Recent United States Department of Energy (DOE) sponsored front-end engineering design (FEED) studies for retrofitting existing fossil-fueled power plants with state-of-the-art carbon capture technology contain previously overlooked real-world design considerations for near-term deployment of carbon capture. Insights from examining seven recently published FEED study reports are summarized in this paper. This includes a discussion of the design, performance, and cost implications associated with (1) location-specific considerations such as water availability, land availability, and accessibility; (2) host-plant-specific factors such as flue gas specifications, allowable degree of integration between the capture system and host plant, and operational mode; and (3) miscellaneous factors such as market conditions, permitting requirements, and business case incentives. This manuscript highlights (1) water availability as a key design and cost driver, with host plant steam extraction increasing capture system cooling water availability, (2) modularization and constructability impacts on the number of capture trains, (3) the impacts of host plant operational mode and capacity factor on the business case for installing capture, and (4) the merit of continued research, development, and demonstration efforts addressing steam extraction, host plant tie-in at the stack, solvent reclamation and air emissions control.

Reversible solid oxide cells(rSOCs) are an enabling energy storage/production technology for a dynamic grid environment. Reversible operation requires strong working knowledge of fuel cell (SOFC) and electrolyzer (SOEC). Performance degradation of SOECs has been observed; however, the details of physical processes related to the performance degradation remain unknown. Multiphysics simulations were performed to investigate the performance degradation of solid oxide electrolysis cells under various working conditions.

An Octave based script for solving defect thermodynamic model to generate Brouwer diagram of triple conducting perovskite as a function of temperature, P(O2)/P(H2O), or P(H2)/P(H2O) based on nonstoichiometry dependent defect formation energies and entropies.

Distinct from the proton defect, the hydride defect species may be present in certain perovskite materials in reducing environments such as in fuel electrodes of solid oxide cells (SOCs) or on the reducing side of ceramic membranes. A generalized defect thermodynamic model was developed for the triple-conducting perovskites (La,Ba)Fe1-xMxO3-delta (M = Y and Zr) to allow inclusion of the hydride defect formation reaction in addition to the other three main defect reactions, namely, the oxygen vacancy formation, hydration, and charge disproportionation reactions. This comprehensive defect model also allows the incorporation of polynomial functional forms of oxygen nonstoichiometry delta to describe the defect reaction energies and entropies and to enable refinements of the defect reaction equilibrium constants in the defect thermodynamic analysis. As a first step, the developed model is applied to the Ba0.95La0.05FeO3-delta material as an illustrative system to obtain its Brouwer diagrams with both the proton and hydride defects in relevant SOC conditions, particularly for more reducing environments. The results provide direct guidance on the influence of electronic and ionic defect concentrations upon thermodynamic properties and ultimately on the performance of Ba0.95La0.05FeO3-delta and potentially other (La,Ba)Fe1-xMxO3-delta perovskite materials involved in SOC applications.

National Energy Technology Laboratory (NETL) provides system-level process, cost, and market analyses on solid oxide cell (SOC) based technologies. Specifically, techno-economic analyses (TEA), market assessments, and other technology evaluations serve to guide the U.S. Department of Energy (DOE) Office of Fossil Energy and Carbon Management (FECM) Reversible Solid Oxide Fuel Cell (R-SOFC) Program technology goals and objectives. These studies are key to describing how the technologies contribute to improving domestic energy infrastructure in a clean, efficient manner. This effort focuses on hydrogen generation technologies, which have received recent attention due to their potential role in economy-wide decarbonization. In particular, the study is part of a series of investigations at NETL that seek to understand the techno-economic impacts of including SOC technology in energy production, hydrogen production, and/or storage configurations. The objective of this study is to establish a detailed TEA to assess the effectiveness of incremental technology improvements needed for solid oxide electrolysis cell (SOEC) technology to achieve the U.S. DOE’s Hydrogen Shot goal of hydrogen production at less than $1 per kilogram. To take advantage of the benefits of economies of scale, the SOEC hydrogen facilities are sized to produce ≈250,000 metric tons of hydrogen annually with an electrolysis load of one gigawatt (direct current). Some additional critical assumptions include stacks that operate near the thermo-neutral voltage of 1.28 V to avoid adverse thermal gradients, all necessary steam and heat is generated by electric boilers and heaters to enable green hydrogen production, and an air sweep is used to control the oxygen concentration in the air electrode exhaust stream. A literature review on long-duration SOEC stack tests informed the state-of-the-art basis for the techno-economic pathway. The pathway considers incremental technology improvements to key system parameters, with system performance and cost assessed for each pathway step. Briefly, the steps include cell voltage degradation rate improvements, operational current density increases, operating temperature reduction, improved steam utilization, increased system capacity factor, and reduced cell/stack capital costs. Each step is assessed at both atmospheric and pressurized (8 bar) operating conditions. To supplement assessment at each of these discrete stepwise improvements, sensitivity studies are conducted to understand the relative impact of each parameter and identify avenues for additional cost reductions. Reductions in electricity price and replacing the electric boiler heat duty with waste heat from an existing industrial source are the most sensitive parameters enabling further cost reductions. System efficiency and levelized costs of hydrogen (LCOH) for each case will be presented. Excluding the costs associated with electricity consumption, the direct impact that research and development can have on the LCOH can be made explicit. For the end-of-pathway case, which includes all the incremental research and development improvements, the cost of hydrogen produced is reduced by 50 percent from the state-of-the-art case. These results provide critical guidance to the DOE-FECM R-SOFC Program to set realistic targets for research and development-based improvements of SOC technology for hydrogen production.

Natural-gas-fueled solid oxide fuel cell (SOFC) systems have the potential for high-efficiency conversion of carbon to power due to the underlying electrochemical conversion process while readily facilitating carbon capture through the separation of the fuel and oxidant sources. Compressed air energy storage (CAES) technology can potentially store significant quantities of energy for later use with a high round-trip efficiency and lower cost when compared with state-of-the-art battery technology. The base load generation capability of SOFC can be coupled with CAES technology to provide a potentially flexible, low-carbon solution to meet the fluctuating electricity demands imposed by the increasing share of intermittent variable renewable energy (VRE) production. SOFC and CAES can be hybridized through thermal integration to maximize power output during periods of high electrical demand and then store power when either demand is low or renewable generation reduces power prices. The techno-economics of a low-carbon hybrid SOFC and CAES system was developed and investigated in the present study. The proposed hybrid system was found to be cost-competitive with other power-generating base-load facilities when power availability was considered. The hybrid system shows increased resilience to changes in a high VRE grid market scenario.

Solid oxide cells with La0.8Sr0.2MnO3/yttria-stabilized zirconia (LSM/YSZ) air electrodes exhibit accelerated performance degradation during electrolysis of hydrogen production. Under galvanic mode with a current density of 0.5 A/cm2, baseline electrolysis cells exhibit a rapid increase in resistance upon 200 h of operation and become utterly delaminated after 350 h at 800 degrees C. To prevent such catastrophic delamination, SrFe2O4-8 solutions are infiltrated into the LSM/YSZ air electrode of as-fabricated cell. Under the identical operation condition, SrFe2O4-8 infiltrated cells exhibit performance enhancement manifested by an immediate decrease in electrolysis operation voltage and reduction of both series and polarization resistance and sustainability of 900 h continuous electrolysis operation without delamination. Nanostructure examination reveals active interaction of the SrFe2O4-8 infiltrate with cells after calcination, Fe diffusion into the LSM backbones, and formation of nanoparticles on the surface of the backbones. During electrolysis, the nanoparticles maintain intact morphology and constant particle size, while there is continuous cation exchange between the nanoparticles and the backbone. The nanostructure origin of the increased electrolysis performance, reduced resistance, and increased durability induced by infiltration are discussed. The present study demonstrates a feasible and viable approach to preventing electrode delamination while increasing the durability of hydrogen production for electrolysis cells.