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Significant research efforts are directed towards finding new ways to reduce the cost, increase efficiency, and decrease the environmental impact of power-generation systems. The poly-generation concept is a promising strategy that enables the development of a sustainable power system. Over the past few years, the Proton Exchange Membrane Fuel Cell-based Poly-Generation Systems (PEMFC-PGSs) have received accelerated developments due to the low-temperature operation, high efficiency, and low environmental impact. This paper provides a comprehensive review of the main PEMFC-PGSs, including Combined Heat and Power (CHP) co-generation systems, Combined Cooling and Power (CCP) co-generation systems, Combined Cooling, Heat, and Power (CCHP) tri-generation systems, and Combined Water and Power (CWP) co-generation systems. First, the main technologies used in PEMFC-PGSs, such as those related to hydrogen production, energy storage, and Waste Heat Recovery (WHR), etc., are detailed. Then, the research progresses on the economic, energy, and environmental performance of the different PEMFC-PGSs are presented. Also, the recent commercialization activities on these systems are highlighted focusing on the leading countries in this field. Furthermore, the remaining economic and technical obstacles of these systems along with the future research directions to mitigate them are discussed. The review reveals the potential of the PEMFC-PGS in securing a sustainable future of the power systems. However, many economic and technical issues, particularly those related to high cost and degradation rate, still need to be addressed before unlocking the full benefits of such systems.

Poly-generation systems are an exciting new technology that provide an alternative to separating existing energy production methods in buildings. A poly-generation system enables the efficient simultaneous production of heating, cooling, fresh water, and electricity, resulting in many technological, economic, energy recovery, and environmental advantages. This study numerically investigates three proposed novel solar-driven poly-generation systems (BS, IS-I, and IS-II) integrated with organic Rankine cycle (ORC), humidification-dehumidification desalination system (HDH), and desiccant cooling system (DCS) with different heat recovery system arrangements. The suggested systems supply residential structures with energy, space conditioning, domestic heating, and fresh water. The effects of system operating circumstances on productivity and performance characteristics and several organic working fluid types (n-octane, R245fa, R113, isopentane, and toluene) on optimum system performance have been investigated. The results show that (i) the average enhancement percentage of TGOR using integrated poly-generation systems over the separated ones is 68.5%, 68.5%, and 95.5% for BS, IS-I, and IS-II systems, respectively; (ii) when comparing the three systems, the IS-I system outperforms the other systems (BS & IS-II); and (iii) the maximum values of W•net, m•fresh, Q•cooling, and Q•heating, obtained for different proposed systems using n-octane are 102 kW (all systems), 214.7 kg/h (IS-II), 29.94 kW (IS-II), and 225.6 kW (IS-I); (iv) R113 has the highest TGOR of 0.6924 (IS-I) compared to other organic fluids. (v) The improvements in Wnet•, mfresh•, Qcooling• and Qheating• with using toluene instead of R113 at tf1 = 40 °C are 177.5%, 105.8%, 389.25%, and 79%, respectively.

Biomass serves as a promising renewable and sustainable feedstock for energy production through thermochemical conversion. It can be transformed into sustainable biofuels by means of pyrolysis. Among these methods, the pyrolytic poly-generation of biomass, a novel biomass thermal conversion technology, can concurrently produce three valuable products, namely biochar, bio-oil, and combustible gas, without generating any byproducts. In contrast, conventional thermal conversion processes, such as carbonization for biochar, liquefaction for bio-oil, gasification for syngas, and combustion for heat, only yield single products, have limited efficiency, and give rise to byproducts. Clearly, pyrolytic poly-generation holds significant advantages over conventional thermal conversion processes. Nevertheless, the pyrolytic poly-generation process and its products are remarkably influenced by numerous factors, including the raw biomass properties, pretreatment methods, operating parameters, and catalysts. This article reviews the processing parameters and technology for biomass pyrolytic poly-generation, and also explores future research areas, with the aim of identifying research gaps and promoting its industrial implementation.

Poly-generation systems are a feasible alternative to conventional energy production techniques in buildings. A poly-generation system allows for the concurrent production of electricity, heat, cold, and fresh water, with considerable advantages regarding technology, finances, energy recovery, and the environment. In the present study, the organic Rankine cycle (ORC), the humidification–dehumidification desalination system (HDH), and the desiccant cooling system (DCS) are merged with three unique solar-driven poly-generation systems (BS, IS-I, and IS-II) and numerically examined. The proposed options provide energy, space cooling, domestic heating, and potable water to buildings of small/medium scale. Using n-octane ORC working fluid, the impact of operational circumstances on system productivity and execution characteristics was considered. The findings show that (i) the suggested poly-generation systems can provide electrical power, conditioned space cooling, local heating, and fresh water, whereas keeping the conditioned area pleasant, (ii) the IS-I system achieves the best system performance among all compared arrangements (BS and IS-II); (iii) the attained extreme values of W˙net, m˙fresh, Q˙cooling, Q˙heating, and TGOR are 102.0 kW (all systems), 214.70 kg/h (IS-II), 29.940 kW (IS-II), 225.6 kW (IS-I), and 0.6303 (IS-I), respectively.

A poly-generation system for cooling, heating, power, and fresh water is proposed, based on SOFC/GT/MED and an absorption chiller, with biogas as fuel. The performance of the system under the designed condition is analyzed using energy, exergy, and economic methods. An efficiency of 69.02% for comprehensive energy utilization and 35.56% for exergy are demonstrated by simulation results under the designed condition. A freshwater production of 469.93 kg/h is achieved, and a cost rate of 22.51 USD/h is incurred by the system. The effects of various parameters on the system characteristics are examined. Multi-objective optimization methods are employed to determine the final optimum operating condition that yields the best results in two schemes with different objectives. In comparison to the initial design, the optimization of the first scheme results in a 4.58% increase in the comprehensive energy utilization rate and a 2.02% increase in the exergy efficiency. However, the cost rate of the entire system increases by 0.63 USD/h. On the other hand, the optimization of the second scheme leads to a 19.51 kW decrease in the total energy output, a 276.38 kg/h increase in the freshwater production rate, and a 0.42 USD/h decrease in the cost rate of the entire system.

India is blessed with good solar resources and many regions of the country receive above-average sunshine compared to other regions of the world. The primary technology used for harnessing and converting solar energy into electrical energy in India is based on photovoltaic (PV) cells. Concentrated solar power (CSP) has hardly contributed to the overall installed solar power capacity in the country. In this article, some of the challenges that have inhibited the growth of CSP are identified and possible solutions suggested. The critical challenges for CSP are related to the lack of reliable direct normal irradiance database, indigenous manufacturing and competition from PV. The results of a case study carried out to assess the impact of indigenous manufacturing and economies of scale on capital costs and levelized cost of electricity are presented. This study shows that even with indigenous manufacturing and considering economies of scale, the capital cost per MW (Megawatt) of installed capacity is higher than the Central Electricity Regulatory Commission benchmark costs. To initiate larger adoption of CSP in India, we may have to consider alternative configurations, such as coupling desalination or thermal cooling systems to a CSP power plant. The merits of such configurations, called poly-generation plants, are presented for the Indian scenario.

The aim of this work is to assess the energy vector poly-generation capabilities of gasification plants equipped with carbon capture and utilization (CCU) features. As evaluated energy carriers, various total or partial decarbonized vectors were investigated (e.g., power, hydrogen, synthetic natural gas, methanol, Fischer-Tropsch fuel). As illustrative examples, the gasification concepts with 100 MW net energy output were considered having an overall plant decarbonization rate of 90%. As decarbonization technologies, the gas – liquid absorption based on chemical and physical scrubbing was assessed. A broad range of process system engineering tools were used (e.g., modeling and simulation, process integration, plant flexibility elements, technical and environmental evaluation). As results show, the application of carbon capture and utilization technologies for gasification-based poly-generation has promising results in term of increasing the overall energy efficiency (up to 68%), reducing CO2 emissions (down to 7 kg/MWh) and improving cycling capabilities.

Supercritical water gasification driven by solar energy is a promising way for clean utilization of biomass with high moisture content, but direct discharge of liquid residual causes energy waste and decreases energy efficiency. To reduce energy waste, a poly-generation system for hydrogen-rich gas production coupling heat supply and power generation based on supercritical water gasification of biomass driven by concentrated solar energy was established in this paper, which also provided a novel energy storage method to overcome the shortcomings of solar discontinuity. Thermodynamic model of the system was proposed and life cycle assessment (LCA) of the system was conducted. Influence of different parameters (temperature of 600°C to 800°C, outlet temperature of heat exchanger of 42°C to 56°C, biomass slurry concentration of 5% to 6.5%) on the gasification performance, energy and exergy efficiency, energy distribution and global warming potential (GWP) was discussed. The results indicated that hydrogen yield increased as gasification temperature increased since free radical reaction was enhanced which gas production reaction was classified into. Molar fraction of hydrogen increased as gasification temperature increased and reached 65.6% at 750°C. Energy and exergy efficiency of the system reached 74.84% and 34.87% at 700°C and 600°C respectively and that of gas production was 18.15% at 650°C, which was the highest. Increasing reaction temperature and decreasing biomass slurry concentration were effective ways to decrease GWP. Optimal operating parameter was reaction temperature of 650°C, outlet temperature of heat exchanger of 50°C and biomass concentration of 5%.

Since the hydrogen-production process is not yet fully efficient, this paper proposes a poly-generation system that is driven by a geothermal energy source and utilizes a combined Kalina/organic Rankine cycle coupled with an electrolyzer unit to produce, simultaneously, power and green hydrogen in an efficient way. A comprehensive thermodynamic analysis and an exergetic evaluation are carried out to assess the effect of key system parameters (geothermal temperature, high pressure, ammonia–water concentration ratio, and terminal thermal difference) on the performance of concurrent production of power and green hydrogen. Thereby, two configurations are investigated with/without the separation of turbines. The optimal ammonia mass fraction of the basic solution in KC is identified, which leads to an overall optimal system performance in terms of exergy efficiency and green hydrogen production rate. In both configurations, the optimal evaluation is made possible by conducting a genetic algorithm optimization. The simulation results without/with the separation of turbines demonstrate the potential of the suggested cycle combination and emphasize its effectiveness and efficiency. Exemplary, for the case without the separation of turbines, it turns out that the combination of ammonia–water and MD2M provides the best performance with net power of 1470 kW, energy efficiency of 0.1184, and exergy efficiency of 0.1258 while producing a significant green hydrogen amount of 620.17 kg/day. Finally, an economic study allows to determine the total investment and payback time of $3,342,000 and 5.37 years, respectively. The levelized cost of hydrogen (LCOH) for the proposed system is estimated at 3.007 USD/kg H2, aligning well with values reported in the literature.

A novel arrangement of a poly-generation system, integrating a combined cooling heating and power (CCHP) system and a hydrogen production unit is introduced and analyzed in this article. The poly-generation system comprises of a gas turbine as the prime mover, a high pressure steam generation unit, a hydrogen production unit and an absorption refrigeration chiller. The simulation and operation analysis of the proposed system is done with Aspen Plus software. Moreover, economic and energy analyses are investigated for the system. Also an optimization is done by the economical profit function as the objective function. The results show that the energy efficiency of the poly-generation system is 55.28% which indicates an increment of 75.82% than the single gas turbine power plant while it earns 79 million dollars per year as profit. Also, the economic evaluation shows a payback period of <1 year. Additionally, sensitivity analysis is conducted by analyzing the influences of the operating parameters like ammonia mass fraction of the absorption chiller and the steam to methane ratio of the hydrogen production cycle on performance of the poly-generation system. The results show that increasing the ammonia mass fraction leads to increment of cooling capacity and consequently the total efficiency of the system. It is also concluded that produced hydrogen mass flow rate has a direct relationship with steam to methane ratio and more hydrogen is produced at higher ratios that leads to increment of the system total efficiency where increasing the ratio from 1 to 3.5 increases the produced hydrogen and total efficiency of the system 115 and 127%, respectively. Optimization shows that, it is more beneficial to have the minimum cooling capacity and increase the hydrogen production to maximize the profit. It also indicates that the profit function at first increases by reducing the reformer temperature but after while decreases due to the greater increment of total capital and operational costs than income. For instance, reducing the reformer temperature from 510 to 500°C increases the total capital and operational costs ~29%.