August 2004 • NREL/CP-520-36401

Solar Photovoltaic Hydrogen:

The Technologies and Their

Place in Our Roadmaps and
Energy Economics

L.L. Kazmerski
National Renewable Energy Laboratory

K. Broussard
Southern University

Prepared for the 19th European PV Solar Energy

Conference and Exhibition

Paris, France

June 7–11, 2004

National Renewable Energy Laboratory

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 SOLAR PHOTOVOLTAIC HYDROGEN:
THE TECHNOLOGIES AND THEIR PLACE IN OUR ROADMAPS AND ENERGY ECONOMICS

Lawrence L. Kazmerski and Kara Broussard*

National Renewable Energy Laboratory, Golden, Colorado 80401, USA
*Research Intern from Southern University, Baton Rouge, Louisiana, USA
Tel: (303) 384-6600; Fax: (303) 384-6601; e-mail: kaz@nrel.gov

ABSTRACT: Future solar photovoltaics-hydrogen systems are discussed in terms of the evolving hydrogen econ­

omy. The focus is on distributed hydrogen, relying on the same distributed-energy strengths of solar-photovoltaic

electricity in the built environment. Solar-hydrogen residences/buildings, as well as solar parks, are presented. The

economics, feasibility, and potential of these approaches are evaluated in terms of roadmap predictions on photovol­

taic and hydrogen pathways—and whether solar-hydrogen fit in these strategies and timeframes. Issues with the “hy­

drogen future” are considered, and alternatives to this hydrogen future are examined.

Keywords: solar hydrogen, system, roadmaps, electrolysis, photolysis

1. INTRODUCTION which is difficult and potentially the most costly segment

of the hydrogen energy system.
Solar electricity is real and on a path as a power of Alternatives? Just as the distributed solar-PV system
choice for world consumers [1,2]. Advances in photovol­ makes use of the economics of “electricity generation at
taic (PV) performance over the past 25 years—with crys­ point of use,” an alternative distributed hydrogen system
talline silicon more than doubling in efficiency, thin films links “production” and “delivery” at the point of use
nearly quadrupling, and concentrator cells converting [16]—distributed solar electricity and distributed solar
almost 40% of incident photon energy into electrical hydrogen. The recent U.S. National Academy study of
power—have been the foundation for credible electricity hydrogen provided a partial look at this approach, as well
generation [2–4]. History has offered strong indicators [18]. This concept can be visualized in two distinct im­
for progress and reliability. Fifty years ago, one 2-cm2 Si plementations. The first is at the individual residence or
solar cell at Bell Telephone Laboratories broke the 5%­ building level [9]. This concept expands on the zero-
efficiency mark—delivering a power of 5 mW. This last energy home with the inclusion of production, storage,
year, the industry shipped over 500 million cells having and “in-property” distribution. The primary source of
an area of more than 6 billion cm2—representing a power energy is the sun, with PV providing the electricity and
of nearly 0.75 GW [5]. That original cell still functions a with solar thermal providing for the building’s heating
half century later—and current module technology is and cooling needs. In the longer term, this would be a
warranted for 20–30 years. The versatility, clean and hybrid electricity/thermal system integrated into the
secure power, and scalability of this solar technology building structure. As the PV and solar thermal tech­
offers even more for the world energy portfolio— nologies advance, integration into the building structure
including perhaps serving as the perfect partner for our will be essential in ensuring architectural integrity and
potential hydrogen prospects [6]. The major focus herein desirability. But coincidentally, it will also maximize the
is to look at solar PV in this application—focusing on use of the building’s skin. The solar electricity is used
combining the distributed-energy delivery strengths of for (1) generating daytime electricity for the building, (2)
PV with a similar energy-distribution scheme for hydro­ providing power to the electrolyzer to produce the hydro­
gen and its related technologies to afford our future gen­ gen (and oxygen) for the fuel cell and storage, and (3)
erations with 24-hour solar-hydrogen power. supplying excess electricity to the grid. The stored hy­
drogen could even be used to fuel the “family Freedom
2. SOLAR HYDROGEN SCENARIOS Car,” in addition to providing the hydrogen for the fuel
cell (24-hour power). Thus, this concept could fulfill the
When the United States rolled out its hydrogen vision “zero-energy home” objective, but could also result in the
in 2002 [7,8] and its strategy in 2003 [9], the source of “energy-plus” residence—providing more energy than it
the hydrogen was perceived primarily to be natural gas— needs. The excess could be shared with the utility, as
an approach that hardly ignited the renewables commu­ well as with neighbors.
nity. Within a few months of the U.S. President’s an­ This situation extends into the second distributed
nouncements in his 2003 State of the Union Address, the PV/hydrogen concept: the solar hydrogen park (Fig. 1).
developing natural gas shortage has precluded this source In this approach, a number of residences, structures, and
from being the primary one—and other technologies local community buildings share the solar-collection
have come forward. Nuclear, wind, bioenergy, and solar tasks to generate the necessary electricity—and share the
have positioned themselves to serve as the energy re- hydrogen generation from a community “plant.” Thus,
sources to produce the required hydrogen [10–13]. the stored hydrogen would feed their fuel cells for night-
Among these resources, solar possesses some special time power, and community fueling stations are used for
attributes that may make it the power of choice in the hydrogen-powered automobiles, vans, and trucks.
future. If one looks at the more than 14 TW total primary Protected parking covers would also support PV (which
energy equivalent required currently worldwide—or the would not only feed into the community power, but also
26–30 TW predicted to be consumed at the coming half- be offered for electric or hybrid vehicles). Note that
century point, only solar of the renewable resources other smaller generation schemes could also be used,
could actually meet this total—and only nuclear from the which could include concentrating PV—with small para­
nonrenewables [14]. Questions about PV-for-electricity bolic dishes. Although some individual residences might
and solar-for-hydrogen production land-area require­ have problems with local zoning and/or covenants, the
ments, water use, electricity needs, and technology pro­ use of dishes, or even CSP troughs, could be landscaped
duction pathways/performances have been addressed— into visual acceptability. Such approaches are currently
with no showstoppers identified on the horizon [15–17]. being developed in Australia, where hybrid CPV-
What limitations exist? hydrogen production units have been demonstrated suc­
As centralized facilities, both concentrating cessfully. The case for the “solar hydrogen park” is that
solar power (CSP) and nuclear provide clean-generation the distribution of hydrogen is over a small distance,
thermal roadmaps toward generating economical hydro­ generating the fuel very near the point of use. In fact, the
gen [9]. Additionally, CSP, concentrating PV (CPV), efficiency of the system and the effectiveness of generat­
and flat-plate PV can meet electricity prices that are ing the hydrogen can be increased with technology evolu­
needed for large- scale electrolysis. However, all these tion—such as a thin-layer electrolyzer integrated with the
centralized approaches require long-distance delivery, PV modules (e.g., integrated into the PV/thermal roof

1
 module) and/or having pyrolysis systems integrated with the $3/W (2015) for the realigned roadmap can be ex­
the PV. Both of these approaches reduce the hydrogen pected to lower the electricity price to the levels required
“transportation” distances during the production cycles. by the hydrogen Multi-Year Plan for the defined cost-
It is also possible that the hydrogen storage could be competitive region. The major goal is $0.06–0.08/kWh
integrated into this structure, using carbon-nanotube in 2020 (for both the Roadmap [19] and the U.S. DOE
technology in a thin-layer configuration. Solar Energy Technologies Program [12]). With more
aggressive policies, the realigned roadmap could bring
about electricity prices below this. This electricity price
meets the hydrogen goal for 2010, but is still below the
more sound expectation of about $0.04/kWh, reached in
2030—or about 2025 possible in the realignment. Prices
beyond the roadmap timeframes can be deduced from the
learning curve data [28], which shows that PV has his­
torically followed an “80% learning curve” (i.e., for each
doubling of cumulative production, the price decreases
by 20%) [28]. Similar timeframes can be anticipated for
both the residential and the solar village concepts—if the
PV Roadmap goals are met & the learning curve contin­
ues past 2020. For a central PV station, by comparison,
the required electricity price is the wholesale electricity
price, which will not be reached until at least 2040 (about
5–8 years sooner in the realignment). This corresponds
to hydrogen at about $1.60–$1.70/kg, which, in the case
of transportation, is equivalent to $1.25–$1.35/gallon of
gasoline with a 0.2%/year escalation [7,9].
Figure 1: Distributed Solar-Hydrogen Residence Concept. This analysis shows that even the roadmap projections
allow PV to fit well into an eventual hydrogen economy
This paper examines these future possibilities—the in the United States. But how can we get there sooner?
energy-plus home and the solar hydrogen park—for If some of the “predictors” are off, then certainly the
technical feasibility and economics feasibility, and time- competition with other energy sources can bring about
expectations are evaluated in terms of expected technology this solar scenario faster. For example, if the Energy
advancements and predictions from the U.S. PV Industry Information Administration gasoline escalation was
Roadmap [19]. higher than 1%/year, this would mean that roughly
$0.35/kWh to $0.45/kWh PV would be economical—
3. ECONOMICS AND TIMES VERSUS ROADMAPS realizing the 2040 centralized goal about 10 years sooner,
or accelerating the 2030 expectations by 3–5 years.
The economics of producing hydrogen using PV has However, it is difficult to propose such an alternative
been examined by a number of sources [20–27]. A sim­ without also pointing out that the roadmap goals may not
plistic economic potential might be gauged by comparing be reached, that the learning curve for PV might be 85%,
the “market” selling price of hydrogen to the correspond­ or that prices and availabilities of competing fuel sources
ing solar production cost—and the portion of this cost might be more, rather than less, favorable. Moreover, the
that is attributed to the electricity. Currently, purified, realigned roadmap would accelerate the longer­
noncompressed hydrogen is produced for about $0.75/kg timeframe goals (e.g., beyond 2025) by as much as a
to $2/kg, depending on the volume and quality pur­ decade—if the realigned roadmap conditions are met.
chased. Currently, PV electrolysis is about an order of Expectations that disruptive technologies will favora­
magnitude more expensive ($7/kg–$25/kg), depending on bly alter the learning curve also present risk. However,
the tax credit and rate and on the internal rate of return the risk depends on reasonable science, rather than specu­
[7–9,12,19]. (There is no current “cost” for hydrogen lation. These breakthrough technologies lower prices and
from PV photolysis because there is no production, ex­ open markets more rapidly. An example is that of the
cept in the research laboratory. However, some analysts transistor, which was continuing on a 90% learning curve
still estimate this cost near the $20/kg level—with ample until the late 1950s. With the introduction of the inte­
assumptions!) Hydrogen (from natural gas) is currently grated circuit—certainly a disruptive technology from
delivered at about $5/kg to a car at a refueling station. Of business as usual—that electronic technology followed a
this, about $1.90/kg is credited to the electricity (at a rate 50%-60% learning curve for a brief period, until it settled
of $0.035/kWh). For a smaller electrolysis system, the on an 80% characteristic, similar to that of PV. Thus, as
current cost is $7.40/kg to $8.00/kg), with the electricity the cumulative units that were produced quickly in-
portion at $4.10/kg (at a $0.06/kWh rate). These two creased due to the integrated processing, the cost per unit
cases correspond to the distributed-generation scenarios fell—and the demand for this new technology increased
in Figs. 2 and 1, respectively. Of course, current PV substantially. This “integrated” innovation is not much
electricity is generated at a rate in the range of different than the second and third generations of PV that
$0.18/kWh–$0.25/kWh—higher than conventional elec­ are already being pursued. This same impact of innova­
tricity without some incentives. Can PV eventually meet tion can bring about PV—and PV for hydrogen—more
the price criteria for generating electricity competitive for rapidly. Thin-film technologies (especially multijunction
the distributed hydrogen requirements? As a basis, we polycrystalline approaches), nanotechnologies, and “plas­
will use the U.S. PV Industry Roadmap as a guide to tic” cells all address low-cost breakthrough PV, primarily
2020—and some preliminary (not finalized) targets from for our distributed scenarios [2,29]. On the other hand,
the in-progress industry roadmap realignment (which super-high-efficiency PV using quantum dots, rods, or
provides a new set of targets because funding and policy pods, ultra-multijunctions, impurity or intermediate layer
assumptions were not met for the original strategy)—as cells, thermophotovoltaics or thermophotonic all pose
well as learning or experience curves to predict the fu­ breakthrough possibilities on the other end of the tech­
tures to 2050. The requirements for hydrogen (and the nology spectrum [2,29]. They are aimed at both central­
electricity cost to produce it) will be taken from the new ized and distributed power-park applications. Addition-
Multi-Year Technical Plans. Levelized electricity cost­ ally, the direct production of hydrogen by photolysis
ing (LEC) is used. (electrochemical methods) is also a breakthrough tech­
Table 1 presents a comparison of relevant nology. This has considerable potential for cost effec­
costs, goals, and predictions over the timeframe of 2003 tiveness—but the problems of performance (efficiency
through 2050. Current (2003) PV electricity prices are
certainly not competitive. Neither the end-of-the-decade
goal of $3–$4/W for systems in the current roadmap nor

2
Table 1: Competitiveness comparison of PV-hydrogen based roadmaps and multiyear plans. Italiziced numbers projected from road-
map using technology learning/experience curves. Proposed (not final) roadmap targets and projected indicated in grey tones.

2004–05 2010 2015 2020 2030 2040–50

PV System Price $6–$15/W $3–$4/W [$3/W] $1.50–$2.00/W ~$1.00/W ~$0.50/W
[<$1.50/W]
PV Electricity Price $0.18– $0.11– [$0.061– $0.06–0.08/kWh ~$0.045/kW ~0.03/kWh
0.25/kWh 0.16/kWh $0.10/kWh+] [$0.05–0.07/kWh] h
[<0.04/kWh
]
U.S. PV Capacity or 0.2–0.4 0.8– [2-2.75GW/yr 7–8GW/yr of [130GW 1000–1600TWh/yr
Shipments (for that GW/yr 1.0GW/yr U.S.] which installed [2000–3000TWh/yr]
year or cumulative in- 3.1GW/yr U.S. cumulative] [450–630GW in-
stalled) stalled cumulative]
Targets 15% of new 10% of total 15%–18% of total
(added) U.S. gen­ U.S. genera­ U.S. generation ca­
eration capacity* tion capac­ pacity
ity** [50% of all build­
ings;
1/4–1/3 of U.S. elec­
tricity]
Performance-Efficiency 10–20%/ 18–25%/ [Likely at 20–28%/ 20+–40%/ Ultra-high-efficiency
Range for Best Com­ 11–15%/ 14–17%/ higher end of 16–20+%/ 18+–28%/ modules: >40%
mercial 7–12% 9–14% 2010 goals] 13–18% 16–20% Ultra-low-cost mod­
(Cell/ Module/ Sys­ [20+-35%/ [22–40+%/ ules: >20%
tem)*** 18–24%/ 20–30%/
14–20%] 18–25%]
Distributed Hydrogen:
Solar Park (Electroly­
sis)
Total Price $4.70/kg $2.50/kg
Electricity Price $1.90/kg $1.60/kg
Distributed Hydrogen:
Residence (Electrolysis)
Total Price $7.40/kg $3.80/kg
Electricity Price $4.10/kg $2.80/kg
Distributed Hydrogen:
Photolysis (Electro­
chem)
Price N/A $22/kg $5/kg
Efficiency (solar- 7% 9% 14%
hydrogen)
Roadmap assumptions: R&D budget (original: $100 million/year, never reached; new $150 million/year, 10–15 years)
+ Major aggressive policy changes (incentives, etc.) on state and federal levels; 30-year system lifetime
Depends on discount rate
*Target reached in 2018 with new roadmap.
**Target reached in 2026 with new roadmap.
***Higher efficiencies are noted in the 2020–2050 timeframe for concentrating PV technologies and
preliminary ultrahigh-efficiency concepts leading toward commercialization.

and reliability) need to be proven (see Table 1). In the very rigid. Because of the nature of hydrogen (and the
1980 timeframe [30], a rooftop system was demonstrated, pressure requirements), there are safety issues raised, as
but it used hydrogen bromide—which had inherent envi­ well. It might be better to choose a liquid that could be
ronmental concerns. If the same type of system could be generated from the solar source. Such is the interesting
realized using water splitting, the distributed hydrogen approach proposed by Lewis [31]—the “methanol econ­
scenario would be widespread. If the performance levels omy.” His careful analysis is based on considering the
for modules and systems, indicated in Table 1, are best options, using closed approaches to control the carbon
reached, the solar-PV hydrogen option will certainly be emissions, and examining all the “electricity sources.” His
one of choice, not imposition. The increased focus on conclusion is liquid methanol, produced by solar (and
R&D through enhanced budgets—providing a balanced actually, solar photovoltaics). Lewis is strong in his belief
investment between now-, near-, and next-term PV tech­ that the total energy must be considered in any long-term
nologies would certainly lower the risk for the required energy planning [31]—not just electricity (which he re-
technology developments in these timeframes. ports is only 10% of the world’s primary energy now),
chemicals, fuels, etc. In some sense, this is a parallel to
the hydrogen approach just discussed: conversion of solar
4. HYDROGEN LOOKS GREAT...BUT MAYBE NOT energy to electricity via PV, driving a “methalyzer” to
What are the limitations for this approach? Certainly, produce liquid methanol, and then transporting the liquid
the arguments for hydrogen are abundant—and at first fuel (from central sites in the Lewis concept) to the point
glance, compelling. However, if the academic exercise of use. Of course, it might also be possible to use the dis­
were given to a graduate student to find the best fuel alter- tributed approach—depending on the efficiencies of the
native to transportation, for example—perhaps hydrogen processes involved. Other approaches exist, as well (e.g.,
would not be the answer. Because of its density, it has to other fuels, hybrids, pure electrical economies [32]).
be compressed to high pressures. Because of its atomic However, the ensemble of metrics (relative economics,
number, the constraints on the distribution (e.g., leaks) are materials availability/security, impacts on related products,

3
technological feasibilities, and, of course, politics) will 6. REFERENCES
lead to the eventual winners. Hydrogen is certainly a
promising technology that is an ideal partner to solar. But [1] P. Maycock, PV News, Vol. 23(3), Mar. 2004; Pho­
ton International, April (2004) pp.40–41.
do not close the deal; do not rule out other approaches yet. [2] See, for example, technical reports in the Pro­
It is too early to lock in on a single approach. We should ceedings of this conference (2004).
remain technically flexible...and provide the innovation [3] L.L. Kazmerski, Proc. 39th IEEE Photovoltaics Spec.
and creativity to provide our coming generations with Conf., (IEEE, New York; 2003) pp. 21–27.
coming generations of abundant clean, secure energy. [4] T. Surek and L.L. Kazmerski, SPIE oeMagazine
(SPIE, Bellingham, WA.) May 2003, pp.24–27.
[5] J. Perlin, L.L. Kazmerski, and S. Moon, Solar To-
5. SUMMARY day, Jan.-Feb. (2004) pp.24–27.
Future energy can (should) include PV and hydrogen. [6] G. Davis, Evolving Sources or Revolutionary Tech­
The concept of the zero-energy building can be envisioned nology—Exploring Alternative Energy Paths to
2050, Proc. Oil & Money Conference, London, Oct.,
to expand to the “energy-plus home” that produces more 2001 (pp.1–11).
energy (electricity for the residence, hydrogen for night- [7] National Vision of America’s Transition to a Hydro­
time power and the family “Freedom Car”). The solar- gen Economy to 2030 and Beyond, Feb. 2002.
hydrogen park or village is an extension of this, in which [8] National Hydrogen Energy Roadmap, Nov. 2002.
the solar energy and hydrogen is shared in the community. [9] Hydrogen, Fuel Cells & Infrastructure Technologies
Again, additional electricity can be supplied to the grid Program, Multi-Year Research, Development and
and any excess hydrogen can be sold through the commu­ Demonstration Plan (U.S. Department of Energy,
nity’s refueling stations. The marriage between hydrogen Energy Efficiency and Renewable Energy, Washing-
and solar brings secure, clean energy—as well as making ton, DC), June 2003.
PV a “24-hour power” option. [10] Scientific American, May 2004, pp.66–74.
The “but when?” can be estimated from the predictions [11] National Energy Policy, Report of the National En­
ergy Policy Development Group, May 2001
of the U.S. PV Industry Roadmap, the hydrogen and solar [12] U.S. DOE Solar Energy Technology Program Multi-
Multi-Year Technical Plans, and considerations of the Year Technical Plan, 2003-2007 (NREL, Golden,
learning curves for the technology. Centralized PV- CO; 2004).
hydrogen will not likely be available until the 2040 [13] J. Deutch and E. Moniz, Editorial, N-Power Key to
World’s Future, Arizona Daily Star, Friday, August
timeframe. Decentralized approaches can be reached by 15, 2003 (www.azstarnet.com).
2035, depending on the escalation factors for other fuels. [14] Energy Information Administration, International
Through the acceleration of technology fueled by the poli­ Energy Annual Report, 2002 (Washington, DC).
cies, investments, and strategies of the new realigned U.S. [15] L.L. Kazmerski, Solar Today, Vol. 16, No. 4, pp.40–
43, 2002.
PV Industry Roadmap, distributed and decentralized ap­ [16] L.L. Kazmerski, Proc. Hybrid Conf. (2004). Also,
proaches can be accelerated by 5–8 years. The result PV FAQ (www.nrel.gov/ncpv).
would be an acceleration, similar to that anticipated in the [17] PV FAQ sheets, www.nrel.gov/ncpv
United States by the current hydrogen program. [18] NAC, The Hydrogen Economy: Opportunities,
Disruptive technologies—second-generation thin films, Costs, Barriers, and R&D (National Academies
Press, 2004).
organics, and nanotechnologies—can accelerate the nearer [19] Solar Electric Power: U.S. Photovoltaics Industry
term by 5–10 years or more. Third-generation higher-cost Roadmap (U.S. PV Industry; May, 2001).
approaches (such as quantum technology cells, ultra­ [20] J.A. Turner, Science, Vol. 285, July 30, 1999,
multijunctions, new materials, novel structures, and novel pp.687–689.
[21] See, for example, New York Times, Augustth 15, 2003
concentrators having performances beyond 50% efficien­ [22] M.K. Mann, P.L. Spath, and A.S. Watt, 9 Canadian
cies) can accelerate both distributed and centralized ap­ Hydrogen Association Meeting, Vancouver, B.C.
proaches. The further investment and careful strategy- (Hydrogen Association).
controlled path into these next-generation breakthrough [23] R. Rocheleau, E. Miller, and A. Misra, Proc. U.S.
DOE Hydrogen Prog. Rev. NREL/CP-430-21968
technologies will benefit the learning curve to bring not (National Renewable Energy Laboratory, Golden,
only solar-PV electricity, but also, solar-PV hydrogen CO; 1996) pp.345–352.
significantly closer. They can be realities within a genera­ [24] J.M. Vidueria, A. Contreras, and T.N. Vesiroglu, Int.
tion of our population. J. Hydrogen Energy, Vol. 28, 927-937 (2003).
[25] D.L. Block and I. Melody, Int. J. Hydrogen Energy ,
Acknowledgements: The technical work was supported by the Vol. 17, 857 (1992).
U.S. Department of Energy through Contract No. DE-AC36- [26] A. Kazim and T.N. Veziroglu, Renewable Energy,
99GO10337 with the National Renewable Energy and the U.S. Vol. 24, 259–274 (2001).
DOE MURA (Minority University Research Associates) Program. [27] C.C. Elam, C.E. Gregoire Padro, G. Sandrock, A.
The views are primarily those of the authors. Kara Broussard is a Luzzi, P. Lindblad, and E. Fjermestad Hagen, Int. J.
student at Southern University, Baton Rouge, Louisiana, serving Hydrogen Energy, Vol. 28, 601–607 (2003).
as a summer intern at NREL. The assistance, input, and encour­ [28] T. Surek, Proc. 3rd World Conference on Photovol­
agement of Professor Rhambabu Boba of Southern University, taic Energy Conversion, Osaka, Japan, May 2003.
Allen Barnett and Robert Birkmire of the University of Delaware, [29] R. McConnell, S. Moon, and L.L. Kazmerski, Solar
and Roland Hulstrom, Robert McConnell, John Turner, Tom Today, to be published, June 2004.
Surek, Robert Margolis, Don Gwinner, Al Hicks, and Fannie [30] W.R. McKee, D.R. Carson, and J.D. Levine, Proc.
Posey-Eddy of NREL are gratefully acknowledged. 16th IEEE Photovoltaics Spec. Conf. (IEEE, New
York; 1982) pp.257–261.
[31] N. Lewis, see Web page for detailed presentation
http://www.its.caltech.edu/~mmrc/nsl/default.htm
[32] J.J. Romm, The Hype About Hydrogen (Island
Press, New York; 2004).

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13. SUPPLEMENTARY NOTES

14. ABSTRACT (Maximum 200 Words)

Future solar photovoltaics-hydrogen systems are discussed in terms of the evolving hydrogen economy. The focus
is on distributed hydrogen, relying on the same distributed-energy strengths of solar-photovoltaic electricity in the
built environment. Solar-hydrogen residences/buildings, as well as solar parks, are presented. The economics,
feasibility, and potential of these approaches are evaluated in terms of roadmap predictions on photovoltaic and
hydrogen pathways—and whether solar-hydrogen fit in these strategies and timeframes. Issues with the “hydrogen
future” are considered, and alternatives to this hydrogen future are examined.
15. SUBJECT TERMS
PV; solar hydrogen; system; roadmaps; electrolysis; photolysis

16. SECURITY CLASSIFICATION OF: 17. LIMITATION 18. NUMBER 19a. NAME OF RESPONSIBLE PERSON
OF ABSTRACT OF PAGES
a. REPORT b. ABSTRACT c. THIS PAGE
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19b. TELEPONE NUMBER (Include area code)

Standard Form 298 (Rev. 8/98)

Prescribed by ANSI Std. Z39.18

F1147-E(05/2004)