International Journal of Hydrogen Energy 32 (2007) 2703–2711
A comparison of PV/electrolyser and photoelectrolytic technologies
for use in solar to hydrogen energy storage systems
G.J. Conibeera,∗, B.S. Richardsb
aCentre of Excellence for Advanced Silicon Photovoltaics and Photonics, University of New South Wales, Sydney, New South Wales 2052, Australia
bCentre for Sustainable Energy Systems, Australian National University, Canberra, ACT 0200, Australia
Available online 30 October 2006
The approach of using hydrogen for an energy store to offset seasonal variations in solar energy is one very much at the periphery of current
renewable energy system design. Nonetheless, its inherent advantages for long term storage in stand alone power systems warrant further
detailed investigation. This paper provides a comparative overview of the very disparate technologies within two generic approaches to achieving
this goal. These are: photovoltaic (PV) powered electrolysis of water and direct photoelectrolytic (PE) generation of hydrogen from water.
Comparison of these is difficult, however, the paper compares devices of similar material system and structure within each generic scheme.
PV/electrolysis is the more mature technology but there is still a wide range of potential ‘solar to hydrogen’ efficiencies. A figure of about 9%
is estimated for comparison, with justification given. The comparative figure for PE is more difficult to judge because of even more disparate
approaches to specific problems of sufficient photovoltage and stability, but an approximate comparative figure of 5% is estimated. Thus making
PV/electrolysis more appropriate at present. Nonetheless, inherent advantages of simplicity of system design and potential robustness mean
that PE may become more appropriate as the technology develops.
2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.
Keywords: Hydrogen; Photovoltaic; Electrolysis; Photoelectrolysis; Photoelec