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3.1 Hydrogen Production

Hydrogen can be produced from a diversity of energy
resources, using a variety of process technologies.
Energy resource options include fossil, nuclear and
renewables. Examples of process technologies include
thermochemical, biological, electrolytic and photolytic.

3.1.1 Technical Goal and Objectives

Goal

Research and develop low-cost, highly efficient hydrogen production technologies from diverse
domestic sources, including natural gas and renewable sources.

Objectives

Reduce the cost of hydrogen to $2.00-$3.00/gge1 (delivered) at the pump.2 This goal is independent
of the technology pathway. Technologies are being researched to achieve this goal in timeframes
relative to their current states of development.
• By 2010, reduce the cost of distributed production of hydrogen from natural gas to $2.50/gge
(delivered) at the pump. By 2015, reduce the cost of distributed hydrogen production from
natural gas to $2.00/gge (delivered) at the pump.
• By 2012 reduce the cost of distributed production of hydrogen from biomass-derived renewable
liquids to $3.80/gge (delivered) at the pump. By 2017, reduce the cost of distributed production
of hydrogen from biomass-derived renewable liquids to <$3.00/gge (delivered) at the pump.
• By 2012, reduce the cost of distributed production of hydrogen from distributed water
electrolysis to $3.70/gge (delivered) at the pump. By 2017, reduce the cost of distributed
production of hydrogen from distributed water electrolysis to <$3.00/gge (delivered) at the
pump. By 2012, reduce the cost of central production of hydrogen from wind water electrolysis
to $3.10/gge at plant gate ($4.80/gge delivered), By 2017, reduce the cost of central production
of hydrogen from wind water electrolysis to <$2.00/gge at plant gate (<$3.00/gge delivered).
• By 2012, reduce the cost of hydrogen produced from biomass gasification to $1.60/gge at the
plant gate (<$3.30/gge delivered). By 2017, reduce the cost of hydrogen produced from biomass
gasification to $1.10/gge at the plant gate ($2.10/gge delivered).

1 The energy content of a gallon of gasoline and a kilogram of hydrogen are approximately equal on a lower heating value basis; a

kilogram of hydrogen is approximately equal to a gallon of gasoline equivalent (gge) on an energy content basis
2 This cost range results in equivalent fuel cost per mile for a hydrogen fuel cell vehicle compared to gasoline internal combustion

engine and gasoline hybrid vehicles. The full explanation and basis can be found in DOE Record 5013 (see
www.hydrogen.energy.gov/program_records.html). All costs, unless otherwise noted, are in 2005 dollars.

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• By 2017, develop high-temperature thermochemical cycles driven by concentrated solar energy

to produce hydrogen with a projected cost of $3.00/gge at the plant gate ($4.00/gge delivered)
and verify the potential for this technology to be competitive in the long term. 3
• Develop advanced renewable photoelectrochemical and biological hydrogen generation
technologies. By 2018, verify the feasibility of these technologies to be competitive in the long
term.

3.1.2 Technical Approach

Hydrogen production research is focused on meeting the objectives outlined in Section 3.1.1. by
conducting R&D through industry, national laboratory, and university projects. The Hydrogen
Production Program element will develop the technologies to produce hydrogen for transportation
and stationary applications. Integrated systems will be validated in the field by the Technology
Validation Program element to obtain real-world data (see Section 3.6 Technology Validation).
Results of validation projects will guide continued R&D efforts.
A portfolio of feedstocks and technologies for hydrogen production will be necessary to address
energy security and environmental needs. This program element addresses multiple feedstock and
technology options for hydrogen production for the short and long term. The research focus for
the near term is on distributed reforming of natural gas and renewable liquid fuels, and on
electrolysis to meet initial lower volume hydrogen needs with the least capital equipment costs. For
the long-term, research is focused on renewable feedstocks and energy sources, with emphasis on
centralized options to take advantage of economies of
scale when an adequate hydrogen delivery
infrastructure is in place. There is collaboration with
DOE’s Office of Fossil Energy
(http://fossil.energy.gov/programs/fuels/index.html)
to develop centralized production from coal with
carbon sequestration, and with DOE’s Office of
Nuclear Energy
(http://www.ne.doe.gov/NHI/neNHI.html) to
develop centralized production from advanced nuclear
energy-driven high-temperature thermochemical cycles
and high temperature electrolysis. DOE’s Office of
Science (www.sc.doe.gov/bes/hydrogen.html) is a
collaborator on longer-term technologies such as
biological and photoelectrochemical hydrogen Figure 3.1.1 Distributed hydrogen
production. production facility
The development of a national hydrogen production infrastructure will likely take multiple pathways.
Some of these pathways and their roles within the strategy of the Hydrogen Production Program
element are described below.

3 Collaboration with DOE's Office of Nuclear Energy and the DOE EERE Solar Program.

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Distributed Production Pathway

Distributed production of hydrogen may be the most viable approach for introducing hydrogen as
an energy carrier. It requires less capital investment for the smaller capacity of hydrogen needed
initially, and it does not require a substantial hydrogen transport and delivery infrastructure.
Two distributed hydrogen production technologies that have good potential for development are (1)
reforming of natural gas or liquid fuels, including bio-derived liquids, such as ethanol and bio-oil,
and (2) small-scale water electrolysis located at the point of use (i.e., refueling stations or stationary
power generation sites). Of these technologies, small-scale natural gas reformers are the closest to
meeting the hydrogen production cost targets. Research will focus on applying the latest small-scale
natural gas reforming systems to reform renewable liquid feedstocks at a competitive hydrogen cost.
Distributed reforming using bio-derived liquids offers dramatically lower net greenhouse gas
emissions. The second research focus is on small-scale electrolyzers for splitting water. To be cost
competitive the cost of electricity needs to be very low (see Figure 3.1.2). Electrolyzers present the
opportunity for non-carbon-emitting hydrogen production when a renewable electricity source such
as wind or hydro power is used without grid backup. Additionally, photoelectrochemical hydrogen
production has the potential to be used in the long term for distributed hydrogen production.

Effect of Electricity Price on Distributed Hydrogen Production Cost

Assumes: 1500 gge/day, electrolyzer system at 74% efficiency (LHV),
uninstalled capital cost of $125/kW

$5.00 Other Variable Costs (including utilities) ($/gge of H2)

Fixed O&M ($/gge of H2)
$4.50 Capital Costs ($/gge of H2)
Electricity Costs ($/gge of H2)
Distributed Hydrogen Cost

$4.00
$3.50
$3.00
$/gge

$2.50
$2.00
$1.50
$1.00
$0.50
$0.00
$0.02 $0.03 $0.04 $0.05 $0.06 $0.07 $0.08
Electricity Price ($/kWh)

Figure 3.1.2 Effect of Electricity Price on Distributed Hydrogen Production Cost

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Centralized Production Pathway

Large hydrogen production facilities that can take advantage of economies of scale will be needed in
the long term to meet increases in hydrogen fuel demand. Central hydrogen production allows
management of greenhouse gas emissions through strategies like carbon sequestration. In parallel
with the distributed production effort, DOE is pursuing central production of hydrogen from a
variety of resources - fossil, nuclear and renewable.
• Coal (DOE Office of Fossil Energy) and natural gas are possibly the least expensive feedstocks,
and carbon sequestration is required to reduce or eliminate greenhouse gas emissions.
Centralized natural gas reforming is not being pursued because it is already commercially viable
and because there are limited domestic natural gas resources for the long term.
• Biomass gasification offers the potential of a renewable option and near-zero greenhouse gas
emissions.
• Centralized wind-based water electrolysis is a viable approach - as the cost of capital equipment
is reduced through advanced development.
• DOE’s Office of Nuclear Energy (http://www.ne.doe.gov/NHI/neNHI.html) is developing
high-temperature electrolysis technology.
• High-temperature thermochemical hydrogen production that uses concentrated solar energy may
be viable with the development of efficient water-splitting chemical process cycles and materials.
• Photoelectrochemical and biological hydrogen production are long-term technologies that have
the potential to produce hydrogen with sunlight, but they can currently only produce small
amounts of hydrogen at high cost.
Other feedstocks and technologies for hydrogen production that show promise may also be
considered. Central production of hydrogen includes a wide diversity of feedstocks, but to be viable
it would require development of a distribution and delivery infrastructure for hydrogen. DOE is
pursuing projects to identify a cost-effective, energy-efficient, safe infrastructure for the delivery of
hydrogen or hydrogen carriers from centrally located production facilities to the point of use (see
Section 3.2).

Semi-Central/City-Gate Production Pathway

Another option for hydrogen production is semi-central facilities that could be located, for example,
on the edge of urban areas. These would be intermediate in production capacity. They would have
limited economies of scale while being located only a short distance from refueling sites and thus
reduce the cost and infrastructure needed for hydrogen delivery. Several technologies may be well
suited to this scale of production including wind or solar driven electrolysis, reforming of renewable
bio-derived liquids, natural gas reforming and photoelectrochemical hydrogen production.
Although many of the technologies currently under development are applicable to the semi-central
concept, it is not a major focus of the program to emphasize development at the semi-central scale.

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Co-Production Pathways

Other production pathways being explored combine production of hydrogen fuel, heat, and electric
power. In these scenarios, hydrogen fuel could be produced for use: (1) in stationary fuel cells to
produce electricity and heat and (2) as a transportation fuel in fuel cell vehicles or hydrogen internal
combustion engine vehicles. This allows two markets for the hydrogen that could help to initiate the
use of hydrogen when hydrogen demand is small. As the demand grows, more of the hydrogen
could be produced for vehicle fuel rather than used for power production.

Separations

Hydrogen separation is a key technology that cross-cuts hydrogen production options. Both dense
metallic and microporous separation membranes are being developed as part of distributed and
central hydrogen production systems. Dense metallic and microporous separation membranes have
multiple applications that include an array of system configurations. Reducing the cost of membrane
materials, achieving higher flux rates, increasing hydrogen recovery, developing durable membranes,
and purifying hydrogen to levels similar to that of pressure swing adsorption (PSA) purification will
be measured based on analysis of actual system configurations and requirements. Thus, the
technology targets presented in Section 3.1.4 are guideposts for membrane developers.
Separations systems that best reduce the cost to produce hydrogen more efficiently from diverse
feedstocks will be down-selected. These separations sub-system components must be optimized to
achieve the cost and hydrogen quality requirements. In collaboration with the Office of Fossil
Energy, Energy Efficiency and Renewable Energy (EERE) sponsored the DOE Workshop on
Hydrogen Separations and Purification where input on hydrogen membrane separation performance
targets was provided by industry, government researchers, and academia (Report of the DOE
Workshop on Hydrogen Separations and Purification, September 8-9, 2004 Arlington VA. U.S.
Department of Energy Office of Hydrogen, Fuel Cells & Infrastructure Technologies) 4
In addition to hydrogen separation membranes, oxygen separation membranes are being developed
by the DOE Office of Fossil Energy (http://fossil.energy.gov/programs/fuels/index.html). These
could be used to replace expensive oxygen cryogenic separation technologies, reducing the cost of
hydrogen production from processes that use oxygen such as coal gasification, potentially biomass
gasification, or even auto-thermal distributed reforming.

4DOE’s Office of Fossil Energy (http://fossil.energy.gov/programs/fuels/index.html) is responsible for developing coal to

hydrogen membrane separations systems that will operate in large-scale integrated gasification combined cycle plants to separate
hydrogen and to capture and sequester carbon dioxide.

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3.1.3 Programmatic Status

Current Activities

Major hydrogen production program element activities are listed in Table 3.1.1.

Table 3.1.1 FY 2006 Current Hydrogen Production Program Activities

FY 2006 Activities (competitively

Challenge Approach
selected)

Cost reduction of • Improve reforming and separation • Praxair: Low-cost production platform using
distributed hydrogen efficiencies design for manufacture and assembly
production from • Identify more durable reforming (DFMA)
natural gas and bio- catalysts • National Renewable Energy Laboratory
derived liquids (NREL): Lower-cost technology for
• Incorporate breakthrough separations
technology distributed reforming of biomass pyrolysis-
derived bio-oils
• Reduce space needed
• Pacific Northwest National Laboratory
• Optimize system operation
(PNNL): Lower-cost technology to reform
• Intensify and consolidate the number biomass-derived liquids such as sugars,
of process steps, unit operations sugar alcohols, and ethanol via liquid-phase
or gas-phase reforming
• Argonne National Laboratory (ANL): Novel
technology to reform natural gas using high-
temperature membranes and water splitting
• ANL: High-pressure ethanol reforming
technology combined with efficient
separations and purification
• Virent Energy Systems, LLC: Novel one-
step liquid-phase reforming of
carbohydrates
• H2Gen Innovations: Advanced steam
methane reformer system; and ethanol fuel
processing
• GE Global Research: Integrated short
contact time natural gas/bio-derived
feedstock, compact reformer
• The BOC Group, Inc.: Integrated hydrogen
production, purification and compression
system
• Ohio State University Research Foundation:
Ethanol steam reforming catalysts
• Air Products and Chemicals Inc: Turn-key
hydrogen refueling station using integrated
natural gas steam methane reforming
technologies (Transferred to Technology
Validation)

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Table 3.1.1 FY 2006 Current Hydrogen Production Program Activities (continued)

FY 2006 Activities
Challenge Approach
(competitively selected)

Hydrogen production • Reduce electricity costs of hydrogen • Teledyne Energy Systems: New alkaline
from water via production by developing new electrolysis materials for high efficiency and
electrolysis materials and systems to improve high pressure with lower maintenance costs
efficiency • Proton Energy Systems: PEM electrolysis
• Reduce capital costs of electrolysis system for reduced cost, improved
system through new designs with subsystem/component performance, and
lower cost materials increased durability
• Develop low-cost hydrogen production • Giner Electrochemical Systems: Lower cost,
from electrolysis using wind and other higher pressure PEM electrolysis system
renewable electricity sources • Arizona State University: Combinatorial
approach to develop water-splitting catalysts
for higher efficiency electrolysis
• GE Global Research: Lower cost alkaline
electrolysis system using a system with
fewer parts and requiring less manufacturing
time
• NREL: Integrated electrolysis with the
renewable power source, including power
electronics development
• Ceramatec, Inc.: Hybrid, high-temperature
electrolysis/fuel cell process using solid
oxide fuel cells for co-generation of
hydrogen and electricity
• GE: High-temperature reversible solid oxide
electrolysis materials and system
development
• SRI International: Modular system for low-
cost generation of hydrogen by high-
temperature electrolysis using solid oxide
technology with anodic depolarization by
carbon monoxide
• Avalence: High-efficiency, ultra high-
pressure electrolysis with direct linkage to
photovoltaic arrays (SBIR funded project)

Biomass Gasification • Develop advanced, lower-cost • Gas Technology Institute, NETL, University
reforming technologies for hydrogen of Cincinnati, Allegheny Technology
production from biomass Company: Novel technology for one-step
gasification/pyrolysis gasification, reforming, water-gas shift, and
H2 separation
• United Technologies Research Center,
University of North Dakota: Innovative
integrated slurry-based biomass hydrolysis
and reforming process for low-cost
hydrogen production

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Table 3.1.1 FY 2006 Current Hydrogen Production Program Activities (continued)

FY 2006 Activities
Challenge Approach
(competitively selected)

High-temperature, • Utilize the high-temperature energy ƒ Science Applications International

solar-driven from concentrated solar power to Corporation: Solar-driven carbon dioxide
thermochemical produce hydrogen through cycles for hydrogen production; pilot-scale
cycles for splitting thermochemical cycles testing of most promising system
water to produce ƒ University of Colorado: Manganese-based
hydrogen
5 solar-driven high-temperature
thermochemical cycle to split water

Photoelectrochemical • Develop high-efficiency PEC materials ƒ NREL, University of Hawaii, University of

hydrogen production California Santa Barbara, MV Systems, GE
• Improve the durability of materials
from water (direct Global Research, and Midwest
water splitting)
6 • Identify functional requirements and Optoelectronics: Durable and efficient
develop auxiliary device and systems photoelectrochemical material(s), devices
materials and systems
• Develop photoelectrochemical devices
and systems

Biological production • Develop modifications to green algae, • NREL, Oak Ridge National Laboratory
6
of hydrogen cyanobacteria, photosynthetic (ORNL), University of California Berkeley,
bacteria, and dark fermentative and J. Craig Venter Institute: Identification
microorganisms that will facilitate of and research on the physical and
efficient production of hydrogen chemical variables needed to optimize
• Develop biochemical and process biological systems based on new algal,
methods to facilitate efficient cyanobacterial, photosynthetic bacterial, and
production of hydrogen dark fermentative microorganism strains

Separation and • Develop separation technology for • Praxair: Integrated ceramic membrane
purification systems distributed and central hydrogen system
(cross-cutting production • Media and Process Technologies: Carbon
7
research) molecular sieve membrane in a single-step
water-gas shift reactor
• Pall Corporation: Palladium alloy membrane
• University of Cincinnati: Zeolite membrane
reactor for single-step water-gas shift
reaction

5 In collaboration with DOE Office of Nuclear Energy.

6 In collaboration with the DOE Office of Science (www.sc.doe.gov/bes/hydrogen.html).
7 In collaboration with DOE Office of Fossil Energy (http://fossil.energy.gov/programs/fuels/index.html).

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3.1.4 Technical Challenges

The overarching technical challenge to hydrogen production is reducing cost. Hydrogen (as of
2003) 8 costs $5/gge delivered to a car at a refueling station based on distributed production using
natural gas (see Table 3.1.2). This is significantly higher than the 2015 goal of $2.00/gge (the cost in
2006 is estimated to be $3.00/gge 9 ). Estimates of the delivered cost of hydrogen using currently
available technology for all production feedstocks is considerably higher than that required for
hydrogen to be a cost-competitive primary energy carrier.
The capital costs of current water electrolysis systems, along with the high cost of electricity in many
regions, limit widespread adoption of electrolysis technology for hydrogen production. Water
electrolyzer capital cost reductions and efficiency improvements are required along with the design
of utility-scale electrolyzers capable of grid integration and compatible with low-cost, near-zero
emission electricity sources. Electrolytic production of hydrogen, where coal is the primary energy
resource, will not lead to carbon emission reduction without carbon sequestration technologies.
Hydrogen can be produced from biomass either by distributed reforming of bio-derived liquids or
through gasification or pyrolysis of biomass feedstocks. The costs of currently available bio-derived
liquids such as ethanol or sugar alcohols (e.g., sorbitol) need to be reduced. Significant
improvements in ethanol reforming and improved technologies need to be developed for other bio-
derived liquids to reduce the capital and operating costs for this distributed production option to
become competitive. The efficiencies of biomass gasification, pyrolysis and reforming need to be
increased and the capital costs need to be reduced by developing improved technologies and
approaches.
High-temperature, solar-driven, thermochemical hydrogen production using water-splitting chemical
cycles is in an early stage of research. Research is also needed to cost-effectively couple the
thermochemical cycles with advanced concentrated solar energy technology. If these efforts are
successful, high-temperature thermochemical processes may provide a clean, efficient, and
sustainable route for producing hydrogen from water.
Photoelectrochemical hydrogen production (direct water splitting), also in an early stage of
development, depends on a breakthrough in materials development and could require large areas of
land. Research in this area is progressing on three fronts: (1) the study of high-efficiency materials
in order to attain the fundamental understanding needed for improving lower-efficiency lower-cost
materials; (2) the study of low-cost durable materials in order to attain the fundamental
understanding needed for modifying higher-efficiency lower-durability materials; and 3) the

8 This cost for hydrogen in 2003 is based on analysis of distributed production utilizing natural gas reforming technology

available in 2003. Details can be found in DOE Record 5030 (see www.hydrogen.energy.gov/program_records.html). A cost
of hydrogen of $3.60/gge has been projected based on 2004 technology for an energy station producing both hydrogen
and electricity (U.S. Department of Energy, Hydrogen Program 2004 Annual Progress Report (December 2004),
“Research and Development of a PEM Fuel Cell, Hydrogen Reformer, and Vehicle Refueling Facility” (Air Products
and Chemicals, Inc.), 701, retrieved September 15, 2005, from
http://www.hydrogen.energy.gov/pdfs/progress04/vd5_wait.pdf.
9 The 2006 current status of $3.00/gge was estimated through H2A analysis (see Table 3.1.2) and confirmed by the 2006

Independent Assessment of the Status of Distributed Natural Gas Reforming

(http://www.hydrogen.energy.gov/peer_review_production.html).

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development of multijunction devices incorporating multiple material layers to achieve efficient

water splitting.
Biological hydrogen production is in an early stage of research and presents many technical
challenges, beginning with bioengineering of microorganisms that can produce hydrogen at high
rates. Some of the challenges are related to increased light utilization efficiency, increased rate of
hydrogen production, improved continuity of photoproduction, and increased hydrogen molar yield.
The advantages of biological hydrogen production are that high-purity water is not required and
toxic or polluting by-products are not generated.

Technical Targets

A variety of feedstocks and processes are being researched and developed for producing hydrogen
fuel. Each technology is in a different stage of development, and each offers unique opportunities,
benefits, and challenges. Economics favor certain technologies more than others in the near term,
but other technologies are expected to become economically viable as the technologies mature and
market drivers shift.
Tables 3.1.2 through 3.1.13 list the DOE technical targets for hydrogen production from a variety of
feedstocks. The targets and timeline for each technology reflect a number of factors, including the
expected size/capacity of a production unit, the current stage of technology development, and the
costs and characteristics of the feedstock. Where appropriate, target tables are accompanied by
another table that details the estimated cost breakdown as determined using the H2A hydrogen
production cost models. This accompanying table is provided as an example only. The cost
breakdown are not targets.
Out-year targets are R&D milestones for measuring progress. For hydrogen to become a major
energy carrier, the combination of its cost and that of the power system it is used in, must be
competitive with the alternatives available in the marketplace. For light duty vehicles, this means
that the combination of the hydrogen cost, and its use in a hydrogen fuel cell vehicle, must be
competitive with conventional fuels used in internal combustion engine and hybrid vehicles on a
cost per mile basis to the consumer. The estimated cost of hydrogen needed to be competitive (with
gasoline ICE or hybrid) is $2.00-$3.00/gge (untaxed) at the dispenser. This estimate will be
periodically re-evaluated to reflect projected fuel costs and vehicle power system energy efficiencies
on a cost-per-mile basis. The ultimate target for all of the production technologies being researched
is a hydrogen cost that will be competitive for transportation on a well-to-wheels basis, regardless of
the production method.
Tables 3.1.6 and 3.1.7 on membrane technology have been included for completeness. The Program
has a limited amount of work on membrane materials in support of hydrogen separation processes
associated with renewable pathways and is evaluating work being funded by the Office of Fossil
Energy (http://fossil.energy.gov/programs/fuels/index.html).
Although not listed in each table, it is understood that the quality of the hydrogen produced by each
of these production technologies must meet the rigorous hydrogen quality requirements as described
in Appendix C.

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Table 3.1.2. Technical Targets: Distributed Production of Hydrogen

a, b, g
from Natural Gas
2003 2006 2010 2015
Characteristics Units c d, e d d
Status Status Target Target

f
Production Unit Energy Efficiency %(LHV) 65.0 70.0 72.0 75.0

Production Unit Capital Cost (Uninstalled) $ 12.3M 1.1M 900K 580K

f
Total Hydrogen Cost $/gge H2 5.00 3.00 2.50 2.00

a, b, g
Table 3.1.2.A. Distributed Natural Gas H2A Example - Cost Contributions

2003 2006 d d
Characteristics Units c d, e 2010 2015
Status Status

Production Unit Capital Cost Contribution $/gge H2 3.40 0.55 0.45 0.30
Storage, Compression, Dispensing Capital
$/gge H2 0.40 0.70 0.45 0.30
Cost Contribution

Fixed O&M Cost Contribution $/gge H2 0.15 0.55 0.40 0.35

Feedstock Cost Contribution $/gge H2 0.75 0.90 0.90 0.75

Other Variable O&M Cost Contribution $/gge H2 0.30 0.30 0.30 0.30

Total Hydrogen Cost $/gge H2 5.00 3.00 2.50 2.00

aThe H2A Forecourt Production Model (http://www.hydrogen.energy.gov/h2a_production.html) was used for the cost

modeling. Economic parameters used were for a production design capacity of 1500 kg/day of hydrogen: 20 yr. analysis
period, 10% IRR after taxes, 100% equity financing, 1.9% inflation, 38.9% total tax rate, MACRS 7-year depreciation,
and a 70% capacity factor for 2006, 2010, and 2015. The results for 2006, 2010, and 2015 are in 2005 dollars.
bThe natural gas cost and electricity cost used for 2006, 2010, and 2015 were $5.24/MMBTU (LHV) and $0.08/kWhr

(commercial rate) respectively based on the EIA 2005 Annual Energy Outlook High A case projection for 2015 in
2005$. The natural gas cost assumes industrial gas cost is available for distributed production of hydrogen.
cThe 2003 analysis is based on work first done by TIAX LLC and documented in “Guidance for Transportation

Technologies: Fuels Choice for Fuel Cell Vehicles”, Phase II Final Report to DOE, February 2002. The results from
this analysis were utilized in the H2A Production tool in the fall of 2004 while it was under development. The economic
parameters used were: 1500 kg/day of hydrogen, 15-year analysis period, 5% IRR after taxes, 100% equity financing,
1.9% inflation, 38.9% tax rate, and MACRS 7-year depreciation, and a capacity factor of 87% based on the parameters
used in the original TIAX analysis. The natural gas cost used was $4.40/MMBTU (LHV) and the electricity cost was
$.07/kWhr. The results are in 2000 dollars. Further details can be found in DOE Record 5030.
dFor the 2006, 2010, and 2015 the following assumptions were made: (See Record 6004,

www.hydrogen.energy.gov/program_records.html for more details)

- Based on the recommendations made by the 2006 Independent Assessment of the Status of Distributed Natural Gas
Reforming (www.hydrogen.energy.gov/peer_review_production.html) start-up time was set to 0.5 years, % variable
costs in year 1 was set to 50%, and % fixed cost in year 1 was set to 75%.
- It is assumed that Design for Manufacture and Assembly (DFMA) would be employed and that about 500 units per
year would be produced.

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- The capital cost for the forecourt station compression and storage are consistent with the status and targets in the
Delivery Section 3.2.
eThe 2006 current status is consistent with the 2006 Independent Assessment of the Status of Distributed Natural Gas

Reforming (www.hydrogen.energy.gov/peer_review_production.html).
fEnergy efficiency is defined as the energy of the hydrogen out of the process (LHV) divided by the sum of the energy

into the process from the feedstock (LHV) and all other energy needed. The electrical energy utilized does not include
the efficiency losses from the production of the electricity.
gStorage capacity for 1000 kg of hydrogen at the forecourt is included. It is assumed that the hydrogen refueling fill

pressure is 5000 psi for 2003, 2006 and 2010. It is assumed that in 2015, the hydrogen refueling fill pressure is 10,000
psi.

Table 3.1.3. Technical Targets: Distributed Production of Hydrogen from Bio-Derived

a, b, e, h
Renewable Liquids

2006 2012 2017

Characteristics Units c c d
Status Target Target
f g
Production Unit Energy Efficiency % 70.0 72.0 65-75

c
Production Unit Capital Cost (Un-installed) $ 1.4M 1.0M 600K

Total Hydrogen Cost $/gge 4.40 3.80 <3.00

Table 3.1.3.A. Distributed Bio-Derived Renewable Liquids H2A Example -

a, b, e, h
Cost Contributions

2006 c d
Characteristics Units c 2012 2017
Status
b
Production Unit Capital Cost Contribution $/gge 0.75 0.45 0.40

Storage, Compression, Dispensing Capital Cost

h
Contribution $/gge 0.75 0.55 0.35

Fixed O&M Cost Contribution $/gge 0.60 0.50 0.40

Feedstock Cost Contribution $/gge 2.10 2.10 1.55

Other Variable O&M Cost Contribution $/gge 0.20 0.20 0.30

Total Hydrogen Cost $/gge 4.40 3.80 3.00

aThese costs are based on modeling the cost of distributed bio-derived liquids reforming in the H2A “Forecourt
Production Modeling Tool” downloadable from www.hydrogen.energy.gov/h2a_production.html. Specific assumptions
used to achieve the overall hydrogen cost objectives are documented in Record 6003
(www.hydrogen.energy.gov/program_records.html).
bThe H2A Forecourt Production Model was used with the following standard economic assumptions: All values are in

2005 dollars, 1500 kg/day design capacity, 1.9% inflation rate, 10% After Tax Return on Investment, 100% Equity
Financing, 7-year MACRS depreciation, 20-year analysis period, 38.9% overall tax rate, 70% capacity factor, and 15%
working capital. It is assumed that Design for Manufacture and Assembly (DFMA) would be employed and that about

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of 500 units per year would be produced. The capital cost for the forecourt station compression and storage are
consistent with the status and targets in the Delivery Section 3.2. Based on the recommendations made by the 2006
Independent Assessment of the Status of Distributed Natural Gas Reforming
(www.hydrogen.energy.gov/peer_review_production.html) start-up time was set to 0.5 years, % variable costs in year 1
was set to 50%, and percent fixed cost in year 1 was set to 75%.
cThe 2006 Status and 2012 values are based on the H2A distributed ethanol reforming analyses Current and Advanced

cases respectively (www.hydrogen.energy.gov/h2a_production.html) with respect to the production unit capital and
operating efficiency. The cost of ethanol utilized is $1.07/gal (no tax credit assumed). This is the DOE EERE Biomass
Program target for cellulosic based ethanol in 2012. The electricity cost utilized is $.08/kWh (commercial rate) based on
the EIA 2005 Annual Energy Outlook High A case projection for 2015 in 2005$.
dThe 2017 Target has been set to achieve <$3.00/gge hydrogen. Aqueous phase reforming of sugars is a technology

being researched that has the potential to reach this target and was used as the example H2A Distributed Production
case run. The cost of sugar used was $.07/lb which is consistent with the target cost of cellulosic sugar for ethanol
production in 2012 in the DOE EERE Biomass Program. The electricity cost utilized is $.08/kWh (commercial rate)
based on the EIA 2005 Annual Energy Outlook High A case projection for 2015 in 2005$. The capital cost and energy
efficiency of the production unit are based on preliminary analyses and projections for what could be achieved with
successful development of this technology. (See record 6003, www.hydrogen.energy.gov/program_records.html for
more details.) Alternatively, the target of <$3.00/gge could be achieved with ethanol reforming if the cost of ethanol
could be reduced to <$.90/gal. This ethanol cost is consistent with the longer term (>2015) DOE EERE Biomass
Program cost target for cellulosic ethanol.
eFor the 2006, 2010, and 2015 the following assumptions were made: (See Record 6003,

www.hydrogen.energy.gov/program_records.html for more details.)

- Based on the recommendations made by the 2006 Independent Assessment of the Status of Distributed Natural Gas
Reforming (www.hydrogen.energy.gov/peer_review_production.html) start-up time was set to 0.5 years, % variable
costs in year 1 was set to 50%, and % fixed cost in year 1 was set to 75%.
- It is assumed that Design for Manufacture and Assembly (DFMA) would be employed and that on the order of 500
units per year would be produced.
- The capital cost for the forecourt station compression and storage are consistent with the status and targets in the
Delivery Section 3.2.
fEnergy efficiency is defined as the energy in the hydrogen produced (on a LHV basis) divided the sum of the feedstock

energy (LHV) plus all other energy used in the process

gProduction unit energy efficiency may vary (as low as 65%) as the capital cost, feedstock costs and other costs

associated with aqueous phase reforming are low enough to still achieve the target of <$3.00/gge hydrogen cost.
hStorage capacity for 1000 kg of hydrogen at the forecourt is included. It is assumed that the hydrogen refueling fill

pressure is 5000 psi for 2006 and 2012. It is assumed that in 2017, the hydrogen refueling fill pressure is 10,000 psi.

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a, b, c
Table 3.1.4. Technical Targets: Distributed Water Electrolysis Hydrogen Production

2003 2006 2012 2017

Characteristics Units c
Status Status Target Target
Hydrogen Cost $/gge 5.15 4.80 3.70 <3.00
d $/gge N/A 1.20 0.70 0.30
Electrolyzer Capital Cost
$/kW N/A 665 400 125
f
Electrolyzer Energy Efficiency % (LHV) N/A 62 69 74

a, b, c
Table 3.1.4A. Distributed Electrolysis H2A Example Cost Contributions

2006
Characteristics Units c 2012 2017
Status
d
Cost Contribution $/gge H2 1.20 0.70 0.30
e
Electrolysis Unit Capacity Factor % 70 70 70
f
Energy Efficiency % (LHV) 62 69 74
Compression, Storage, $/gge H2 0.60 0.40 0.30
Safety and Dispensing Cost Contribution
g,h,i,j,k
Energy Efficiency % (LHV) 93.8 93.7 95.0
O&M Cost Contribution $/gge H2 0.80 0.60 0.40
L
Electricity Cost Contribution $/gge H2 2.20 2.00 1.80

m
Energy Efficiency % (LHV) 60.0 66.2 71.0
Total
Cost $/gge H2 4.80 3.70 <3.00

aThe H2A Forecourt Production Model (www.hydrogen.energy.gov/h2a_production.html) was used to generate the
values in the table with the exceptions described in the notes below. See Record #6002 for more details
(www.hydrogen.energy.gov/program_records.html).
bThe H2A Forecourt Production Model was used with the standard economic assumptions: All values are in 2005

dollars, 1.9% inflation rate, 10% After Tax Real Internal Rate of Return, 100% Equity Financing, 7-year MACRS
depreciation schedule, 20-year analysis period, 38.9% overall tax rate, and 15% working capital. The electrolyzer design
capacity is 1500 kg/day of hydrogen. The cell stack for forecourt electrolyzers is assumed to be replaced every 7 years at
a cost of 30% of the initial capital cost.
cThe 2006 Status is based on the H2A Current Forecourt Electrolysis Hydrogen Production Case

(www.hydrogen.energy.gov/h2a_production.html) with modifications as outlined in the notes. See Record #6002

(www.hydrogen.energy.gov/program_records.html) for more details.
dElectrolyzer capital costs assume high volume annual production of 1,000 units for all purposes and markets. See “The

Hydrogen Economy: Opportunities, Costs, Barriers and R&D Needs,” by the National Research Council and National
Academy of Engineering, pg. 182 for $125/kW for the electrolyzer.
eThe capacity factor for the electrolyzer is assumed to be 70%.
fElectrolyzer systems (including all auxiliaries other than compression) are assumed to operate at 53.4 kWh/kg, 62%

efficient LHV or 73% efficient HHV in 2006; 47.9 kWh/kg, 69% efficient LHV or 81% efficient HHV in 2012; and,
46.9 kWh/kg, 71% efficient LHV or 83% efficient HHV in 2017.
gIn 2006 and 2012, compressors are assumed to operate at 2.2 kWh/kg of hydrogen.
hIn 2017, hydrogen is produced from the electrolyzer at 1000 psi, and electricity cost contribution is lowered by $0.09/kg

as a result of a stage reduction due to electrolyzer producing hydrogen at 1000 psi. (From estimate resulting from a run

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of the H2A Delivery Components Model [www.hydrogen.energy.gov/h2a_production.html] that shows if hydrogen is

produced in the electrolyzer at 1000psi it reduces the number of stages in the compressor by one.)
iDispensers must be replaced every 10 years at 100% of initial capital cost. Dispenser costs based on 3 dispensers, each

at $22,400.
jCompressor costs are based on $4580/(kg/hr) in 2006, $4000/(kg/hr) in 2012, and $3000/(kg/hr) in 2017 for

1500kgH2/day size compressor which are consistent with Delivery (Section 3.2) status and cost targets.
kStorage costs based on $820/kg at 6250psi in 2006, $500/kg at 6250psi in 2012 and $300/kg H at 10,000 psi in 2017
2
which are consistent with the Delivery (Section 3.2) status and cost targets. Storage capacity for 1000 kg of hydrogen at
the forecourt is included. It is assumed that the hydrogen refueling fill pressure is 5000 psi for 2003, 2006 and 2012. It is
assumed that in 2017, the hydrogen refueling fill pressure is 10,000 psi.
LElectricity costs are $0.039/kWh. Electricity costs are based on the lowest average industrial grid electricity price 25%

of the population paid from 2000-2005 according to EIA.

mStandard H2A assumptions "Start Up Time" changed from 1 yr. to 0.5 yrs., "Percent Variable Costs During Start-up"

changed from 100% to 50%, and "Fixed Costs During Start-up" changed from 100% to 75% based on the
recommendations from the 2006 Independent Assessment of the Status of Distributed Natural Gas Reforming
(www.hydrogen.energy.gov/peer_review_production.html).

a, b
Table 3.1.5. Technical Targets: Central Wind Water Electrolysis
2006 2012 2017
Characteristics Units c
Status Target Target
Hydrogen Cost (Plant Gate) $/gge H2 5.90 3.10 <2.00
b, d
Electrolyzer Capital Cost $/gge H2 2.20 0.80 0.20
$/kW 665 350 109
e
Electrolyzer Energy Efficiency % (LHV) 62 69 74

a, b
Table 3.1.5A. Central Wind Electrolysis H2A Example Cost Contributions

2006
Characteristics Units c 2012 2017
Status

f Cost Contribution $/gge H2 2.50 2.10 3.00

Wind Farm
Capacity Factor % 41 50 54
d
Cost Contribution $/gge H2 2.20 0.80 0.20
Electrolysis Unit Capacity Factor % 44 58 77
e
Energy Efficiency % (LHV) 62 69 74
O&M Cost Contribution $/ggeH2 1.50 0.80 0.80
g
Cost Contribution $/gge H2 -0.30 -0.60 -2.00
By-product Electricity Percentage of electricity
produced sold as
h
by-product % 10 27 59
Total Cost $/gge H2 5.90 3.10 <2.00

aThe H2A Central Production Model (www.hydrogen.energy.gov/h2a_production.html) was used to generate the values
in the table with the exceptions described in the notes below. See Record #6002 for more details
(www.hydrogen.energy.gov/program_records.html).
bThe H2A Central Production Model was used with the standard economic assumptions: All values are in 2005 dollars,

1.9% inflation rate, 10% After Tax Real Internal Rate of Return, 100% Equity Financing, 40-year analysis period, 38.9%
overall tax rate, and 15% working capital. A MACRS 15-year depreciation schedule was used. The plant design capacity

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is 50,000 kg/day of hydrogen. The plant gate hydrogen pressure is 300 psi. The cell stacks for central electrolyzers are
assumed to be replaced every 10 years at a cost of 30% of the initial capital cost. Assumes no grid assistance.
cThe 2006 Status is based on the H2A Current Central Hydrogen Production from Wind Electrolysis Case

(www.hydrogen.energy.gov/h2a_production.html) with modifications as outlined in the other footnotes. See Record

#6002 for more details (www.hydrogen.energy.gov/program_records.html).
dElectrolyzer capital costs assume high volume annual production of 1,000 units for all purposes and markets. The 2012

electrolyzer capital costs assume a 12.5% savings on a standard H2A assumption for advanced electrolyzer cost of
$400/kW (see “Modeling the Market Potential of Hydrogen from Wind and Competing Sources,” by W. Short, N. Blair,
and D. Heimiller, p. 6 for 12.5% reduction of electrolyzer cost for combined wind/electrolyzer electronic controls).
2017 electrolyzer capital costs assume a 12.5% savings on a $125/kW system (see “The Hydrogen Economy:
Opportunities, Costs, Barriers and R&D Needs,” by the National Research Council and National Academy of
Engineering, pg. 182 for $125/kW for the electrolyzer).
eElectrolyzer systems (including all auxiliaries other than compression) are assumed to operate at 53.4 kWh/kg, 62%

efficient LHV or 73% efficient HHV in 2006; 47.9 kWh/kg, 69% efficient LHV or 81% efficient HHV in 2012; and,
44.7 kWh/kg, 74% efficient LHV or 87% efficient HHV in 2017.
fWind farm is 303 MW in the 2006 case, 276 MW in the 2012 case, and 423 MW in the 2017 case. Sizes are based on

optimization as outlined in WindPOWER report, “An Economic Analysis of Hydrogen Production from Wind” by J.
Levene. Wind capital costs are assumed to be $873/kW installed in 2006, $754/kW in 2012, and $706/kW in 2017. The
wind capacity factor is 0.41 in 2006, 0.50 in 2012, and 0.54 in 2017 based on class 6 wind regimes. The wind farm cost
contribution ($/gge) increases in 2017 to accommodate an increase in the capacity factor of the electrolyzer unit. The
increase in capacity factor requires a higher capacity wind farm, but lowers the overall hydrogen cost due to the value of
the electricity not needed by the electrolyzer. It is assumed the wind turbine rotor will need to be replaced after 20 years
at 20% of initial investment.
gIn the 2006 case, a production tax credit (PTC) of $0.018/kWh is applied to the by-product electricity produced for the

first 10 years.
hIn 2006, 10% of the electricity produced is sold as a by product; in 2012, 27% of the electricity produced is sold as a

byproduct; in 2017, 59% of the electricity produced is sold as a by-product.

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Table 3.1.6. Technical Targets: Dense Metallic Membranes for

a
Hydrogen Separation and Purification

Performance Criteria Units 2006 Status 2010 Target 2015 Target

b 2
Flux Rate scfh/ft >200 250 300

2
Module Cost (including membrane $/ft of
c 1,500 1,000 <500
material) membrane

d
Durability hr <8,760 26,280 >43,800

e
Operating Capability psi 200 400 400-600

Hydrogen Recovery % 60 >80 >90

f % of total (dry)
Hydrogen Quality 99.98 99.99 >99.99
gas
aBased on membrane water-gas shift reactor with syngas.
bFlux at 20 psi hydrogen partial pressure differential with a minimum permeate side total pressure of 15 psig, preferably
>50 psi and 400°C.
cAlthough the cost of Pd does not present a significant cost barrier due to the small amount used, the equipment and

labor associated with depositing the material (Pd), welding the Pd support, rolling foils or drawing tubes account for the
majority of membrane module costs. The $1,500 cost status is based on emerging membrane manufacturing techniques
achieved by our partners and is approximately $500 below commercially available units used in the microelectronics
industry.
dIntervals between membrane replacements.
eDelta P operating capability is application dependent. There are many applications that may only require 400 psi or less.

For coal gasification 1000 psi is the target.

fIt is understood that the resultant hydrogen quality must meet the rigorous hydrogen quality requirements as described

in Appendix C. These membranes are under development to achieve that quality. Membranes must also be tolerant to
impurities. This will be application specific. Common impurities include sulfur and carbon monoxide.

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Table 3.1.7. Technical Targets: Microporous Membranes for

a
Hydrogen Separation and Purification
Performance Criteria Units 2006 Status 2010 Target 2015 Target
b 2
Flux Rate scfh/ft 150 200 300

Membrane Material and All 2

c $/ft of Membrane 200 200 <100
Module Costs
d
Durability hr 1,100 26,280 >43,800
e
Operating Capability psi 500 400 400-1000

Hydrogen Recovery % 80 >80 >90

f
Hydrogen Quality % of total (dry) gas >95 99.5 99.99

aBased on membrane water-gas shift reactor with syngas

bFlux at 20 psi hydrogen partial pressure differential with a minimum permeate side total pressure of 15 psi, preferably
>50 psi and 400°C.
cThe membrane support structure cost is approximately three times more than membrane material costs.
dIntervals between membrane replacement.
eDelta P operating capability is application dependent. There are many applications that may require 400 psi or less. For

coal gasification 1000 psi is the target.

fIt is understood that the hydrogen quality produced by production technologies must meet the rigorous hydrogen

quality requirements as described in Appendix C. These membranes are under development to achieve that quality.
Membranes must also be tolerant to impurities. This will be application specific. Common impurities include sulfur and
carbon monoxide.

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a, b
Table 3.1.8. Technical Targets: Biomass Gasification/Pyrolysis Hydrogen Production
2005 2012 2017
Characteristics Units c c d
Status Target Target
e
Hydrogen Cost (Plant Gate) $/gge <$2.00 $1.60 $1.10
f
Total Capital Investment $M <$194 $150 $110
g
Energy Efficiency % >35% 43% 60%

a,b
Table 3.1.8 A. Biomass Gasification H2A Example Cost Contributions
c d
Characteristics Units 2005 2012 2017
Capital Cost Contribution $/gge $0.70 $0.50 $0.30
Feedstock Cost Contribution $/gge $0.70 $0.60 $0.40
Fixed O&M Cost Contribution $/gge $0.30 $0.20 $0.15
Other Variable Cost Contribution $/gge $0.30 $0.30 $0.25
Total Hydrogen Cost (Plant Gate) $/gge $2.00 $1.60 $1.10

aThese costs are based on modeling the cost of hydrogen production utilizing the H2A Central Production Model and
the results of the H2A Biomass Gasification analyses (www.hydrogen.energy.gov/h2a_production.html). Record 6001
(www.hydrogen.energy.gov/program_records.html) provides additional details.
bThe H2A Central Production Model was used with the standard economic assumptions: All values are in 2005 dollars,

1.9% inflation rate, 10% After Tax Return on Investment, 100% Equity Financing, 20-year MACRS straight line
depreciation, 40-year analysis period, and 38.9% overall tax rate, 90% capacity factor, and 15% working capital. The
plant gate hydrogen pressure is 300 psi. The plant is designed for a nominal processing capacity of 2000 dry metric tons
of biomass per day. The specific hydrogen design capacities are 155 and 194 metric tons per day for 2005 and 2017,
respectively, based on the plant efficiencies shown in the table. All feedstock and utility costs are based on their
projected costs in 2015 consistent with approach used to determine the overall delivered hydrogen production cost
objective of $2-3/gge. The biomass feedstock cost used is $41/dry metric ton consistent with the EERE Biomass
Program estimate for 2012. The utility costs are based on the 2005 AEO High A projection for 2015 consistent with the
standard H2A methodology.
cThe 2005 Status is based on the H2A Biomass Gasification Current Case

(www.hydrogen.energy.gov/h2a_production.html) with some modification. No one has actually operated an integrated

biomass gasification process designed specifically for hydrogen production at any scale. The H2A analysis is based on
actual results of biomass gasification for power generation and available information from other similar processes for the
rest of the process to yield hydrogen. As a result, a more conservative approach is taken for this status column by
increasing the capital cost, reducing the process efficiency, and increasing the labor to the limits of the sensitivity analysis
in the H2A Biomass Gasification Current Case. See Record #6001 (www.hydrogen.energy.gov/program_records.html)
for more details. The 2012 Target is based on verifying the H2A Biomass Gasification Current Case estimate with actual
data from a fully integrated biomass gasification unit designed to produce hydrogen.
dThe 2017 Targets are based on the capital cost and performance (energy efficiency) required to approach the low end of

the $2-3/gge overall delivered hydrogen production cost consistent with the 2017 delivery cost target of $1.00/gge. This
falls within the sensitivity analysis of the H2A Biomass Gasification Longer-term case. See Record #6001
(www.hydrogen.energy.gov/program_records.html) for more details.
eThe H2A Central Production Model (www.hydrogen.energy.gov/h2a_production.html) was used to generate these

values at the total invested capital and process energy efficiency indicated in the table. See Record #6001
(www.hydrogen.energy.gov/program_records.html) for more details.
fAll cases assume capital replacement at 0.5%/yr of total depreciable capital investment.
gEnergy efficiency is defined as the energy in the hydrogen produced (on a LHV basis) divided by the sum of the

feedstock energy (LHV) plus all other energy used in the process.

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a
Table 3.1.9. Solar-Driven High-Temperature Thermochemical Hydrogen Production

Characteristics Units 2008 Target 2012 Target 2017 Target

Solar-Driven High-Temperature Thermochemical Cycle

$/gge H2 10.00 6.00 3.00
Hydrogen Cost

b 2
Heliostat Capital Cost (installed cost) $/m 180 140 80

c
Process Energy Efficiency % 25 30 >35

aBased on initial analysis utilizing the H2A production analysis approach and standard H2A economic parameters
(www.hydrogen.energy.gov/h2a_production.html). Two potential high-temperature cycles were examined: the
Westinghouse modified sulfur cycle with electrolysis and a zinc oxide cycle. The capacity basis was central production of
100,000 kg/day of hydrogen. All targets are expressed in 2005 dollars. These costs are at the plant gate. The cost target
for delivery of hydrogen from the plant gate to the point of refueling at a refueling station in 2017 is $1.00/gge (See
Section 3.2)
bThese capital cost targets are consistent with the current viewpoint of the EERE Solar Program. The Solar Program is

in the process of updating their targets in this area.

cThe process energy efficiency is defined as the energy of the hydrogen produced (LHV) divided by the sum of the

energy from the solar concentrator system plus any other net energy required for the process.

a
Table 3.1.10. Technical Targets: Photoelectrochemical Hydrogen Production
b
Characteristics Units 2003 Status 2006 Status 2013 Target 2018 Target
c
Usable semiconductor bandgap eV 2.8 2.8 2.3 2.0
d
Chemical conversion process efficiency (EC) % 4 4 10 12
e
Plant solar-to-hydrogen efficiency (STH) % not available not available 8 10
f
Plant durability hr not available not available 1000 5000

aThe targets in this table are for research tracking. The final targets for this technology are costs that are market
competitive.
bTechnology readiness targets (beyond 2015) are 16% plant solar-to-hydrogen (STH) efficiency and 15,000 hours plant

durability.
cThe bandgap of the interface semiconductor establishes the photon absorption limits. Useable bandgaps correspond to

systems with adequate stability, photon absorption and charge collection characteristics for meeting efficiency, durability
and cost targets.
dEC reflects the process efficiency with which a semiconductor system can convert the energy of absorbed photons to

chemical energy [based on air mass 1.5 insolation] and is a function of the bandgap, IPEC and electronic transport
properties. A multiple junction device may be used to reach these targets.
eSolar-to-hydrogen (STH) is the projected plant-gate solar-to-hydrogen conversion efficiency based on AM (Air Mass)

1.5 insolation. Both EC and STH represent peak efficiencies, with the assumption that the material systems are
adequately stable.
fDurability reflects projected duration of continuous photoproduction, not necessarily at peak efficiencies.

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a
Table 3.1.11. Technical Targets: Photolytic Biological Hydrogen Production from Water

2013 2018
Characteristics Units 2003 Status 2006 Status b c, d
Target Target

Utilization Efficiency of Incident Solar Light

e % 10 15 15 20
Energy (E0*E1)

Efficiency of Incident Light Energy to Hydrogen

f % 0.1 0.1 2 5
from Water (E0*E1*E2)
g
Duration of Continuous Photoproduction Time Units not available not available 30 min 4 hr

O2 Tolerance (half life in air) Time Units 1 sec 1 sec 10 min 2 hr

E0 Absorbed Light E2
E1
Solar Light + Electrons H2
H2O

aThe targets in this table are for research tracking. The final targets for this technology are costs that are market
competitive
b2013 target is based on analysis of best technologies available, theoretically integrated into a single organism.
c2018 targets are based on analysis of best technologies available, actually integrated into a single organism.
dTechnology readiness targets (beyond 2018) are 25% utilization efficiency of incident solar light energy (E0*E1), 10%

efficiency of incident light energy to H2 from water (E0*E1*E2), ≥12h (O2 tolerant) duration of continuous
photoproduction, and 6h O2-tolerance (half-life in air).
eE0 reflects the light collection efficiency of the photoreactor and the fact that only a fraction of solar incident light is

photosynthetically active (theoretical maximum is 45%). E1 is the efficiency with which algae convert the energy of
absorbed photons to chemical energy (i.e., chemical potential; theoretical maximum is 71%). E0*E1 represents the
efficiency of conversion of incident solar light to chemical potential (theoretical maximum is 32%).
fE2 reflects the efficiency with which the chemical potential generated by the absorbed photons is converted to

hydrogen (theoretical maximum is 41%). E0*E1*E2 represents the efficiency of conversion of incident solar light to H2
(theoretical maximum is 13% when water is the substrate); only peak efficiencies are meant.
gDuration reflects continuous production in the light, not necessarily at peak efficiencies. Targets reflect oxygen tolerant

system.

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a
Table 3.1.12. Technical Targets: Photosynthetic Bacterial Hydrogen Production

2018
Characteristics Units 2003 Status 2006 Status 2013 Target b
Target

Efficiency of Incident Solar Light Energy to H2 d d

c % 1.9 1.9 3 4.5
(E0*E1*E2) from organic acids

Molar Yield of Carbon Conversion to H2 (depends % of e e

e 42 42 50 65
on nature of organic substrate) E3 maximum
f g g
Duration of continuous photoproduction Time 6 days 6 days 30 days 3 months

aThe targets in this table are for research tracking. The final targets for this technology are costs that are market
competitive.
bTechnology readiness targets (beyond 2018) are 5.5% efficiency of incident solar light energy to H (E0*E1*E2) from
2
organic acids, 80% of maximum molar yield of carbon conversion to H2 (depends on nature of organic substrate) E3,
and 6 months duration of continuous photoproduction.
cE0 reflects the light collection efficiency of the photoreactor and the fact that only a fraction of incident solar light is

photosynthetically active (theoretical maximum is 68%, from 400 to 1000 nm). E1*E2 is equivalent to the efficiency of
conversion of absorbed light to primary charge separation then to ATP; both are required for hydrogen production via
the nitrogenase enzyme. E0*E1*E2 represents the efficiency of conversion of incident solar light to hydrogen through
the nitrogenase enzyme (theoretical maximum is 10% for 4-5 electrons). This efficiency does not take into account the
energy used to generate the carbon substrate.
dAverage from data presented by Akkerman, I., M. Janssen, J. Rocha, and R. H. Wijffels. 2002. Intl. J. Hydrogen Energy

27: 1195-1208.
eE3 represents the molar yield of H per carbon substrate (the theoretical maximum is 7 moles per mole carbon in the
2
substrate, in the case of acetate and butyrate). Average of data presented by Koku, H., I. Eroglu, U. Gunduz, M. Yucel,
and L. Turker. 2002. Intl. J. Hydrogen Energy 27: 1315-1329.
fDuration reflects continuous production in the light, not necessarily at peak efficiencies. It includes short periods during

which ammonia is re-added to maintain the system active.

gAverage from data presented by Koku, H., I. Eroglu, U. Gunduz, M. Yucel, and L. Turker. 2002. Intl. J. Hydrogen

Energy 27: 1315-1329.

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a
Table 3.1.13. Technical Targets: Dark Fermentative Hydrogen Production
b
Characteristics Units 2003 Status 2006 Status 2013 Target 2018 Target

c mol H2 d d
Yield of H2 production from glucose 2 2 4 6
mol glucose
e
Feedstock Cost cents/lb sugar 13.5 13.5 10 8
f f
Duration of continuous production Time 17days 17days 3 months 6 months

aThe targets in this table are for research tracking. The final targets for this technology are costs that are market
competitive.
bTechnology readiness targets (beyond 2018) are 10 molar yield of H production from glucose, 6 cents/lb sugar
2
feedstock cost, and 12 months duration of continuous production.
cThe theoretical maximum from known fermentative pathways is 4, although the H content of 1 mole of glucose is 12.
2
Clearly, in order to achieve molar yields greater than 4, the feasibility of developing new pathways or discovering new
microbes needs to be assessed.
dDOE Workshop on Hydrogen Production via Direct Fermentation (June 2004)

www1.eere.energy.gov/hydrogenandfuelcells/pdfs/fermentation_wkshp.pdf and Boundary Analysis for H2 Production

by Fermentation, T. Eggeman, www.nrel.gov/docs/fy05osti/36129.pdf
eTargets set by the DOE Biomass Program for glucose from lignocellulosic biomass. NREL Report TP-510-32438,

www.nrel.gov/docs/fy02osti/32438.pdf; NREL E Milestone #586, May 2004.

fVan Ginkel, S., and S. Sung. 2001. Environ. Sci. Technol. 35: 4726-4730.

Barriers

The following sections detail the technical and economic barriers that must be overcome to attain
the Hydrogen Production goal and objectives. The barriers are divided into sections depending on
the hydrogen production method.

Distributed Hydrogen Production from Natural Gas or Renewable Liquid

Feedstocks
A. Reformer Capital Costs. Current small-scale distributed natural gas and renewable liquid
feedstock reforming technologies have capital costs that are too high to achieve the targeted
hydrogen production cost. Multiple-unit operations and low energy efficiencies are key contributors
to the high capital cost. Improved reforming and water-gas shift catalysts are needed to increase
yield and improve performance. Water-gas shift and hydrogen separation and purification costs need
to be reduced. Process intensification by combining unit operations could significantly reduce costs.
For example, combining the current two step water-gas shift reactor and pressure swing adsorption
(PSA) separation into a single unit operation could significantly reduce capital costs.

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B. Reformer Manufacturing. Distributed reforming units are currently designed and built one at a
time. Efforts such as Design for Manufacture and Assembly (DFMA) need to be applied to develop
more compact, skid mounted units that can be produced using currently available low-cost, high-
throughput manufacturing methods (see the Manufacturing section of this plan).
C. Operation and Maintenance (O&M). O&M costs for distributed reforming hydrogen
production from natural gas and renewable feedstocks are too high. Robust systems that require
little maintenance and that include remote monitoring capability need to be developed.
D. Feedstock Issues. Availability of some feedstocks is limited in certain areas. Feedstock-flexible
reformers are needed to address location-specific feedstock supply issues. Effects of impurities on
the system from multiple feedstocks as well as the effects of impurities from variations in single
feedstocks need to be addressed in the reformer design.
E. Greenhouse Gas Emissions. Distributed natural gas reformers emit greenhouse gases.
Feedstocks and/or technologies that can approach near zero net greenhouse gas emissions are
needed.
F. Control and Safety. Control and safety issues are associated with natural gas and renewable
feedstock reforming, including on-off cycling. Effective operation control strategies are needed to
minimize cost and emissions, maximize efficiency, and enhance safety. Hydrogen leakage is
addressed within the Delivery and Safety Program elements.

Hydrogen Generation by Water Electrolysis

G. Capital Cost. The capital costs of water electrolysis systems are prohibitive to widespread
adoption of electrolysis technology for hydrogen production. R&D is needed to develop lower cost
materials with improved manufacturing capability to lower capital while improving the efficiency and
durability of the system. Development of larger systems is also needed to take advantage of
economies of scale. Technically viable systems for low-cost manufacturing need to be developed for
this technology (see the Manufacturing section of this plan).
H. System Efficiency. New membrane, electrode and system designs are needed to improve
system efficiency and durability. Mechanical high-pressure compression technology exhibits low
energy efficiency and may introduce impurities while adding significantly to the capital and operating
cost. Efficiency gains can be realized using compression in the cell stack. Development is needed
for low-cost cell stack optimization addressing efficiency, compression, and durability.
I. Grid Electricity Emissions (for distributed). The current grid electricity mix in most
locations results in greenhouse gas emissions in large-scale electrolysis systems. Low-cost, carbon-
free electricity generation is needed. Electrolysis systems that can produce both hydrogen and
electricity need to be evaluated. (Renewable electricity costs are being addressed by the DOE EERE
renewable power programs – Solar, Wind, Hydropower, Geothermal and Biomass.)
J. Renewable Electricity Generation Integration (for central). More efficient integration with
renewable electricity generation is needed to reduce costs and improve performance. Development
of integrated renewable electrolysis systems is needed, including optimization of power conversion
and other system components from renewable electricity to provide high-efficiency, low-cost
integrated renewable hydrogen production.

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Hydrogen Separations
There are a number of technology options available that can be used to separate and purify
hydrogen. The following is a set of broad, cross-cutting barriers that must be overcome to reduce
the cost and increase the efficiency of these separation technologies. This plan currently focuses on
hydrogen separation technologies for thermochemical processes including distributed reforming and
biomass gasification. In the future, additional separations technologies may be necessary for other
production technologies.
K. Durability. Hydrogen embrittlement can reduce the durability and effectiveness of metallic
membrane systems. Thermal cycling can cause failure, reducing durability and operating life. This is
especially problematic in distributed applications that may be subject to frequent start-up and shut-
down cycles. Support structures with more uniform pore sizes and less surface roughness are
needed to avoid membrane defects. Interactions between membrane and support structure materials
need to be better understood. Materials science research is needed to understand microstructural
evolution during operation and its effect on membrane permeability, selectivity, and failure modes.
Combinatorial methods are needed for rapid testing and evaluation of novel materials and alloys.
L. Impurities. The presence of trace contaminants as well as CO, water, and CO2 in the product
stream from a gasifier or reformer can reduce the hydrogen flux across different types of
membranes. It is not understood whether these effects are caused by competitive adsorption,
poisoning, or compositional changes on the membrane surface. Additionally, some membranes
exhibit poor thermochemical stability in carbon dioxide environments, resulting in the conversion of
membrane materials into carbonates.
M. Membrane Defects. Oxidizing gas mixtures (oxygen, steam, and carbon oxides) have been
observed to cause metallic membranes to rearrange their atomic structure at temperatures greater
than 450ºC. This results in the formation of permanent defects that reduce membrane selectivity for
hydrogen. High-temperature and high-pressure seals can be an issue with membrane systems. Seals
and joints are a weak link in membrane module construction and one of the most common points
of membrane system failure. The chemical deposition of thin palladium or palladium-alloy
membranes onto support structures is also an important technical challenge.
N. Hydrogen Selectivity. The hydrogen selectivity of microporous membranes is lower than
desired for cost-effective use, especially for zeolite-supported membranes where selectivity decreases
with increasing temperature (inadequate above 150ºC). Process stream temperatures typically are
greater than 300ºC in various applications.
O. Operating Temperature. Membrane modules that can be designed to operate at or near
process conditions, without the need for cooling and/or re-heating, will be more efficient. For
example, dense ceramic proton hydrogen separation membranes currently operate only at high
temperatures (~900ºC).
P. Flux. Flux rates for membranes need to be improved to reduce the membrane size and lower
overall cost of hydrogen separation and purification systems.
Q. Testing and Analysis. Better information is needed to guide researchers and membrane
technology developers towards performance targets that are application specific. Standard methods
for evaluating and screening membrane materials and modules are needed to provide a solid basis

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for comparison of alternatives and to conduct needed tests such as accelerated durability tests.
Testing under real-world operating conditions is needed to demonstrate durability and robust,
reliable performance. Additionally, there is currently a lack of understanding of tradeoffs between
different system configurations and operating parameters. Operation at higher temperatures and
partial pressure differentials can increase flux rates but results in more expensive membrane
modules. Very thin membranes increase flux but they are harder to fabricate defect-free. Analysis is
also needed to understand options and tradeoffs for process intensification in different applications.
R. Cost. In addition to precious metals, membrane materials and support structures are costly.
Fabrication of high quality (ultra-thin) membranes dominates membrane systems cost.

Biomass Gasification/Pyrolysis Hydrogen Production

S. Feedstock Cost and Availability. Feedstock costs are high. Improved feedstock/agriculture
technology (higher yields per acre, etc.), lower cost feedstock collection, and improved feedstock
preparation are needed. Because biomass feedstocks are seasonal in nature, feedstock-flexible
processes and cost-effective feedstock storage are needed. (Tasks to overcome these barriers are the
responsibility of the DOE Biomass Program and the U.S. Department of Agriculture.)
T. Capital Cost and Efficiency of Biomass Gasification/Pyrolysis Technology. The capital
cost for biomass gasification/pyrolysis needs to be reduced. Process intensification by combining
unit operations can significantly reduce capital costs. This could range from combining the current
two step water-gas shift and PSA separation to a one step water-gas shift with integrated separation,
to integrating gasification, reforming, water-gas shift and separation all in one unit operation.
Improved process efficiency and higher hydrogen yields and selectivities through catalyst research,
better heat integration, and alternative gas clean-up approaches are needed. Improved catalysts or
engineering approaches for tar cracking are also needed.

High-Temperature Thermochemical, Solar-Driven Production of Hydrogen 10

U. High-Temperature Thermochemical Technology. There are over 200 potential
thermochemical cycles for solar-driven water splitting. These cycles have been evaluated and ranked
for their suitability. The most promising cycles need to be fully explored and verified to down select
to a few cycles. The most promising cycles will require extensive research and development efforts.
V. High-Temperature Robust Materials. High temperatures are required for these
thermochemical systems (500-2000°C). Cost-effective, durable materials are needed that can
withstand these high temperatures and the thermal duty cycles present in solar concentrator systems.
W. Concentrated Solar Energy Capital Cost. Concentrated solar energy collection is currently
expensive and requires large areas of land. Improved, lower-cost solar concentrator/collection
technology, including materials, is needed.11

10 DOE's Office of Nuclear Energy has the lead responsibility for hydrogen production utilizing nuclear energy for high-
temperature (700°-1000°C) thermochemical water-splitting chemical cycles. The Office of Hydrogen, Fuel Cells &
Infrastructure Technologies will collaborate with Nuclear Energy on the thermochemical hydrogen production R&D
activities.
11 The Hydrogen Program will rely on and collaborate with the DOE EERE Solar Program for the advancement of

concentrated solar energy technology.

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X. Coupling Concentrated Solar Energy and Thermochemical Cycles. Coupling concentrated

solar energy with thermochemical cycles presents many challenges. Receivers, heat transfer and
systems, as well as reactors need to be developed and engineered. Cost effective approaches and
systems to deal effectively with the diurnal nature of sunlight need to be researched and developed.

Photoelectrochemical Hydrogen Production

Photoelectrochemical hydrogen production is in an early stage of development and requires
breakthroughs in materials development. The primary research in this area is progressing on three
fronts: (1) the study of high-efficiency materials to attain the fundamental understanding needed for
improving lower-efficiency, low-cost materials; (2) the study of low-cost durable materials to attain
the fundamental understanding needed for modifying higher-efficiency, lower-durability materials;
and (3) the development of multijunction devices incorporating multiple material layers to achieve
efficient water splitting. Methods of engineering and manufacturing these systems need to be
developed in conjunction with the materials and device research (see the Manufacturing section of
this plan).
Current materials for photoelectrochemical hydrogen production can be broadly divided into three
categories, each with its own characteristics and research challenges. These groupings are: (i) stable
materials with low visible light absorption efficiency (e.g., oxides), (ii) highly efficient light absorbers
with low lifetimes (e.g., Group III-Vs), and (iii) hybrid and multijunction systems which combine
multiple materials in multi-photon devices. The group (i) materials are characterized by high
bandgaps and low integrated incident-photon-to-electron conversion (IPEC) over the solar
spectrum; the group (ii) materials have very high IPEC (better than 90% throughout the visible
spectra), but have low corrosion resistance and poor energetics; and the group (iii) systems can have
very high efficiency and long lifetime, depending on the material set, but can be complicated and
expensive to build. Research in all three categories is necessary for developing systems that meet the
targets reflected in the PEC target table. To date, a range of materials and material systems have met
individual 2010 targets of chemical efficiency or durability, but no single material/system has
simultaneously met efficiency, durability and cost targets. This is the primary research challenge for
photoelectrochemical hydrogen production.
Y. Materials Efficiency. Materials with smaller bandgaps more efficiently utilize the solar
spectrum, but are often less energetically favorable for hydrogen production because of the
bandedge mismatch with respect to either hydrogen or oxygen redox potentials. Materials with
appropriate bandedge and bandgap for hydrogen production must be developed.
Z. Materials Durability. Durable materials with the appropriate characteristics for
photoelectrochemical hydrogen production that meet the program goals have not been identified.
The high-efficiency materials currently available corrode quickly during operation, and the most
durable materials are very inefficient for hydrogen production.
AA. PEC Device and System Auxiliary Material. The functional requirements for auxiliary
materials must be determined and materials discovered, developed, and tested to facilitate PEC
device and systems development. The auxiliary materials may include protective coatings, catalytic
coatings, photoelectrode substrates, hydrogen impervious materials, and photovoltaic layer materials.

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AB. Bulk Materials Synthesis. Fabrication techniques for materials identified to have potential for
high efficiency, durability and low cost need to be developed on scales consistent with
implementation in commercial reactors.
AC. Device Configuration Designs. Hybrid and other device designs that combine multiple
layers of materials could address issues of durability and efficiency. Techniques are needed for
manufacturing appropriate photoelectrochemical materials in these device configurations at
commercial scales (see the Manufacturing section of this plan).
AD. Systems Design and Evaluation. System designs incorporating the most promising device
configurations, and using cost-effective, hydrogen-impermeable, transparent materials are also
needed to implement photolytic production routes. The complete systems evaluation will need to
consider a range of important operational constraints and parameters, including the diurnal
operation limitations and the effects of water purity on performance and lifetime. Engineering
options need to be carefully analyzed to minimize capital requirements.
AE. Diurnal Operation Limitations. Photolytic processes are discontinuous because they depend
on sunlight, which is unavailable at night and available only at low intensities on cloudy days. This
results in increased capital costs for larger facilities to accommodate higher short-term production
rates and larger hydrogen storage needs.

Biological Hydrogen Production

A number of technologies for biological H2 production are available, but they are not mature at
present. Technical barriers related to each individual technology must be overcome, integrated
models must be developed, and barriers related to an integrated system must be identified before
economic barriers can be meaningfully considered. Methods for engineering and manufacturing
these systems have not been fully evaluated.
AF. Lack of Naturally Occurring Microorganism Characterization. Only a small fraction of
the world’s microorganisms have been discovered and functionally characterized. Research is needed
to discover naturally occurring microorganisms with characteristics necessary for biological
hydrogen production.
Barriers are listed below for each technology, followed by a model for how these different
technologies could be integrated and a list of barriers for the integrated process.

Photolytic H2 Production from Water (green algae or cyanobacteria):

AG. Light Utilization Efficiency. The microorganisms used for photobiological H2 production
possess large arrays of light-capturing antenna pigment molecules. Under bright sunlight, pigment
antennae absorb much more light than can be utilized by the photosynthetic electron transport
apparatus, resulting in heat dissipation and loss of up to 80% of the absorbed sunlight. Research is
needed to identify ways to increase the light conversion efficiency, including the identification of
better and/or modified photosynthetic organisms for H2 production.
AH. Rate of Hydrogen Production. The current H2 production rate from photosynthetic
microorganisms is too low for commercial viability. The low rates have been attributed to (a) the
non-dissipation of a proton gradient across the photosynthetic membrane, which is established

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during electron transport from water to the hydrogenase (the H2-producing enzyme) under
anaerobic conditions, and (b) the existence of competing metabolic flux pathways for reductant.
Genetic means to overcome the restricting metabolic pathways, such as the insertion of a proton
channel across the thylakoid membrane, must be used to significantly increase the rate of H2
production. Under aerobic conditions, with an O2-tolerant hydrogenase catalyzing H2 production,
the competition between CO2 fixation and hydrogenase will have to be addressed.
AI. Continuity of Photoproduction. Hydrogen-producing algae co-produce oxygen, which
inhibits the hydrogenase enzyme activity. This inhibition needs to be alleviated, possibly by (a)
identifying or engineering a less O2-sensitive enzyme; (b) separating the oxygen and hydrogen
production cycles; or (c) affecting the ratio of photosynthesis to respiration by a variety of means,
such that O2 does not accumulate in the medium, the quantum yield of photosynthesis is
maintained, and full hydrogenase activity is achieved (see details under Integrated System).
AJ. Systems Engineering. System requirements for cost-effective implementation of photolytic
hydrogen-production technologies have not been adequately evaluated. Analysis and research are
needed on inexpensive/transparent materials for H2 containment, H2 collection systems, prevention
of the build-up of H2/O2 gas mixtures, separation of co-produced H2 and O2 gases, continuous
bioreactor operation, monoculture maintenance, land area requirements and capital costs.
AK. Diurnal Operation Limitations. The same issues apply as for photolytic systems (see Barrier
AE).

Photosynthetic Bacterial Hydrogen Production, Required for an Integrated

System:
AL. Light Utilization Efficiency. Same issues apply as for photolytic systems (see Barrier X).
AM. Rate of Hydrogen Production. Photosynthetic bacteria can metabolize a variety of organic
substrates that are waste by-products of various fermentative processes. However, the metabolism
of acetic and lactic acids to H2 also generates by-products such as the polymer polyhydroxyalkanoate
(PHA). Synthesis of PHA competes with H2 production for the same source of electron donors.
Genes controlling PHA synthesis and perhaps other pathways must be inactivated to maximize H2
production. Alternative types of nitrogenase are needed to produce larger stoichiometric amounts of
H2/ammonia.
AN. Hydrogen Re-oxidation. Most photosynthetic bacteria contain an H2-oxidation pathway
catalyzed by an uptake hydrogenase enzyme. This enzyme will recycle the H2 produced by the
nitrogenase to support cell growth. Uptake hydrogenase enzyme(s) must be inactivated to ensure net
H2 accumulation by photosynthetic bacteria.
AO. Carbon/Nitrogen Ratio. To maximize nitrogenase activity, the proper ratio of carbon to
nitrogen (C/N) nutrients must be maintained. The C/N nutrient content in the photoreactor (algal
and cyanobacteria) and in the dark fermentor needs to be evaluated to assess whether the media
composition is suitable for subsequent photosynthetic bacterial hydrogen production. Enzyme
engineering approaches may be needed to alleviate inhibition of nitrogenase by elevated levels of
nitrogen nutrient.

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AP. Systems Engineering. The same issues apply as for photolytic systems (see above), except for
the mixture of gases. Photosynthetic bacteria do not co-evolve H2 and O2 but release H2 and CO2.
The cost of H2 and CO2 separation must be evaluated.
AQ. Diurnal Operation Limitation. The same issues apply as for photolytic systems (see Barrier
AE).

Dark Fermentative Hydrogen Production, Required for an Integrated System:

AR. H2 Molar Yield. Up to 4 moles of H2 can theoretically be produced per mole of glucose
through the known fermentative pathways. However, various biological limitations such as H2-end-
product inhibition and waste-acid and solvent accumulation limit the molar yield to around 2 moles
per mole glucose consumed. Hydrogen molar yields must be increased significantly through
metabolic engineering efforts. New pathways must be discovered to directly take full advantage of
the 12 moles of H2 available in a mole of glucose.
AS. Waste Acid Accumulation. Organic acids such as acetic and butyric acids are waste by-
products of the fermentation process. The production of these acids poses several challenges such
as lowering the molar yield of H2 by diverting the metabolic pathway toward solvent production and
requiring subsequent wastewater treatment. Elimination of this pathway or subsequent processing
(such as in an integrated biological hydrogen production system) of the organic acids by
photosynthetic bacteria is needed to increase hydrogen yields. Potential release of toxins during dark
fermentation and their inhibition of the subsequent steps (such as in an integrated system) will need
to be evaluated.
AT. Feedstock Cost. The glucose feedstock is the major cost driver for economic H2 production
via fermentation. For renewable H2 to be cost competitive with traditional transportation fuels, the
glucose cost must be around $0.05 per pound and provide a molar yield of H2 approaching 10 (see
Barrier AI and Target Table 3.1.9). Lower-cost methods for producing glucose from whole biomass
are needed. Cellulolytic microbes with a high rate of H2 production are also needed to use the cell
biomass of the green algal/cyanobacterial and photosythetic bacterial co-culture (in an integrated
biological H2 production system).
AU. Systems Engineering. The same issues apply as above, plus prevention of methanogen
contamination is needed.

Integrated Biological Hydrogen Production System (many configurations are

possible, Figure 3.1.3):
AV. Photosynthesis/Respiration Capacity Ratio. Green algae and cyanobacteria become
anaerobic when their P/R (photosynthesis/respiration) capacity ratio is 1 or less. Under such
anaerobic conditions, photosynthetic water oxidation produces H2 (instead of starch), and the O2
evolved by photosynthesis is consumed by respiration, producing CO2. Currently, this process is
achieved by nutrient deprivation, with the drawback that the resulting P/R ≤ 1 ratio is achieved by
partially decreasing the quantum yield of photosynthesis. Alternative mechanisms to bring the P/R
ratio to 1 need to be investigated, particularly those methods that focus on achieving a P/R ratio of
1 without changing the quantum yield of photosynthesis. Two further issues will need to be
investigated under these conditions: (a) rate limitations due to the non-dissipation of the proton

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gradient and (b) the ability of the culture to take up a variety of exogenous carbon sources under the
resulting anaerobic conditions.

Figure 3.1.3. Integrated Biological System

AW. Co-Culture Balance. To extend the absorption spectrum of the H2-photoproducing cultures
to the infrared (700-900 nm), the possibility of co-cultivating oxygenic photosynthetic organisms
with anoxygenic photosynthetic bacteria should be investigated. However, in addition to light in the
infrared region, photosynthetic bacteria also absorb light in the visible (400 to 600 nm), thus
potentially competing with green algae for these latter wavelengths. Strategies need to be devised to
either maintain the appropriate biomass ratio of the two organisms as suspensions in the same
reactor, or to physically separate them in the same photoreactor via immobilization of one or both
cultures. The competition for organic carbon substrates between two organisms in the same medium
also needs to be investigated.
AX. Concentration/Processing of Cell Biomass. In an integrated system, cell biomass from
either green algae/cyanobacteria or photosynthetic bacteria can serve as the substrate for dark
fermentation. The green algal and cyanobacterial cell walls are made mostly of glycoproteins, which
are rich in arabinose, mannose, galactose and glucose. Purple photosynthetic bacterial cell walls
contain peptidoglycans (carbohydrate polymers cross-linked by protein, and other polymers made of
carbohydrate protein and lipid). Pretreatment of cell biomass may be necessary to render it more
suitable for dark fermentation. Methods for cell concentration and processing will depend on the
type of organism used and how the biological system is integrated.

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3.1.5 Technical Task Descriptions

The technical task descriptions and the barriers associated with each task are presented in Table
3.1.14. Concerns regarding safety and environmental effects will be addressed within each task in
coordination with the appropriate Program element.

Table 3.1.14. Technical Task Descriptions (continued)

Task Description Barriers

Low-Cost, Distributed Production of Hydrogen from Natural Gas

ƒ Develop advanced small-scale reformer technology for greater efficiency, selectivity,
and durability.
ƒ Develop advanced water-gas shift catalysts that are more efficient and impurity
tolerant. Evaluate strategies for improving conventional water-gas-shift catalysts and
reactors, including single-stage shift. A, B, C, D,
1
ƒ Develop advanced technology that integrates process steps and energy to minimize E, F
capital, unit size/footprint, and energy use in an intensified process.
ƒ Utilize Design for Manufacture and Assembly (DFMA) to design appliance type units
for high-throughput low-cost manufacture.
ƒ Design for robust operations that minimize maintenance and process monitoring
needs.
Distributed Reforming of Renewable Liquid Feedstocks
ƒ Analyze and research options for alternative renewable feedstocks (e.g., ethanol,
methanol, sugars, sugar alcohols, bio-oils, bio-based Fischer Tropsch liquids) for
distributed production. A, B, C, D,
2 ƒ Utilizing the technology concepts developed for distributed natural gas reforming, E, F
develop efficient, integrated, compact, robust process technology for bio-derived
liquid feedstocks.
ƒ Explore novel technology for reforming bio-derived renewable liquid feedstocks that
could result in a cost breakthrough.

Advanced Electrolysis Technologies to Reduce Cost and Increase Efficiency

ƒ Evaluate low cost electrolysis pathways by developing a model for analyzing various
options for low cost renewable and nonrenewable electricity and then analyzing
distributed and central electrolysis
ƒ Reduce distributed electrolyzer capital and operating costs by reducing cell stack cost
3 and increasing energy efficiency, developing novel compression designs, integrating G, H, I, J
system components, and developing efficient manufacturing process technology.
ƒ Develop central renewable integrated electrolysis technologies by evaluating viable
renewable electricity integration approaches, developing advanced power electronics
interface components, developing a stack module pilot scale (250 - 500 kW)
electrolysis system suitable for renewable and grid electricity integration, and
integrating and verifying feasibility of renewable hydrogen production at pilot scale.

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Table 3.1.14. Technical Task Descriptions (continued)

Task Description Barriers

Separation and Purification Systems (Cross-Cutting Research)

ƒ Develop a membrane reactor system that combines water-gas shift reaction for
hydrogen production with a membrane for hydrogen separation and purification in a
single step to achieve reductions in system operations and maintenance costs as well
as reductions in overall system capital costs. A, B, C, E,
ƒ Investigate new lower-cost alloys to achieve fundamental improvements in metallic K, L, M, N,
4 membrane technology to achieve necessary hydrogen quality levels. O, P, Q, R,
ƒ Overcome embrittlement and fracture issues associated with producing high-purity T, AJ, AP,
hydrogen at high concentrations to promote system durability. AU
ƒ Verify that inorganic, metallic, and ion transport membrane systems can meet or
exceed separation targets under realistic commercial operating conditions.
ƒ Develop membranes that optimize hydrogen and carbon dioxide selectivity.
ƒ Develop integrated membrane/reactor systems for reforming.
Hydrogen Production from Biomass Gasification/Pyrolysis
ƒ Reduce the cost and increase the feedstock flexibility of biomass feedstock
preparation (e.g., handling, size reduction, etc.)
ƒ Research and develop more cost-effective, efficient, and robust biomass product gas
clean-up technologies for feeding into reforming operations, including hot-gas clean-
up, tar cracking, and other related technologies. (This will be coordinated with the
Office of Fossil Energy for coal-gasifier product gas clean-up technologies and with
the EERE Biomass Program.)
ƒ Investigate opportunities for catalyst and reactor improvement for tar cracking,
reforming and conditioning of biomass producer gases.
5 ƒ Improve process overall heat integration and improve hydrogen yields and
S, T
selectivities to improve energy efficiency and reduce cost.
ƒ Intensify and reduce the capital cost by combining/integrating process steps and
operations. This could include single step water-gas shift with an integrated
membrane, combining shift and reforming in one operation, combining gasification,
tar cracking, and reforming in one operation, etc.
ƒ Investigate and develop alternative biomass gasification technology approaches such
as biomass hydrolysis followed by aqueous phase reforming.
ƒ Verify an integrated biomass gasification system for hydrogen production at targeted
costs.

High-Temperature, Solar-Driven, Thermochemical Processes

ƒ Evaluate and research potential high-temperature, solar driven thermochemical
water-splitting cycles and down-select to the most promising cycles.
ƒ Develop lower capital cost solar heliostat, secondary concentrators and solar tower
technology. (This will leverage the efforts in the EERE Solar Program.)
ƒ Develop cost-effective, high-temperature materials compatible with thermochemical
6 processes. U, V, W, X
ƒ Develop cost-effective solar receivers, heat transfer medium and systems, and
reactors.
ƒ Develop a viable integrated, solar-driven high-temperature thermochemical water-
splitting process
ƒ Verify an integrated, solar-driven high-temperature thermochemical water-splitting
cycle with targeted costs.

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Table 3.1.14. Technical Task Descriptions (continued)

Task Description Barriers

Development of Semiconductor Materials for Photoelectrochemical Hydrogen

Production
ƒ Develop and optimize the current state-of-the-art materials for meeting near term
efficiency and durability targets.
7 ƒ Discover, utilizing combinatorial or other screening methods, new materials for Y, Z, AB
meeting long-term efficiency, durability, and cost targets.
ƒ Develop cost-effective synthesis techniques for fabricating the most promising
semiconductor materials.
ƒ Develop accelerated screening protocols to evaluate and validate long-term material
efficiencies and durability.

Development of PEC Device and System Auxiliary Material

ƒ Determine the functional requirements for auxiliary materials including protective
8 coatings, catalytic coatings, photoelectrode substrates, hydrogen impervious AA
materials, and photovoltaic layer materials.
ƒ Discover, develop, and test materials to facilitate PEC device and systems
development

Material Configurations and Device Engineering for Photoelectrochemical

Hydrogen Production
ƒ Evaluate device configurations, including multi-junction configurations and other
9 advanced designs, for improved efficiency and durability and lower device cost. Y, Z, AB, AC
ƒ Develop and optimize the most promising device configurations.
ƒ Develop cost-effective fabricating techniques that are scalable and manufactureable
for the most promising materials systems, devices, and configurations.
Systems Development for Photoelectrochemical Hydrogen Production
ƒ Design reactor systems to optimize light-capture efficiency, hydrogen production, gas
collection and reactor life – including utilization of novel geometries and electrolyte
options.
ƒ Identify or develop auxiliary materials and components necessary for
photoelectrochemical hydrogen production systems, including cost effective
10 transparent, hydrogen-impermeable materials for reactors.
AD
ƒ Develop accelerated testing protocols to evaluate and validate long-term system
efficiencies and durability.
ƒ Apply economic modeling tools for predicting cost potentials for photolytic production
technologies.
ƒ Develop methods to overcome diurnal operation limitations.

Naturally Occurring Biological Hydrogen Production

ƒ Research to discover naturally occurring microorganisms with characteristics
necessary for biological hydrogen production. This research includes naturally
11 occurring microorganisms and hydrogenase enzymes that are O2 tolerant and AF
produce hydrogen efficiently, nitrogenase enzymes that tolerate elevated nitrogen
levels, and cellulolytic fermentative microbes that allow for higher H2 molar yield
selected; microorganisms with the most promising water-splitting capability; and
microorganisms with the most promising fermentative hydrogen-producing capability.

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Table 3.1.14. Technical Task Descriptions (continued)

Task Description Barriers

Molecular and Physiological Engineering of Organisms for Photolytic Hydrogen

Production from Water
ƒ Generate organisms that are O2-tolerant, have increased light conversion efficiency,
allow more efficient photosynthetic electron transport toward H2, and eliminate
12 competing pathways for enhanced H2 production. Eliminate H2 uptake pathways in AG, AH, AI
cyanobacteria.
ƒ Research and develop systems in which water photolysis occurs under anaerobic
conditions (i.e., in which the P/R ratio is ≤1). Test different methods to achieve that
ratio without affecting H2 production (priority for the development of an integrated
system). Incorporate elements from the first bullet, if necessary.
12
Systems Engineering for Photolytic Hydrogen Production from Water
ƒ Optimize photoreactor material and system designs.
13 ƒ Discover and develop cost-effective, transparent, H2-impermeable materials for AJ, AK
photolytic production of H2.
ƒ Develop hydrogen collection and gas-separation technologies.
ƒ Verify economic and technical viability of continuous hydrogen production.

Molecular Engineering of Organisms for Photosynthetic Bacterial Hydrogen

Production
ƒ Increase the useful portion of the solar spectrum beyond the visible and into the
infrared by co-cultivating green algae/cyanobacteria and photosynthetic bacterial
(priority for the development of an integrated system). AL, AM, AN,
14 ƒ Generate photosynthetic bacteria that have increased sunlight conversion efficiency AO
and display more efficient photosynthetic electron transport. Eliminate competitive
pathways such as H2 oxidation and polymer accumulation. Engineer organisms that
have a functional nitrogenase at elevated nitrogen-nutrient concentration. Investigate
the H2-production activity and solar efficiency of organisms containing alternative
nitrogenases.

Systems Engineering for Photosynthetic Bacterial Hydrogen Production

ƒ Optimize photoreactor material and system designs.
15 ƒ Discover and develop cost effective, transparent, H2-impermeable materials for AP, AQ
photosynthetic bacterial H2 production.
ƒ Develop H2-collection and gas-separation technologies.
ƒ Verify economic and technical viability of continuous H2 production.

Molecular Engineering of Organisms for Dark Fermentative Hydrogen Production

ƒ Eliminate competing pathways for H2 production.
ƒ Bioprospect for cellulolytic microbes that can ferment cellulose along with mixed
16 sugars and for organisms with pathways that allow for higher H2 molar yield. AR, AS, AT
Investigate fermentation of green alga/photosynthetic bacteria cell biomass from the
co-culture for H2 production. Investigate the potential production of toxins by different
fermentative organisms that could prevent integration with other components of the
overall system.

12The Hydrogen Program will rely on and collaborate with the DOE EERE Solar Program for the advancement of
concentrated solar energy technology

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2007

Technical Plan — Production

Table 3.1.14. Technical Task Descriptions (continued)

Task Description Barriers

Systems Engineering for Dark Fermentative Hydrogen Production

ƒ Develop catalytic degradation processes of cell biomass to be more suitable for the
subsequent dark fermentation. Industrial-scale enzymes, or chemical processes,
need to be defined that can be applied in large scale for the catalytic breakdown of
17 these cell wall biopolymers to their monomeric constituents. Dark anaerobic AU
fermentations for the production of H2 can then utilize the resulting sugars as a
suitable feedstock.
ƒ Develop H2-collection and gas-separation technologies.
ƒ Develop methanogen management approaches.

Integrated Biological Hydrogen Production (dependent on configuration used)

ƒ Investigate the best way to integrate anaerobic water photolysis (green algal and/or
cyanobacterial H2 production) with photosynthetic bacterial H2 production. This could
involve co-cultivation of organisms or immobilized cultures.
ƒ Determine the efficacy of green algae/cyanobacteria and photosynthetic bacteria to
18 metabolize different exogenous organic carbon substrates. AV, AW, AX
ƒ Regulate competition (for sunlight and/or nutrients) between different organisms in
the case of co-cultivation, and eliminate transfer of potential cell-growth inhibitors
from the fermentor to the photoreactors.
ƒ Investigate low-cost methods to concentrate/process organisms in suspension, as
necessary.

3.1.6 Milestones
The following chart shows the interrelationship of milestones, tasks, supporting inputs from other
Program elements, and technology outputs for the Hydrogen Production Program element from FY
2006 through FY 2018. The input-output relationships are also summarized in Appendix B.

Page 3.1 - 36 Multi-Year Research, Development and Demonstration Plan

 Hydrogen Production Milestone Chart

FY2006 FY2007 FY2008 FY2009 FY2010 FY2011 FY2012 FY2013 FY2014 FY2015 FY2016 FY2017 FY2018

A1

A0 M4

C1 V9 P4 P5
1 C8
P1 P3 F1 2 3

Task 1: Low-Cost, Distributed Production of Hydrogen from Natural Gas

A1

A0

C1 P6 M5
F1
P2 P3 V9 C8 6
4 5

Task 2: Distributed Reforming of Renewable Liquid Feedstocks

A1 9
A0 P8
P3 11
C8 P7
C1 7 V9 M6 8 10

Task 3: Advanced Electrolysis Technologies to Reduce Cost and Increase Efficiency

13

12 14 15 16 17

Task 4: Separation and Purification Systems (Cross-Cutting Research)

A1 P9

18 19 20 21
C1 A0 C8

Task 5: Hydrogen Production from Biomass Gasification/Pyrolysis

Milestone Input Output Go/No-Go Multi-Year RD&D Plan Page 3.1 - 37

 Hydrogen Production Milestone Chart

FY2006 FY2007 FY2008 FY2009 FY2010 FY2011 FY2012 FY2013 FY2014 FY2015 FY2016 FY2017 FY2018

22 23 24 25

Task 6: High-Temperature, Solar-Driven, Thermochemical Processes

26
27 28 30
29 31 32

Task 7: Development of Semiconductor Materials for Photoelectrochemical Hydrogen Production

29 30 31 32

Task 8: Development of PEC Device and System Auxiliary Material

29 30 31 32

Task 9: Material Configurations and Device Engineering for Photoelectrochemical Hydrogen Production

29 30 31 32

Task 10: Systems Development for Photoelectrochemical Hydrogen Production

33 34

Task 11: Naturally Occurring Biological Hydrogen Production

37 43

36 42 45
35 38 39 40 41 44

Task 12: Molecular and Physiological Engineering of Organisms for Photolytic Hydrogen Production from Water

Milestone Input Output Go/No-Go Multi-Year RD&D Plan Page 3.1 - 38

 Hydrogen Production Milestone Chart

FY2006 FY2007 FY2008 FY2009 FY2010 FY2011 FY2012 FY2013 FY2014 FY2015 FY2016 FY2017 FY2018

46

45

Task 13: Systems Engineering for Photolytic Hydrogen Production from Water

49 53

48 52 54

47 50 51 46

Task 14: Molecular Engineering of Organisms for Photosynthetic Bacterial Hydrogen Production

54
55 46

Task 15: Systems Engineering for Photosynthetic Bacterial Hydrogen Production

49 56 57
Task 16: Molecular Engineering of Organisms for Dark Fermentative Hydrogen Production

57

Task 17: Systems Engineering for Dark Fermentative Hydrogen Production

57

45
54

Task 18: Integrated Biological Hydrogen Production (dependent on configuration used)

Milestone Input Output Go/No-Go Multi-Year RD&D Plan Page 3.1 - 39

39
2007

Technical Plan — Production

Task 1: Low-Cost, Distributed Production of Hydrogen from Natural Gas

1 Verify feasibility of achieving $3.00/gge (delivered) from distributed natural gas. (3Q, 2006)

2 Verify feasibility of achieving $2.50/gge (delivered) from distributed natural gas. (4Q, 2010)

3 Verify feasibility of achieving $2.00/gge (delivered) from distributed natural gas. (4Q, 2015)

Task 2: Distributed Reforming of Renewable Liquid Feedstocks

4 Down-select research for distributed production from distributed renewable liquids. (4Q, 2010)

5 Verify feasibility of achieving $3.80/gge (delivered) from distributed renewable liquids. (4Q, 2012)

6 Verify feasibility of achieving less than $3.00/gge (delivered) from bio-derived renewable liquid fuels
(4Q, 2017)

Task 3: Advanced Electrolysis Technologies to Reduce Cost and Increase Efficiency

7 Establish a wind to hydrogen research, development and demonstration facility to allow national
lab/industry collaboration in renewable electrolysis technology. (3Q, 2007)

8 Verify feasibility of achieving $3.10/gge (plant gate) from central wind electrolysis. (4Q, 2012)

9 Verify feasibility of achieving $3.70/gge (delivered) from distributed electrolysis. (4Q, 2012)

10 Verify feasibility of achieving <$2.00/gge (plant gate) from central wind electrolysis. (4Q, 2017)

11 Verify feasibility of achieving <$3.00/gge (delivered) from distributed electrolysis. (4Q, 2017)

Task 4: Separation and Purification Systems (Cross-Cutting Research)

12 Determine if membrane separation technology can be applied to natural gas distributed reforming.
(4Q, 2008)

13 Down-select separation technology for development in distributed natural gas reforming. (4Q, 2008)

14 Demonstrate pilot-scale use of integrated separation (membrane) reactor system for natural gas.
(4Q, 2009)

15 Down-select separation technology for distributed bio-derived renewable liquid feedstocks

reforming. (4Q, 2010)

16 Demonstrate pilot-scale use of integrated separation (membrane) reactor system for renewable
feedstocks. (1Q, 2012)

17 Verify 2015 membrane cost and performance targets. (4Q, 2015)

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 2007

Technical Plan — Production

Task 5: Hydrogen Production from Biomass Gasification/Pyrolysis

18 Go/No-Go decision on central aqueous phase reforming approach to biomass gasification.

(4Q, 2009)

19 Verify 2012 cost and energy efficiency targets through the operation of an integrated biomass
gasification development unit. (4Q, 2012)

20 Laboratory research results project to achieving 2017 cost and energy efficiency targets. (4Q, 2015)

21 Verify 2017 cost and energy efficiency targets in an integrated pilot operation. (4Q, 2017)

Task 6: High-Temperature, Solar-Driven, Thermochemical Processes

22 Down-select to 5-10 promising high-temperature solar-driven thermochemical cycles for R&D based
on analysis and initial laboratory work. (4Q, 2006)

23 Verify the successful on-sun operation of a promising high-temperature solar-driven thermochemical

cycle that projects to the 2012 cost and efficiency targets. (4Q, 2012)

24 Laboratory research results project to achieving 2017 cost and energy efficiency targets. (4Q, 2015)

25 Verify 2017 cost and energy efficiency targets in an integrated on-sun pilot operation. (4Q, 2017)

Task 7: Development of Semiconductor Materials for Photoelectrochemical Hydrogen Production

26 Complete structure and initial data population of a photoelectrochemical materials database.

(4Q, 2007)

27 Establish standard cell and testing protocols for PEC materials for validation efficiencies. (4Q, 2007)

28 Install testing laboratory for the standard cell and testing protocol for PEC materials. (4Q, 2009)

29 Update technoeconomic analysis on the projected technology. (3Q, 2007)

30 Update technoeconomic analysis on the projected technology. (4Q, 2010)

31 Identify materials/systems with a 2.3-eV useable semiconductor bandgap, 8% plant solar-to-

hydrogen efficiency, and projected durability of 1,000 hours. (4Q, 2013)

32 Build a consensus, lab-scale PEC panel based on best available 2013 technology to validate
technoeconomic analysis. (4Q, 2015)

Multi-Year Research, Development and Demonstration Plan Page 3.1 - 41

2007

Technical Plan — Production

Task 8: Development of PEC Device and System Auxiliary Material

29 Update technoeconomic analysis on the projected technology. (3Q, 2007)

30 Update technoeconomic analysis on the projected technology. (4Q, 2010)

31 Identify materials/systems with a 2.3-eV useable semiconductor bandgap, 8% plant solar-to-

hydrogen efficiency, and projected durability of 1,000 hours. (4Q, 2013)

32 Build a consensus, lab-scale PEC panel based on best available 2013 technology to validate
technoeconomic analysis. (4Q, 2015)

Task 9: Material Configurations and Device Engineering for Photoelectrochemical

Hydrogen Production

29 Update technoeconomic analysis on the projected technology. (3Q, 2007)

30 Update technoeconomic analysis on the projected technology. (4Q, 2010)

31 Identify materials/systems with a 2.3-eV useable semiconductor bandgap, 8% plant solar-to-

hydrogen efficiency, and projected durability of 1,000 hours. (4Q, 2013)

32 Build a consensus, lab-scale PEC panel based on best available 2013 technology to validate
technoeconomic analysis. (4Q, 2015)

Task 10: Systems Development for Photoelectrochemical Hydrogen Production

29 Update technoeconomic analysis on the projected technology. (3Q, 2007)

30 Update technoeconomic analysis on the projected technology. (4Q, 2010)

31 Identify materials/systems with a 2.3-eV useable semiconductor bandgap, 8% plant solar-to-

hydrogen efficiency, and projected durability of 1,000 hours. (4Q, 2013)

32 Build a consensus, lab-scale PEC panel based on best available 2013 technology to validate
technoeconomic analysis. (4Q, 2015)

Task 11: Naturally Occurring Biological Hydrogen Production

33 Identify 5 naturally occurring microorganisms with characteristics necessary for biological hydrogen
production for further applied research. (4Q, 2008)

34 Identify 5 additional naturally occurring microorganisms with characteristics necessary for biological
hydrogen production for further applied research. (4Q, 2010)

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 2007

Technical Plan — Production

Task 12: Molecular and Physiological Engineering of Organisms for Photolytic

Hydrogen Production from Water

35 Identify or generate an Fe-hydrogenase with a half-life of 5 min in air for photolytic hydrogen
production. (4Q, 2011)

36 Produce one cyanobacterial recombinant evolving H2 through an O2-tolerant NiFe-hydrogenase.

(4Q, 2011)

37 Increase the duration of H2 production by immobilized, sulfur-deprived algal cultures to 40 days.

(4Q, 2011)

38 Complete research to develop a photosynthetically efficient green alga/cyanobacterial system in

which the P/R ratio is < 2. (4Q, 2012)

39 For photolytic hydrogen production, achieve 15% primary utilization efficiency of incident solar light
energy (E0*E1), 2% efficiency of incident light energy to H2 from water (E0*E1*E2), and 30 min (O2
tolerant system) duration of continuous photoproduction. (4Q, 2013)

40 Identify or generate an Fe-hydrogenase with a half life of 30 min in air for photolytic hydrogen
production. (4Q, 2015)

41 Complete research to regulate growth/competition between different organisms in co-cultivation

(e.g., to maintain optimal Chl/Bchl ratios). (4Q, 2017)

42 Complete research to identify cell-growth inhibitors and eliminate transfer of such compounds from
bacterial fermentors to photoreactors. (4Q, 2017)

43 Complete research to develop a photosynthetically efficient green alga/cyanobacterial system in

which the P/R ratio is ~ 1. (4Q, 2017)

44 Demonstrate H2 production in air in a cyanobacterial recombinant. (4Q, 2018)

45 For photolytic hydrogen production, achieve 20% primary utilization efficiency of incident solar light
energy (E0*E1), 5% efficiency of incident light energy to H2 from water (E0*E1*E2), 4 h (O2 tolerant)
duration of continuous photoproduction, and 2 h O2 tolerance (half-life in air) at a projected hydrogen
production cost of less than $4/kg, with projected research improvements that will achieve costs that
are competitive with traditional fuels for transportation applications and with other non-biological
technologies for central hydrogen production. (4Q, 2018)

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2007

Technical Plan — Production

Task 13: Systems Engineering for Photolytic Hydrogen Production from Water

For photolytic hydrogen production, achieve 20% primary utilization efficiency of incident solar light
energy (E0*E1), 5% efficiency of incident light energy to H2 from water (E0*E1*E2), 4 h (O2 tolerant)
duration of continuous photoproduction, and 2 h O2 tolerance (half-life in air) at a projected hydrogen
45
production cost of less than $4/kg, with projected research improvements that will achieve costs that
are competitive with traditional fuels for transportation applications and with other non-biological
technologies for central hydrogen production. (4Q, 2018)

Identify materials/systems with 12% chemical conversion process efficiency, 10% plant solar-to-
46
hydrogen efficiency, projected durability of 5,000 hours and cost of hydrogen of $50/gge. (4Q, 2018)

Task 14: Molecular Engineering of Organisms for Photosynthetic Bacterial Hydrogen Production

46 Identify materials/systems with 12% chemical conversion process efficiency, 10% plant solar-to-
hydrogen efficiency, projected durability of 5,000 hours and cost of hydrogen of $50/gge. (4Q, 2018)

47 Complete research to generate photosynthetic bacteria that have 50% smaller (compared to wild-
type) Bchl antenna size and display increased sunlight conversion efficiency. (4Q, 2012)

48 Complete research to engineer photosynthetic bacteria with a 30% expression level of a functional
nitrogenase/hydrogenase at elevated nitrogen-carbon ratios (expression level is defined relative to
that detected at low N:C ratios). (4Q, 2012)

49 Complete research to inactivate competitive uptake of H2 by hydrogenase. (4Q, 2012)

50 For photosynthetic bacterial hydrogen production, achieve 3% efficiency of incident solar light
energy to H2 (E0*E1*E2) from organic acids, and 50% of maximum molar yield of carbon conversion
to H2 (depends on nature of organic substrate). (4Q, 2013)

51 Complete research to generate photosynthetic bacteria that have 70% smaller (compared to wild-
type) Bchl antenna size and display increased sunlight conversion efficiency. (4Q, 2017)

52 Complete research to engineer photosynthetic bacteria with a 60% expression level of a functional
nitrogenase/hydrogenase at elevated nitrogen-carbon ratios (expression level is defined relative to
that at low N:C ratios). (4Q, 2017)

53 Complete research to inactivate the photosynthetic bacterial metabolic pathway leading to polymer
accumulation that competes with H2 production. (4Q, 2017)

54 For photosynthetic bacterial hydrogen production, achieve 4.5% efficiency of incident solar light
energy to H2 (E0*E1*E2) from organic acids, and 65% of maximum molar yield of carbon conversion
to H2 (depends on nature of organic substrate) at a projected hydrogen production cost of less than
$4/kg, with projected research improvements that will achieve costs that are competitive with
traditional fuels for transportation applications and with other non-biological technologies for central
hydrogen production. (4Q, 2018)

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Technical Plan — Production

Task 15: Systems Engineering for Photosynthetic Bacterial Hydrogen Production

46 Identify materials/systems with 12% chemical conversion process efficiency, 10% plant solar-to-
hydrogen efficiency, projected durability of 5,000 hours and cost of hydrogen of $50/gge. (4Q, 2018)

54 For photosynthetic bacterial hydrogen production, achieve 4.5% efficiency of incident solar light
energy to H2 (E0*E1*E2) from organic acids, and 65% of maximum molar yield of carbon conversion
to H2 (depends on nature of organic substrate) at a projected hydrogen production cost of less than
$4/kg, with projected research improvements that will achieve costs that are competitive with
traditional fuels for transportation applications and with other non-biological technologies for central
hydrogen production. (4Q, 2018)

Complete research to determine the efficacy of green algae/cyanobacteria and photosynthetic

55
bacteria to metabolize carbon substrates (C<4) and produce H2 in co-cultivation. (4Q, 2012)

Task 16: Molecular Engineering of Organisms for Dark Fermentative Hydrogen Production

49 Complete research to inactivate competitive uptake of H2 by hydrogenase. (4Q, 2012)

56 For dark fermentative hydrogen production, achieve 4 molar yield of H2 production from glucose.
(4Q, 2013)

57 For dark fermentative hydrogen production, achieve 6 molar yield of H2 production from glucose at a
projected hydrogen production cost of less than $4/kg, with projected research improvements that
will achieve costs that are competitive with traditional fuels for transportation applications and with
other non-biological technologies for central hydrogen production. (4Q, 2018)

Task 17: Systems Engineering for Dark Fermentative Hydrogen Production

57 For dark fermentative hydrogen production, achieve 6 molar yield of H2 production from glucose at a
projected hydrogen production cost of less than $4/kg, with projected research improvements that
will achieve costs that are competitive with traditional fuels for transportation applications and with
other non-biological technologies for central hydrogen production. (4Q, 2018)

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2007

Technical Plan — Production

Task 18: Integrated Biological Hydrogen Production (dependent on configuration used)

For photolytic hydrogen production, achieve 20% primary utilization efficiency of incident solar light
energy (E0*E1), 5% efficiency of incident light energy to H2 from water (E0*E1*E2), 4 h (O2 tolerant)
duration of continuous photoproduction, and 2 h O2 tolerance (half-life in air) at a projected hydrogen
45
production cost of less than $4/kg, with projected research improvements that will achieve costs that
are competitive with traditional fuels for transportation applications and with other non-biological
technologies for central hydrogen production. (4Q, 2018)

54 For photosynthetic bacterial hydrogen production, achieve 4.5% efficiency of incident solar light
energy to H2 (E0*E1*E2) from organic acids, and 65% of maximum molar yield of carbon conversion
to H2 (depends on nature of organic substrate) at a projected hydrogen production cost of less than
$4/kg, with projected research improvements that will achieve costs that are competitive with
traditional fuels for transportation applications and with other non-biological technologies for central
hydrogen production. (4Q, 2018)

57 For dark fermentative hydrogen production, achieve 6 molar yield of H2 production from glucose at a
projected hydrogen production cost of less than $4/kg, with projected research improvements that
will achieve costs that are competitive with traditional fuels for transportation applications and with
other non-biological technologies for central hydrogen production. (4Q, 2018)

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Technical Plan — Production

Outputs
P1 Output to Technology Validation: Hydrogen production technology for distributed systems using
natural gas with projected cost of $3.00/gge hydrogen at the pump, untaxed, assuming 500 units
of production per year. (4Q, 2005)
P2 Output to Delivery, Storage, Fuel Cells, and Technology Validation: Assessment of H2 quality cost
and issues relating to hydrogen production. (4Q, 2006)
P3 Output to Technology Validation and Systems Integration: Impact of hydrogen quality on cost and
performance. (3Q, 2007)
P4 Output to Technology Validation and Manufacturing: Hydrogen production technologies for
distributed systems using natural gas with projected cost of $2.50/gge hydrogen at the pump,
untaxed, assuming 500 manufactured units per year. (4Q, 2010)
P5 Output to Technology Validation and Systems Integration: Hydrogen production technologies for
distributed systems using natural gas with projected cost of $2.00/gge hydrogen at the pump,
untaxed, assuming 500 manufactured units per year. (4Q, 2015)
P6 Output to Technology Validation and Manufacturing: Hydrogen production technologies for
distributed systems using renewable liquids with projected cost of $3.80/gge hydrogen at the
pump, untaxed, assuming 500 manufactured units per year. (4Q, 2012)
P7 Output to Technology Validation and Manufacturing: System making hydrogen for $3.70/gge
(delivered) from distributed electrolysis. (4Q, 2012)
P8 Output to Technology Validation: System making hydrogen for $3.10/gge (plant gate) from central
wind electrolysis. (4Q, 2012)
P9 Output to Technology Validation: Hydrogen production system making hydrogen for $1.60/gge
from biomass at the plant gate. (4Q, 2012)

Inputs
C1 Input from Codes and Standards: Hydrogen fuel quality standard as ISO Technical Specification.
(3Q, 2006)
C8 Input from Codes and Standards: Final hydrogen fuel quality standard as ISO Standard.
(2Q, 2010)
F1 Input from Fuel Cells: Reformer results of advanced reformer development. (4Q, 2007)
V9 Input from Technology Validation: Final report on safety and O&M of three refueling stations.
(4Q, 2007)
A0 Input from Systems Analysis: Initial recommended hydrogen quality at each point in the system.
(4Q, 2007)
A1 Input from Systems Analysis: Complete techno-economic analysis on production and delivery
technologies currently being researched to meet overall program hydrogen fuel objective.
(4Q, 2007)
M4 Input from Manufacturing: Report on manufacturing of distributed reforming of natural gas
system to achieve $2.00/gge (delivered). (4Q, 2015)
M5 Input from Manufacturing: Report on manufacturing distributed reforming of bio-derived
renewable liquid fuels system to achieve $3.00/gge (delivered). (4Q, 2017)
M6 Input from Manufacturing: Report on high-volume manufacturing processes for electrolysis
membrane assemblies. (4Q, 2011)

Multi-Year Research, Development and Demonstration Plan Page 3.1 - 47