Review: An Economic Perspective on Liquid Solar Fuels

Newman, John; Hoertz, Paul G.; Bonino, Christopher A.; Trainham, James A.

doi:10.1149/2.046210jes

Cited by 91 publications

(85 citation statements)

References 23 publications

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“…[34][35][36][37] In this study, an electrolyzer efficiency of 73.0% and a DC-to-DC converter efficiency of 85% (representative of values for converters that need to perform dynamic maximum power point tracking on the input DC power from the PV array as well as independent tracking on the output DC power that is supplied to the electrolyzer to insure maximum electrolyzer efficiency) were used in the calculation. The efficiency of the PV was chosen to be the detailed balance limit, for the same tandem photoabsorber system with the same bandgap combination.…”

Section: Comparison To Photovoltaic Cell In Series With An Electrolyzmentioning

confidence: 99%

Modeling the Performance of an Integrated Photoelectrolysis System with 10 × Solar Concentrators

Chen

Xiang

et al. 2014

J. Electrochem. Soc.

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Two designs for an integrated photoelectrolysis system that uses a 10× concentrating solar collector have been investigated in detail. The system performance was evaluated using a multi-physics model that accounted for the properties of the tandem photoabsorbers, mass transport, and the electrocatalytic performance of the oxygen-evolution and hydrogen-evolution reactions (OER and HER, respectively). The solar-to-hydrogen (STH) conversion efficiencies and the ohmic losses associated with proton transport in the solution electrolyte and through the membrane of the photoelectrolysis system were evaluated systematically as a function of the cell dimensions, the operating temperatures, the bandgap combinations of the tandem cell, and the performance of both the photoabsorbers and electrocatalysts. Relative to designs of optimized systems that would operate without a solar concentrator, the optimized 10× solar concentrator designs possessed larger ohmic losses and exhibited less uniformity in the distribution of the current density along the width of the photoelectrode. To minimize resistive losses while maximizing the solar-to-hydrogen conversion efficiency, η STH , both of the designs, a two-dimensional "trough" design and a three-dimensional "bubble wrap" design, required that the electrode width or diameter, respectively, was no larger than a few millimeters. As the size of the electrodes increased beyond this limiting dimension, the η STH became more sensitive to the performance of the photoabsorbers and catalysts. At a fixed electrode dimension, increases in the operating temperature reduced the efficiency of cells with smaller electrodes, due to degradation in the performance of the photoabsorber with increasing temperature. In contrast, cells with larger electrode dimensions showed increases in efficiency as the temperature increased, due to increases in the rates of electrocatalysis and due to enhanced mass transport. The simulations indicted that cells that contained 10% photoabsorber area, and minimal amounts of Nafion or other permselective membranes (i.e. areal coverages and volumetric fractions of only a few percent of the cell), with the remaining area comprised of a suitable, low-cost inert, non porous material (flexible polymers, inert inorganic materials, etc.) should be able to produce high values of η STH , with η STH = 29.8% for an optimized design with a bandgap combination of 1.6 eV/0.9 eV in a tandem photoabsorber system at 350 K. Artificial photosynthesis could provide a promising route to largescale solar energy conversion and storage.1-4 Recent techno-economic studies have evaluated various designs for integrated photoelectrolysis systems, including a very promising system that makes use of concentrated illumination. 5,6 A discrete III-V photovoltaic cell connected electrically in series with a discrete polymer-electrolyte membrane (PEM) electrolyzer has demonstrated a solar-to-hydrogen (STH) conversion efficiency of 18% under 500 Suns.7 Although concentrated photovoltaics (CPV) typically i...

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Section: Comparison To Photovoltaic Cell In Series With An Electrolyzmentioning

confidence: 99%

Modeling the Performance of an Integrated Photoelectrolysis System with 10 × Solar Concentrators

Chen

Xiang

et al. 2014

J. Electrochem. Soc.

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“…[1][2][3] Electrochemical reduction of CO 2 (CO2R) has been proposed as one possible technology for the production of fuels from CO 2 using electricity obtained from renewable sources. [4][5][6][7] Studies of CO2R in aqueous solution date back to the 1950s, 8 and an extensive and thorough body of work was published by Hori and co-workers starting in the 1980s. [9][10][11][12][13][14] This work identified the key challenges in implementing electrochemical CO2R for fuel or chemical synthesis.…”

Section: Introductionmentioning

confidence: 99%

Effects of temperature and gas–liquid mass transfer on the operation of small electrochemical cells for the quantitative evaluation of CO₂reduction electrocatalysts

Lobaccaro

Singh

Clark

et al. 2016

Phys. Chem. Chem. Phys.

158

182

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TitleEffects of temperature and gas-liquid mass transfer on the operation of small electrochemical cells for the quantitative evaluation of CO2 reduction electrocatalysts In the last few years, there has been increased interest in electrochemical CO 2 reduction (CO2R). Many experimental studies employ a membrane separated, electrochemical cell with a mini H-cell geometry to characterize CO2R catalysts in aqueous solution. This type of electrochemical cell is a mini-chemical reactor and it is important to monitor the reaction conditions within the reactor to ensure that they are constant throughout the study. We show that operating cells with high catalyst surface area to electrolyte volume ratios (S/V) at high current densities can have subtle consequences due to the complexity of the physical phenomena taking place on electrode surfaces during CO2R, particularly as they relate to the cell temperature and bulk electrolyte CO 2 concentration. Both effects were evaluated quantitatively in high S/V cells using Cu electrodes and a bicarbonate buffer electrolyte. Electrolyte temperature is a function of the current/total voltage passed through the cell and the cell geometry.Even at a very high current density, 20 mA cm À2 , the temperature increase was less than 4 1C and a decrease of o10% in the dissolved CO 2 concentration is predicted. In contrast, limits on the CO 2 gas-liquid mass transfer into the cells produce much larger effects. By using the pH in the cell to measure the CO 2 concentration, significant undersaturation of CO 2 is observed in the bulk electrolyte, even at more modest current densities of 10 mA cm À2 . Undersaturation of CO 2 produces large changes in the faradaic efficiency observed on Cu electrodes, with H 2 production becoming increasingly favored. We show that the size of the CO 2 bubbles being introduced into the cell is critical for maintaining the equilibrium CO 2 concentration in the electrolyte, and we have designed a high S/V cell that is able to maintain the near-equilibrium CO 2 concentration at current densities up to 15 mA cm À2 .

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“…7 These electricity prices can nowadays indeed be achieved with PV, as illustrated by a recent successful bid for a 50 MW solar PV field in Europe for 5.38 €ct/kW h. 8 The hydrogen production costs for integrated solar fuel generators are likely to be higher and have been estimated in several studies. [9][10][11] One often cited study estimates a cost of $10.40/kg H 2 assuming a solar-to-hydrogen efficiency of 10%, a panel cost of $153/m 2 , and a lifetime of 10 years. 11 Last but not least, there are significant advantages to generating the amount of hydrogen at the desired pressure on demand where and when it is needed.…”

Section: Direct Versus Indirect Routesmentioning

confidence: 99%

Perspectives on the photoelectrochemical storage of solar energy

Krol

Parkinson

2017

MRS Energy & Sustainability

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Direct photoelectrochemical water splitting offers several advantages over PV-powered electrolysis and may become the technology of choice in the future. However, significant R&D efforts and breakthroughs are needed to accomplish this goal.The sustainable production of hydrogen would be an important first step for both powering fuel cells and for enabling large-scale and technologically mature gas phase processes to reduce CO 2 and nitrogen to get desired products. Specifically, the central challenge is to produce hydrogen from water using sunlight. Photovoltaics and wind-powered electrolysis are likely to be the technology of choice to produce renewable hydrogen for the next few decades. However, the integration of light absorption and catalysis in 'direct' photoelectrolysis routes offers several advantages, such as lower current densities and better heat management, and may become technologically relevant in the second half of this century. This article discusses the research and development efforts and needed breakthroughs to achieve this goal. New chemically stable semiconductors with a band gap between 1.5 and 2.0 eV and long carrier lifetimes are urgently needed to make efficient tandem devices.Scale-up of these research level devices beyond a few cm 2 introduces mass transport limitations that require creative electrochemical engineering solutions. Last but not least, standardized methods for measuring efficiencies and stabilities need to be implemented and should lead to official benchmarking and certification laboratories to guide commercial scale up efforts. Keywords: photochemical; energy storage; energy generation RevIew DISCUSSION POINTS• Water splitting will be a central challenge for any future fossil fuel-free energy infrastructure that relies on liquid or gaseous chemical fuels.• While the main materials challenge for solar-and wind-driven electrolysis is the development of better catalysts, the main challenge for photoelectrochemical water splitting is to find new chemically stable optimal-bandgap semiconducting light absorbers.• Further progress in the development of photo-driven water splitting generators requires significant additional efforts in electrochemical engineering and the development of standardized methods for benchmarking device performance and stability.

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Review: An Economic Perspective on Liquid Solar Fuels

Cited by 91 publications

References 23 publications

Modeling the Performance of an Integrated Photoelectrolysis System with 10 × Solar Concentrators

Modeling the Performance of an Integrated Photoelectrolysis System with 10 × Solar Concentrators

Effects of temperature and gas–liquid mass transfer on the operation of small electrochemical cells for the quantitative evaluation of CO₂reduction electrocatalysts

Perspectives on the photoelectrochemical storage of solar energy

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Review: An Economic Perspective on Liquid Solar Fuels

Cited by 91 publications

References 23 publications

Modeling the Performance of an Integrated Photoelectrolysis System with 10 × Solar Concentrators

Modeling the Performance of an Integrated Photoelectrolysis System with 10 × Solar Concentrators

Effects of temperature and gas–liquid mass transfer on the operation of small electrochemical cells for the quantitative evaluation of CO2reduction electrocatalysts

Perspectives on the photoelectrochemical storage of solar energy

Contact Info

Product

Resources

About

Effects of temperature and gas–liquid mass transfer on the operation of small electrochemical cells for the quantitative evaluation of CO₂reduction electrocatalysts