Technology White Paper 

on 

Generation of Hydrogen and 

Transportation and Transmission of Energy Generated 

on the U.S. Outer Continental Shelf to Onshore 

Minerals Management Service 

Renewable Energy and Alternate Use Program 

U.S. Department of the Interior 

Available for Downloading at http://ocsenergy.anl.gov 

May 2006 
GENERATION OF HYDROGEN AND 

TRANSPORTATION AND TRANSMISSION OF ENERGY GENERATED 

ON THE U.S. OUTER CONTINENTAL SHELF TO ONSHORE 

INTRODUCTION 

With the passage of the Energy Policy Act of 2005 (EPAct), Public Law 109-58 (H.R. 6), 

the Minerals Management Service (MMS), a bureau of the U.S. Department of the Interior, was 

given jurisdiction over Renewable Energy and Alternate Use Program projects, such as wind, 

wave, ocean current, solar energy, hydrogen generation, and projects that make alternative use of 

existing oil and natural gas platforms in Federal waters. A new program within MMS has been 

established to oversee these operations on the U.S. Outer Continental Shelf (OCS). MMS is 

developing rules to guide the application and permitting process for development of Renewable 

Energy and Alternate Use Program projects on the OCS. To apply the requirements of the 

National Environmental Policy Act (NEPA) in the establishment of national offshore alternate 

energy development policy and a national alternate-energy-related use program and rules, MMS 

plans to prepare a programmatic environmental impact statement (Programmatic EIS). The 

Programmatic EIS process will (1) provide for public input concerning the scope of national 

issues associated with offshore alternate-energy-related use activities; (2) identify, define, and 

assess generic environmental, sociocultural, and economic impacts associated with offshore 

alternate-energy-related use activities; (3) evaluate and establish effective mitigation measures 

and best management practices to avoid, minimize, or compensate for potential impacts; and 

(4) facilitate future preparation of site-specific NEPA documents—subsequent NEPA documents 

prepared for site-specific Renewable Energy and Alternate Use Program projects will tier off of 

the Programmatic EIS and Record of Decision. The Programmatic EIS will evaluate the issues 

associated with development, including all foreseeable potential monitoring, testing, commercial 

development, operations, and decommissioning activities in Federal waters on the OCS. 

Information defining the issues and current technology will be obtained primarily from Federal 

research organizations, MMS, industry, and other valid sources. 

In preparation for the Programmatic EIS, MMS has developed a series of White Papers 

on topics of interest to the Renewable Energy and Alternate Use Program. The overall objective 

of the White Papers is to provide sufficient information on the prospective alternative 

technologies to support assessments of the potential environmental impacts of the technologies 

and of the viable impact mitigation strategies in the Programmatic EIS. The White Papers also 

will serve as sources of information for stakeholder outreach. 

This paper discusses the transportation of energy generated on the U.S. OCS to onshore. 

The options considered are (1) the generation of hydrogen offshore and transportation of 

hydrogen onshore and (2) the transport of electricity.1 Companion papers in the series address 

the generation of energy on the OCS from wind, waves, solar radiation, and ocean currents. 

 

1 Reference herein to any specific commercial product, process, or service by trade name, trademark, 

manufacturer, or otherwise does not represent its endorsement, recommendation, or favoring by MMS, the 

United States government, or any agency thereof. 

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CONSIDERATIONS FOR HYDROGEN AS AN ENERGY RESERVE 

 For the alternative energy sources under consideration, energy is not always produced 

when it is needed. To address the sporadic and sometimes unpredictable nature of energy 

production from these sources, methods for the interim storage of excess alternative energy must 

be developed. One currently proposed approach is the use of hydrogen (H2) produced in OCS 

alternative energy facilities. Hydrogen can be generated on location on a variety of scales; it can 

then be compressed and stored in tanks, transported in tanks or pipelines, and later consumed by 

vehicles for power or by industrial facilities or generating stations to produce process steam or 

provide electricity. No serious proposals have yet been made to use other energy storage 

technologies, such as batteries, flywheels, superconducting magnetic energy, compressed air, 

pumped hydropower, and supercapacitors, with OCS alternative energy facilities on the scale of 

a small power generation facility in a marine environment. 

If hydrogen is to be used as a means of energy storage for potential OCS energy 

generation, options for the locations and designs of the conversion facilities must be considered. 

For example, hydrogen could be produced offshore at the point of energy generation in a colocated facility, or it could be produced at an onshore location near the offshore power 

generation facility. Any final design would have to take into account the general location and 

type of the alternative energy source and the location of the area for which it is providing energy. 

Hydrogen production at a co-located facility would require additional construction in a 

marine environment and equipment capable of long-term function in an offshore setting. Routine 

servicing of the hydrogen generation plant would require personnel travel and work in the marine 

environment. Additionally, if multiple power generation units were involved (such as the 

individual turbines found on a wind energy facility), a hydrogen production unit could be 

associated with each turbine or with the entire facility. In the former case, consolidation of the 

hydrogen would be necessary for shipment off-site; in the latter case, electrical connections 

between the individual turbines and the hydrogen production unit would be required. 

Hydrogen production at a nearby onshore location would offer particular advantages 

when operated in conjunction with OCS energy sources already connected to a land-based 

electric power grid. In such systems, electricity from OCS sources could be diverted for use in 

hydrogen production when available energy on the grid from conventional sources was sufficient 

to meet existing power demands. 

HYDROGEN GENERATION 

 The alternative energy sources under consideration for the OCS (i.e., wind, wave, ocean 

current, and solar) involve processes that directly produce electricity. If this energy is to be 

stored, the electricity can be used to produce hydrogen. This conversion can be accomplished 

using electrolysis. For solar power, electricity may be generated with the use of a photovoltaic 

cell, but hydrogen may also be generated directly through one of two photolytic processes. 

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Electrolysis 

Electrolysis is the process of producing hydrogen and oxygen from water in an 

electrochemical cell. Two types of electrochemical methods, alkaline or proton exchange 

membrane (PEM), are used in commercially available equipment commonly referred to as 

electrolyzers (Ivy 2004). An alkaline electrolyzer immerses the two electrodes, the cathode and 

the anode, into an aqueous alkaline electrolyte, typically a solution of sodium or potassium 

hydroxide, and a voltage is applied across the electrodes. The resulting migration of ions in 

solution results in the production of hydrogen at the cathode and oxygen at the anode according 

to: 

− −

2 2 +→+ 4244 OHHeOH Cathode reaction − − 4 2 2 ++→ 42 eOHOOH Anode reaction 

In a PEM electrolyzer, the mobile ion is a proton in an electrolyte that is a proton-conducting 

polymer membrane. The reactions at the electrodes in this case are: 

→+ 244 HeH 2

−+ Cathode reaction −+ 2 2 2 ++→ 44 eHOOH Anode reaction 

Currently, the best conversion efficiency (i.e., overall system efficiency for converting electrical 

power to power stored as hydrogen) for commercial electrolyzers is approximately 70% 

(Ivy 2004; DOE 2005a). 

 Solid oxide electrolyzers are currently under development. This method uses a solid 

ceramic material as the electrolyte that allows the transmission of negatively charged oxygen 

ions at elevated temperatures. Water at the cathode reacts with electrons to form hydrogen gas 

and negatively charged oxygen ions. The oxygen ions migrate through the electrolyte to the 

anode where they react to form oxygen gas and give up electrons. Operation occurs at 

temperatures (500 to 800°C) conducive to oxygen ion migration in the ceramic electrolyte. 

Operation at these elevated temperatures reduces the amount of electrical energy required to 

produce hydrogen from water. However, a heat source is needed, making this option more 

attractive in combination with an energy source that is capable of producing large amounts of 

heat. 

Photolytic Methods 

 Solar energy can be used to convert water to hydrogen and oxygen directly; electricity 

need not be first generated with a photovoltaic cell. This conversion can be accomplished by 

using either photoelectrochemical or photobiological methods. 

 A particular type of photoelectrochemical cell can directly dissociate water into hydrogen 

and water using specialized semiconductor materials at one or both electrodes (Lewis 2001). 

Different electrode materials work at different wavelengths of light. Research to identify waterstable semiconductor materials that have the highest efficiency in the solar spectrum is ongoing. 

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 Photobiological methods rely on the production of hydrogen by certain types of algae and 

bacteria (Melis and Happe 2004; Akkerman et al. 2002). Analogous to plants that produce 

oxygen from water as a by-product of their metabolism, these microorganisms produce 

hydrogen. Although this process is presently too slow to harness for use with offshore solar 

energy collection, researchers are investigating ways to enable this process to become an 

important piece in sustainable hydrogen production with low environmental impact. 

TRANSPORTATION OF HYDROGEN FROM THE OCS TO ONSHORE 

Offshore-generated hydrogen could be delivered to onshore facilities by several means. 

The three that have the highest potential are: 

1. Transport as gaseous hydrogen, 

2. Transport as liquid hydrogen, and 

3. Transport after incorporation into a solid or liquid “hydrogen carrier.” 

In the first two pathways, hydrogen would be transferred from the OCS to shoreline 

facilities as pure hydrogen in its molecular form (H2), either as compressed gas or as liquid, via 

pipeline, tanker, or a ship. The carrier path would use materials that would transport hydrogen in 

a form other than free H2 molecules. These materials would include liquid hydrocarbons, 

absorbents, metal hydrides, and other hydrogen-rich compounds. 

Transport as Gaseous Hydrogen 

For economic reasons, H2 would need to be compressed to be transported ashore in 

gaseous form. The actual transport could be through a pipeline that runs between a generating 

facility on the OCS and an onshore receiving facility. After arriving on land, the hydrogen would 

need to be connected to the onshore distribution and delivery system. This paper assumes that 

such a distribution and delivery system exists. The focus of this paper is limited to delivery of 

OCS-produced hydrogen to the facilities on the shoreline. 

Pipelines have been used extensively in the United States and elsewhere to transport 

natural gas and crude oil. Currently, approximately 1,000 km of dedicated hydrogen transmission 

pipelines exist in the U.S. (DOE 2005b). Some of these hydrogen pipelines were built expressly 

for hydrogen delivery, while others were previously used for natural gas or crude oil 

transmission. In addition, there are also pipelines that transport oil from offshore production 

facilities to the shore. Therefore, it is foreseeable that pipelines for transmission of hydrogen 

from an offshore alternative energy facility to an onshore point of delivery could be constructed. 

There are some technical concerns with hydrogen transport that do not exist with natural 

gas or oil. The primary concern is the potential for hydrogen to embrittle the steel and the welds 

used to fabricate the pipelines. Other potential obstacles include the need for improved seal 

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technology and techniques to control permeation and leakage in general. Because of hydrogen’s 

low molecular weight, leakage from equipment is difficult to control. At the same time, 

hydrogen, particularly high-pressure hydrogen, presents special safety concerns. The relatively 

low activation energy required for hydrogen ignition and the broad range of hydrogen 

concentrations in air that can be explosive mandate extremely low equipment leakage. Although 

these concerns are common to both offshore and onshore equipment, the explosion hazard is 

relevant only in confined air spaces. While these problems are not insurmountable, they add to 

the cost of generation, storage, delivery, and use of hydrogen. Research is ongoing to find 

cheaper and more flexible options for the handling of hydrogen. 

Compressed hydrogen can also be transported to shore in pressurized containers loaded 

on a ship or in specially designed tankers. The United States has considerable industry 

experience in handling and transporting pressurized gas cylinders; the shipment of high-pressure 

hydrogen cylinders is now commonplace. Once the specific concerns about the handling and 

leakage of hydrogen are addressed, the remaining issue is one of economics. 

Transport as Liquid Hydrogen 

The transportation of hydrogen as a liquid in molecular form requires liquefaction, which 

is a well-understood but costly operation. The liquefaction process involves cooling gaseous 

hydrogen to below −253°C using liquid nitrogen and a series of compression and expansion steps 

(FCFP 2005), a very energy-intensive process. With current technologies, this process can 

consume one-third or more of the energy contained in the hydrogen (FCFP 2005). Once 

liquefied, hydrogen would need to be stored and transported at cryogenic temperatures until it is 

ready to be vaporized to a high-pressure gaseous form for dispensing. These requirements would 

rule out the use of pipelines for transport from the OCS to the shore. Therefore, the only practical 

pathway would be via ship or tanker. 

Transport after Incorporation into a Hydrogen Carrier 

A hydrogen carrier is any substance that can be used to store and transport hydrogen in a 

chemical state other than as free diatomic hydrogen molecules (i.e., H2). An effective potential 

carrier would have the following characteristics (FCFP 2005): 

• Operate at reasonable temperatures and pressures; 

• Provide high hydrogen capacity per unit volume or mass; 

• Allow for the safe and relatively simple addition or removal of hydrogen 

at low cost and high efficiency; and 

• Be safe and environmentally benign. 

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A one- or two-way carrier could be employed. In a one-way carrier, hydrogen is added to 

the carrier at the point of initial charge and remains with the carrier until it reaches its point of 

use. At the point of use, the carrier/hydrogen combination is decomposed to yield hydrogen and 

an environmentally benign substance with no economic value. Hydrogen is used, and the 

remaining by-product is lost to the environment. An example of a one-way carrier would be 

ammonia (DOE 2006). The by-product material would be nitrogen. 

In a two-way system, the carrier would be charged with hydrogen at an OCS hydrogen 

generation station and transported to the shore. On shore, the carrier would be stripped of its 

hydrogen and sent back offshore for recharging. Whether the carrier is one-way or two-way, it 

could be transported between the offshore generating station and an onshore facility by pipeline 

(if it is in a liquid or slurry state) or by ship or tanker. Potential two-way carriers include metal 

hydrides and liquid hydrocarbons. A considerable amount of research has been conducted in the 

United States and abroad on hydrogen carriers, but no commercial-scale methods have yet been 

developed. 

TRANSMISSION OF ELECTRICITY FROM THE OCS TO ONSHORE 

Direct transmission of electricity from offshore locations is more straightforward and 

more energy efficient than the use of hydrogen as an intermediate stage, but demand is not 

always concurrent with supply. Transmission of electricity from an alternative energy source on 

the OCS to an onshore location would likely require a submarine cable. Submarine cables are 

used to provide power to island communities and are also used extensively in offshore oil and 

gas exploration to provide power, communication, and control lines to offshore platforms. 

Submarine cable technology is already used to provide electricity from offshore wind facilities to 

onshore electric power substations in Europe. 

High-voltage alternating-current (AC) electric transmission lines are typically used, but 

transmission distances are generally on the order of a few kilometers. Because the economic 

limit on high-voltage AC transmission is estimated to be between approximately 30 and 250 km 

(Wright et al. 2002), the use of high-voltage AC transmission lines would be problematic for 

offshore energy generation locations farther from land. Transmission of AC power suffers from 

losses due to capacitance and other factors, such as induced current in the shielding, that are not 

present with direct-current (DC) power transmission. 

With the same size cable, DC transmission lines can carry more power than AC lines and 

require fewer conductors. Also, the AC voltage at either end of the DC cable can be different, 

possibly eliminating the use of a transformer, and the direction and magnitude of the power flow 

can be controlled. The limiting factors for the use of high-voltage DC (HVDC) tend to be cable 

cost, laying cost, and manufacturability rather than distance (Wright et al. 2002). One of the 

larger impediments to the use of HVDC has been the lack of power electronics to convert 

between voltage levels (DC-to-DC) as is accomplished through the use of step-up and step-down 

transformers in AC power systems. New, commercialized HVDC converter technology may 

make HVDC an even more attractive option as there are already a number of HVDC submarine 

power cables in use. 

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While some alternative energy sources are better suited to AC power generation 

(i.e., wind, ocean current, or wave) and others (i.e., solar) are better suited to DC power 

generation, interconversion between AC and DC power is a relatively mature technology. The 

driving factor for the selection of AC or DC transmission to onshore facilities might be expected 

to depend on costs. 

ENVIRONMENTAL CONSIDERATIONS 

Environmental impacts that would need to be considered in evaluating the options for 

transmission of energy generated at the OCS facilities to shore would include construction and 

operation impacts associated with activities such as submarine cable installation and use, 

hydrogen generation facility construction and use, and hydrogen transport. 

Hydrogen Generation 

 The co-location of hydrogen generation and potential storage offshore with an alternative 

energy source would increase the disturbed area in the marine environment. Such a disturbance 

would be similar to that posed by an offshore oil platform (e.g., support pillars extending from a 

platform into the seafloor). However, the primary source material, water, and the primary 

by-product, oxygen, of hydrogen generation from electrolysis are environmentally friendly. In 

the case of an offshore operation, seawater would be preprocessed (i.e., desalinized) before use 

in the electrolyzer. Precautions would need to be taken to minimize any leaks or spills of 

hazardous material (e.g., gasoline or oil) associated with maintenance craft and routine facility 

operation or repair of equipment. Maintenance of the water purification and electrolysis 

equipment would pose typical industrial physical and mechanical hazards. Additional safeguards 

related to hydrogen handling would be required to mitigate hazards associated with its explosive 

nature and compressed gases or cryogenic liquids. 

Hydrogen Transport 

 Hydrogen generated at offshore locations would be sent to onshore facilities via 

pipelines, ships, or tankers. The same hydrogen-specific hazards discussed above for hydrogen 

generation apply to all transport modes. Care would have to be taken to guard against hydrogen’s 

flammable nature and leaks and embrittlement of piping and equipment. 

 The use of a hydrogen pipeline would entail proper design, installation, and operation to 

minimize environmental impacts. Pipelines may lie on or be buried below the seabed. However, 

in shallow water, typically 5 m or less, offshore pipelines must be placed below the seabed to 

avoid exposure to navigation hazards (DOT 2006). Route determination for the pipeline should 

minimize its length to reduce its impact, but other issues such as sensitive underwater habitats 

(e.g., shellfish beds), pipeline size, ease of construction, seismic faults, seabed terrain and soil, 

and physical access for inspection and repairs must also be considered. Design considerations 

include minimizing the hazards from and to boat anchors and fishing vessel activity, as well as 

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hazards from corrosion and the potential for winter ice in northern areas. Temporary disturbances 

to marine life would occur during pipeline construction and removal but would be minimal 

during operation for buried pipelines. Pipelines situated on the seafloor might cause some loss of 

seafloor habitat but would be installed to minimize migratory and feeding impacts on local 

marine life. 

 Environmental impacts associated with ship and tanker transport of H2 include normal 

vessel traffic, loading and unloading accidents, and transportation accidents. Impacts from 

normal vessel traffic would result from air emissions and surface water disturbance due to vessel 

passage and docking at the offshore facility. Vessel traffic could also result in the inadvertent 

leakage of waste, gas, or oil to the marine environment. Accidents could result in the explosive 

release of hydrogen and/or the release of materials such as waste, gas, or oil to the marine 

environment. 

Electricity Transmission 

The environmental issues from transmission of electricity from offshore alternative 

energy sources include many of the same considerations discussed above for buried pipelines, 

namely: underwater length, disturbance of sensitive underwater habitats, time and area 

associated with installation, protection against seismic faults, seabed terrain and soil, and 

physical access for inspection and repairs. An additional concern for electricity transmission 

would be the potential effects on aquatic organisms resulting from magnetic fields around the 

cables during operation. 

ECONOMIC CONSIDERATIONS 

 The costs associated with offshore power generation and the transport of electricity alone 

include the cost of the transmission cable and the components required to interconnect the cable 

with the energy source on the offshore side and the power grid onshore. As discussed, HVDC 

transmission lines may become more economically attractive as the transmission distances 

increase. Additional costs are incurred for the installation of the cable and future maintenance 

activities. 

 Generation of electricity by alternative energy sources may not always coincide with 

demand, resulting in lost energy when demand is less than the power output. However, this 

excess energy could be stored for later use if a suitable storage method is available. For any 

storage method to be practical, it must perform reliably and be economically competitive and/or 

fill a niche market. In the case of H2 generation and storage, viable processes are available for 

use. Also, extensive research on implementing a hydrogen economy, primarily in the area of 

transportation to supplant waning supplies of crude oil, is ongoing. What must be considered is 

the energy (or substitute H2 fuel) that may be lost when an alternative energy source provides 

excess power in periods of low demand. Is it economically realistic to construct and operate an 

H2 storage and transport operation in conjunction with an alternative energy source? In other 

words, would the H2 generated pay for itself? 

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 Costs associated with the use of H2 include its generation, storage, and transport. The 

electrolysis of water to produce H2 is a commercially proven technology, the cost of which is 

slowly declining as the conversion efficiency (the amount of H2 produced per amount of energy 

input) increases with improvements in electrolyzer design. It should also be recognized that a 

certain energy loss will occur when H2 is used as fuel, because no fuel cell is 100% efficient. 

Hydrogen storage at the points of generation and use requires an investment in 

compressed gas vessels, storage tanks, and equipment designed to handle hydrogen’s chemical 

and physical properties and to prevent or mitigate adverse consequences of accidental release. If 

H2 is to be stored in liquid form (with an energy density about seven times that of the 

compressed gas), transportation costs may be reduced, but liquefaction requires a high energy 

input and additional costs are incurred for cryogenic equipment. The use of H2 carriers is not yet 

a viable technology and will require an unknown investment in future research. 

 The use of pipelines for the transport of H2 is feasible, but most existing pipelines have 

been converted from the transport of oil or gas to H2 and operate at lower pressures. To support a 

higher throughput volume of H2, higher pressure operation would be needed, which would entail 

extra energy for compression of the gas. In addition to the installation, maintenance, and higher 

material costs for an H2 pipeline, the availability of the infrastructure on land for distribution and 

delivery of the H2 to users must be considered. 

A comparative evaluation of the costs of producing and delivering hydrogen on offshore 

facilities is presented in Altmann and Richert (2001). In this evaluation, hydrogen is produced by 

offshore electrolysis with the electricity having been generated via wind power. Four options for 

transporting the hydrogen to an onshore facility are considered: (1) pipeline from the offshore 

facility to the nearest large city; (2) pipeline to an onshore liquefaction center followed by truck 

transport of the liquid hydrogen to the city; (3) offshore liquefaction followed by the loading of 

standard 40-ft-long liquid hydrogen cylinders; and (4) offshore liquefaction followed by the 

loading of the liquid hydrogen onto large tanks mounted on floating barges. The first option is 

used as a reference case in this comparative assessment. 

From a capital-cost perspective, the second option is approximately 50% more expensive 

than the reference case. Most of the capital-cost differential is in the onshore liquefaction. The 

third option is approximately 150% more expensive than the reference case, principally due to 

the container, the cylinders, the larger offshore platform required, and offshore liquefaction. The 

barge option is approximately twice that of the reference case, with the capital cost difference 

primarily due to offshore liquefaction, the larger platform, and the barge. Similar results are 

observed in the comparison of the cost of the delivered hydrogen. The electrolysis costs are 

considerably higher in the liquefaction cases because much electrical energy must be generated 

to operate the liquefaction units. 

Conclusions from the above comparisons include: (1) sea transport of liquid hydrogen 

appears to be significantly more costly than pipeline transport, and (2) the pipeline costs would 

make only a modest contribution to the cost of delivered hydrogen in this specific application. 

Significant improvements and cost reductions in the liquefaction technology, and in the storage 

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and transport of liquid hydrogen, would be needed to make these options economically 

competitive with gaseous hydrogen transport via pipeline. 

SUMMARY 

 Electricity generated by alternative energy sources on the OCS can be brought onshore 

by using submarine cables that connect to the power grid. Relatively short HVAC cables, on the 

order of a few kilometers, have been used in past offshore wind facilities. However, distances 

beyond 50 km may be proposed for future sources on the OCS. At such distances, it may be 

more practical and economical to use HVDC transmission as newer HVDC converter technology 

is commercialized. 

Because the alternative energy sources do not always produce electricity during periods 

of demand, the use of H2 has been suggested as an energy storage medium. Presently, the most 

practical method for the generation of H2 from alternative energy sources is the electrolysis of 

water. (Direct photochemical or photobiological methods of H2 generation from solar energy, 

bypassing the initial production of electricity, are under investigation, but these methods are not 

currently viable on a commercial scale.) The H2 may then be stored and transported in gaseous 

form to end-use locations. Hydrogen could be liquefied for storage and transport, but such 

processing is complex and may not be cost-effective. Hydrogen carriers are under investigation 

but are not yet commercially feasible. Transport of H2 would occur in pressure vessels and/or 

pipelines to the end user. 

REFERENCES 

Akkerman, I., et al., 2002, “Photobiological Hydrogen Production: Photochemical Efficiency and 

Bioreactor Design,” International Journal of Hydrogen Energy 27:1195−1208. 

Altmann, M., and F. Richert, 2001, “Hydrogen Production at Offshore Wind Farms,” presented 

at the Offshore Wind Energy Special Topic Conference, Brussels, Belgium, December 10−12. 

FreedomCar & Fuel Partnership (FCFP), 2005, Hydrogen Technology Roadmap, Draft, April. 

Ivy, J., 2004, Summary of Electrolytic Hydrogen Production, Milestone Completion Report, 

NREL/MP-650-36734, National Renewable Energy Laboratory, Golden, Colo. 

Lewis, N.S., 2001, “Light Work with Water,” Nature 414:589−590. 

Melis, A., and T. Happe, 2004, “Trails of Green Alga Hydrogen Research⎯from Hans Gaffron 

to New Frontiers,” Photosynthesis Research 80:401−409. 

U.S. Department of Energy (DOE), 2005a, Hydrogen, Fuel Cells & Infrastructure Technologies 

Program Multi-Year Research, Development and Demonstration Plan, Office of Energy 

Efficiency and Renewable Energy, Washington, D.C. 

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U.S. DOE, 2005b, Hydrogen Pipeline Working Group Workshop: Workshop Proceedings, Office 

of Energy Efficiency and Renewable Energy, Washington, D.C. Available at http://www1.eere.

energy.gov/hydrogenandfuelcells/pdfs/hpwgw_proceed05.pdf. Accessed May 11, 2006. 

U.S. DOE, 2006, Potential Roles of Ammonia in a Hydrogen Economy. Available at 

http://www.hydrogen.energy.gov/pdfs/nh3_paper.pdf. Accessed May 10, 2006. 

U.S. Department of Transportation (DOT), 2006, “Pipeline Factsheet,” Pipeline and Hazardous 

Materials Safety Administration. Available at http://primis.phmsa.dot.gov/comm/FactSheets/

FSOffshorePipelines.htm. Accessed April 21, 2006. 

Wright, S.D., et al., 2002, “Transmission Options for Offshore Wind Farms in the United 

States,” American Wind Energy Association. Available at 

http://www.ceere.org/rerl/publications/published/2002/Transmission_Options_For_Offshore_Wi

nd_Farms_In_The_US,_AWEA_June_2002_.pdf. Accessed May 10, 2006. 

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