Performance Of Fuel Cell System Research Articles

Performance and Durability of Heavy-Duty Fuel Cell Systems with an Advanced Ordered Intermetallic ORR Alloy Catalyst and Novel Support

Abstract Ordered PtCo intermetallic (OIM) catalyst (L10-PtCo/C) is a promising candidate as the oxygen reduction reaction (ORR) catalyst in hybrid fuel cell systems (FCS) for class-8 heavy duty (HD) trucks. Compared to a baseline annealed Pt on high surface area carbon (a-Pt/HSC) catalyst, its mass activity (MA) is 71% higher initially and 144% higher after 90,000 potential cycles in an accelerated stress test (AST). Analysis of the AST data indicates that the ORR kinetic constants do not change with aging and the degradation in the OIM catalyst activity is linearly proportional to the loss in the electrochemically active surface area (ECSA). Several operational strategies are investigated to mitigate catalyst degradation and achieve 25,000-h electrode lifetime and 2.5 kW/g Pt utilization on a HD truck duty cycle including load sharing with the hybrid battery, regulating the radiator fan power to maintain the coolant temperature close to 60oC, clipping the maximum cell voltage below 850 mV, limiting the ECSA loss to 55%, and oversizing the membrane active area by 20%. Drive cycle simulations indicate that the lifetime average voltage degradation rate is about 1.8 V/h and the integrated stack and FCS drive cycle efficiencies decrease by 3.5 to 3.9%.

Experimental assessment of a heavy-duty fuel cell system in relevant operating conditions

During the past few years, the research interest in fuel cell systems (FCS) has increased significantly. Thus, this kind of powertrain is now at high Technology Readiness Levels (TRLs) and even starting to be commercialized. However, the currently available technology still has room for optimization. The existing bibliography shows studies mainly related to stack-level characterization or FCS studies with a poor level of detail. The present paper focuses on producing a detailed database about the performance of a specific FCS designed for heavy-duty vehicle (HDV) applications. The obtained dataset provides information about the influence of ambient conditions on the performance of the system, plus information about the anode and cathode circuits. These factors represent an important novelty with respect to other pieces of literature present in the actual research framework. Additionally, the obtained data regarding the performance of an FCS is highly significant for HDV manufacturers in the transportation sector and eases the pathway to the optimization of these technologies. The written piece of research proves the importance of studying the ambient conditions. The experimental campaign has shown that increasing relative humidity can improve the performance of the membrane up to a 2% for a 25% change in the humidity level. Additionally, the study shows the importance of implementing an appropriate supply gas strategy, both for anode and cathode, and designing the right purging mechanisms for H2 at the anode inlet. The obtained results show how there exist a relation between the optimal efficiency operating point and a H2 excess from the supply strategy.

Application of Multiple Linear Regression and Artificial Neural Networks in Analyses and Predictions of the Thermoelectric Performance of Solid Oxide Fuel Cell Systems

Application of Multiple Linear Regression and Artificial Neural Networks in Analyses and Predictions of the Thermoelectric Performance of Solid Oxide Fuel Cell Systems

Performance and Durability of Hybrid Fuel Cell Systems for Class-8 Long Haul Trucks

Hybrid fuel cell-battery configurations are investigated that overcome thermal management issues in fuel cell powertrains for heavy-duty Class 8 trucks. The battery is sized so that it has sufficient capacity to provide supplemental power and energy on a hill climb transient at end-of-life. A dynamic load sharing strategy is developed to distribute the power demand between the fuel cell system (FCS) and the energy storage system in a manner that optimizes their lifetimes. The FCS end-of-life is identified as the terminal point beyond which the stack cannot generate the rated power with target power density at 0.7 V and 40 °C ambient temperature. Reaching the target lifetime with a-Pt/C cathode catalyst in one hybrid configuration requires voltage clipping to 813 mV, idle power limited to 50 kW, catalyst overloading to 0.45 mg cm−2 total Pt in anode and cathode, and 44% active membrane area oversizing. The stack and FCS drive cycle efficiencies decrease by 4.2% and 5.4%, respectively, during the electrode lifetime. The FCS performance, durability and cost are compared with the targets of 68% peak efficiency, 0.30 mg cm−2 total Pt loading, 2.5 kW/gPGM Pt group metal (PGM) loading, 750 mW cm−2 power density, 25,000-h lifetime and $80/kW cost.

Comparative Study of Thermodynamic Performance and System Characteristics of Solid Oxide Fuel Cell System with Three Different Fuels

The global demand for hydrogen is increasing as the global warming problem emerges. Hydrogen, which does not produce air pollutants, is attracting attention in various fields such as transportation and power generation. However, there are drawbacks in storing and transporting hydrogen in its own form. Hydrogen must be stored in the form of low-temperature and high-pressure liquefied hydrogen, which requires a lot of energy, and transportation costs are also high due to the low mass energy density of hydrogen. Therefore, there is a need to store and transport hydrogen in different forms, and a means to convert and use these different forms of hydrogen is needed.Solid oxide fuel cell (SOFC) is one of the energy conversion devices capable of using various types of hydrogen with high efficiency. Due to the high operating temperature of SOFC, fuel can receive adequate heat for reforming process from high temperature SOFC exhaust gas. Therefore, SOFC can use various types of fuels, such as methane and ammonia.Due to the fuel flexibility of SOFC, many SOFC system study using various fuels have been conducted. However, the SOFC operating conditions and system layout used in each study are all different. Also, most of studies lacked parasitic power consideration due to the pressure drop in system components. These limitations make it difficult to compare each SOFC system and find out effect of fuel on SOFC system.In this study, a quantitative comparison of SOFC using three different fuels, methane, ammonia, and hydrogen, was conducted. Thermodynamic models of a SOFC stack and balance of plant components developed from the previous study are used for the system simulations. Two system layouts, non-recirculation, and anode recirculation were chosen, and thermodynamic feasibility test was conducted based on T-Q diagram analysis at heat exchanger and reformer. With these system layouts, thermodynamic performance of the system and the design characteristics of the system components were compared. Boundary conditions, such as SOFC operating temperature, air and fuel utilization remains the same to compare each system result quantitatively. Also, most of design variables of system components are fixed to find out the effect of fuel on system components.Among three non-recirculation systems, ammonia fed non-recirculation system showed the highest electrical efficiency, while methane fed anode recirculation system showed the highest electrical efficiency among the anode recirculation systems. With the anode recirculation, SOFC power drop occurs due to the lower hydrogen concentration in the SOFC. However, fuel input drop due to anode recirculation is greater than the SOFC power drop, which positively affects system performance. But parasitic power is also increased due to recycle blower and higher mass flow rate of anode recirculation flow. In the case of ammonia fueled system, this increase in parasitic power leads to decrease in electrical efficiency.In this study, there are many constraints in operating conditions and BoPs designs to compare each system with different fuel. Therefore, operating conditions and BoPs designs are not optimized, so each system performance for each fuel may increase with appropriate system design. This optimization will be done in further study. Figure 1

Comparative Study of Thermodynamic Performance and System Characteristics of Solid Oxide Fuel Cell System with Three Different Fuels

This work focuses on the fuel characteristic of the Solid Oxide Fuel Cell (SOFC) system. Three types of fuel have been considered and two type of the SOFC system layout have been analyzed with in-house SOFC system simulator (H-Twin). In the case of non-recirculation system, ammonia fed system shows the highest efficiency. In the case of recirculation system, methane fed system show the highest efficiency. The hydrogen-fed system shows the lowest efficiency in both types of systems.

Performance and Total Cost of Ownership of a Fuel Cell Hybrid Mining Truck

The main objective of this work was to investigate the potential of hydrogen and fuel cells replacing diesel and internal combustion engines in the ultraclass haul trucks deployed in the mining sector. Performance, range, durability, and cost are the main criteria considered for comparing the two fuels and engine options. Fuel cell system (FCS) performance is characterized in terms of heat rejection, efficiency, and fuel consumption for a hybrid platform equivalent to a 3500 hp diesel engine operating on a representative open pit mining duty cycle. A hybrid platform was chosen because the heat rejection, with a constrained radiator frontal area, limits the maximum fuel cell-rated power by about 50% compared to that of the diesel truck. The hybrid powertrain was 81–88% more efficient than the diesel powertrain on the truck duty cycle. A liquid hydrogen storage system is required for an equal range or time between refilling, but the packaging remains a challenge. Fuel cell and battery durability were evaluated for their performance degradation and lifetime. Achieving a fuel cell lifetime comparable to the time between major overhauls for diesel trucks necessitates the oversizing of the membrane-active area, catalyst overloading, and voltage clipping. For an equal lifetime, the battery must be oversized to control its depth of discharge and charge/discharge rates. A total cost of ownership (TCO) analysis considering the initial capital expenditures, as well as the lifetime cost of fuel, operation, and maintenance, indicates that fuel cells and hydrogen can compete with diesel. A breakeven fuel cost for TCO parity is obtained if H2 is available at USD 5.79–6.85/kg vs. diesel at USD 3.25/gal and the FCS-specific cost is USD 323/kWe relative to USD 250/kW for a diesel genset. Volume manufacturing is required for FCS cost reduction. High volume is possible through the standardization, modularity, and proliferation of class 8 long-haul truck systems across different heavy-duty applications.

Modeling of the dynamic behavior of an integrated fuel cell system including fuel cell stack, air system, hydrogen system, and cooling system

1-dimentional (1-D) physical modeling methods of the dynamic behavior of an integrated fuel cell (FC) system are investigated, which consist of the models of the FC stack and subsystems of the air, hydrogen (H2), and cooling systems. To ensure numerical simulation of the entire FC system in life-long system operation (> 10 years) in acceptable calculation time, a proper model resolution is selected. The subsystem models are integrated with the FC stack model and controllers developed in our previous research to build a closed-loop simulator of an integrated FC system. It demonstrated that the impacts of the FC stack material properties on the overall FC system performance can be investigated by numerical simulation.

Hybrid Ageing Model of a Proton Exchange Membrane Fuel Cell (PEMFC)

Today the world is full of time-dependent phenomena in all fields: physics, chemistry, mechanics and many others. Time acts on the performance of any system whatever its nature is. When a system operates over time, aging becomes a real concern. Regarding fuel cells, several degradation phenomena can occur in a short or long term. Short-term phenomena are generally referred to as reversible degradations, these degradations are of the order of the microsecond and can go up to hours and sometimes to days, such as problems related to water management. The long term degradations are usually called irreversible degradations; it can be defined as aging. This phenomenon is of the order of a day and can increase up to months. In order to mitigate the impact of aging on the fuel cell system performance, good corrective actions must be taken. To do so, the performance prediction during the aging of the fuel cell system must be conducted. In this paper a verified and tested prognosis approach applicable to fuel cells is presented. The novelty in the approach used is linked to its modular structure. In fact, this approach has three phases. The first one aims to identify the internal physical parameters of the stack using an optimization algorithm on experimental data and a static fuel cell model. The second one predicts the temporal evolution of these parameters using a prediction algorithm. Finally, the reconstruction phase consists in the prediction of parameters that are re-injected into the model to reconstruct polarization curves and thus reflect the performance degradation of the fuel cell. The reliability and repeatability of the proposed approach have been successfully validated on two data sets from two different experimental campaigns.

Fuzzy Logic based Control Strategies for Proton Exchange Membrane Fuel Cell System

In this work, new fuzzy logic-based control strategies have been proposed to improve the performance of the non-linear Proton Exchange Membrane Fuel Cell (PEMFC) system. This paper considers the empirical approach to designing the controller. This allows the controller’s design to be straightforward, and the controller can be fine-tuned as and when necessary. Three control strategies have been proposed in this paper, viz. Fuzzy feedforward control strategy (Strategy 1), Fuzzy feedforward controller with a feedback loop (Strategy 2), and Fuzzy feedforward controller with a feedback loop and conditional switch (Strategy 3) are proposed. The performance comparison of the proposed strategies is evaluated in terms of performance indicators such as the integral square error (ISE), integral absolute error (IAE), and total variation (TV) of the closed-loop control system. Furthermore, the proposed strategies keep the voltage at a given setpoint under load current variation. Finally, Strategy 3 is used to regulate the oxygen excess ratio (OER) at a reasonable value under load current variation to avoid oxygen starvation and keep the voltage at a defined point of a PEM fuel cell system. The results show that Strategy 3 provides better performance than other strategies

Investigation of gas purging and cold storage impact on PEM fuel cell system performance for aeronautical applications

Durability of proton exchange membrane fuel cell systems under cold weather conditions is essential and a critical challenge for transportation applications. During cold storage the water remaining in the cells can freeze causing damage to the cell components. In order to avoid this degradation, fuel cells are commonly purged with dried gases during shutdown prior to its storage at subzero temperatures. This work investigates cold storage of PEMFC systems at temperatures down to -40°C with the aim of developing a shutdown procedure that leads to minimal degradation due to cold storage, while meets energy efficient and time requirements of aeronautical applications. To that end, several experiments were carried out with two different stacks (a 4 kW liquid cooled and a 100 W air cooled) under a wide range of operating parameters: cathode gas, purge temperature, anode and cathode gas purge flow rates, purge time and cold storage temperature. The fuel cell performance degradation due to ice formation was measured by the polarization curves conducted prior and after every F/T cycle. The effects of these operating parameters on the durability of the PEMFC systems under cold storage are evaluated. The obtained experimental results showed that very long purge process lead to further performance degradation at -10°C than shorter process at -40°C, which indicates that eliminating all remained water in the cells is not only inefficient, but also lead to degradation due to the drying process. Moreover, guidelines to improve shutdown procedure for cold storage of proton exchange membrane fuel cell systems for aeronautical applications are discussed.

상용차용 고분자 전해질 연료전지 냉각시스템 배열에 따른 성능 특성

상용차용 고분자 전해질 연료전지 냉각시스템 배열에 따른 성능 특성

Improving Water Management and Performance of an Air-Cooled Fuel Cell System Using Pressurized Air for Aviation Applications

Air-cooled fuel cell systems feature a light-weight and simple design and are thus recognized as a suitable technology for drone and aviation applications. As compared to liquid-cooled fuel cell systems, however, they suffer from low specific power per unit volume and unstable performance due to severe electrolyte dehydration and nonuniform profiles of current density and temperature inside a fuel cell stack. Here, we present a high-pressure air-cooled fuel cell system in which atmospheric air is pre-compressed by a compressor and then fed into the fuel cell stack. To minimize the compressor power consumption, the system is designed to recirculate the exhaust air from the fuel cell stack. A three-dimensional two-phase fuel cell model is implemented with a high-pressure air-cooled fuel cell system mainly consisting of an air-cooled fuel cell stack, compressor, air chamber and duct, and heat exchanger and is used to predict superior fuel cell performances under various high-pressure conditions. Simulation results show that the fuel cell operation at 2 atm allows an increase of up to two times the stack power and 1.5 times the net system power compared to a 1-atm fuel cell operation.

Microstructure Evolution in a Solid Oxide Fuel Cell Stack Quantified with Interfacial Free Energy

Degradation of electrode microstructure is one of the key factors affecting long term performance of Solid Oxide Fuel Cell systems. Evolution of a multiphase system can be described quantitatively by the change in its interfacial energy. In this paper, we discuss free energy of a microstructure to showcase the anisotropy of its evolution during a long-term performance experiment involving an SOFC stack. Ginzburg Landau type functional is used to compute the free energy, using diffuse phase distributions based on Focused Ion Beam Scanning Electron Microscopy images of samples taken from nine different sites within the stack. It is shown that the rate of microstructure evolution differs depending on the position within the stack, similar to phase anisotropy. However, the computed spatial relation does not correlate with the observed distribution of temperature.

An intelligent parametric modeling and identification of a 5 kW ballard PEM fuel cell system based on dynamic recurrent networks with delayed context units

This article presents a dynamic simulation study for the modeling and identification of a 5 kW Proton Exchange Membrane (PEM) fuel cell system using intelligent ANN approach to get rid of the complexity involved in the analytical modeling as it is intricate with the highly non-linear dynamics such as electrochemical, thermodynamic and water-transport mechanisms. The proposed artificial networks for the prediction and identification of a highly non-linear fuel cell system performance are Radial Basis Function Network (RBFN), dynamic Elman Recurrent Network (ERN) and NARX Recurrent Network (NRN) that has delayed context unit. A comparative study is made between the performances of the proposed neural network models for identifying an optimal network structure and configuration based on network performance measures. The optimal NARX network ascertained having an appreciable learning and generalization ability is adopted for the prediction and identification of the fuel cell system for its static and dynamic behavior. The network prediction over the system behavior shows good agreement with the benchmark results acquired from a 5 kW-Ballard fuel cell system. The proposed optimal intelligent parametric model can facilitate in replacing a highly non-linear fuel cell system in the fuel cell related model developments that are adopted in several research sectors particularly in transportation applications.

Prediction of high frequency resistance in polymer electrolyte membrane fuel cells using long short term memory based model

High-frequency resistance (HFR) is a critical quantity strongly related to a fuel cell system's performance. It is beneficial to estimate the fuel cell system's HFR from the measurable operating conditions without resorting to costly HFR measurement devices. In this study, we propose a data-driven approach for a real-time prediction of HFR. Specifically, we use a long short-term memory (LSTM) based machine learning model that takes into account both the current and past states of the fuel cell, as characterized through a set of sensors. These sensor signals form the input to the LSTM. The data is experimentally collected from a vehicle lab that operates a 100 kW automotive fuel cell stack running on an automotive-scale test station. Our current results indicate that our prediction model achieves high accuracy HFR predictions and outperforms other frequently used regression models. We also study the effect of the extracted features generated by our LSTM model. Our study finds that only very few dimensions of the extracted feature are influential in HFR prediction. The study highlights the potential to monitor HFR condition accurately and timely on a car.

Performance of Fuel Cell Systems for Heavy Duty Vehicles

Polymer electrolyte membrane fuel cell (PEMFC) systems for heavy-duty vehicles (HDV) are attracting attention for several reasons including tighter emission regulations and, compared with light duty vehicles (LDVs), possibility of a gradual build-up of hydrogen infrastructure during the market introduction phase, and higher allowable cost (60 $/kWe vs. 30 $/kWe) and Pt loadings.1 However, competing with the incumbent diesel technology requires longer stack lifetimes than for LDVs (30,000 h vs. 8,000 h) and higher efficiencies to compensate for the likely price differential between diesel and hydrogen.2 Heat rejection in fuel cells for HDVs can also be an issue. We conducted simulations to compare radiator heat loads in two propulsion systems for a Class-8 HDV: a 450-hp turbocharged diesel engine, and a hybrid 275-kWe FCS with a 35-kWh battery. The simulations showed that the radiator heat load at rated power is higher for the hybrid propulsion system even though it is 20% more efficient than the diesel engine. Higher heat load combined with lower operating temperature makes heat rejection in an HDV radiator more challenging for the hybrid powertrain. We conducted system analysis to determine the stack operating conditions (cell voltage and temperature) and the radiator fan power required to reject the waste heat in the HDV radiator at rated power. Figure 1 summarizes the important results of the analysis of an FCS with a compressor-expander module (CEM) for air management, 2.5-atm stack inlet pressure, no cathode humidifier, de-alloyed PtCo cathode catalyst supported on a high surface-area carbon, and 0.25 mg/cm2 total Pt loading.3, 4 Figures 1a and 1b show that the heat load and radiator fan power are strong functions of the cell voltage and stack coolant temperature. These indicate a heat transfer limit that sets the minimum coolant temperature which only depends on the cell voltage. For example, at 0.7 V cell voltage, the minimum coolant temperature is 88oC corresponding to 265 kW radiator heat load and 30 kWe fan power. The cell voltage needs to be higher than 0.75 V for stacks that operate below 80oC. Figures 1c and 1d present the net stack power (stack power minus the parasitics including radiator fan power) density and system efficiency (net power produced divided by the lower heating value of H2 consumed) as functions of cell voltage and coolant temperature. Increasing the cell voltage at fixed coolant temperature improves the system efficiency at the expense of lower power density. For a fixed cell voltage, there is an optimum temperature at which the net power density is highest. The net power density is smaller below the optimum temperature because of higher fan power, and above it because of the adverse effects of low relative humidity on Ohmic losses and ORR kinetics. As a reference point, the stack can reach 1200 mW/cm2 gross and 1015 mW/cm2 net stack power density for 0.7 V cell voltage at rated power and 88oC optimum coolant temperature. The projected power density and operating conditions are based on a model formulated using the experimental data for d-PtCo/C cathode catalysts with 0.05, 0.1 and 0.15 mg/cm2 Pt loading. Further work is required to confirm these projections by building and optimizing electrodes with 0.2 mg/cm2 Pt loading. References Marcinkoski, R. Vijayagopal, J Adams, B. James, J. Kopsz, and R. Ahluwalia, DOE Advance Truck Technologies https://www.hydrogen.energy.gov/pdfs/19006_hydrogen_class8_long_haul_truck_targets.pdf L. Borup, A. Kusoglu, K. C. Neyerlin, R. Mukundan1, R. K. Ahluwalia, D. A. Cullen, K. L. More, A. Z. Weber, and D. J. Myers, “Recent Developments in Catalyst-related PEM Fuel Cell Durability,” Current Opinion in Electrochemistry, 21, 192–200 (2020)Ahluwalia, X. Wang and J-K Peng. "Fuel Cell System Modeling and Analysis," 2019 DOE Hydrogen and Fuel Cells Program Annual Merit Review and Peer Evaluation Meeting, Arlington, VA, April 29 - May 1, 2019.K. Ahluwalia, X. Wang, and A.J. Steinbach, “Performance of Advanced Automotive Fuel Cell Systems with Heat Rejection Constraint,” Journal of Power Sources, 309 (2016), 178-191. Figure 1

Performance of a Natural Gas Solid Oxide Fuel Cell System With and Without Carbon Capture

Abstract The fuel cell program at the United States Department of Energy (DOE) National Energy Technology Laboratory (NETL) is focused on the development of low-cost, highly efficient, and reliable fossil-fuel-based solid oxide fuel cell (SOFC) power systems that can generate environmentally friendly electric power with at least 90% carbon capture. NETL’s SOFC technology development roadmap is aligned with near-term market opportunities in the distributed generation sector to validate and advance the technology while paving the way for utility-scale natural gas (NG)- and coal-derived synthesis gas-fueled applications via progressively larger system demonstrations. The present study represents a part of a series of system evaluations being carried out at NETL to aid in prioritizing technological advances along research pathways to the realization of utility-scale SOFC systems, a transformational goal of the fuel cell program. In particular, the system performance of utility-scale NG fuel cell (NGFC) systems with and without carbon dioxide (CO2) capture is presented. The NGFC system analyzed features an external auto-thermal reformer (ATR) feeding the fuel to the SOFC system consisting of planar anode-supported SOFC with separated anode and cathode off-gas streams. In systems with CO2 capture, an air separation unit (ASU) is used to provide the oxygen for the ATR and for the combustion of unutilized fuel in the SOFC anode exhaust along with a CO2 purification unit to provide a nearly pure CO2 stream suitable for transport for usage in enhanced oil recovery (EOR) operations or for storage in underground saline formations. Remaining thermal energy in the exhaust gases is recovered in a bottoming steam Rankine cycle while supplying any process heat requirements. A reduced order model (ROM) developed at the Pacific Northwest National Laboratory (PNNL) is used to predict the SOFC performance. The ROM, while being computationally effective for system studies, provides other detailed information about the state of the stack, such as the internal temperature gradient, generally not available from simple performance models often used to represent the SOFC. Such additional information can be important in system optimization studies to preclude operation under off-design conditions that can adversely impact overall system reliability. The NGFC system performance was analyzed by varying salient system parameters, including the percent of internal (to the SOFC module) NG reformation—ranging from 0 to 100%—fuel utilization, and current density. The impact of advances in underlying SOFC technology on electrical performance was also explored.

Three-dimensional simulation of solid oxide fuel cell with metal foam as cathode flow distributor

In this study, the use of metal foam as a flow distributor at cathode is evaluated numerically by a comprehensive three-dimensional solid oxide fuel cell (SOFC) model. The results show that the adoption of metal foam improves the power density by 13.74% at current density of 5000 A m−2 in comparison with conventional straight channel design. It is found that electronic overpotential, oxygen concentration and reaction rates distribute more uniformly without the restriction of ribs. The effects of cathode thickness on the two different flow distributors are compared. Compared with conventional straight channel, the metal foam is found to be more suitable as a distributor for anode supported SOFC with thin cathode gas diffusion layer. Moreover, when metal foam is applied to the fuel cell with a larger reaction area, a more uniform velocity distribution and a lower temperature distribution can be achieved. It is also found that an appropriate permeability coefficient should offer a reasonable pressure drop, which is beneficial for the fuel cell system performance improvement.

Impacts of Hydrogen-Natural Gas Mixtures on a Commercial Solid Oxide Fuel Cell System

In this study, the emissions and performance of a commercial Solid Oxide Fuel Cell system with micro-combined heat and power (SOFC mCHP) capabilities are analyzed at various power output levels and with various hydrogen (H2) – natural gas (NG) fuel mixture concentrations. The SOFC mCHP system, although designed to be fueled by pure NG, is intentionally fueled with mixtures between 0 and 30% vol of H2 mixed with NG (balance) and is operated between 0.5 and 1.5 kW. Since these units are used in residential and commercial applications, it is important to ensure that if H2 becomes widely injected into the NG system that the corresponding H2-NG mixtures would not negatively impact the emissions or performance of the system. The performance of the system is characterized by measurement of major exhaust species concentrations (carbon dioxide, carbon monoxide, methane, water, nitric oxide, nitrogen dioxide, etc.). These measurements confirm that NOx emissions are extremely low and that adding hydrogen to the NG system does not increase NOx emissions. In addition, the system’s efficiency at part load experienced a small reduction with increasing H2 concentrations in the mixture, compared to pure NG operation.