.95 0.9 0.8

Total direct capital cost (million $) 110 135 190

Natural gas use (Nm3/kg hydrogen) 4.0 4.5 6.5

Feedstock price ($/Nm3) 0.17 0.24 0.32

1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9

Total Fixed Operating Cost [$4.8M

to $9M; ± 30%]

Operating Capacity Factor [80% to

90%]

Total Direct Capital Cost [$110M to

$190M]

Industrial Natural Gas Usage [(4 to

6.5)Nm3/kg H2]

Feedstock Price (2005$)/Nm3

[($0.17 to $0.32)/Nm3; ± 30%]

Hydrogen Cost ($/kg)

Figure 29. Central Current Natural Gas without CO2 Sequestration: Sensitivity Analysis Results
54

Table 38. Central Future Natural Gas without CO2 Sequestration: Sensitivity Analysis Values

Variable Lower Value Nominal Value Upper Value

Fixed operating cost (million $/year) 4.1 5.8 7.5

Operating capacity factor 0.95 0.9 0.8

Total direct capital cost (million $) 80 101 160

Natural gas use (Nm3/kg hydrogen) 4.0 4.5 6.5

Feedstock price ($/Nm3) 0.16 0.22 0.29

1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9

Total Fixed Operating Cost [range ±

30%]

Operating Capacity Factor [range

80% - 95%]

Total Direct Capital Cost [range

$80M - $160M]

Industrial Natural Gas Usage [(4 to

6.5)Nm3/kg H2]

Feedstock Price [range $0.155/Nm3

- $0.287/Nm3; ± 30%]

Hydrogen Cost ($/kg)

Figure 30. Central Future Natural Gas without CO2 Sequestration: Sensitivity Analysis Results

Natural Gas with CO2 Sequestration

Process Description

In the central natural gas with CO2 sequestration technology cases, natural gas is fed to the plant 

from the pipeline at a pressure of 450 psia (Figure 31). The desulfurized natural gas feedstock is 

mixed with process steam to be reacted over a nickel-based catalyst contained inside a system of 

high-alloy steel tubes. The reforming reaction is strongly endothermic, and the metallurgy of the 

tubes usually limits the reaction temperature to 1400°–1700°F. The flue gas path of the fired 

reformer is integrated with additional boiler surfaces to produce about 700,000 lb/hour of steam. 

Of this, about 450,000 lb/hour is superheated to 450 psia and 750°F to be added to the incoming 

natural gas. Additional steam from the boiler is used to regenerate the CO2. After the reformer, 
55

the process gas mixture of CO and hydrogen passes through a heat recovery step and is fed into a 

water gas shift reactor to produce additional hydrogen. 

The PSA process is used for hydrogen purification based on its ease of operation and ability to 

produce high-purity hydrogen and low amounts of CO and CO2. Shifted gas is fed directly to the 

PSA unit, where hydrogen is purified up to approximately 99.6%. This plant uses a proprietary 

amine-based process to remove and recover 99% of the CO2 from the syngas stream. From the 

shift reactor, gas is passed through an amine tower, where it is contacted counter-currently with a 

circulating stream of lean aqueous amine solution. The rich amine from the absorber is then sent 

to a stripper column where the amine is regenerated with a steam reboiler to remove the CO2 by 

fractionation. The regenerated CO2 stream is recovered at 27 psia and 121°F and is compressed 

to be sent off site. To reach 90% CO2 removal, a secondary MEA treatment process is installed 

on the reformer stack.

PRESSURE

SWING

ADSORBER

SULFUR

GUARD

SHIFT

REACTORS

STEAM

 REFORMER

NATURAL G AS

1

HRSG 6

3

AMBIENT AIR

STACK G AS

AMINE AG R

UNIT

 

5

H2 PR

FUEL G AS

2

STEAM

4

CO2 PRODUCT

Figure 31. Process Flow Diagram—Natural Gas with CO2 Sequestration

H2A Model Inputs

The following tables show the H2A Model input values for the central current and future natural 

gas with CO2 sequestration technology cases. Default values that are common to all central cases 

are not shown in the tables below; see Common Input Parameters and Processes (page 16) for 

those values. 

Table 39 shows the technical operating parameters and specifications. The central natural gas 

with CO2 sequestration cases produce approximately 341,000 kg of hydrogen per day. Table 40

summarizes the cost inputs, including capital, fixed operating, and variable operating costs. 

Table 41 summarizes the energy inputs.
56

Table 39. Central Natural Gas with CO2 Sequestration: Technical Operating Parameters and 

Specifications

Current Future

Plant design capacity (kg hydrogen/day) 379,000 379,000

Plant output (kg hydrogen/day) 341,000 341,000

Plant output (kg hydrogen/year) 125,000,000 125,000,000

Table 40. Central Natural Gas with CO2 Sequestration: Cost Input Summary

Capital Costs (million 2005$) Current Future

Initial Direct

Process plant equipment (reformer) 95.9 76.8

Balance of plant and offsites 38.3 30.7

Process CO2 removal 11.7 9.3

Stack CO2 removal 10.3 8.2

CO2 compressor 28.7 25.2

CO2 injection (site and wells) 2.4 2.4

CO2 pipeline 64.9 64.9

Total Initial Direct 252.1 217.4

Indirect depreciable

Site preparation 2.2 1.8

Engineering and design 25.2 10.1

Project contingency 37.8 15.2

Up-front permitting 16.5 7.9

Indirect non-depreciable Land cost 0.1 0.1

Total Indirect 81.8 35.1

Totala 334.0 252.6

Fixed Operating Costs (million 2005$/year) Current Future

Labor 2.6 2.6

G&A 0.5 0.5

Property taxes and insurance 6.7 5.1

Material for maintenance and repairs 1.0 0.8

Totala 10.8 9.0

Variable Operating Costs (million 2005$/year)b Current Future

Energy feedstocks, 

utilities, byproducts

Natural gas feedstock 135.9 123.7

Industrial electricity (production) 4.1 4.2

Industrial electricity (CO2 sequestration) 5.6 4.9

Other materials and byproducts

Demineralized water 2.1 2.1

Cooling water 0.0 0.0

Other variable operating costs Other variablec 4.6 4.6

CO2 sequestration O&M 2.9 2.7

Totala 155.2 142.3 a

Components might not add to total owing to rounding. b

These costs vary over time in accordance with H2A Model price tables; startup year costs are shown here. c

SMR catalyst, SCR, MEA, PSA sorbent, and shift catalyst.
57

Table 41. Central Natural Gas with CO2 Sequestration: Energy Input Summary

Feed Lower Heating Value

Material Use

(per kg hydrogen)

Current Future

Natural gas feedstock 36.6 MJ/Nm3 4.5 Nm3 4.5 Nm3

Electricity (production) 3.6 MJ/kWh 0.6 kWh 0.6 kWh

Electricity (CO2 sequestration) 3.6 MJ/kWh 0.8 kWh 0.7 kWh

H2A Model Results

The following tables and figures show the H2A Model results for the central current and future 

natural gas with CO2 sequestration technology cases. Table 42 summarizes the cost results. The 

central current natural gas with CO2 sequestration case produces hydrogen for $1.64/kg. The 

future case produces hydrogen for $1.65/kg. As for the natural gas cases without carbon 

sequestration, feedstock costs account for the hydrogen cost increase in the future case.

Table 42. Central Natural Gas with CO2 Sequestration: Cost Results Summary

Cost Component

Cost Contribution 

($/kg hydrogen)

Percentage of 

Hydrogen Costa

Current Future Current Future

Production capitalb 0.31 0.23 19% 14%

CO2 sequestration capitalb 0.14 0.12 9% 7%

Production fixed O&Mc 0.07 0.05 4% 3%

CO2 sequestration O&Mc 0.02 0.02 1% 1%

Feedstock 0.94 1.08 58% 65%

Other variabled 0.11 0.11 7% 7%

CO2 sequestration energy 0.04 0.04 2% 2%

Total hydrogen cost 1.64 1.65 100% 100% a

Total might not add to 100% owing to rounding. b

CO2 capture capital costs are included as part of production capital costs. CO2 sequestration capital costs 

include compression, injection, and pipeline costs.

c

CO2 capture O&M costs are included as part of production fixed O&M costs. CO2 sequestration O&M costs 

include compression, injection, and pipeline costs.

d

Including utilities.

Table 43 summarizes the process energy results. Energy inputs are in the form of natural gas 

feedstock and electricity. The energy output is hydrogen. The process energy efficiency (energy 

output divided by energy input) is 70.8% for the current case and 71.0% for the future case. 

These are process energy inputs only and do not include energy used upstream of the process. 

The results also do not include energy used for hydrogen compression, storage, and dispensing or 

for consumption in vehicles; thus they do not represent life-cycle or "well-to-wheel" energy use.
58

Table 43. Central Natural Gas with CO2 Sequestration: Process Energy Results Summary

Energy Component

Energy Input 

(MJ per kg hydrogen)

Energy Output 

(MJ per kg hydrogen)

Current Future Current Future

Natural gas feedstock 164 164 — —

Electricity (production) 2 2 — —

Electricity (CO2 sequestration) 3 3 — —

Hydrogen — — 120 120

Total 169 169 120 120

Process energy efficiency (LHV)a

Current = 70.8%

Future = 71.0% a

Process energy efficiency = process energy output ÷ process energy input.

Table 44 (current) and Table 45 (future) show the values used in the sensitivity analyses. See 

Sensitivity Analysis (page 15) to learn how these values were chosen. Figure 32 (current) and

Figure 33 (future) show the sensitivity analysis results. For both cases, natural gas feedstock 

price has the largest effect on hydrogen price.

Table 44. Central Current Natural Gas with CO2 Sequestration: Sensitivity Analysis Values

Variable Lower Value Nominal Value Upper Value

Fixed operating cost (million $/year) 7.6 10.8 14.1

Operating capacity factor 0.95 0.9 0.8

Direct production capital cost (million $) 150 156 220

CO2 sequestration capital cost (million $) 75 96 175

Natural gas use (Nm3/kg hydrogen) 4.2 4.5 6.4

Feedstock price ($/Nm3) 0.17 0.24 0.32

Table 45. Central Future Natural Gas with CO2 Sequestration: Sensitivity Analysis Values

Variable Lower Value Nominal Value Upper Value

Fixed operating cost (million $/year) 6.3 8.9 11.6

Operating capacity factor 0.95 0.9 0.8

Direct production capital cost (million $) 105 125 190

CO2 sequestration capital cost (million $) 70 93 170

Natural gas use (Nm3/kg hydrogen) 4.2 4.5 6.4

Feedstock price ($/Nm3) 0.16 0.22 0.29
59

1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2

Total Fixed Operating Cost [range ±

30%]

Operating Capacity Factor [range

80% - 95%]

Direct Production Capital Cost

[range $150M - $220M]

CO2 sequestration capital cost

[range $75M - $175M]

Natural Gas Use [range 4.2 - 6.4]

Industrial Natural Gas Price [range ±

30%]

Hydrogen Cost ($/kg)

Figure 32. Central Current Natural Gas with CO2 Sequestration: Sensitivity Analysis Results

1.2 1.4 1.6 1.8 2 2.2

Total Fixed Operating Cost [range ±

30%]

Operating Capacity Factor [range

80% - 95%]

Direct Production Capital Cost

[range $105M - $190M]

CO2 Sequestration Capital Cost

[$70M - $170M]

Natural Gas Use [range 4.2 - 6.4]

Industrial Natural Gas Price [range

$0.155/Nm3 - $0.287/Nm3]

Hydrogen Cost ($/kg)

Figure 33. Central Future Natural Gas with CO2 Sequestration: Sensitivity Analysis Results
60

Nuclear Energy via High-Temperature Electrolysis

Process Description

The central nuclear energy via high-temperature electrolysis technology case is based on the 

application of an advanced nuclear plant providing high-efficiency electric power and heat (high 

temperature steam) to a central high-temperature electrolysis (HTE) plant (Figure 34). The 

nuclear plant capital and operating costs are not modeled in this case. Instead, heat and electricity 

are purchased from the nuclear plant. HTE operation and performance is modeled on the design 

being developed by Idaho National Laboratory (INL), including published pilot-scale plant 

parameters. Only a future case (startup year 2030) is considered for this technology.

Figure 34. Process Flow Diagram—Nuclear Energy via High-Temperature Electrolysis

H2A Model Inputs

The following tables show the H2A Model input values for the central nuclear energy via hightemperature electrolysis technology case. Default values that are common to all central cases are 

not shown in the tables below; see Common Input Parameters and Processes (page 16) for those 

values. 

Table 46 shows the technical operating parameters and specifications. The central nuclear energy 

via high-temperature electrolysis technology case produces approximately 734,000 kg of 
61

hydrogen per day. Table 47 summarizes the cost inputs, including capital, fixed operating, and 

variable operating costs. Table 48 summarizes the energy inputs.

Table 46. Central Nuclear Energy via High-Temperature Electrolysis: Technical Operating 

Parameters and Specifications

Future

Plant design capacity (kg hydrogen/day) 816,000

Plant output (kg hydrogen/day) 734,000

Plant output (kg hydrogen/year) 268,000,000
62

Table 47. Central Nuclear Energy via High-Temperature Electrolysis: Cost Input Summary

Capital Costs (million 2005$) Future

Initial direct

Steam generator/superheater 27.9 

Oxygen recuperator 22.4

Hydrogen recuperator 24.5

Sweep heater 7.5

High-temperature (electric) heater 5.3

Power recovery system 20.0

Water supply system 4.0

Miscellaneous plant equipment 10.0

Electrolyzer system 584.0

Total initial direct 705.6

Indirect depreciable Project contingency 141.1

Other depreciablea 141.1

Indirect non-depreciable Land cost 1.0

Total indirect 283.2

Total initial (initial direct + indirect) 988.8

Expected replacementb 216.9

Totalc 1,205.7

Fixed Operating Costs (million 2005$/year) Future

Labor 20.0

G&A 3.0

Property taxes and insurance 19.8

Material for maintenance and repairs 13.1

Totalc 55.8

Variable Operating Costs (million 2005$/year)d Future

Energy feedstocks, utilities, byproducts Thermal energy 36.6

Industrial electricity 491.1

Other materials and byproducts Demineralized water 3.2

Totalc 530.9

a

Covers site preparation, engineering and design, licensing, permitting, etc. b

Sum of expected replacement capital costs over the 40-year plant life, adjusted to the year in which they are incurred using an NPV 

calculation.

c

Components might not add to total owing to rounding. d

These costs vary over time in accordance with H2A Model price tables; startup year costs are shown here.

Table 48. Central Nuclear Energy via High-Temperature Electrolysis: Energy Input Summary

Feed Lower Heating Value Material Use (per kg hydrogen)

Future

Thermal energy 3.6 mmBtu/MWh 6.8 kWh

Industrial electricity 3.6 MJ/kWh 33.2 kWh

H2A Model Results

The following tables and figure show the H2A Model results for the central nuclear energy via 

high-temperature electrolysis technology case. Table 49 summarizes the cost results. This 
63

technology case produces hydrogen for $2.93/kg. Feedstock (electricity and thermal energy) is 

the largest expense.

Table 49. Central Nuclear Energy via High-Temperature Electrolysis: Cost Results Summary

Cost Component

Cost Contribution 

($/kg hydrogen)

Percentage of 

Hydrogen Costa

Future Future

Capital 0.77 26%

Fixed O&M 0.22 7%

Feedstock 1.94 66%

Other variableb 0.01 0.4%

Total hydrogen cost 2.93 100% a

Total might not add to 100% owing to rounding. b

Including utilities.

Table 50 summarizes the process energy results. The energy inputs are in the form of thermal 

energy and electricity. The energy output is hydrogen. The process energy efficiency (energy 

output divided by energy input) is 83.3%. These are process energy inputs only and do not 

include energy used upstream of the process. The results also do not include energy used for 

hydrogen compression, storage, and dispensing or for consumption in vehicles; thus they do not 

represent life-cycle or "well-to-wheel" energy use.

Table 50. Central Nuclear Energy via High-Temperature Electrolysis: Process Energy Results 

Summary

Energy Component Energy Input

(MJ per kg hydrogen)

Energy Output

(MJ per kg hydrogen)

Future Future

Thermal energy 25 —

Industrial electricity 119 —

Hydrogen — 120

Total 144 120

Process energy efficiency (LHV)a

Future = 83.3% a

Process energy efficiency = process energy output ÷ process energy input.

Table 51 shows the values used in the sensitivity analysis. See Sensitivity Analysis (page 15) to 

learn how these values were chosen. Figure 35 shows the sensitivity analysis results. Total direct 

capital cost has the largest effect on hydrogen price.
64

Table 51. Central Nuclear Energy via High-Temperature Electrolysis: Sensitivity Analysis Values

Variable Lower Value Nominal Value Upper Value

Thermal energy cost ($/MWh) 14 20 26

Total fixed operating cost (million $) 41.9 55.8 67.0

Operating capacity factor 0.95 0.90 0.85

Total direct capital cost (million $) 529 706 847

2.7 2.75 2.8 2.85 2.9 2.95 3 3.05 3.1

Thermal Energy Cost [range

$14/MWh - $26/MWh]

Hydrogen Production Process Total

Fixed Operating Cost [range

$42M/year - $67M/year]

Operating Capacity Factor [range

85% - 95%]

Hydrogen Production Process Total

Direct Capital Cost [range $529M -

$847M]

Hydrogen Cost ($/kg)

Figure 35. Central Nuclear Energy via High-Temperature Electrolysis: Sensitivity Analysis Results

Forecourt Cases

The following sections describe the processes, inputs, and results for the H2A forecourt 

production technology cases (see Table 2 for a list of cases). Values common to all cases are not 

shown in these sections; see Common Input Parameters and Processes (page 16) for those 

values. All forecourt technology cases have a design capacity of 1,500 kg of hydrogen per day 

and an output of 1,278 kg/day (85.2% capacity factor). Annual hydrogen production is 466,470

kg/year.

Unlike the central technology cases, the forecourt cases include refueling station compression, 

storage, and dispensing costs and energy use. It is important to keep this in mind when 

comparing results from forecourt cases with results from central cases. Hydrogen produced from 

central technologies would also incur CSD costs and energy use in order for the hydrogen to be 

delivered and dispensed for use in vehicles.
65

The refueling station subsystem is based on the assumptions and layout of DOE's HDSAM 

model. That model, which applies only to current/2007 technology, consists of hydrogen 

compression for storage in low-pressure (up to 2,500 psi) gas cylinders, followed by further 

compression to 6,250 psi for transfer to a 4-stage, high-pressure cascade system to allow rapid 

filling of 5,000-psi onboard vehicular hydrogen tanks.

Grid Electrolysis

Process Description

The forecourt current and future grid electrolysis technology cases are based on a standalone 

grid-powered electrolyzer system with a total hydrogen production capacity of 1,500 kg/day

(Figure 36). The system is based on the Hydro bi-polar alkaline electrolyzer system 

(Atmospheric Type No. 5040–5150 Amp DC) which produces 485 Nm3 of hydrogen per hour; 

for the future case, improvements in cost and performance were determined in consultation with 

the H2A development group. The electrolyzer system modeled is a skid-mounted unit, including 

the electrolyzer system and necessary auxiliary subsystems. The electrolyzer units use process 

water and electricity input for electrolysis. Potassium hydroxide (KOH, or lye) is needed for the 

electrolyte in the system. The system includes the following equipment: transformer, thyristor, 

electrolyzer unit, lye tank, feed-water demineralizer, hydrogen scrubber, gas holder, two 

compressor units to 30 bar (435 psig), deoxidizer, and twin tower dryer.

The electrolyzer system receives AC grid electricity, which is converted via transformer and 

rectifier subsystems into DC electricity for use by the electrolyzer stack. The transformer 

subsystem is an oil-immersed, ambient air-cooled unit, manufactured to IEC-76. The rectifier 

subsystem converts the AC voltage to DC voltage using thyristors. Cooling is generally 

accomplished via forced air achieved by fans on the bottom of the rectifier cabinet but can also 

be accomplished with cooling water. The electrolyzer system uses 4.8 kWh (current case) or 4.0 

kWh (future case) of electricity per Nm3 of hydrogen produced, i.e., 53.4 kWh (current case) or 

44.7 kWh (future case) per kg of hydrogen produced.

The electrolyzer system requires high-purity water to avoid deterioration of electrolyzer 

performance. Process water is demineralized and softened to a specific resistance of 1–2 

megaohm/cm in the water demineralizer unit. The system requires 1 L/Nm3 (2.939 gal/kg) of 

hydrogen produced. 

The electrolyzer system produces hydrogen and oxygen from the electrolysis of feed water. The 

gas from each cell in the electrolyzer stack is collected in the hydrogen and oxygen flow 

channels and fed into the gas/lye (KOH) separators. The lye, separated from the produced gas, is 

recycled through the lye pump, through the lye cooler, and back into the lye tank. Excess heat in 

the electrolyzer is removed by the lye cooler. Oxygen is removed from the lye in the oxygen/lye 

separator. The system modeled does not capture the oxygen gas, but capture of the high-purity 

oxygen gas is a possibility. Saturated hydrogen gas from the hydrogen/lye separator is fed to the 

gas scrubber subsystem, which purifies the hydrogen. The hydrogen gas is held in a small gas 

holder unit and is compressed to 435 psig. Following compression, residual oxygen is removed 

from the hydrogen gas by the deoxidizer unit, and the hydrogen gas is dried in the twin tower 

dryer. The purity of the hydrogen gas coming off the electrolyzer stack is 99.9%. Following the 

gas purifier, deoxidizer, and dryer stages, the purity of hydrogen increases to 99.9998% (2 ppm).
66

Figure 36. Process Flow Diagram—Grid Electrolysis
67

H2A Model Inputs

The following tables show the H2A Model input values for the forecourt current and future grid 

electrolysis technology cases. Default values that are common to all central cases are not shown 

in the tables below; see Common Input Parameters and Processes (page 16) for those values. 

Table 52 summarizes the cost inputs, including capital, fixed operating, and variable operating 

costs; note that the values in this table are in units of thousand 2005$, unlike the central case cost 

input tables, which have units of million 2005$. Table 53 summarizes the energy inputs.
68

Table 52. Forecourt Grid Electrolysis: Cost Input Summary

Capital Costs (thousand 2005$) Current Future

Initial direct production

Electrolyzer unit 790 300 

Transformer/rectifier unit 150 60

Compressor units to 30 bar/435 psig (2) 720 270

Gas holder 370 140

Balance of planta 450 170

Total initial direct productionb 2,480 920

Initial direct CSD

Compressors (3) 940 940

Dispensers (2) 50 50

Cascade storage (325 kg) 390 390

Low-pressure storage (16 × 89 kg) 1,670 1,670

Electrical upgrading 80 80

Trenching for higher-voltage lines 120 120

Total initial direct CSDb 3,240 3,240

Total initial direct3 5,720 4,170

Indirect depreciable (production + CSD)

Site preparation 240 240

Engineering and design 350 350

Project contingency 290 210

Up-front permitting 130 130

Total indirectb 1,000 930

Total initial (direct + indirect)3 6,730 5,090

Expected replacement (production + CSD)c 690 580

Total3 7,420 5,680

Fixed Operating Costs (thousand 2005$/year) Current Future

Production + CSD

Licensing, permits, and fees 10 10

Property taxes and insurance 130 90

Rent 60 60

Operating, maintenance, and repairs 170 90

Labor 40 40

Overhead and G&A 10 10

Totalb 400 290

Variable Operating Costs (thousand 2005$/year)d Current Future

Energy feedstocks, utilities, byproducts Industrial electricity (feedstock + CSD) 1,430 1,220

Other materials and byproducts Process water 0 0

Compressed inert gas 0 0

Other variable operating costs Other variable operatinge 0 0

Other materialf 20 20

Totalb 1,460 1,250

a

Includes gas purifier (hydrogen scrubber), feed-water purifier/demineralizer, lye tank, deoxidizer, and twin tower drier. b

Components might not add to total owing to rounding (all numbers rounded to the nearest $10,000; all values less than $10,000 are 

entered as zero). c

Sum of expected replacement capital costs over the 20-year plant life, adjusted to the year in which they are incurred using an NPV 

calculation.

d

These costs vary over time in accordance with H2A Model price tables; startup year costs are shown here. e

Waste disposal costs, non-feedstock fuels, environmental surcharges, etc. f

Electrolyte solution.
69

Table 53. Forecourt Grid Electrolysis: Energy Input Summary

Feed Lower Heating Value Material Use (per kg hydrogen)

Current Future

Industrial electricity1 3.6 MJ/kWh 55.2 kWh 46.4 kWh 1 Electricity used for feedstock and compression.

H2A Model Results

The following tables and figures show the H2A Model results for the forecourt current and future 

grid electrolysis technology cases. Table 54 summarizes the cost results. The forecourt current 

grid electrolysis case produces hydrogen for $4.23/kg, with a total delivered hydrogen cost of 

$6.05/kg. The future case produces hydrogen for $3.10/kg, with a total delivered hydrogen cost 

of $4.92/kg. Feedstock (electricity) is the largest expense for both cases. Capital costs decrease 

substantially from the current to the future timeframe. CSD costs account for approximately onethird of the delivered hydrogen cost for both cases.

Hydrogen from the forecourt electrolysis cases is less expensive than from the central 

electrolysis cases ($4.50/kg for current and $3.24 for future) because the forecourt electrolyzer is 

assumed to be skid mounted and inexpensive to install, whereas the installation and coordination 

of multiple electrolyzers for the central cases are assumed to be more costly.

Table 54. Forecourt Grid Electrolysis: Cost Results Summary

Cost Component

Cost Contribution 

($/kg hydrogen)

Percentage of 

Hydrogen Costa

Current Future Current Future

Capital 0.98 0.43 16% 9%

Fixed O&M 0.40 0.16 7% 3%

Production Feedstock 2.80 2.47 46% 50%

Other raw material 0.04 0.04 1% 1%

Other variable2 0.01 0.01 0% 0%

Total production cost 4.23 3.10 70% 63%

Capital 1.26 1.26 21% 26%

CSD Fixed O&M 0.46 0.46 8% 9%

Other variableb 0.10 0.10 2% 2%

Total CSD cost 1.82 1.82 30% 37%

Total delivered hydrogen cost 6.05 4.92 100% 100% a

Total might not add to 100% owing to rounding. b

Including utilities.

Table 55 summarizes the process energy results. The energy inputs are in the form of electricity 

feedstock and electricity used for hydrogen compression. The only energy output is hydrogen. 

Results are reported based on both the LHV and HHV of hydrogen. The HHV—which accounts 

for the latent and sensible heat of vaporization of the combustion products (i.e., water vapor) 

between 150°C and 25°C—represents the actual amount of energy required to electrolyze water 

and is a more thermodynamically accurate measure for this production technology because liquid 
70

water (not water vapor) is produced. However, LHV—which assumes the latent and sensible 

heat of vaporization of the combustion products are not recovered between 150°C and 25°C—is 

also given because it is customary to use LHV to measure the performance of hydrogen 

production technologies. The HHV of hydrogen is 18% greater than the LHV. Only LHV results 

are given for the other hydrogen production technologies discussed in this report because LHV is 

a more accurate measure for those higher-temperature processes.

The process energy efficiency (energy output divided by energy input) is 71.6% for the current 

case and 85.0% for the future case (HHV). These are process energy inputs only and do not 

include energy used upstream of the process or consumed in vehicles; thus they do not represent 

life-cycle or "well-to-wheel" energy use.

Table 55. Forecourt Grid Electrolysis: Process Energy Results Summary

Energy Component

Energy Input 

(MJ per kg hydrogen)

Energy Output 

(MJ per kg hydrogen)

Current Future Current Future

Industrial electricitya 198 167 — —

Hydrogen — — 120 120

Total 198 167 120 120

Process energy efficiency (LHV)b

Current = 60.5%

Future = 71.9%

Process energy efficiency (HHV)b

Current = 71.6%

Future = 85.0% a Electricity used for feedstock and compression.

b

Process energy efficiency = process energy output ÷ process energy input.

Table 56 (current) and Table 57 (future) show the values used in the sensitivity analyses. See 

Sensitivity Analysis (page 15) to learn how these values were chosen. Figure 37 (current) and 

Figure 38 (future) show the sensitivity analysis results. For both cases, electricity price has the 

largest effect on hydrogen price.
71

Table 56. Forecourt Current Grid Electrolysis: Sensitivity Analysis Values

Variable Lower Value Nominal Value Upper Value

Production fixed operating cost (thousand $) 130 184 260

Storage system capital cost (thousand $) 1,000 1,665 2,200

Industrial electricity use (kWh/kg hydrogen) 50 53.4 57

Forecourt hydrogen storage capacity (% of daily 

production capacity ) 70 117 200

Operating capacity factor 0.95 0.85 0.6

Production system total direct capital cost (thousand $) 1,000 2,480 4,000

Industrial electricity price ($/kWh) 0.039 0.055 0.072

5.3 5.5 5.7 5.9 6.1 6.3 6.5 6.7 6.9 7.1

Total Fixed Operating Cost [range

$130K/y - $260K/y]

Storage System Capital Cost [range

$1M - $2.2M]

Industrial Electricity Usage (kWh/kg

H2) [range 50 - 57]

Forecourt Hydrogen Storage

Capacity [range 70 - 200 % of daily

production capacity]

Operating Capacity Factor [range

60% - 95%]

Production System Total Direct

Capital Cost [range $1M - $4M]

Industrial Electricity Price [range

$0.039/kWh - $0.072/kWh; ± 30%]

Hydrogen Cost ($/kg)

Figure 37. Forecourt Current Grid Electrolysis: Sensitivity Analysis Results
72

Table 57. Forecourt Future Grid Electrolysis: Sensitivity Analysis Values

Variable Lower Value Nominal Value Upper Value

Production fixed operating cost (thousand $) 50 73 100

Storage system capital cost (thousand $) 600 1,665 1,950

Industrial electricity use (kWh/kg hydrogen) 44 44.7 52

Forecourt hydrogen storage capacity (% of daily 

production capacity) 70 117 200

Operating capacity factor 0.95 0.85 0.6

Production system total direct capital cost (thousand $) 500 922 1,700

Industrial electricity price ($/kWh) 0.040 0.057 0.074

4.2 4.4 4.6 4.8 5 5.2 5.4 5.6 5.8

Total Fixed Operating Cost [range

$50K/y - $100K/y]

Industrial Electricity Usage [range 44

kWh/kg H2 - 52 kWh/kg H2]

Storage System Capital Cost [range

$600K - $1.95M]

Production System Total Direct

Capital Cost [range $500K - $1.7M]

Operating Capacity Factor [range

60% - 95%]

Forecourt Hydrogen Storage

Capacity [range 70 - 200 % of daily

production capacity]

Industrial Electricity Price [range

$0.040/kWh - $0.074/kWh; ± 30%]

Hydrogen Cost ($/kg)

Figure 38. Forecourt Future Grid Electrolysis: Sensitivity Analysis Results
73

Natural Gas

Process Description

The forecourt current natural gas technology case is based on a 20-atm conventional tube-inshell steam methane reactor (SMR) with hydro-desulfurization pretreatment and PSA gas 

cleanup (Figure 39). The PSA is based on a 4-bed Batta cycle achieving 75% hydrogen recovery. 

The unit is assumed to be factory built (as opposed to onsite construction) and is skid mounted 

for easy and rapid installation. A single 1,500-kg/day unit is assumed (as opposed to the previous 

H2A assumption of parallel 750-kg/day units.) The system is assumed to be air cooled (and thus 

requires no cooling water flow). The product hydrogen exits the PSA at 300 psi and is 

compressed for storage in metal cylinder storage tanks (2,500 psi maximum pressures). The 

hydrogen is next compressed to 6,250 psi (maximum) for transfer into a 4-bed high-pressure 

cascade system to allow rapid filling of 5,000-psi onboard vehicular hydrogen tanks.

The forecourt future natural gas technology case is based on a 20-atm integrated membrane 

stream reformer (reforming catalyst, water gas shift catalyst, and Pd-alloy membrane tubes 

integrated into a single vessel) (Figure 40). A 1:7.5 (by volume) admixture of reforming catalyst 

(Ni-Al-Ru at $150/kg, 2 g/cc) and water gas shift catalyst (Fe/Cr Ox at $7/kg, 1 g/cc) is assumed. 

Gas hourly specific space velocity (GHSV) of the reactor catalyst system is 1,344 per hour and is 

based on a 50% reduction of combined reformer/WGS catalyst volume compared with a nonintegrated natural gas steam reforming configuration. The reactor vessel is based on a 4-pass 

annular heat exchange reformer configuration. Maximum process gas temperature is 550°C. 

Natural gas and water are fed directly to the reactor at a 3:1 steam/C ratio without use of a prereformer. The membrane separator tubes are modeled as thin Pd-alloy layer supported on 1.27-

cm diameter porous stainless steel support tubes. Hydrogen permeance is 527 scf/(hr•ft2

•atm0.5). 

Overall membrane surface area is 34.1 ft2 with a 90% hydrogen recovery. The required 

membrane surface area is calculated by a 1-D differential model based on a single pass, nonreacting chemistry and a membrane separator configuration wherein the reformate enters the 

membrane tubes and has hydrogen removed according to the permeance and differential 

hydrogen pressures across the membrane. Cost of the Pd-coated porous stainless-steel membrane 

tubes is estimated at $700/ft2 to be consistent with the DOE target of $1,000/ft2 for a complete 

standalone membrane system (tubes plus housing, manifolds, etc.).

Natural gas is the sole feedstock and is also used as a supplemental fuel to the burner. Flue gas is 

exhausted at 160°C as excessive waste heat is generated that cannot be used for recuperation. 

The unit is assumed to be factory built (as opposed to onsite construction) and is skid mounted 

for easy and rapid installation. A single 1,500-kg/day unit is assumed (as opposed to the previous 

H2A assumption of parallel 750-kg/day units.) The system is assumed to be air cooled (and thus 

requires no cooling water flow). The product hydrogen exits the reactor at 15 psi and, after 

cooling, is compressed to 300 psi before transfer to the refueling subsystem. The refueling 

subsystem further compresses the hydrogen for storage in metal cylinder storage tanks (2,500 psi 

maximum pressure) and then additionally compresses the hydrogen to 6,250 psi (maximum) for 

transfer into a 4-bed high-pressure cascade system to allow rapid filling of 5,000 psi onboard 

vehicular hydrogen tanks.
74

Figure 39. Process Flow Diagram—Current Natural Gas
75

Figure 40. Process Flow Diagram—Future Natural Gas
76

H2A Model Inputs

The following tables show the H2A Model input values for the forecourt current and future 

natural gas technology cases. Default values that are common to all central cases are not shown 

in the tables below; see Common Input Parameters and Processes (page 16) for those values. 

Table 58 summarizes the cost inputs, including capital, fixed operating, and variable operating 

costs; note that the values in this table are in units of thousand 2005$, unlike the central case cost 

input tables, which have units of million 2005$. Table 59 summarizes the energy inputs.

Table 58. Forecourt Natural Gas: Cost Input Summary

Capital Costs (thousand 2005$) Current Future

Initial direct production

Water feed system 0 0

Primary feed system 10 10

Burner feed system — 0

Boiler 30 10

Superheater 10 —

HDS & absorbent bed 10 —

Burner 0 0

Annular Ref-WGS-MS — 150

Reformer 200 —

Water gas shift 170 —

HDS preheater 0 —

Primary air feed system 0 0 

Hydrogen cooler — 10

Reformate cooler 30 —

Condenser 40 —

Air feed system for condenser 0 —

PSA unit 70 —

Water purification 30 30

Structural supports 20 20 

Controls system 40 40

System assembly 210 160

Miscellaneous 90 50

Hydrogen compressor — 230

Total initial direct productiona 960 720

Initial direct CSD

Compressors (3) 940 940

Dispensers (2) 50 50

Cascade storage (325 kg) 390 390

Low-pressure storage (16 × 89 kg) 1,670 1,670

Electrical upgrading 80 80

Trenching for higher-voltage lines 120 120

Total initial direct CSDa 3,250 3,250

Total initial directa 4,200 3,970

Indirect depreciable (production + CSD)

Site preparation 240 240

Engineering and design 350 350

Project contingency 210 200

Up-front permitting 130 130

Total indirecta 930 920
77

Total initial (direct + indirect)a 5,130 4,890

Expected replacement (production + CSD)b 680 530

Totala 5,810 5,420

Fixed Operating Costs (thousand 2005$/year) Current Future

Production + CSD

Licensing, permits, and fees 0 0

Property taxes and insurance 90 90

Rent 50 50

Operating, maintenance, and repairs 90 80

Labor 40 40

Overhead and G&A 10 10

Totala 280 270

Variable Operating Costs (thousand 2005$/year)c Current Future

Energy feedstocks, utilities, byproducts Industrial natural gas 510 430

Commercial electricity (production + CSD) 120 160

Other materials and byproducts Process water 0 0

Other variable operating costs Other variable operatingd 0 0

Total2 630 590

a

Components might not add to total owing to rounding (all numbers rounded to the nearest $10,000; all values less than $10,000 are 

entered as zero). b

Sum of expected replacement capital costs over the 20-year plant life, adjusted to the year in which they are incurred using an NPV 

calculation.

c

These costs vary over time in accordance with H2A Model price tables; startup year costs are shown here. d

Waste disposal costs, non-feedstock fuels, environmental surcharges, etc.

Table 59. Forecourt Natural Gas: Energy Input Summary

Feed Lower Heating Value Material Use (per kg hydrogen)

Current Future

Industrial natural gas 36 MJ/Nm3 4.5 Nm3 4.2 Nm3

Commercial electricitya 3.6 MJ/kWh 3.1 kWh 4.2 kWh a

Electricity used for production and compression.

H2A Model Results

The following tables and figures show the H2A Model results for the forecourt current and future 

natural gas technology cases. Table 60 summarizes the cost results. The forecourt current natural 

gas case produces hydrogen for $1.61/kg, with a total delivered hydrogen cost of $3.50/kg. The 

future case produces hydrogen for $1.59/kg, with a total delivered hydrogen cost of $3.47/kg. 

CSD capital costs are the largest expense for both cases; feedstock (natural gas) is the largest 

production expense. CSD costs account for more than half of the delivered hydrogen cost for 

both cases.
78

Table 60. Forecourt Natural Gas: Cost Results Summary

Cost Component

Cost Contribution 

($/kg hydrogen)

Percentage of 

Hydrogen Costa

Current Future Current Future

Production

Capital 0.45 0.32 13% 9%

Fixed O&M 0.16 0.13 5% 4%

Feedstock 0.91 0.96 26% 28%

Other variableb 0.10 0.19 3% 5%

Total production cost 1.61 1.59 46% 46%

Capital 1.26 1.26 36% 36%

CSD Fixed O&M 0.46 0.46 13% 13%

Other variableb 0.16 0.16 5% 5%

Total CSD cost 1.88 1.88 54% 54%

Total delivered hydrogen cost 3.50 3.47 100% 100% a

Total might not add to 100% owing to rounding. b

Including utilities.

Table 61 summarizes the process energy results. The energy inputs are in the form of natural gas 

feedstock and electricity used for hydrogen production and compression. The only energy output 

is hydrogen. The process energy efficiency (energy output divided by energy input) is 68.4% for 

the current case and 71.0% for the future case. These are process energy inputs only and do not 

include energy used upstream of the process or consumed in vehicles; thus they do not represent 

life-cycle or "well-to-wheel" energy use.

Table 61. Forecourt Natural Gas: Process Energy Results Summary

Energy Component

Energy Input 

(MJ per kg hydrogen)

Energy Output 

(MJ per kg hydrogen)

Current Future Current Future

Industrial natural gas 164 154 — —

Commercial electricitya 11 15 — —

Hydrogen — — 120 120

Total 175 169 120 120

Process energy efficiency (LHV)b

Current = 68.4%

Future = 71.0% a

Electricity used for production and compression. b

Process energy efficiency = process energy output ÷ process energy input.

Table 62 (current) and Table 63 (future) show the values used in the sensitivity analyses. See 

Sensitivity Analysis (page 15) to learn how these values were chosen. Figure 41 (current) and 

Figure 42 (future) show the sensitivity analysis results. For both cases, forecourt hydrogen 

storage capacity has the largest effect on hydrogen price.
79

Table 62. Forecourt Current Natural Gas: Sensitivity Analysis Values

Variable Lower Value Nominal Value Upper Value

Feedstock conversion efficiency (%) 76 73 68

Total fixed operating costs (thousand $) 45 75 120

Storage system capital cost (thousand $) 1,000 1,665 2,200

Industrial natural gas feedstock price ($/Nm3) 0.17 0.24 0.32

Production system total direct capital cost (thousand $) 600 957 2,800

Operating capacity factor 0.95 0.85 0.60

Forecourt hydrogen storage capacity (%) 70 120 200

3.1 3.3 3.5 3.7 3.9 4.1

Feedstock Conversion Efficiency,

ranging from 68% to 76% (LHV)

Total Fixed Operating Costs, with a

range of +/- 30%

Storage System Capital Cost,

ranging from $1M to $2.2M

Industrial Natural Gas Feedstock

Price, with a range of +/- 30%

Production System Total Direct

Capital Cost, ranging from $600K to

$2.8M

Operating Capacity Factor, ranging

from 60% to 95%

Forecourt Hydrogen Storage

Capacity, ranging from 70% to 200

% of daily production capacity

Hydrogen Cost ($/kg)

Figure 41. Forecourt Current Natural Gas: Sensitivity Analysis Results
80

Table 63. Forecourt Future Natural Gas: Sensitivity Analysis Values

Variable Lower Value Nominal Value Upper Value

Feedstock conversion efficiency (%) 80 78 70

Total fixed operating costs (thousand $) 35 58 93

Storage system capital cost (thousand $) 600 1,665 1,950

Industrial natural gas feedstock price ($/Nm3) 0.15 0.22 0.29

Production system total direct capital cost (thousand $) 500 719 1,700

Operating capacity factor 0.95 0.85 0.60

Forecourt hydrogen storage capacity (%) 70 120 200

3 3.2 3.4 3.6 3.8 4

Total Fixed Operating Costs, with a

range of +/- 30%

Feedstock Conversion Efficiency,

ranging from 70% to 80% (LHV)

Storage System Capital Cost,

ranging from $600K to $2M

Production System Total Direct

Capital Cost, ranging from $500K to

$1.7M

Industrial Natural Gas Feedstock

Price, with a range of +/- 30%

Operating Capacity Factor, ranging

from 60% to 95%

Forecourt Hydrogen Storage

Capacity, ranging from 70% to 200

% of daily production capacity

Hydrogen Cost ($/kg)

Figure 42. Forecourt Future Natural Gas: Sensitivity Analysis Results

Ethanol

Process Description

The forecourt current ethanol technology case is based on a 20-atm conventional tube-in-shell 

steam reactor (SR) with PSA gas cleanup (Figure 43). Precious metal catalyst is assumed. The 

catalyzed conversion of ethanol to methane is judged to occur rapidly to near-full ethanol 

conversion in a compact adiabatic reformer. Because methane is the primary component of the 

pre-reformer, the remainder of the system is nearly identical to that of a natural gas reformer 

system. Ethanol is the sole feedstock and is also used as a supplemental fuel to the burner. A 

950°C burner adiabatic flame temperature and an 850°C reformer temperature are assumed. Flue 
81

gas is exhausted at 110°C. The PSA is based on a 4-bed Batta cycle achieving 75% hydrogen 

recovery. 

The forecourt future ethanol technology case is based on a 20-atm integrated membrane stream 

reformer (reforming catalyst, water gas shift catalyst, and Pd-alloy membrane tubes integrated 

into a single vessel) (Figure 44). A 1:6.3 (by volume) admixture of reforming catalyst (Ni-Al-Ru 

at $150/kg, 2g/cc) and water gas shift catalyst (Fe/Cr Ox at $7/kg, 1 g/cc) is assumed. Gas hourly 

specific space velocity (GHSV) of the reactor catalyst system is 1,374 per hour (and is based on 

a 50% reduction of combined reformer/WGS catalyst volume compared with a non-integrated 

ethanol stream reforming configuration). The reactor vessel is based on a 4-pass annular heat 

exchange reformer configuration. Maximum process gas temperature is 500°C.

Ethanol and water are fed directly to the reactor at a 3:1 steam/C ratio without use of a prereformer. The membrane separator tubes are modeled as thin Pd-alloy layer supported on 1.27-

cm diameter porous stainless steel support tubes. Hydrogen permeance is 527 scf/(hr•ft2•atm0.5). 

Overall membrane surface area is 46.8 ft2 with a 90% hydrogen recovery. The required 

membrane surface area is calculated by 1-D differential model based on a single pass, nonreacting chemistry and membrane separator configuration wherein reformate enters the 

membrane tubes and has hydrogen removed according to the permeance and differential 

hydrogen pressures across the membrane. Cost of the Pd-coated porous stainless-steel membrane 

tubes is estimated at $700/ft2 to be consistent with the DOE target of $1,000/ft2 for a complete 

standalone membrane system (tubes plus housing, manifolds, etc.). Ethanol is the sole feedstock 

and is also used as a supplemental fuel to the burner. Flue gas is exhausted at 110°C. 

For the current and future cases, the unit is assumed to be factory built (as opposed to onsite 

construction) and is skid mounted for easy and rapid installation. A single 1,500-kg/day unit is 

assumed (as opposed to the previous H2A assumption of parallel 750-kg/day units.) The system 

is assumed to be air cooled (and thus requires no cooling water flow). For the current case, the 

product hydrogen exits the PSA at 300 psi and is compressed for storage in metal cylinder 

storage tanks (2,500 psi maximum pressures). For the future case, the product hydrogen exits the 

reactor at 15 psi and, after cooling, is compressed to 300 psi before transfer to the refueling 

subsystem. The hydrogen is next compressed to 6,250 psi (maximum) for transfer into a 4-bed 

high-pressure cascade system to allow rapid filling of 5,000-psi onboard vehicular hydrogen 

tanks.
82

Figure 43. Process Flow Diagram—Current Ethanol
83

Figure 44. Process Flow Diagram—Future Ethanol
84

H2A Model Inputs

The following tables show the H2A Model input values for the forecourt current and future 

ethanol technology cases. Default values that are common to all central cases are not shown in 

the tables below; see Common Input Parameters and Processes (page 16) for those values. 

Table 64 summarizes the cost inputs, including capital, fixed operating, and variable operating 

costs; note that the values in this table are in units of thousand 2005$, unlike the central case cost 

input tables, which have units of million 2005$. Table 65 summarizes the energy inputs.

Table 64. Forecourt Ethanol: Cost Input Summary

Capital Costs (thousand 2005$) Current Future

Initial direct production

Water feed system 0 0 

Primary feed system 0 0

Burner feed system 0 0

Boiler 40 50

Superheater 10 10

Pre-reformer 20 —

Burner 0 0

Annular Ref-WGS-MS — 190

Reformer 240 —

Water gas shift reactor 190 —

Air preheater 20 20

Primary air feed system 0 0

Reformate cooler 40 —

Condenser 40 —

Air feed system for condenser 0 —

PSA unit 70 —

Water purification 30 30

Structural supports 20 20

Controls system 40 40

System assembly 210 210

Miscellaneous 100 60

Hydrogen compressor — 230

Ethanol underground storage tank 140 140

Total initial direct productiona 1,210 1,010

Initial direct CSD

Compressors (3) 940 940

Dispensers (2) 50 50

Cascade storage (325 kg) 390 390

Low-pressure storage (16 × 89 kg) 1,670 1,670

Electrical upgrading 80 80

Trenching for higher-voltage lines 120 120

Total initial direct CSDa 3,250 3,250

Total initial directa 4,460 4,260

Indirect depreciable (production + CSD)

Site preparation 240 240

Engineering and design 350 350

Project contingency 220 210

Up-front permitting 130 130

Total indirecta 930 920
85

Total initial (direct + indirect)a 5,390 5,180

Expected replacement (production + CSD)b 740 610

Totala 6,130 5,790

Fixed Operating Costs (thousand 2005$/year) Current Future

Production + CSD

Licensing, permits, and fees 0 0

Property taxes and insurance 100 90

Rent 50 50

Operating, maintenance, and repairs 100 90

Labor 40 40

Overhead and G&A 10 10

Totala 300 280

Variable Operating Costs (thousand 2005$/year)c Current Future

Energy feedstocks, utilities, byproducts Ethanol 1,090 980

Commercial electricity (production + CSD) 90 150

Other materials and byproducts Process water 10 10

Other variable operating costs Other variable operatingd 0 0

Totala 1,190 1,140

a

Components might not add to total owing to rounding (all numbers rounded to the nearest $10,000; all values less than $10,000 are 

entered as zero). b

Sum of expected replacement capital costs over the 20-year plant life, adjusted to the year in which they are incurred using an NPV 

calculation.

c

These costs vary over time in accordance with H2A Model price tables; startup year costs are shown here.

d

Waste disposal costs, non-feedstock fuels, environmental surcharges, etc.

Table 65. Forecourt Ethanol: Energy Input Summary

Feed Lower Heating Value Material Use (per kg hydrogen)

Current Future

Ethanol 0.076 mmBtu/gal 2.2 gal 2.0 gal

Commercial electricitya 3.6 MJ/kWh 2.5 kWh 3.9 kWh a

Electricity used for production and compression.

H2A Model Results

The following tables and figures show the H2A Model results for the forecourt current and future 

ethanol technology cases. Table 66 summarizes the cost results. The forecourt current ethanol 

case produces hydrogen for $3.18/kg, with a total delivered hydrogen cost of $5.07/kg. The 

future case produces hydrogen for $2.91/kg, with a total delivered hydrogen cost of $4.79/kg. 

Ethanol feedstock is the largest expense for both cases. CSD costs account for more than onethird of the delivered hydrogen cost for both cases.
86

Table 66. Forecourt Ethanol: Cost Results Summary

Cost Component

Cost Contribution 

($/kg hydrogen)

Percentage of 

Hydrogen Costa

Current Future Current Future

Production

Capital 0.58 0.46 11% 10%

Fixed O&M 0.20 0.17 4% 4%

Feedstock 2.34 2.11 46% 44%

Other variableb 0.05 0.17 1% 4%

Total production cost 3.18 2.91 63% 61%

Capital 1.26 1.26 25% 26%

CSD Fixed O&M 0.46 0.46 9% 10%

Other variableb 0.16 0.16 3% 3%

Total CSD cost 1.88 1.88 37% 39%

Total delivered hydrogen cost 5.07 4.79 100% 100% a

Total might not add to 100% owing to rounding. b

Including utilities.

Table 67 summarizes the process energy results. The energy inputs are in the form of ethanol 

feedstock and electricity used for hydrogen production and compression. The only energy output 

is hydrogen. The process energy efficiency (energy output divided by energy input) is 64.9% for 

the current case and 69.5% for the future case. These are process energy inputs only and do not 

include energy used upstream of the process or consumed in vehicles; thus they do not represent 

lifecycle or "well-to-wheel" energy use.

Table 67. Forecourt Ethanol: Process Energy Results Summary

Energy Component

Energy Input 

(MJ per kg hydrogen)

Energy Output 

(MJ per kg hydrogen)

Current Future Current Future

Ethanol 176 159 — —

Commercial electricitya 9 14 — —

Hydrogen — — 120 120

Total 185 173 120 120

Process energy efficiency (LHV)b

Current = 64.9%

Future = 69.5% a

Electricity used for production and compression. b

Process energy efficiency = process energy output ÷ process energy input.

Table 68 (current) and Table 69 (future) show the values used in the sensitivity analyses. See 

Sensitivity Analysis (page 15) to learn how these values were chosen. Figure 45 (current) and 

Figure 46 (future) show the sensitivity analysis results. For both cases, ethanol price has the 

largest effect on hydrogen price.
87

Table 68. Forecourt Current Ethanol: Sensitivity Analysis Values

Variable Lower Value Nominal Value Upper Value

Total fixed operating cost (thousand $) 50 93 130

Ethanol use (gal/kg hydrogen) 2.0 2.2 2.3

Storage system capital cost (thousand $) 1,000 1,665 2,200

Operating capacity factor 0.95 0.85 0.6

Low-pressure storage excess capacity (% of design capacity) 11 58 150

Production system total direct capital cost (thousand $) 700 1,207 3,000

Ethanol price ($/gal) 0.75 1.07 1.39

4.2 4.4 4.6 4.8 5 5.2 5.4 5.6 5.8 6 6.2

Storage System Installed Capital

Cost ($)

Total Fixed Operating Cost

Feedstock Ethanol Usage

Low Pressure Storage Vessel

Excess Capacity (percent of design

capacity)

Operating Capacity Factor (fraction)

Feedstock Ethanol Price

Total Direct Capital Cost

Hydrogen Cost ($/kg)

Figure 45. Forecourt Current Ethanol: Sensitivity Analysis Results
88

Table 69. Forecourt Future Ethanol: Sensitivity Analysis Values

Variable Lower Value Nominal Value Upper Value

Total fixed operating cost (thousand $) 40 79 110

Ethanol use (gal/kg hydrogen) 1.9 2.0 2.1

Storage system capital cost (thousand $) 600 1,012 1,950

Operating capacity factor 0.95 0.85 0.6

Low-pressure storage excess capacity (% of design capacity) 11 58 150

Production system total direct capital cost (thousand $) 500 1,012 1,800

Ethanol price ($/gal) 0.75 1.07 1.39

4 4.2 4.4 4.6 4.8 5 5.2 5.4 5.6

Total Fixed Operating Cost [range

$40K/year - $110K/year]

Feedstock Ethanol Conversion

Efficiency [range 70% - 80%]

Storage System Capital Cost [range

$600K - $1.95M]

Production System Total Direct

Capital Cost [range $500K - $1.8M]

Operating Capacity Factor [range

60% - 95%]

Hydrogen Storage Capacity [range

70 - 200 % of daily production

capacity]

Ethanol Price [range ± 30%]

Hydrogen Cost ($/kg)

Figure 46. Forecourt Future Ethanol: Sensitivity Analysis Results
89

Sources

This report draws from the following two sources. Each H2A technology case contains 

additional references specific to the technology; download the technology cases for detailed 

information.

Steward, D.; Ramsden, T.; Zuboy, J. H2A Production Model, Version 2 User Guide. NREL/TP560-43983. Golden, CO: National Renewable Energy Laboratory, September 2008.

www.nrel.gov/docs/fy08osti/43983.pdf.

U.S. Department of Energy. H2A Production Analysis Web Site and Case Studies. Washington, 

DC: U.S. Department of Energy Hydrogen Program, 2008. 

www.hydrogen.energy.gov/h2a_production.html.
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Analyzing the Levelized Cost of Centralized and Distributed 

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Analysis of the levelized cost of producing hydrogen via different pathways using the National Renewable Energy 

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