Thermodynamic assessment of photovoltaic systems

In this paper, an attempt is made to investigate the performance characteristics of a photovoltaic (PV) and photovoltaic-thermal (PV/T) system based on energy and exergy efficiencies, respectively. The PV system converts solar energy into DC electrical energy where as, the PV/T system also utilizes the thermal energy of the solar radiation along with electrical energy generation. Exergy efficiency for PV and PV/T systems is developed that is useful in studying the PV and PV/T performance and possible improvements. Exergy analysis is applied to a PV system and its components, in order to evaluate the exergy flow, losses and various efficiencies namely energy, exergy and power conversion efficiency. Energy efficiency of the system is calculated based on the first law of thermodynamics and the exergy efficiency, which incorporates the second law of thermodynamics and solar irradiation exergy values, is also calculated and found that the latter is lower for the electricity generation using the considered PV system. The values of “fill factor” are also determined for the system and the effect of the fill factor on the efficiencies is also evaluated. The experimental data for a typical day of March (27th March 2006) for New Delhi are used for the calculation of the energy and exergy efficiencies of the PV and PV/T systems. It is found that the energy efficiency varies from a minimum of 33% to a maximum of 45% respectively, the corresponding exergy efficiency (PV/T) varies from a minimum of 11.3% to a maximum of 16% and exergy efficiency (PV) varies from a minimum of 7.8% to a maximum of 13.8%, respectively.     

Energy and exergy efficiencies of a hybrid photovoltaic–thermal (PV/T) air collector

In this communication, an attempt has been made to evaluate exergy analysis of a hybrid photovoltaic–thermal (PV/T) parallel plate air collector for cold climatic condition of India (Srinagar). The climatic data of Srinagar for the period of four years (1998–2001) has been obtained from Indian Metrological Department (IMD), Pune, India. Based on the data four climatic conditions have been defined. The performance of a hybrid PV/T parallel plate air collector has been studied for four climatic conditions and then exergy efficiencies have been carried out. It is observed that an instantaneous energy and exergy efficiency of PV/T air heater varies between 55–65 and 12–15%, respectively. These results are very close to the results predicted by Bosanac et al. [Photovoltaic/thermal solar collectors and their potential in Denmark. Final Report, EFP Project, 2003, 1713/00-0014, www.solenergi.dk/rapporter/pvtpotentialindenmark.pdf].     

Efficiency assessment of an integrated gasifier/boiler system for hydrogen production with different biomass types

In this study, we utilize some experimental data taken from the literature, especially on the air-blown gasification characteristics of six different biomass fuels, namely almond shell (ASF), walnut pruning (WPF), rice straw (RSF), whole tree wood chips (WWF), sludge (SLF) and non-recyclable waste paper (NPF) in order to study the thermodynamic performance of an integrated gasifier–boiler power system for its hydrogen production. In this regard, both energy and exergy efficiencies of the system are investigated. The exergy contents of different biomass fuels are calculated to be ranging from 15.89 to 22.07 MJ/kg, respectively. The hydrogen concentrations based on the stack gases at the cyclone exit are determined to be between 7 and 18 (%v/v) for NPF and ASF. Also, percentages of combustible vary from 30% to 46%. The stack gas has physical and chemical exergies. The total specific exergy rates are calculated and illustrated. These values change from 3.54 to 6.41 MJ/kg. Then, two types of exergy efficiencies are calculated, such as that exergy efficiency 1 is examined via all system powers, exergy and efficiency 2 is calculated according to specific exergy rates of biomass fuels and product gases. While the exergy efficiencies 1 change between 4.33% and 11.89%, exergy efficiencies 2 vary from 18.33% to 39.64%. Also, irreversibilities range from 9.76 to 18.02 MJ/kg. Finally, we investigate how nitrogen contents of biomass fuels affect on energy and exergy efficiencies. The SLF has the highest amount of nitrogen content as 5.64% db while the NPF has the lowest one as 0.14% db. The minimum and maximum exergetic efficiencies belong to the same fuels. Obviously, the higher the nitrogen content the lower the efficiency based on an inverse ratio between exergy efficiency and nitrogen content.     

Performance assessment of an integrated PV/T and triple effect cooling system for hydrogen and cooling production

In this paper we study an integrated PV/T absorption system for cooling and hydrogen production based on U.A.E weather data. Effect of average solar radiation for different months, operating time of the electrolyzer, air inlet temperature and area of the PV module on power and rate of heat production, energy and exergy efficiencies, hydrogen production and energetic and exergetic COPs are studied. It is found that the overall energy and exergy efficiency varies greatly from month to month because of the variation of solar radiation and the time for which it is available. The highest energy and exergy efficiencies are obtained for the month of March and their value is 15.6% and 7.9%, respectively. However, the hydrogen production is maximum for the month of August and its value is 9.7 kg because in august, the solar radiation is high and is available for almost 13 h daily. The maximum energetic and exergetic COPs are calculated to be 2.28 and 2.145, respectively and they are obtained in the month of June when solar radiation is high for the specified cooling load of 15 kW.     

非晶硅太阳能光伏/光热空气集热器性能对比实验研究

文章设计了新型非晶硅太阳能PV/T空气集热器,该空气集热器能够解决传统太阳能PV/T热水器在高温波动情况下,晶硅电池热应力大的问题,同时避免了冬季管道发生霜冻的现象。文章通过实验对比,分析了非晶硅太阳能PV/T空气集热器、单独非晶硅光伏电池和传统太阳能空气集热器的能量效率和[火用]效率的差异。分析结果表明:非晶硅太阳能PV/T空气集热器的平均热效率为45.70%,比传统太阳能空气集热器的平均热效率降低了约25.88%;当空气质量流量增大至0.048 kg/s时,非晶硅太阳能PV/T空气集热器中的非晶硅光伏电池的平均电效率高于单独非晶硅光伏电池,它们的平均电效率分别为4.70%,4.54%;非晶硅太阳能PV/T空气集热器的总[火用]效率高于传统太阳能空气集热器的热[火用]效率和单独非晶硅光伏电池的电[火用]效率,非晶硅太阳能PV/T空气集热器总[火用]效率最大值为7.14%。文章的分析结果为非晶硅太阳能PV/T空气集热器的推广提供了参考。     

Energy and exergy efficiencies in Turkish transportation sector, 1988–2004

This study aims at examining energy and exergy efficiencies in Turkish transportation sector. Unlike the previous studies, historical data is used to investigate the development of efficiencies of 17 years period from 1988 to 2004. The energy consumption values in tons-of-oil equivalent for eight transport modes of four transportation subsectors of the Turkish transportation sector, including hard coal, lignite, oil, and electricity for railways, oil for seaways and airways, and oil and natural gas for highways, are used. The weighted mean energy and exergy efficiencies are calculated for each mode of transport by multiplying weighting factors with efficiency values of that mode. They are then summed up to calculate the weighted mean overall efficiencies for a particular year. Although the energy and exergy efficiencies in Turkish transport sector are slightly improved from 1988 to 2004, the historical pattern is cyclic. The energy efficieny is found to range from 22.16% (2002) to 22.62% (1998 and 2004) with a mean of 22.42±0.14% and exergy efficiency to range from 22.39% (2002) to 22.85% (1998 and 2004) with a mean of 22.65±0.15%. Overall energy and exergy efficiencies of the transport sector consist mostly of energy and exergy efficiencies of the highways subsector in percentages varying from 81.5% in 2004 to 91.7% in 2002. The rest of them are consisted of other subsectors such as railways, seaways, and airways. The overall efficiency patterns are basically controlled by the fuel consumption in airways in spite of this subsector's consisting only a small fraction of total. The major reasons for this are that airways efficiencies and the rate of change in fuel consumption in airways are greater than those of the others. This study shows that airway transportation should be increased to improve the energy and exergy efficiencies of the Turkish transport sectors. However, it should also be noted that no innovations and other advances in transport technologies are included in the calculations. The future studies including such details will certainly help energy analysts and policy makers more than our study.     

Exergy analysis of industrial ammonia synthesis

Exergy consumption of ammonia production plants depends strongly on the ammonia synthesis loop design. Due to the thermodynamically limited low degree of conversion of hydrogen–nitrogen mixture to ammonia, industrial ammonia synthesis is implemented as recycle process (so-called “ammonia synthesis loop”). Significant quantities of reactants are recycled back to reactor, after the removal of ammonia at low temperatures. Modern ammonia synthesis plants use well-developed heat- and cold recovery to improve the reaction heat utilisation and to reduce the refrigeration costs. In this work, the exergy method is applied to estimate the effect of the most important process parameters on the exergy efficiency of industrial ammonia synthesis. A specific approach, including suitable definitions of the system boundaries and process parameters, is proposed. Exergy efficiency indexes are discussed in order to make the results applicable to ammonia synthesis loops of various designs. The dependence of the exergy losses on properly selected independent process parameters is studied. Some results from detailed exergy analysis of the most commonly used ammonia synthesis loop design configurations at a wide range of selected parameters values are shown.     

Thermoeconomic analysis of household refrigerators

This study deals with thermoeconomic analysis of household refrigerators for providing useful insights into the relations between thermodynamics and economics. In the analysis, the EXCEM method based on the quantities exergy, cost, energy and mass is applied to a household refrigerator using the refrigerant R134a. The performance evaluation of the refrigerator is conducted in terms of exergoeconomic aspects based on the various reference state temperatures ranging from 0 to 20°C. The exergy destructions in each of the components of the overall system are determined for average values of experimentally measured parameters. Exergy efficiencies of the system components are determined to assess their performances and to elucidate potentials for improvement. Thermodynamic loss rate‐to‐capital cost ratios for each components of the refrigerator are investigated. Correlations are developed to estimate exergy efficiencies and ratios of exergy loss rate‐to‐capital cost as a function of reference (dead) state temperature. The ratios of exergy loss rates to capital cost values are obtained to vary from 2.949 × 10^?4 to 3.468 × 10^?4 kW USThis study deals with thermoeconomic analysis of household refrigerators for providing useful insights into the relations between thermodynamics and economics. In the analysis, the EXCEM method based on the quantities exergy, cost, energy and mass is applied to a household refrigerator using the refrigerant R134a. The performance evaluation of the refrigerator is conducted in terms of exergoeconomic aspects based on the various reference state temperatures ranging from 0 to 20°C. The exergy destructions in each of the components of the overall system are determined for average values of experimentally measured parameters. Exergy efficiencies of the system components are determined to assess their performances and to elucidate potentials for improvement. Thermodynamic loss rate‐to‐capital cost ratios for each components of the refrigerator are investigated. Correlations are developed to estimate exergy efficiencies and ratios of exergy loss rate‐to‐capital cost as a function of reference (dead) state temperature. The ratios of exergy loss rates to capital cost values are obtained to vary from 2.949 × 10^?4 to 3.468 × 10^?4 kW US$^?1. The exergy efficiency values are also found to range from 13.69 to 28.00% and 58.15 to 68.88% on the basis of net rational efficiency and product/fuel at the reference state temperatures considered, respectively. It is expected that the results obtained will be useful to those involved in the development of analysis and design methodologies that integrate thermodynamics and economics. Copyright © 2006 John Wiley & Sons, Ltd.     

Coupling of thermoelectric modules with a photovoltaic panel for air pre‐heating and pre‐cooling application; an annual simulation

Thermoelectric (TE) modules are possible reversible pre‐cooling and pre‐heating devices for ventilation air in buildings. In this study, the opportunity of direct coupling of TE modules with photovoltaic (PV) cells is considered. This coupling is evaluated through a numerical simulation depending on the meteorological conditions of Chambéry, Alpine region in France, and on the cooling or heating use of the TE modules, through annual energy and exergy efficiencies. For the considered conditions, TE module performances are of the same order as the ones of the vapour compression heat pumps, with a TE coefficient of performance higher than 2 for low values of input DC current. The PV–TE coupling efficiency varies between 0.096 and 0.23 over the year, with an average value of 0.157. Evolutions of the exergy effectiveness of PV and TE elements follow the same trends as the corresponding energy efficiencies but with steeper variations for the coupling exergy yield that varies between 0.004 and 0.014, with an annual average value of 0.010. The direct PV–TE coupling does not seem to be a sustainable option for the summer cooling purpose particularly. A case study with indirect coupling under a warm climate is considered and shows that the use of TE devices could be efficient in housing to ensure summer thermal comfort, but the corresponding necessary PV area would induce a high investment. Copyright © 2008 John Wiley & Sons, Ltd.     

Exergy analysis of a dual-level binary geothermal power plant

Exergy analysis of a 12.4 MW existing binary geothermal power plant is performed using actual plant data to assess the plant performance and pinpoint sites of primary exergy destruction. Exergy destruction throughout the plant is quantified and illustrated using an exergy flow diagram, and compared to the energy flow diagram. The causes of exergy destruction in the plant include the exergy of the working fluid lost in the condenser, the exergy of the brine reinjected, the turbine-pump losses, and the preheater–vaporizer losses. The exergy destruction at these sites accounts for 22.6, 14.8, 13.9, and 13.0% of the total exergy input to the plant, respectively. Exergetic efficiencies of major plant components are determined in an attempt to assess their individual performances. The exergetic efficiency of the plant is determined to be 29.1% based on the exergy of the geothermal fluid at the vaporizer inlet, and 34.2% based on the exergy drop of the brine across the vaporizer–preheater system (i.e. exergy input to the Rankine cycle). For comparison, the corresponding thermal efficiencies for the plant are calculated to be 5.8 and 8.9%, respectively.     

Performance assessment and optimization of industrial pasta drying

Drying is a high‐energy‐intensive operation and an important step in the pasta production. In this study, exergy analysis of a four‐step drying system in a farfalle pasta production line using actual operational data obtained from a plant located in Izmir, Turkey, was performed. Exergy loss rates, evaporation rates, exergy efficiencies, and improvement in potential rates for each dryer section were determined in this drying system. The exergy efficiency values varied between 0.25% and 5.27% from the predrying to the final drying section. The exergy efficiency value for the entire drying system was calculated to be 2.96%, and the highest exergetic improvement in potential rate was 165.54 kW for the first dryer section. Copyright © 2013 John Wiley & Sons, Ltd.     

A novel renewable energy-based integrated system with thermoelectric generators for a net-zero energy house

A renewable energy based integrated system is developed to meet the total energy demands of a house located off-grid, and a thermodynamic analysis through energy and exergy methodologies is conducted for analysis, evaluation, and performance assessment. The present novel multigeneration system is mainly driven through the animal residues produced at the farm house. The proposed novel system is composed of nine main units namely, a biomass combustor, photovoltaic (PV) panels, parabolic solar trough collectors, thermoelectric generators, organic Rankine cycle, electrolyzer, homogeneous charged compression ignition (HCCI) engine, absorption chiller, and reverse osmosis (RO) unit. Biomass combustor runs an organic Rankine turbine for additional power during peak loads. The exhaust of gas turbine generates cooling to meet the cooling demand of the residential area of the farm house. PV panels are incorporated to generate hydrogen through electrolyzer. A HCCI engine generates power to compensate peak load as well as charging the farming vehicles of the farm house. The RO unit with energy recovery Pelton turbine produces fresh water for farming and residential use. The advanced integration of subsystems, thermoelectric generators and efficient utilization of waste, improves significant amount of energetic and exergetic efficiencies of overall multigenerational system. The energy and exergy efficiencies are enhanced in the order of 4.8% and 6.3%, respectively, after incorporating innovative cooling system to the PV modules. The overall energy and exergy efficiencies of the proposed multigeneration system with and without thermoelectric are found to be 67.6% and 57.1%, and 68.9% and 58.4%, respectively.     

Concentration ratio and efficiency in thermophotovoltaics

Very high conversion efficiencies may be expected from solar cells for appropriately tailored spectra. In thermophotovoltaics, concentrated sunlight is used to heat a “black body” cavity which re-emits lower-temperature radiation. Solar cells immersed in the cavity can absorb the higher energy photons present and convert these to electric power with high efficiency. A generalization of this scheme is considered as a model for calculating the conversion efficiency expected for a real thermophotovoltaic system. This is shown to depend strongly on the concentration ratio used, as well as other factors. It is shown that conversion efficiencies above 30 per cent will require optics concentration ratios of the order of 10,000, for attainable values of other parameters. Cell conversion efficiencies exceed 60 per cent; however system performance is strongly degraded by parasitic losses and by re-radiation from the entrance aperture of the system.     

A review on solar-hydrogen/fuel cell hybrid energy systems for stationary applications

There are several methods for producing hydrogen from solar energy. Currently, the most widely used solar hydrogen production method is to obtain hydrogen by electrolyzing the water at low temperature. In this study, solar hydrogen production methods, and their current status, are assessed. Solar-hydrogen/fuel cell hybrid energy systems for stationary applications, up to the present day are also discussed, and preliminary energy and exergy efficiency analyses are performed for a photovoltaic-hydrogen/fuel cell hybrid energy system in Denizli, Turkey. Three different energy demand paths – from photovoltaic panels to the consumer – are considered. Minimum and maximum overall energy and exergy efficiencies of the system are calculated based on these paths. It is found that the overall energy efficiency values of the system vary between 0.88% and 9.7%, while minimum and maximum overall exergy efficiency values of the system are between 0.77% and 9.3% as a result of selecting various energy paths. More importantly, the hydrogen path appears to be the least efficient one due to the addition of the electrolyzer, the fuel cells and the second inverter for hydrogen production and utilization.     

Thermal management of metal hydride hydrogen storage using phase change materials for standalone solar hydrogen systems: An energy/exergy investigation

This paper reports on an energy/exergy analysis of a standalone solar-hydrogen system with a metal hydride (MH) system thermally managed using a phase change material (PCM). This is a self-contained thermal management arrangement that stores the heat released from the MH unit, when it is being charged and transfers it back to the MH while discharging hydrogen. The first and second laws of thermodynamics were used to develop a mathematical model in MATLAB to simulate this system and quality its performance from the energy and exergy viewpoints. The model was then applied on a passive standalone house, with ～3.8 MWh/year electricity demand, located in southeast Australia. The exergy efficiencies of the solar PV, electrolyser, fuel cell and the whole solar hydrogen system were found to be 6.5%, 88%, 50.6%, and 3.74%, respectively. The paper also provides the detailed entropy generation and exergy analysis on the MH hydrogen storage unit together with its PCM-based thermal management arrangement. The results show that the annual entropy generation, exergy destruction and exergy efficiency of the MH hydrogen storage unit were 173 Wh/K, 51.5 kWh, and 98.8%, respectively.     

Modified exergoeconomic modeling of geothermal power plants

In this study, a modified exergoeconomic model is proposed for geothermal power plants using exergy and cost accounting analyses, and a case study is in this regard presented for the Tuzla geothermal power plant system (Tuzla GPPS) in Turkey to illustrate an application of the currently modified exergoeconomic model. Tuzla GPPS has a total installed capacity of 7.5 MW and was recently put into operation. Electricity is generated using a binary cycle. In the analysis, the actual system data are used to assess the power plant system performance through both energy and exergy efficiencies, exergy losses and loss cost rates. Exergy efficiency values vary between 35% and 49% with an average exergy efficiency of 45.2%. The relations between the capital costs and the exergetic loss/destruction for the system components are studied. Six new exergetic cost parameters, e.g., the component annualized cost rate, exergy balance cost, overall unavoidable system exergy destruction/loss cost rate, overall unavoidable system exergy destruction/loss cost rate, overall unavoidable system exergy production cost rate and the overall unavoidable system exergy production cost rate are studied to provide a more comprehensive evaluation of the system.     

Enhanced generation of hydrogen,power, and heat with a novel integrated photoelectrochemical system

Hydrogen is an essential component of power-to-gas technologies that are needed for a complete transition to renewable energy systems. Although hydrogen has zero GHG emissions at the end-use point, its production could become an issue if non-renewable, and pollutant energy and material resources are used in this step. Therefore, a crucial step for the fully developed hydrogen economy is to find alternative hydrogen production methods that are clean, efficient, affordable, and reliable. With this motivation, in this study, an integrated and continuous type of hydrogen production system is designed, developed, and investigated. This system has three components. There is a solar spectral splitting device (Unit I), which splits the incoming solar energy into two parts. Photons with longer wavelength is sent to the photovoltaic thermal hybrid solar collector, PV/T, (Unit II) and used for combined heat and power generation. Then the remaining part is transferred to the novel hybrid photoelectrochemical-chloralkali reactor (Unit III) for simultaneous H₂, Cl₂, and NaOH production. This system has only one energy input, which is the solar irradiation and five outputs, namely H₂, Cl₂, NaOH, heat, and electricity. Unlike most of the studies in the literature, this system does not use only PV or only a photoelectrochemical reactor. With this approach, solar energy utilization is maximized, and the wasted portion is minimized. By selecting PV/T rather than PV, the performance of the panels is maximized because recovering the by-product heat as a system output in addition to electricity, and the PV/T has less waste and higher efficiency. The present reactor does not use any additional electron donors, so the wastewater discharge is only depleted NaCl solution, which makes the system significantly cleaner than the ones available in the literature. The specific aim of this study is to demonstrate the optimum operating parameters to reach the maximum achievable production rates and efficiencies while keeping the exergy destruction as little as possible. In this study, there are four case studies, and in each case study, one decision variable is optimized to get the desired performance results. Within the selected operating parameter range, all performance criteria (except exergy destruction) are normalized and ranked for proper comparison. The maximum production rates and efficiencies with the least possible exergy destruction are observed at the operating temperature of 30 °C. At 30 °C, 4.18 g/h H₂, 127.55 g/h Cl₂, 151 W electricity, and 716 W heat are produced with an exergy destruction rate of 95.74 W and 78% and 30% energy and exergy efficiencies, respectively.     

Analysis and performance assessment of a combined geothermal power-based hydrogen production and liquefaction system

In this paper, the thermodynamic study of a combined geothermal power-based hydrogen generation and liquefaction system is investigated for performance assessment. Because hydrogen is the energy of future, the purpose of this study is to produce hydrogen in a clear way. The results of study can be helpful for decision makers in terms of the integrated system efficiency. The presented integrated hydrogen production and liquefaction system consists of a combined geothermal power system, a PEM electrolyzer, and a hydrogen liquefaction and storage system. The exergy destruction rates, exergy destruction ratios and exergetic performance values of presented integrated system and its subsystems are determined by using the balance equations for mass, energy, entropy, energy and exergy and evaluated their performances by means of energetic and exergetic efficiencies. In this regard, the impact of some design parameters and operating conditions on the hydrogen production and liquefaction and its exergy destruction rates and exergetic performances are investigated parametrically. According to these parametric analysis results, the most influential parameter affecting system exergy efficiency is found to be geothermal source temperature in such a way that as geothermal fluid temperature increases from 130 °C to 200 °C which results in an increase of exergy efficiency from 38% to 64%. Results also show that, PEM electrolyzer temperature is more effective than reference temperature. As PEM electrolyzer temperature increases from 60 °C to 85 °C, the hydrogen production efficiency increases from nearly 39% to 44%.     

Exergoeconomic and environmental impact analyses of a renewable energy based hydrogen production system

In this study, exergoeconomic and environmental impact analyses, through energy, exergy, and sustainability assessment methods, are performed to investigate a hybrid version renewable energy (including wind and solar) based hydrogen and electricity production system. The dead state temperatures considered here are 10 °C, 20 °C and 30 °C to undertake a parametric study. An electrolyzer and a metal hydride tank are used for hydrogen production and hydrogen storage, respectively. Also, the Proton Exchange Membrane Fuel Cell (PEMFC) and battery options are utilized for electricity generation and storage, respectively. As a result, the energy and exergy efficiencies and the sustainability index for the wind turbine are found to be higher than the ones for solar photovoltaic (PV) system. Also, the overall exergy efficiency of the system is found to be higher than the corresponding overall energy efficiency. Furthermore, for this system, it can be concluded that wind turbine with 60 gCO₂/month is more environmentally-benign than the solar PV system with 75 gCO₂/month. Finally, the total exergoeconomic parameter is found to be 0.26 W/$, when the energy loss is considered, while it is 0.41 W/$, when the total of exergy loss and destruction rates are taken into account.     

A review on biomass‐based hydrogen production and potential applications

In this paper, a detailed review is presented to discuss biomass‐based hydrogen production systems and their applications. Some optimum hydrogen production and operating conditions are studied through a comprehensive sensitivity analysis on the hydrogen yield from steam biomass gasification. In addition, a hybrid system, which combines a biomass‐based hydrogen production system and a solid oxide fuel cell unit is considered for performance assessment. A comparative thermodynamic study also is undertaken to investigate various operational aspects through energy and exergy efficiencies. The results of this study show that there are various key parameters affecting the hydrogen production process and system performance. They also indicate that it is possible to increase the hydrogen yield from 70 to 107 g H₂ per kg of sawdust wood. By studying the energy and exergy efficiencies, the performance assessment shows the potential to produce hydrogen from steam biomass gasification. The study further reveals a strong potential of this system as it utilizes steam biomass gasification for hydrogen production. To evaluate the system performance, the efficiencies are calculated at particular pressures, temperatures, current densities, and fuel utilization factors. It is found that there is a strong potential in the gasification temperature range 1023–1423 K to increase energy efficiency with a hydrogen yield from 45 to 55% and the exergy efficiency with hydrogen yield from 22 to 32%, respectively, whereas the exergy efficiency of electricity production decreases from 56 to 49.4%. Hydrogen production by steam sawdust gasification appears to be an ultimate option for hydrogen production based on the parametric studies and performance assessments that were carried out through energy and exergy efficiencies. Finally, the system integration is an attractive option for better performance. Copyright © 2012 John Wiley & Sons, Ltd.