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Methods for comparing the performance of energy-conversion systems for use in solar fuels and solar electricity generation

Coridan, Robert H. and Nielander, Adam C. and Francis, Sonja A. and McDowell, Matthew T. and Dix, Victoria and Chatman, Shawn M. and Lewis, Nathan S. (2015) Methods for comparing the performance of energy-conversion systems for use in solar fuels and solar electricity generation. Energy and Environmental Science, 8 (10). pp. 2886-2901. ISSN 1754-5692. doi:10.1039/c5ee00777a.

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The energy-conversion efficiency is a key metric that facilitates comparison of the performance of various approaches to solar energy conversion. However, a suite of disparate methodologies has been proposed and used historically to evaluate the efficiency of systems that produce fuels, either directly or indirectly, with sunlight and/or electrical power as the system inputs. A general expression for the system efficiency is given as the ratio of the total output power (electrical plus chemical) divided by the total input power (electrical plus solar). The solar-to-hydrogen (STH) efficiency follows from this globally applicable system efficiency but only is applicable in the special case for systems in which the only input power is sunlight and the only output power is in the form of hydrogen fuel derived from solar-driven water splitting. Herein, system-level efficiencies, beyond the STH efficiency, as well as component-level figures of merit are defined and discussed to describe the relative energy-conversion performance of key photoactive components of complete systems. These figures of merit facilitate the comparison of electrode materials and interfaces without conflating their fundamental properties with the engineering of the cell setup. The resulting information about the components can then be used in conjunction with a graphical circuit analysis formalism to obtain “optimal” system efficiencies that can be compared between various approaches. The approach provides a consistent method for comparison of the performance at the system and component levels of various technologies that produce fuels and/or electricity from sunlight.

Item Type:Article
Related URLs:
URLURL TypeDescription
Coridan, Robert H.0000-0003-1916-4446
Nielander, Adam C.0000-0002-3639-2427
McDowell, Matthew T.0000-0001-5552-3456
Chatman, Shawn M.0000-0002-7951-5968
Lewis, Nathan S.0000-0001-5245-0538
Additional Information:© 2015 The Royal Society of Chemistry. Received 9th March 2015, Accepted 13th April 2015, First published online 13 Apr 2015. The authors thank Dr Eric Miller for the motivation to participate in this review, and the members of the U.S. Department of Energy’s Photoelectrochemical Working Group and Task 35 (Renewable Hydrogen) of the International Energy Agency’s Hydrogen Implementing Agreement for providing helpful comments and suggestions. This work was supported through the Office of Science of the U.S. Department of Energy under Award No. DE-SC0004993 to the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub. This work was also supported by the Gordon and Betty Moore Foundation under Award No. GBMF1225. R.H.C. and V.D. acknowledge support from the Air Force Office of Scientific Research (AFOSR) through the Multidisciplinary University Research Initiative (MURI) under AFOSR Award Number FA9550-10-1-0572, and A.C.N. acknowledges the National Science Foundation for a Graduate Research Fellowship.
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0004993
Gordon and Betty Moore FoundationGBMF1225
Air Force Office of Scientific Research (AFOSR)FA9550-10-1-0572
NSF Graduate Research FellowshipUNSPECIFIED
Issue or Number:10
Record Number:CaltechAUTHORS:20151005-085140068
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:60741
Deposited By: Tony Diaz
Deposited On:05 Oct 2015 16:27
Last Modified:10 Nov 2021 22:38

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