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In this study, green hydrogen production by utilizing diesel engine exhaust gas waste heat in steam and organic Rankine with internal heat exchanger with two thermoelectric generators and proton exchange membrane electrolyzer combined system under different load conditions is investigated. Thermo-economic, enviro-economic and exergo-environmental analyses of the maximum hydrogen production point determined for different waste heat conditions are carried out. Total and specific investment cost and levelized cost of hydrogen determined under different loads are compared. Simple and dynamic payback period, profit ratio of investment and net present value of the combined system at different selling prices of hydrogen are determined and their feasibility is analyzed. Carbon reduction and carbon credit gain amount due to green hydrogen produced in line with zero emission targets are compared under different waste heat conditions. Exergetic sustainability index of the system were determined within the scope of exergo-environmental analysis. In terms of economic and environmental performance, a hydrogen cost of 2.04 $/kg was obtained under 100% load and a carbon saving of 7211 $ was achieved depending on the hydrogen produced. Dynamic payback period and net present value were found to be 4.467 years and 404,696 $, respectively, if the hydrogen selling price was 5 $/kg under 100% load. It is found that a 50% load reduction leads to an increase in dynamic payback period and levelized cost of hydrogen by 18.6% and 13.72%, respectively, and a decrease in net present value and profit ratio of investment by 54.39% and 12.39%, respectively. On the other hand, since the exergy destruction decreases with the decrease in the load, exergo-environmental index is found to decrease by 2.03%. • 7211 $ carbon recovery was obtained. • Dynamic payback period between 1.942 and 9.578 years was determined. • The maximum net present value reached 1,123,000 $. • Combined hydrogen production system is unfeasible if the hydrogen price is 2 $/kg. • Within the scope of sustainability, exergo-environmental indices were examined. [ABSTRACT FROM AUTHOR]

An assessment was made of the influence of underburning of hydrogen in a hydrogen-oxygen steam generator on the technical and economic efficiency of installing a hydrogen energy complex at a nuclear power plant, which is a well-known approach to solving an urgent problem of modern energy systems – ensuring the further development of nuclear energy as an environmentally friendly source of electricity based on the accumulation of off-peak electricity. An approach is considered and a diagram is presented for increasing the reliability of using the hydrogen energy complex at nuclear power plants by reducing underburning and eliminating the entry of unburned hydrogen into the main steam power cycle of the power unit. Several options for the level of hydrogen underburning and a range of system operating conditions for the hydrogen energy complex are considered. A comprehensive calculation of the technical and economic indicators of the hydrogen energy complex at nuclear power plants was carried out, and the conditions for its effectiveness were determined. As calculations have shown, underburning of hydrogen leads to a noticeable decrease in annual income and average annual profit from the sale of peak electricity. The achieved reduction is 11.67 and 35.01 million rubles/year at 5 and 15% hydrogen underburning, respectively. At the minimum tariff for off-peak electricity, the reduction in accumulated net present value is 96.6, 192.8 and 289.4 with an increase in hydrogen underburning to 5, 10 and 15%, respectively. The dependence of the marginal level of hydrogen underburning on the tariff for off-peak electricity, which ensures the efficiency of implementation of the considered hydrogen energy complex at nuclear power plants, is constructed. As calculations have shown, efficient operation of the hydrogen energy complex is achieved at a tariff for off-peak energy in the range from 0 to 0.45, 0.38, 0.3 and 0.24 rubles/kWh with hydrogen underburning of 0, 5, 10 and 15%, respectively. [ABSTRACT FROM AUTHOR]

The multi-energy complementary system (MECS) is a new mode that converts renewables into electricity and is usually equipped with hydrogen storage. It realizes flexible conversion of electric and hydrogen energy, achieving high efficiency and low carbon. However, how to optimize capacity of each equipment based on operation strategies and objectives becomes the most important issue. Thus, this study focuses on MECS optimal allocation and manages to work out a scientific framework. Firstly, the Density-Based Spatial Clustering of Applications with Noise algorithm and the Calinski Harabasz Index are firstly integrated to improve K-means clustering algorithm and identify typical scenarios. It can efficiently deal with long-sequence scenario reduction under the uncertainty of generation and load demand. Then, different from conventional objective-determining processes, indicators of the net present value, the carbon emission reduction, the power curtailment rate are taken into account to reflect comprehensive benefits from the life cycle of the MECS. Subsequently, for the difficulty of mixed integer fraction optimization, the -constraint method is introduced in model solving. Finally, a case study of Shenzhen is carried out for verification. The proposed models can achieve optimal allocation with different preference, which can provide theoretical and technical reference for MECS development. [Display omitted] • Industrial park multi-energy complementary system with hydrogen storage is built. • DBSCAN algorithm is introduced to extract typical scenarios based on cluster analysis. • Comprehensive benefits are taken into account in configuration optimization. • An ε-constraint is applied to solve the mixed integer fraction optimization problem. • Theoretical and technical reference is provided for low-carbon and green transition. [ABSTRACT FROM AUTHOR]

Based on the energy development strategy of Russia until 2035, the article substantiates the prospect for the development of nuclear energy, according to which nuclear plants are planned to be forced to unload in the range of up to 50% of the rated power while participating in the regulation of daily unevenness of the electrical load. In addition, nuclear power plants will be involved in primary frequency regulation, which is also associated with the unloading mode of operation of nuclear power plants. All these circumstances force us to look for ways to provide nuclear power plants with base load. Along with pumped storage power plants, the article considers an alternative option in the form of using a hydrogen complex based on the electrolysis production of hydrogen, which satisfies the concept of its carbon-free production. The article presents the global dynamics of the introduction of electrolyzers, and in addition to the increase in the share of electrolysis hydrogen produced at nuclear power plants. The hydrogen complex in this case is a means of providing the nuclear power plant with a base load, which involves the consumption of unclaimed electricity at cost. This allows hydrogen to be produced at a competitive price compared to individual producers on the market. The resulting hydrogen is in great demand as a useful product in a number of industries. The article provides examples of hydrogen consumption in various areas of consumption depending on purity, taking into account the requirements of GOST. A number of consumer industries use hydrogen of a special degree of purity, i.e., more than 99.999% vol. In this regard, additional hydrogen purification on palladium membranes was taken into account. A comprehensive assessment of the efficiency of the hydrogen production system was carried out, taking into account its additional purification and delivery to the consumer in various ways, mastered and in demand in world practice. A comparison has been made of the methods of delivering hydrogen to the consumer in comparison with the production of hydrogen by electrolysis at the point of consumption. A comparison was made using the criterion of net present value for the option of third-party consumers who do not have their own hydrogen production. [ABSTRACT FROM AUTHOR]

The increase in the share of energy output from nuclear power plants and the emergence of new requirements of the system operator of the Unified Energy System (UES) of the Russian Federation raise the question of increasing the efficiency of nuclear power plants in alternating mode. At the same time, the operation of nuclear power plants is economically feasible with a maximum utilization rate of installed capacity due to significant capital investments and the low price of nuclear fuel. A possible solution to regulating the level of supplied electricity during off-peak hours of energy consumption is to direct its excess to produce hydrogen with its further sale to consumers without reducing the power of the power unit. According to the analysis, most enterprises that are potential consumers of hydrogen from nuclear power plants have their own modular installations for its production. In the work, a comparative analysis of centralized hydrogen production at nuclear power plants and hydrogen production at places of its consumption was carried out. The daily period of hydrogen production at nuclear power plants is limited to the night period, when there is an excess of generating capacity in the energy system. In this case, local hydrogen production can be carried out evenly throughout the day. This leads to an increase in the cost of hydrogen production at nuclear power plants due to a larger storage system and an increase in the number of compressor and electrolysis units. Nuclear power plants will require significant costs to transport the generated gas. At the same time, the advantage of a nuclear power plant is the cost of consumed electricity, taken at the level of the cost of its production. For industrial consumers, the electricity tariff is significantly higher. In the work, a comparative assessment of the cost of hydrogen production at nuclear power plants and at the site of its consumption was carried out taking into account a range of system conditions. A sales surcharge to the cost of hydrogen production at nuclear power plants was additionally adopted. Zones of competitive efficiency in the implementation of the hydrogen complex at nuclear power plants have been identified, in which the production of hydrogen at the site of its consumption requires greater costs than the purchase of commercial hydrogen from nuclear power plants. Based on the competitive range of the sales surcharge to the selling price of hydrogen at nuclear power plants and the accepted initial conditions, an assessment of the accumulated net present value and payback period of the hydrogen production plant was carried out during its production at nuclear power plants for sale. [ABSTRACT FROM AUTHOR]

The country's first on-site hydrogen refueling station (HRS) is installed at the Hydrogen Energy Laboratory, Bangladesh Council of Scientific and Industrial Research (BCSIR), and its performance is studied to penetrate and prepare the hydrogen refueling network for the future. The study fills the power conditioning and integration information gap to HRS and refueling performances of on-site HRS in the particular conditions of the country. Strategic integration of grid power to the HRS is materialized and its adaptation with on-site HRS. Low-cost frequency & voltage conversion (conversion of 50 Hz, 420 V, or 220 V to stable 60 Hz, 220 V, or 110 V) and its stabilization are successfully made. An initial pressure of 5 MPa and 10 MPa of the vehicle tank (two-time refueling conditions) at 25 °C fills with the hydrogen at the APRR of 5.07 & 6.39 by 5.91& 7.5 min accordingly whereas the target pressure is 35 MPa. Hydrogen transfer to the vehicle tank at the pressure established by SAE J2799 according to the APRR during refueling time. The system consumes 52.71 kW and 3.73 kW of power to produce and compress 1 kg of hydrogen. The temperature profile shows that at the maximum hydrogen flow rate of 20 g/s, the temperature rose to 56 °C maintaining the fueling protocol. The levelized cost of hydrogen (LCOH P) of on-site hydrogen production is $6.68 and the LCOH S&D of storage & dispensing of hydrogen is $1.07 using the grid electricity whereas it gets down to $3.74 and $0.76 for the case of solar PV. Hydrogen vehicles reduce 43% fuel cost (using grid power) as compared to diesel engines. The study also depicts that a solar-powered hydrogen fleet is a better option for replacing fossil fuels and in shaping a sustainable transport system. The economic analyses provide the net present value (NPV 20) and benefit and cost ratio (BCR) of the on-site HRS are 0.09 million and 1.18 at the discount rate of 9.5% which corresponds to the investment to the on-site HRS is feasible and free of risk. • Strategic conversion and integration of power with on-site hydrogen refueling station. • LCOH of hydrogen at on-site HRS $7.5 & $3.50 using grid and Solar PV accordingly. • SAE J2799 nozzle and slow filling are used to refuel the vehicle without precooling. • Hydrogen vehicle reduces 43% of fuel cost as compared to gasoline-burned vehicles. [ABSTRACT FROM AUTHOR]

To achieve the near-zero carbon emissions from chemical looping hydrogen generation (CLHG) power plant, two novel systems were proposed in this study: one integrates CLHG with ammonia decomposition for hydrogen production (ADHP) and CO 2 hydrogenation to methanol (CHM), while the other integrates CLHG with CHM and CO 2 compression storage (CCS). The performance of these two integrated systems was evaluated through analyses of economy, energy, exergy, and ecology (4E). The findings reveal that the CLHG-CHM-CCS system is more economically competitive and environmentally favorable than the CLHG-ADHP-CHM system. Its maximum net present value increases by 2.373×108 $, and annual CO 2 emissions decreases by 361.401 t. Meanwhile, the system's profitable allowable maximum purchasing price of natural gas increases by 0.036 $/Nm3, while its minimum selling price of methanol decreases by 47.583 $/t. However, the CLHG-ADHP-CHM system exhibits improvements in both energy efficiency and exergy efficiency, with improvements of 1.88% and 2.34%, respectively, compared to the CLHG-CHM-CCS system. Moreover, reactors within the CLHG subsystem account for 42.60% of its total exergy loss, offering a potential 3.275 MW improvement. • Two novel CLHG-based systems for achieving near-zero carbon emissions were proposed. • Economy, energy, exergy and ecology analysis for the systems was carried out. • CLHG-CHM-CCS system proved to be more economical. • Carbon capture rates for both systems exceed 99.5%. • Reactors within the CLHG subsystem account for 42.60% of its total exergy loss. [ABSTRACT FROM AUTHOR]

The mixture of cotton straw and plastic mulch film is co-treated by mobile pyrolysis technology for co-production of biochar, bio-oil and electricity, which shows good economic benefits and CO 2 emission reduction capacity while controlling environmental pollution. [Display omitted] • Co-pyrolysis approach resolves the application of high-ash straw and film mixture. • TEA and LCA perform the comparison of mobile pyrolysis and concentrated pyrolysis. • Mobile pyrolysis achieves short PBP of 4.32 years and low GWP of −1.298 kgCO 2 -eq. The widespread use of plastic mulch film (PMF) has led to significant environmental pollution, with PMF residues dispersed and mixed with straw and soil, posing challenges for recycling. Here, we proposed the mobile pyrolysis facility for the cotton straw and mulch film mixture (CMM) to mitigate the collection, storage, and transportation costs, while the application of co-pyrolysis technology for CMM conversion could improve the added value of products. Additionally, centralized combustion power generation and centralized pyrolysis systems were also established to evaluate and compare their sustainability from economic and environmental perspectives. Results showed that mobile pyrolysis has better economic performance than the centralized scenarios, due to its high internal rate of return (31 %) and significant net present value (29.21 M USD). Meanwhile, the mobile pyrolysis facility achieved a GWP of −1.298 kgCO 2 -eq/kg, reducing emissions by 70.79 % and 38.82 % compared to the two centralized scenarios. In conclusion, mobile pyrolysis technology provides a promising solution for PMF residue recycling because of its economically competitive approach with a lower carbon footprint. [ABSTRACT FROM AUTHOR]

To comply with the trend of emission reduction and energy-saving in the industrial sector, a novel integration of the hydrogen liquefaction process based on reversed Brayton cycle (RBC) with the organic Rankine cycle (ORC), for waste heat recovery is proposed. The high temperature gas in the compressor outlet of RBC, which is typically wasted in air-coolers, is recovered in ORC and used as the heat source for power generation for the hydrogen liquefaction process. Thermodynamic analysis showed that compared to the conventional system COP increased by 17.95% from 0.11 to 0.14 and specific energy consumption (SEC) decreased by 16.33% from 10.84 to 9.07 kWh/kg LH2. Parametric analysis was conducted to evaluate the impact of pressure ratio, evaporator temperature and minimum temperature difference (M Δ T) in heat exchangers, on system performance. Changes in these variables affect the system performance and heat transfer area in opposite directions, thus multi-objective optimization by the genetic algorithm was performed to determine the optimum operating conditions. The SEC and the net present value (NPV) were selected as objective functions and were optimized simultaneously. Results from the optimization process indicate that the SEC and NPV were found to be 9.165 kWh/kgH 2 and 1.55 million dollars with the optimal evaporator temperature of 365 K, pressure ratio of 2.85, and the M Δ T of 7.79. • A novel design of hydrogen liquefaction process with heat recovery is examined. • Reversed Brayton cycle is integrated with organic Rankine cycle for the process. • The specific energy consumption is decreased by 16.33% than the conventional one. • Multi-objective genetic algorithm is used to evaluate techo-economic viability. [ABSTRACT FROM AUTHOR]

Volatile electricity prices have raised concerns about the economic feasibility of wind projects in Finland. This study assesses the economic viability and optimal operational strategies for integrating wind-powered green hydrogen production systems. Utilizing modeling and optimization, this research evaluates various wind farms in Western Finland over electricity market scenarios from 2019 to 2022, with forecasts extending to 2030. Key economic metrics considered include internal rate of return, future value, net present value (NPV), and the levelized cost of hydrogen (LCOH). Results indicate that integration of hydrogen production with wind farms shows economic benefits over standalone wind projects, potentially reducing LCOH to €2.0/kgH 2 by 2030 in regular and low electricity price scenarios, and to as low as €0.6/kgH 2 in high-price scenarios. The wind farm with the highest capacity factor achieves 47% reductions in LCOH and 22% increases in NPV, underscoring the importance of strategic site selection and operational flexibility. • Volatility of electricity prices raises viability concerns for wind producers. • Examining the optimal operation and economic feasibility of wind-hydrogen systems. • Evaluated wind farms in Western Finland from 2019 to 2022, with a 2030 outlook. • Integration with hydrogen production enhances financial resilience and adaptability. • Strategic site selection and adaptive PEMEC operational plans found crucial. [ABSTRACT FROM AUTHOR]

[Display omitted] • Coconut shell emerged as a feasible feedstock. • Optimal ER ranges between 0.1 and 0.3, promoting higher syngas yields. • Plant D achieving a significantly lower levelized cost of electricity of US$0.19/kWh. • Larger plant (Plant C-D) demonstrates strong economic performance with a PBP of 3.28 years and 1.69. This research aims to evaluate the techno-economic viability and commercial potential of biomass gasification across different capacities. Sensitivity analysis was conducted based on an established downdraft gasifier model using Aspen Plus. Results underscored the significant impact of gasification temperature and equivalence ratio (ER) on syngas composition, low heating value (LHV), and cold gas efficiency (CGE). Among the feedstocks tested, coconut shell emerged as a feasible feedstock, yielding syngas with an LHV of 8.93 MJ/Nm3 and achieving a CGE of up to 71.12 %. Optimal gasification temperatures ranged between 750 °C to 1,000 °C, with peak ER falling within 0.1 to 0.3. Economic analysis revealed that smaller-scale operations like Plant A resulted in a negative net present value of − US$0.63 million, indicating unfavorable investments. The internal rate of return notably increased from 9.53 % for Plant B compared to −2.56 % for Plant A (20 kW). Plant D, with larger capacity of 20 MW, showed an impressive payback period of less than two years (1.69 years). Medium to large-scale plants such as Plant C (2 MW) and Plant D demonstrated greater economic resilience, with Plant D achieving a significantly lower levelized cost of electricity of US$ 0.19/kWh compared to Plant A at US$ 0.86/kWh. It was noted that the impact of capital costs, operating expenses, and revenue variations is less pronounced at larger scales. The findings from this study shed light on the feasibility of biomass gasification for power generation as a viable option, thereby unlocking the potential for its large-scale commercialization. [ABSTRACT FROM AUTHOR]

Commercial Buildings release large volumes of greenhouse gases, expediting global warming. The commercial building industry accounts for 37% of global CO2 emissions. Geothermal energy technologies are an intriguing solution that provides a low-impact, emission-free, and cost-effective thermal fuel source for baseload energy production. Geothermal energy systems offer a potential solution to dramatically halt global warming and facilitate the transition to a carbon-neutral civilization. This study develops a framework for assessing the geothermal power capabilities of innovative house and district heating systems. The energy requirements are first assessed, and then the spatial evaluation of district heating infrastructure is carried out using a Python-based program. Economic comparisons between geothermal energy and fossil fuels are made using LCC analysis. Environmental impacts are measured by Life Cycle Analysis (LCA). This study compares geothermal energy to fossil fuels, and the LCA results show that geothermal energy has a low environmental impact. With a Net Present Value (NPV) of 34.81 USD, it displays economic viability as well as a satisfactory financial return. The study's findings show that geothermal energy has the ability to compete with fossil fuels in commercial heating applications while still being environmentally beneficial. [ABSTRACT FROM AUTHOR]

This study assesses the competitiveness of producing green hydrogen (H 2) in Saudi Arabia and Germany using a power-to-carrier (P2X) model in PLEXOS for 2030 and beyond. The target amount of H 2 to be produced serves as the only exogenous input, allowing the model, which runs on an hourly temporal resolution, to endogenously optimize the electrolyzer technology (alkaline, proton exchange membrane, or solid oxide electrolyzer cell), the capacity of the electrolyzer to be built, and the optimal carbon-free energy mix. Results suggest the overall investment needs in Saudi Arabia are approximately 25% lower than those for wind-based hydrogen production in Germany, with the best-case scenario to produce 0.213 Mt of green H 2 costing a net present value of $6.20 billion in Saudi Arabia, compared to $8.11 billion in Germany. The findings indicate that alkaline electrolyzers dominate the production process, favored for their low cost despite the higher efficiencies of other electrolyzer types. Moreover, the model opts to dump excess energy rather than construct battery storage. Based on 16 scenarios, the study determines a levelized cost of hydrogen of 2.34–3.08 $/kg for Saudi Arabia, compared with 3.06–3.69 $/kg in Germany. Subsequently, a detailed sensitivity analysis considers various discount rates for both countries. It is concluded that even when considering shipment costs from Saudi Arabia to Germany (∼1 $/kg), green H 2 can still be competitively delivered from Saudi Arabia to Germany. • This study assesses production costs of green hydrogen in Saudi Arabia and Germany. • Optimization carried out using a P2X methodology via PLEXOS with hourly resolution. • The model optimizes for renewable capacity and electrolyzer capacity and type. • In 2030, CAPEX requirements in Saudi Arabia are ∼25% less than in Germany. • Alkaline electrolyzers dominate production due to low capital costs. [ABSTRACT FROM AUTHOR]

Greenhouse gas (GHG) emissions have grown and reached 33.9 Gt of CO 2 equivalents in 2020. Its amounts have continuously increased since the industrial revolution, so, carbon capture and utilization and storage (CCUS) technology can mitigate CO 2 emission and global warming. Dimethyl Carbonate (DMC) has attracted attention as it is used as a solvent in lithium-ion batteries. We proposed a modified process simulation based on the fractional converion of experiment of direct synthesis of the DMC using CO 2. Also, to separate azeotropic mixture, ethylene glycol is used as an entrainer. We changed the feed of the CO 2 and changed the design when CO 2 feed is lower than stoichiometry ratio. Economic feasibility for all cases was evaluated using Aspen Process Economic Analyzer (APEA) V12. As a result, the total annual cost for the case 1, 2 and 3 is US 9.88 M$/yr, US 9.71 M$/yr and US 10.3 M$/yr, respectively. The Net Present value (NPV) for the case 1,2 and 3 is US − 51.6 M$, US − 56.66 M$/yr and US − 56.1 M$. Sensitivity analysis is performed to examine the effect of the NPV while changing the economic parameters such as utility cost and DMC selling price from − 30% to 30%. The most effective parameter of the NPV is the selling price of the DMC for case 1 and utility cost for case 2 and 3. A lower DMC selling price and solving deactivation problem of catalyst are the potential to develop the CCU technology. • A modified process simulation based on fractional conversion of experiment of DMC using CO 2. • Economic feasibility is compared for the three simulated cases using APEA V12. • By sensitivity analysis, the price of DMC for case 1 and utility cost for case 2 and 3 are the most effective parameters. [ABSTRACT FROM AUTHOR]

Plastic waste becomes a major global concern as amounts of plastic waste are rising every year. To solve this problem, various recycling methods of plastic waste have been introduced including a waste-to-energy (WTE). Adopting plastic waste as feed source to WTE process has advantages but it accompanies economic and environmental issues followed by flue gas emission and energy generation efficiency. Therefore, this study developed an integrated assessment considering environmental threat and economic feasibility of targeting plastic waste as WTE fuel while maximizing net present value (NPV). A recycling method with WTE was proposed developing a power plant producing electricity which is based on plastic calorific value and a case study considering flue gas components. Furthermore, a sensitivity analysis identified variables that could influence the economic aspects of the process. As results, the FO cases, which secures residual heat through additional combustion reaction as a flue gas treatment method and generates electricity, had positive NPVs of 20.55, 19.90, 19.39, 18.93, and 18.50 million USD, respectively. Furthermore, sensitivity analysis indicates that the cost of electricity is the main contributor of NPV. [Display omitted] • WTE plant using waste plastic as feed material need to evaluate the economic and environmental feasibility. • Component scenarios of flue gas, incomplete combustion potential and flue gas whether to recycle flue gas are considered. • The FO cases, wherein flue gas was recycled, had positive net present values. • The results indicate the applicability of plastic waste as fuel. [ABSTRACT FROM AUTHOR]

This study provides formal theoretical evidence that patent counts are not robust measures of the innovativeness of economic agents. Study inferences are rationalized by two complementary insights, the first quantitative, the second qualitative. Whereas, feasibly the assumption that the distribution of patent counts is quasiconcave surmounts the quantitative rationale, the qualitative rationale – Net Present Values (NPVs) of patents dominate patent counts as measures of the innovativeness of agents – is binding. The robustness of the qualitative rationale is evident in the finding that it rules out the feasibility, to wit, all other tools for the appropriation of innovations, such as secrecy , lead time , learning curve , etc. are robust proxies for the innovativeness of agents. The realization that a higher NPV can be the outcome of high demand that is induced by consumers' budget constraints, equivalently can be the ' outcome of commercialization ', vis-a-vis the ' technological dominance ' of new products results in the insight that the NPV rule also is, itself not a robust measure of the innovativeness of agents. In aggregate, ' a ranking of the ordinal utility' that rational consumers derive from products, a ranking that, feasibly is violated by their budget constraints, is shown to be a more robust measure of the innovativeness of agents than a ranking of innovations' NPVs. Since technological complexity has, as objective the satisficing of consumers' utility, a ranking of utility also is a more robust measure of the innovativeness of agents than a ranking of technological complexity. [ABSTRACT FROM AUTHOR]

A fuel cell-based combined heat and power (CHP) system holds significant potential to be a viable alternative to conventional diesel generators for providing backup power during disruptions. The system generates power with only water as a byproduct, thus promoting environmental sustainability through reduction in greenhouse gas emissions. This study provides a comprehensive techno-economic assessment for replacement of 488 kW diesel generator that powers a hospital in Nepal during power disruption. The counter power capacity of fuel cell is 500 kW. The scope of hydrogen generation has been considered both on-site and off-site. The economic analysis performed for the on-site hydrogen production resulted in a net present value of USD 42,717 with a corresponding internal rate of return of 8.40 % and a payback period of around 10 years, making it an economically viable option. The uncertainty and sensitivity analysis revealed the electricity tariff rate as the most significant cost factor. For off-site hydrogen production, the proposed system is economically feasible if the hydrogen can be purchased below 3.5 USD/kg. [Display omitted] • Limited past studies exploring potential application of green hydrogen in Nepal. • Feasibility study of application of green hydrogen as a power backup source. • Analysis of two H 2 production cases using various techno economic analysis tools. • Establishes fuel cell CHP system as an economically viable alternative in Nepal. [ABSTRACT FROM AUTHOR]

The present study aims to design and optimize a Hybrid Renewable Energy System (HRES) to facilitate a remote community's electricity and hydrogen load demand at Dungri, Uttarakhand, India. The methodology includes an assessment of energy demand, local resource availability, and the nature of the inhabitant. The findings shows techno-economically an optimal HRES, consisting of 90 kW PV, 25 kW Bio-generator, 30 kW electrolyser, 15 kW hydrogen tank, 10 kWh storage and a 30 kW converter with Net present value (NPV) of Rs. 78.4 lakhs, cost of energy (COE) as Rs. 7.61/kWh and cost of hydrogen (COH) Rs. 330/kg. Annual electricity generation is of 250641 kWh/year and yearly average hydrogen generation of 1838 kg through electricity consumption of 80462 kWh/year and can be utilized for 26280 km/year of operation of hydrogen fuelled buses. Furthermore, sensitivity analysis reveals that, rise in the hydrogen load, boost up the system's NPV and COE, whereas,the COH reduces. Amount of annual CO 2 emission and avoided are 53.9 kg, 209.12 t, respectively. Moreover, it infers that the proposed system serves isolated rural communities with high-quality energy and satisfies local hydrogen fuel demand in the transportation sector in economically viable manner and achieves the SDG 7 & 8. • Achievement of sustainable development goal 7 & 8. • Lowest economy COE Rs. 7.61/kWh and COH of Rs. 330/kg. • Lowest SPB of 6.7 years with IRR 14 %. • Emission avoided is 209.12 tons/year compared to conventional plants. • Electricity generation along with fuel for transport (26280 km/year). [ABSTRACT FROM AUTHOR]

[Display omitted] • Selected 37 typical data comparing the industry's eight MW disposal technologies. • The average disposal of 1 ton of MW produces 0.94–1.2 tons of CO 2. • LCC and NPV results showed that steam sterilization with landfill is the best. • The environmental and economic impacts of MW disposal in 10 megacities were studied. • 10 megacities employ MS-MSWI technology to reduce 279,000 tons of CO 2 emissions. Medical waste (MW) is exploding due to the COVID-19 pandemic, posing a significant environmental threat, and leading to the urgent requirement for affordable and environmentally friendly MW disposal technologies. Prior research on individual MW disposal plants is region-specific, applying these results to other regions may introduce bias. In this study, major MW disposal technologies in China, i.e., incineration technologies (pyrolysis incineration and rotary kiln incineration), and sterilization technologies (steam sterilization, microwave sterilization, and chemical disinfection) with residue landfill or incineration were analyzed from an industry-level perspective via life cycle assessment (LCA), life cycle costing (LCC) and net present value (NPV) methods. Life cycle inventories and economic cost data for 4–5 typical companies were selected from 128 distinct enterprises and academic sources for each technology. LCA results show that microwave sterilization with residue incineration has the lowest environmental impact, emitting only 480 kg CO 2 eq. LCC and NPV analyses indicate that steam sterilization with landfilling is the most economical, yielding revenues of 1,210 CNY/t and breaking even in the first year. Conversely, pyrolysis and rotary kiln incineration break even between the 4th and 5th years. Greenhouse gas emissions from the MW disposal in ten cities with the largest MW production in 2020 increased by 7% over 2019 to 43,800 tons and other pollutants increased by 6% to 12%. Economically, Shanghai exhibits the highest cost-effectiveness, while Nanjing delivers the lowest. It can be observed that the adoption of optimal environmental technologies has resulted in a diminution of greenhouse gas emissions by 279,000 tons and energy conservation of 1.76 billion MJ. [ABSTRACT FROM AUTHOR]

The need of undertaking effective actions against the climate change is pushing industrial companies to find new business models and technological solutions to reduce the resource utilization and the waste production. In this context, several companies are moving towards servitization, that has been proved as a promising strategy to enable sustainable business models in a wide spectrum, namely encompassing environmental, economic and social aspects. Nevertheless, companies lacks of tools for evaluating different servitization models with a clear view of economic and environmental benefits. This paper presents a model to estimate the profitability of servitization opportunities by combining economic Net Present Value index and environmental impacts estimation. The model is targeted on the steel sector, for which a preliminary application has been developed and is discussed in the paper. The results show that adopting different servitization business models, several benefits could be exploited both from providers and customers. [ABSTRACT FROM AUTHOR]

Because of hydrogen's low energy density, hydrogen storage is a critical component of the hydrogen economy, particularly when large-scale and flexible hydrogen utilization is required. There is a sense of urgency to develop hydrogen geological storage projects to support large-scale yet flexible hydrogen utilization. This study aims to answer questions not yet resolved in the research literature discussing the valuation of hydrogen geological storage options for commercial development. This study establishes a net present value (NPV) evaluation framework for geological hydrogen storage that integrates the updated techno-economic analysis and market-based operations. The capital asset pricing model (CAPM) and the related finance theories are applied to determine the risk-adjusted discount rate in building the NPV evaluation framework. The NPV framework has been applied to two geological hydrogen storage projects, a single-turn storage serving downstream transportation seasonal demand versus a multiturn storage as part of an integrated renewables-based hydrogen energy system providing peak electric load. From the NPV framework, both projects have positive NPVs, $46, 560, 632 and $12, 457, 546, respectively, and International Rate of Return (IRR) values, which are higher than the costs of capital. The NPV framework is also applied to the sensitivity analysis and shows that the hydrogen price spread between withdrawal and injection prices, site development, and well costs are the top three factors that impact both NPV and IRR the most for both projects. The established NPV framework can be used for project risk management by discovering the key cost drivers for the storage assets. • Establish a Net Present Value (NPV) framework for evaluating geological hydrogen storage assets. • Techno-economic analysis of hydrogen storage and renewable hydrogen production for peak power support. • Comparison of single-cycle and multi-cycle storage scenarios for hydrogen geological storage. • Insights into the impact of site development and well costs on project valuation. • Application of the NPV framework for risk management and identification of key cost drivers. [ABSTRACT FROM AUTHOR]

To support the energy transition in the area of defence, we developed a tool and conducted a feasibility study to transform a military site from being a conventional energy consumer to becoming an energy-positive hub (or prosumer). Coupling a green energy source (e.g., photovoltaic, wind) with fuel cells and hydrogen storage satisfied the dynamic energy consumption and dynamic hydrogen demand for both the civilian and military mobility sectors. To make the military sector independent of its civilian counterpart, a military site was connected to a renewable energy hub. This made it possible to develop a stand-alone green-energy system, transform the military site into a positive energy hub, and achieve autonomous energy operation for several days or weeks. An environmental and economic assessment was conducted to determine the carbon footprint and the economic viability. The combined installed capacity of the solar power plant and the wind turbine was 2.5 times the combined peak consumption, with about 19% of the total electricity and 7% of the hydrogen produced still available to external consumers. • Military sites can become near zero or even zero RES energy hubs. • RES power generation components must be oversized to meet dynamic consumption. • RES energy hubs enable economic feasibility of large-scale hydrogen technologies. • The mathematical model developed allows environmental assessment and economic viability. • RES energy hub produces surplus green electricity and supports hydrogen mobility. [ABSTRACT FROM AUTHOR]

In order to improve the energy efficiency of hydrogen storage for power generation, in this work, an improved Graz cycle (R-Graz cycle) was proposed, which can realize more efficient hydrogen to electricity conversion. The modeling and optimization program of the cycle was developed based on MATLAB, and the thermodynamic properties of the working fluid were obtained by REFPROP. The results show that the R-Graz cycle can reach a net efficiency of 70.98% at the design point, which is about 0.5% higher than that of the Graz cycle with the same input parameters, and much higher than that of the modern gas-steam combined cycle. With the same amount of hydrogen input, the R-Graz cycle can produce 0.34% more electricity than the Graz cycle. At the design point, the levelized cost of electricity (LCOE) of the R-Graz cycle is 156.23 $/MWh, which is 0.22% lower than that of the Graz cycle, and the net present value is also higher. Analysis on the influence of key parameters shows that increasing the inlet temperature and pressure of the high-temperature gas turbine and the inlet temperature of the high-pressure steam turbine as well as reducing the condenser pressure are conducive to improving the R-Graz cycle efficiency, among which the influence of the inlet pressure of the high-temperature gas turbine and condenser pressure is particularly significant. This study also presents the impact of these key parameters on the LCOE. This research can effectively increase the conversion efficiency of electricity-hydrogen-electricity mode, and provides a new path for hydrogen utilization. • A revised Graz cycle for power generation based on hydrogen storage is proposed. • The net efficiency of proposed cycle is higher than 70%. • Total efficiency of about 50% can be achieved in the hydrogen storage scenario. • The economy of revised cycle is better than that of Graz cycle on LCOE and NPV. [ABSTRACT FROM AUTHOR]

The current study aims to assess the water quality in Wadi El-Natrun (Egypt) for agricultural purposes and to design an optimal desalination system that considers the water quality, the power consumption, and the total cost of the system. Water quality was evaluated based on four indices: electrical conductivity (EC), sodium adsorption ratio (SAR), residual sodium carbonate (RSC), and toxicity risk of three ions (sodium, boron, and chloride). The proposed desalination systems are single- and double-stage hybrid systems based on reverse osmosis (RO) and nanofiltration (NF) membranes. The performance of these systems was evaluated and compared in terms of the quality of permeated water for agricultural uses. The net present value (NPV) was also used as an economic criterion to determine the optimal system for agricultural purposes from an economic point of view. The results showed that most of the wells investigated are not suitable for direct irrigation before treatment due to problems of salinity, sodium adsorption, and chloride toxicity. Reverse osmosis membranes have proven to be superior to nanofiltration for producing high-quality water for agricultural purposes. However, single-stage systems with nanofiltration membranes are the most cost-effective option for most of the wells investigated in the study; they are the best for 30 out of 47 wells. It is also concluded that the use of nanofiltration desalination technology for irrigation purposes is a feasible solution that would encourage investors to expand reclamation projects in the Western desert in Egypt. [ABSTRACT FROM AUTHOR]

The development of solar desalination technology industry can play an important role in the economic development of the country. In addition to reducing carbon emissions, these technologies can create more jobs in rural and urban areas and strengthen traditional energy systems. To start a new business, the profitability of the business should be evaluated separately based on economic analysis. Banks provide loans according to the economic attributes of the project. Therefore, an economic evaluation of basin-type building material-based solar thermal desalination device was carried out to evaluate the feasibility of solar technology investment in order to guide new entrepreneurs. For determining the economic viability of constructing solar desalination unit, many economic criteria such as break-even point, net present value (NPV), payback period (PBP), benefit-cost ratio (BCR), annuity (A), internal rate of return were determined. The entire annual operating cost of the business was calculated by adding fixed and variable charges. The business of solar thermal desalination unit has a huge potential because of the high BCR (1.15), NPV (INR 4,916,083) (59,040.68 USD), A (INR 721,151) (8,660.81 USD), and short PBP (1 month) values when producing 365 units/y. In addition, according to the break-even analysis, the manufacturing and sale of only 52 units are sufficient to achieve a condition of no profit and no loss. This firm generates a net average yearly benefit (A) of INR 721,151 (8,660.81 USD). Furthermore, this firm has the potential to not only generate cash but also provide work for four people. It also has a great potential for lowering CO2 emissions. [ABSTRACT FROM AUTHOR]

Considering the benefits of geothermal energy in low-temperature combined processes, this study intends to present, examine, and optimize a novel thermal integration process incorporated into a two-stage geothermal flash cycle. In order to meet this objective, a modified bi-evaporator refrigeration technology using an ejector has been designed, with the capability of generating coolant for air-conditioning and industrial requirements. Furthermore, the entire system utilizes a low-temperature water electrolysis process for hydrogen production. In addition to designing a new process, this study incorporates advanced methodologies to comprehensively analyze the proposed system's thermodynamic, economic, and exergoenvironmental aspects. In this context, an extensive parametric study is undertaken, followed by the definition of two distinct multi-objective optimization scenarios: the energy-environment and the energy-cost scenarios. Based on the outcomes derived from the first scenario, the corresponding objective functions, namely energy efficiency and exergoenvironmental index, are determined to be 52.89% and 0.5, respectively. This condition is also responsible for generating net output electricity, cooling load, and hydrogen production rate of 3.897 MW, 26.88 MW, and 4.02 kg/h, respectively. Moreover, it exhibits an exergy destruction rate of 5493 kW. In the second scenario, the objective functions, i.e., energetic efficiency and payback period, are calculated to be 39.37% and 3.94 years, respectively. The aforementioned products demonstrate capacities of 3.697 MW, 17.66 MW, and 5.0 kg/h, respectively. Besides, the exergy destruction rate is determined to be 4667 kW. [ABSTRACT FROM AUTHOR]

Waste-to-energy is one of the most effective methods to save energy and reduce carbon emissions in the cement industry. In this study, a novel process of CO 2 reduction coupled with municipal solid waste gasification by recycling flue gas during co-disposal in cement kiln is proposed. The model of MSW gasification by recycling flue gas is developed in Aspen Plus based on Gibbs free energy minimization. Meanwhile, the techno-economic-environmental analysis of the proposed process is also evaluated via taking clinker production capacity of 5000 tones/day as the objective. Results indicate that the low heating value of syngas, the cold gasification efficiency, and total exergy efficiency are respectively 4.42 MJ/m3, 91.96%, and 82.33%, indicating a high energy conversion efficiency is obtained during MSW gasification by recycling flue gas from cement kiln. Moreover, the net present value, internal rate of return, and payback period of the proposed process are in sequence as 86.73 M$, 82.21%, and 2.67 years, assuming the coal price is 150 $/ton. The proposed process can reduce about 172.11 kg eq.CO 2 /ton clinker compared to the traditional cement clinker generation. • MSW gasification by recycling flue gas during co-disposal of cement kiln is proposed. • 82.33% of energy efficiency for MSW gasification is obtained during co-disposal in cement kiln. • The NPV, IRR and PBR of the proposed process are in sequence as 86.73 M$, 82.21% and 2.67 years. • The proposed process can reduce about 172.11 kg eq.CO 2 /ton clinker. [ABSTRACT FROM AUTHOR]

The article presents a comparative analysis of effectiveness of the approaches developed by the authors to ensuring a further development of nuclear energy industry as a pollution-free energy source. To solve this problem, several options for using environmentally friendly hydrogen fuel were considered to ensure a high installed power factor of NPPs and/or maneuverability of existing and planned double-loop NPPs with a water coolant. It is proposed to accumulate off-peak electricity by means of water electrolysis to obtain hydrogen and oxygen, which ensures the basic operation mode of NPP and provides a possibility to use hydrogen/oxygen to produce peak electricity. The given approach is compared with the basic scheme of marketable hydrogen and oxygen production including their additional purification. The economic feasibility is estimated with account for the effect from replacement of environmentally harmful plants based on gas turbine units, including the effect of preventing forced unloading of NPPs and various options to the target prices for nuclear and hydrocarbon fuel. As a result, the main technical and economic indicators of the proposed approaches were determined, including the cost and accumulated net present value. Based on the assessments made, it is shown that the options for providing NPPs with a basic electrical load based on the proposed approaches are efficient and competitive. Production of hydrogen and oxygen with a subsequent production of peak electricity, i.e. the use of a hydrogen power complex as an off-peak energy storage allows achieving the maximum economic effect. The provided estimates show the relevance and prospects for solving the problem of providing NPPs with a baseline electrical load under conditions of increasing their share in the energy grid based on the combination with a hydrogen power complex. [ABSTRACT FROM AUTHOR]

The study of multi-source energy systems, due to higher performance and producing various products, is an interesting subject. The current study designs a multi-source system including a gas turbine cycle with CH 4 and municipal solid waste digester, a geothermal system with an organic Rankine, organic flash, and a double-effect absorption refrigeration subsystem to produce power, cooling, and heating loads simultaneously. The thermodynamic and economic analyses are utilized to estimate the system's performance and multi-objective optimization has been applied to define the optimum state of the system concerning two scenarios. The results indicate that the system provides 423.4 kW net power, 384.7 kW heating load, and 106.3 kW cooling load with 39.28% exergetic efficiency and 6.67 years payback period. These values are improved to 664.9 kW net power, 446.5 heating load, 42.01% exergetic efficiency, and 6.05 years payback period at the best optimum scenario. The sensitivity analysis reveals that the air compressor's pressure ratio mainly impacts the net power, heating load production, and net present value. The cooling load production and exergetic efficiency are mainly affected by the air preheater effectiveness variation. [ABSTRACT FROM AUTHOR]

The present study proposes a techno-economic study for an off-grid combined green energy system (CGES). The system uses a photovoltaic (PV) system as a primary mover and a backup PEMFC system (Proton Exchange Membrane Fuel Cells). The suggested CGES is conditioned by a new advanced nature-inspired approach, named Fractional-order Pathfinder Optimizer (FOPA), which is used for the factors' optimal size selection to decrease the value of Total Net Present (TNPV) based on the power supply possibility Loss (PSPL) for the system. To improve the performance of the system, FOPA is used for minimizing the power supply possibility loss (PSPL). For analyzing of the method efficiency, it is performed to a building in Nanping shi Village (Ye Village), Fujian, Sheng, China. Finally, the sensitivity assessment was implemented by levelized cost of energy (LCOE). Final results have been compared with several published approaches to specify the technique with higher efficacy. The outcomes demonstrate that utilizing the offered FOPA, the optimal numbers of FCs, Electrolyzers, PV systems, and hydrogen reservoir tanks are 25, 50, 20, and 30, respectively, that are happened with 4.86% EEP and 1.38% PSPl. • A techno-economic analysis for an off-grid hybrid renewable energy system (HRES). • PV system is used as primary mover and PEMFC system as a backup energy system. • Optimization is based on a Fractional version of Pathfinder Algorithm (FOPA). • The method is a case study in Nanping shi Village (Ye Village), Fujian Sheng, China. [ABSTRACT FROM AUTHOR]

Operating costs are dominant in the hydrogen production of a power-to-hydrogen system. An optimal operational strategy or bidding framework is effective in reducing these costs. However, it is still found that the production cost of hydrogen is high. As the electrolysis unit is characterized by high flexibility, providing ancillary service to the grid becomes a potential pathway for revenue stacking. Recent research has demonstrated the feasibility of providing such a service, but the related economics have not been well evaluated. In this work, we propose a comprehensive operation model to enable participation in the day-head, balancing and reserve markets. Three types of reserves are considered by using different operational constraints. Based on the proposed operation framework, we assess the economic performance of a power-to-hydrogen system in Denmark using plentiful actual market data. The results reveal that providing frequency containment reserve and automatic frequency restoration reserve efficiently raises the operational contribution margins. In parallel, by investing in the cash flows, net present value, and break-even hydrogen prices, we conclude that providing reserves makes the power-to-hydrogen project more profitable in the studied period and region. • Optimal operation for power-to-hydrogen systems when participating in reserve markets. • Three types of reserves, FCR, aFRR and mFRR, are included in the operation model. • Utilize numerous market data to conduct economic evaluations of the system operation. • Life-cycle economic analysis to assess the values of offering reserves. [ABSTRACT FROM AUTHOR]

• The financial and ecological viability of power from pyrolysis oil is assessed. • The process has high oil yield and power generation potential. • The project is economically feasible and profitable in China. • Power generation from the project contributes to global warming. • Consumption of power from the project reduces coal usage and global warming. The increased plastic waste generation worldwide poses ponderous issues for public health and the environment. China is the highest generator of plastic waste around the world. The current treatment process (incineration) of the increased plastic waste causes dangerous environmental consequences. Pyrolysis has recently surfaced as an ecologically friendly technique for energy and material recovery from plastic waste. The present study assesses the financial and ecological viability of power production from oil derived from the pyrolysis of mixed plastic wastes in China from 2009 to 2028. The prominent findings show that the amount of plastic waste collected in 2020 (24.16 Mt) increased by 53.19% in 2028.The pyrolysis of mixed plastic wastes during the project period yielded 359.29 Mt oil, which has a power potential of 1,060.86 GWh. The economic analysis indicated the project is viable and profitable with a positive net present value (US$8.80 million) and profitability index (1.26) greater than 1. The project has 10.6 y payback period, US$0.0752/kWh levelized cost of energy, 22.5% return on investment, and 13.0% internal rate of return. The life cycle assessment results show that conversion of mixed plastic waste to pyrolysis oil for electricity generation during the project period has a total global warming potential (GWP) of 1,311.4 kt CO 2 eq. The GWP is mainly from conversion of pyrolysis oil to electricity (73.42%), pyrolysis oil production (15.01%) and upgrading of pyrolysis oil (11.38%). The consumption of power from the project could avoid the combustion of 2,659.0 t coal, minimizing global warming by 11,278.8 kt CO 2 eq. Sensitivity analysis, which examines the influence of variation in sensitive factors on the success of the project, is presented. This paper provides scientific strategies for optimal investment and decision-making on the environmental sustainability of plastic waste-to-energy pyrolysis projects. [ABSTRACT FROM AUTHOR]

Floating photovoltaics is a solution that is getting significant attention worldwide. It consists of installing photovoltaic modules on water basins. This contributes to alleviating the land occupancy issue associated with the growing deployment of photovoltaics. However, because of the early stage of deployment, the costs of floating systems are still higher than traditional land-based photovoltaics. Nonetheless, in some cases, the installation of floating photovoltaics might occur independently of the cost competition with the in-land technology. In this light, the current work presents an analysis of the profitability and cost competitiveness of floating photovoltaics in Europe. The Levelized Cost of Electricity of floating photovoltaics is found to be generally higher than onshore wind and land-based photovoltaics, but lower than fossil gas. Furthermore, floating photovoltaics is found to be a profitable investment in countries with low capital costs, high energy yields and/or high market price of electricity. In these countries, the internal rate of return is typically higher than the weighted average cost of capital, confirming the profitability of the investigated solution. Last, the economic parameters are found to influence the economic viability of FPV more than the energy related factors such as the tilt angle or the heat transfer. [Display omitted] • Profitability and cost competitiveness of floating photovoltaics (FPV) are analyzed. • FPV has higher LCOE than land-based photovoltaics (LPV) but lower than fossil gas. • In Italy, Spain, and Switzerland, the LCOE is lower than 5 € cents /kWh. • Positive NPVs are found in Turkey, Italy, Spain, Romania, Bulgaria, and Greece. • FPV viability is more affected by the economic conditions than by the energy yield. [ABSTRACT FROM AUTHOR]

• The lifetime of PV power plants does not reach the expected 20–25 years. • Data monitoring from 85 PV power plants in central Europe is used. • The real lifetime of PV power plants is about half the planned time. After 10 years of operation the frequency of serious failures rises sharply. • The examples of delamination, the formation of a conductive channel between the electrode and the grounded frame of the PV panels are demonstrated, the number of damaged inverters is analysed. • To calculate the economic efficiency of investments in PV power plants, the methods: payback period (PP), net present value (NPV), and internal rate of return (IRR) were used. The maintenance and analyzing failures of PV systems and plants are becoming more and more important issues. Our data from the long-term operation of 85 photovoltaic power plants in central Europe show that their actual lifetime is about half that of the originally planned lifetime. After about 10 years, serious failures of 1st tier (bankable) PV panels occur at an increasing rate. This article presents selected typical data and describes the most serious failures. Furthermore, economic calculations of returns on investment are carried out in relation to the price of electricity, which is currently changing at a rapid pace. It shows that the PV panel lifetime reduction from 20 to 30 years, declared at commercial leaflets, to real lifetime about 10–12 years can reduce PV power plant profit substantially, but the investment is still worth it. The reason is that after 10–12 years ser vice/maintenance expenses to replace damaged PV panels and inverters are growing very quickly. The new information could be helpful for owners of PV power plants to get a more realistic estimation of profits. [ABSTRACT FROM AUTHOR]

• Designed an automated Material Recovery Facility for mixed waste. • Estimated a capital cost of $23 MM for 120,000 tonne/year of MSW. • The NPV ranged from $3.57 to $60 MM based on location. • Global warming potentials ranged from 5.98 to 8.53 kg CO 2-eq /MT. Material Recovery Facilities (MRFs) are crucial players in achieving a circular economy. MRFs receive complex waste streams and separate valuable recyclables from these mixtures. This study conducts techno-economic analysis (TEA) to estimate the net present value (NPV) and life cycle assessment (LCA) to estimate different environmental impacts of a commercial scale standalone, single-stream MRF to assess the economic feasibility and environmental impacts of recovering valuable recyclables from an MRF processing 120,000 tonnes per year (t/y). The TEA employs a discounted cash flow rate of return (DCFROR) analysis over a 20-year facility lifetime, along with a sensitivity analysis on the impact of different operating and economic parameters. Results show that the total fixed cost of building the MRF facility is $23 MM, and the operating cost is $45.48/tonne. The NPV of the MRF can vary from $3.57 MM to $60 MM, while 100-year global warming potential can range from 5.98 to 8.53 kg carbon dioxide equivalents (CO2-eq) per tonne of MSW. We have also found that MSW composition (arising from regional effects) significantly impacts costs, 100-year global warming potential, and other impact categories such as acidification potential, eutrophication potential, ecotoxicity, ozone depletion, photochemical oxidation, carcinogenic effects, and non-carcinogenic effects. Sensitivity and uncertainty analysis indicate that waste composition and market prices significantly impact the profitability of the MRF, and the waste composition mostly impacts global warming potential. Our analysis also indicates that facility capacity, fixed capital cost, and waste tipping fees are vital parameters that affect the economic viability of MRF operations. [ABSTRACT FROM AUTHOR]

Renewable energy sources such as solar, wind, and geothermal energy have become increasingly popular due to their environmental benefits and long-term sustainability. This study proposes an innovative integration of a solar system and a geothermal system to optimize the performance of a geothermal power plant. The geothermal system is coupled with a solar system, which utilizes a direct and storage system to increase the efficiency of solar energy utilization and minimize energy loss. To recover waste heat, an electrolyzer is used in a triple-flash geothermal system that operates at high feed geofluid temperatures, producing hydrogen as a byproduct. The organic Rankine cycle with a zeotropic mixture working fluid is employed to generate additional power. After considering eight candidate working fluids, Butene/R123 is selected. The designed system exhibits an impressive 10.83 MW net power, 9.87 kg/h hydrogen, 18.86% energetic efficiency, 29.45% exergetic efficiency, and 4.88 years payback period with a 29.72 M$ net present value. Additionally, two energy-economic and exergy-economic scenarios are evaluated to determine the optimum state. The energy-economic scenario has a lower payback period, whereas the exergy-economic scenario offers greater profitability over the system's lifetime. [Display omitted] • Designing an integrated triple-flash geothermal and modified solar system. • Performing comprehensive economic and sensitivity analyses. • Utilizing and selecting zeotropic mixture in the ORC subsystem. • Achieving 30.02% exergetic efficiency with 4.82 years payback period. [ABSTRACT FROM AUTHOR]

The limitations of the single-flash cycle (SFC) include low efficiency, limited power output, and the inability to produce multiple products simultaneously. Additionally, the SFC requires a large amount of water and can have negative environmental impacts. In this study, to improve performance and produce multiple products, subsystems such as a branched GAX cycle assisted by a thermoelectric generator, a domestic water heater, and a reverse osmosis unit are coupled with the SFC. Then, thermodynamic, environmental, sustainability, and net present value approaches are devoted to analyzing system performance. This study utilizes MATLAB software to achieve a two-objective optimization that uses both CO 2 emission rate and exergetic efficiency as objectives. The CO 2 emissions rate represents a downward inclination with an increase in temperature in the generator inlet. Net electricity, cooling load, and pure water rate have a downward inclination with an augmentation of the temperature in the generator inlet due to reducing mass flow rate in the branched GAX/TEG cycle. At the optimum point, the payback period of the designed system with increasing selling prices of the products is decreased. The polygeneration gain output ratio in the optimized conditions reduces compared to the base case, whereas the sustainability index increases. Compared to similar works, the designed system produces a higher output. [ABSTRACT FROM AUTHOR]

Meeting the European Commission's 'Fit for 55' climate goals by the year 2030 in the context of the trilemma of security of supply, environmental sustainability, and competitiveness will require concerted efforts from the Member States on all fronts. Among others, it will require optimised techno-economic solutions that offer sustainable decarbonisation pathways for the concurrent decarbonisation of many sectors of the economy. This paper attempts to provide empirical evidence of the 'rooftop solar PV+EV concept' efficacy as a promising pathway to decarbonise France's transport, power and building sectors concurrently. Using the System Advisor Model (SAM), we find that if rooftop solar PV is installed on half of the available roof space, and if half of the passenger vehicle owners replace their internal combustion engine vehicles (ICEVs) with EVs by 2030, then France can meet 20 %–42 % of total electricity demand in the three most populous cities. Moreover, the solar PV + EV coupling can reduce CO 2 emissions from passenger vehicle use and electricity generation by 43 %–48 %. Also, the coupling can be a potentially worthwhile investment with a payback period of 2–3 years, a levelised cost of energy (LCOE) of about €0.04/kWh, and a net present value (NPV) of €6–19 billion without a feed-in tariff. We analyse the potential implementation challenges of the 'rooftop solar PV + EV concept' and propose some solutions. Finally, we argue that coupling rooftop solar PV + EV in cities is a cost-effective strategy to decarbonise urban energy, transport and building sectors concurrently. Therefore, the government should consider enacting combined rooftop solar PV + EV decarbonisation policies that offer economic and environmental benefits. • Rooftop solar PV+EV can meet 20%-42% of electricity demand in France's three most populous cities. • Rooftop solar PV+EV can reduce CO 2 emissions from vehicle use and power generation by 43%-48%. • Coupling PV+ EV can be a potentially worthwhile investment with a payback period of 2-3 years, an LCOE of €0.04/kWh, and an NPV of €6-19 billion without a feed-in tariff. • Coupling rooftop solar PV+EV in cities is a cost-effective strategy to decarbonise urban energy, transport and building sectors. • The government should consider enacting PV+EV combined decarbonisation policies that can offer economic and environmental benefits. [ABSTRACT FROM AUTHOR]

Closed-loop fluid circulation in wellbores has gained considerable attention for harnessing the earth's thermal energy. Recent studies with analytical and numerical models show that geothermal gradient and well depth constitute the two most consequential variables in fluid output temperature at the surface. This study presents a new strategy for managing geothermal-gradient cooling to ensure more prolonged operation by adopting another energy source, such as solar or wind, with a day/night cycle over the years. In other words, the fluid circulation will occur at night, while the solar or wind source will operate in the daytime. Well-depth and geothermal gradients dictate which geographic area provides the best opportunity for power generation or hot water production to meet various industrial needs. Economic tools, such as Net Present Value and Levelized Cost of Electricity, helped gauge their strengths and limitations, thereby offering business decisions objectively. Considering a 20-year power generation period, this study provides some pragmatic lessons. For example, retaining the near-wellbore geothermal gradient is essential for assuring about 130 °C for the binary cycle. We can attain this objective with a 12-h fluid-circulation cycle by juxtaposing a second well or a solar/wind source for a day/night cycle. Also, besides being a safety net, a power grid can aid the economic value proposition in this energy-transition phase. The generation of hot water for direct industrial usage for low-geothermal prospects also becomes economically viable, particularly in repurposing abandoned wells. These industries include food and agriculture, requiring 60 to 85 °C. • Harnessing thermal energy by wellbore fluid circulation • Combining thermal/solar/wind energy strategy with the grid power as a backup • Meaningful thermal energy occurs for power generation in favorable geothermal gradient and well depth • Hot water can meet various industrial needs even in unfavorable geothermal gradient situation • Economic analysis with NPV and LCOE suggests very lucrative value propositions [ABSTRACT FROM AUTHOR]

As public resources are scarce, investments from the private sector are essential to scale up rural electrification and thus to achieve universal access to electricity by 2030. However, the lack of clear public policies, together with a high perceived risk, have been a deterrent to investors' participation in off-grid electrification projects. In this paper, we focus on identifying the main drivers of risk, namely the set of uncertainties and perceived risks that prevent private companies from investing in off-grid electrification projects. We use a stochastic discount cash flow technique — net present value (NPV) combined with Monte Carlo simulation — to incorporate these uncertainties and quantify the business and investment risks associated with an off-grid solar PV project. The technique is applied to the case of Colombia, wherein major contributors to risk are the variability in revenues and the annual revenue growth rate. For this case, we estimate the probability of project failure and investigate how private companies could mitigate risks by keeping operating costs to <50 % of revenues. In this regard, the role of the government proves to be essential in providing a better investment environment for private investors. We suggest that government interventions could take the form of financial de-risking instruments, including better-designed end-user subsidies and the implementation of concession agreements through long-term contracts. These results are of interest to private investors who need to account for risk analysis when deciding whether to invest or not in off-grid projects. Also, our findings guide policymakers seeking to understand the private sector perspective while designing efficient policy mechanisms to increase access to electricity in developing countries. • Investments from the private sector and better-designed tariffs are essential to scale-up rural electrification • Monte Carlo Simulation with multiple sources of uncertainty • Stand-alone PV systems are a cost-effective solution to expand electricity access • Revenue uncertainty impacts the variability of the NPV of the project • Business Risk affects the off-grid private companies' willingness to invest [ABSTRACT FROM AUTHOR]

Flash-based geothermal cycles correspond to environmentally friendly and cost-effective processes in a renewable framework and provide an opportunity for combined cycles. However, these cycles are characterized by significant energy losses and their waste stream's low/medium operational temperature is the principal defect for managing multiple generation arrangements without assisting other energy resources. Hence, the main aim of this study is to propose a novel polygeneration scheme, integrated with a dual-flash geothermal cycle equipped with self-superheaters, able to mitigate the discussed defect. A new coupled series and parallel design of energy recovery is established, allowing to increase the compatibility of combined cycles and enable a larger production. This design encompasses a single-effect refrigeration cycle, a modified transcritical CO 2 cycle, a polymer electrolyte membrane electrolyzer, and a thermal desalination cycle. The proposed process is examined from thermodynamic, sustainability, and economic (exergoeconomic and net present value analyses) points of view. Besides, a detailed sensitivity study is conducted by which the trend of performance variables in response to the increasing five main decision parameters is viewed. Afterward, an intelligent approach relying on an artificial neural network is built to learn and validate the behavior of defined objective functions (exergetic efficiency and products' levelized cost). Moreover, a multi-objective grey wolf optimization (MOGWO) procedure endeavors to optimize the operation of the system. According to the results of this study, flash tank 2′s inlet pressure is the effective parameter, and its mean sensitivity index equals 0.289. Besides, the aforementioned objectives are gauged at 37.45% and 0.0625 $/kWh, respectively. [ABSTRACT FROM AUTHOR]

Real hybrid energy systems based on developing fuel cell (FC) technology are promising in addressing energy and environmental problems. Before looking at the research investigations, the earlier review studies are briefly examined to spot any gaps in the literature. In the present study, a novel scheme of fuel cells is introduced with higher efficiency and compatibility. The exhaust gases are then introduced to the transcritical carbon dioxide cycle for the production of more power and to extract heat from the intercoolers. The system is analyzed from the multiple objective functions aspect, and the net present value method is occupied for determining the system's payback period. The important design conditions are then put to the test to seek their effect on the overall system. The genetic algorithm is applied for the sake of optimization, and the efficiency is maximized while minimization of environmental impact and the cost of the system. The results indicate that maximum η I I and minimum of LCOP and ζ at the ideal point which equals to 73.8%, 0.24 $/MWh and 0.07 kg/kWh, can be reached correspondingly. Also, by changing the selling price of electricity from 0.19 $/kWh to 0.22 $/kWh, the net present value and the payback period reach 1329000 $ and 6.24 years, respectively. [ABSTRACT FROM AUTHOR]

If an affordable infrastructure for low-carbon-intensity hydrogen can be developed, then hydrogen is expected to become a key factor in decarbonizing the atmosphere. This research focuses on factors an existing wind farm operator would consider when weighing participating in the electricity market, the hydrogen market, or both. The solutions depend on the state of technology, which is changing rapidly, the local market structures, the local natural resources, and the local pre-existing infrastructure. Consequently, this investigation used an assessment approach that examined the variation of net present value. The investigation identified profitability conditions under three different scenarios: 1) Make and sell what makes economic sense at the time of production, 2) Use electrolyzer and fuel cell to consume power from the grid at times of low net demand and to produce electricity at times of high net demand, 3) Same as #2 but also market hydrogen directly when profitable. • Existing electricity market structures set hydrogen price floor. • Underground hydrogen storage makes grid support attractive. • Markets and technology affect profitability. • Hydrogen and wind power can be synergistic. [ABSTRACT FROM AUTHOR]

The design of solid oxide fuel cells (SOFC) using biogas for distributed power generation is a promising alternative to reduce greenhouse gas emissions in the energy and waste management sectors. Furthermore, the high efficiency of SOFCs in conjunction with the possibility to produce hydrogen may be a financially attractive option for biogas plants. However, the influence of design variables in the optimization of revenues and efficiency has seldom been studied for these novel cogeneration systems. Thus, in order to fulfill this knowledge gap, a multi-objective optimization problem using the NSGA-II algorithm is proposed to evaluate optimal solutions for systems producing hydrogen and electricity from biogas. Moreover, a mixed-integer linear optimization routine is used to ensure an efficient heat recovery system with minimal number of heat exchanger units. The results indicate that hydrogen production with a fuel cell downstream is able to achieve high exergy efficiencies (65–66%) and a drastic improvement in net present value (1346%) compared with sole power generation. Despite the additional equipment, the investment costs are estimated to be quite similar (12% increase) to conventional steam reforming systems and the levelized cost of hydrogen is very competitive (2.27 USD/kg H 2). • Hydrogen production can achieve 63% of exergy efficiency, 8% more than power generation. • The optimization is able to minimize the levelized cost of hydrogen to 2.27 USD/kgH 2. • The inclusion of a fuel cell system can increase 23% of hydrogen production net present value. [ABSTRACT FROM AUTHOR]

The growth of power demand and environmental issues of fossil fuels lead to renewable energy utilization. A novel combination of parabolic trough solar collectors with a double-flash geothermal system is proposed to generate power and cooling simultaneously. Two parabolic trough solar collectors are employed; the first one directly supplies the solar heat during the day and the second one stores the solar heat for the night operating time. Zeotropic mixtures in an integrated ejector refrigeration-organic Rankine cycle are employed to improve waste heat recovery and overall performance. Exergy and exergoeconomic assessment criteria are employed to evaluate the performance of the designed plant. The subsystem's working fluid selection was performed by comparison of the performance of six zeotropic mixtures. The parametric investigation reveals that the exergetic efficiency and net power are affected by the inlet pressure of the separators, and direct normal irradiation presents the highest effect on the payback period. Moreover, the system's optimum state is evaluated by a multi-objective optimization scheme. [ABSTRACT FROM AUTHOR]

Sector coupling will play a key role in the future energy system to realise greenhouse gas emission reductions. A major factor will be green hydrogen based on renewable energies to defossilise consumption sectors. Related business models of power to gas are not yet implemented on the market. However, given the urgency of the change, this is essential. This paper investigates hydrogen business models under current market conditions of high power prices, no existing market for green hydrogen and the given regulatory framework with no levies for green hydrogen production in the German market. For this purpose, an open-source business model evaluation tool for sector coupling, which enables a simple and generic evaluation of sector coupling business models including production and possible transportation infrastructure, is developed and applied. Furthermore, the impact of changes of the input parameters like power prices and the influence of regulatory changes on profitability are assessed. The results show that X-to-power business cases can be already profitable due to high power prices on the wholesale market. However, power-to-X business models like hydrogen production still have negative net present values and the net present value is worsened when infrastructure for hydrogen transportation is considered. Key parameters for the negative result are investment costs and low hydrogen prices. Nevertheless, it must be considered that higher hydrogen prices have a negative impact on the X-to-power business model. To allow for profitable business cases, the market conditions need to be adjusted to ensure sufficiently high prices for green hydrogen. Furthermore, subsidies on investment or operational and maintenance costs can support the integration of power-to-X into the market. Transportation infrastructure has a significant impact on profitability. Given these facts, it is necessary to create the required framework conditions to ensure the realisation of sector coupling. • Presentation of an open-source approach to assessing sector coupling business models. • Case study on hydrogen including renewables, transportation infrastructure, and regulatory and market conditions in Germany. • No market-based introduction of power-to-X business models without subsidies. • X-to-power business models profitable due to high power prices. • Power-to-X and X-to-Power jeopardise each other as they require opposing hydrogen and electricity prices. [ABSTRACT FROM AUTHOR]

Concerns about limited fossil fuel and environmental degradation have promoted the interest in waste-to-fuel technology. The integration of municipal solid waste (MSW) gasification and electrolysis unit can achieve the triple goals of energy generation, environmental protection and energy storage. In this study, the MSW gasification integrated with solid oxide electrolysis cell (SOEC) unit to produce the methane, methanol and dimethyl ether (DME) technologies is compared to explore the potential benefits and weaknesses from the perspective of techno-economic performance and carbon emission analysis. The results show that the SOEC-assisted MSW-to-methane system owns the highest exergy efficiency with 60.60%, followed by methanol system (59.83%) and DME system (57.37%). Considering the direct and indirect CO 2 emission, the methanol system owns the lowest CO 2 emission intensity (CEI) with 1.57 kg/h•t. In addition, DME system owns the highest net present value (NPV) with 771.59 $/t compared with methane system (433.80 $/t) and methanol system (297.57 $/t). Economic analysis further reveals that DME system is not competitive compared with fossil-based fuel in the current market environment. Sensitivity analysis shows that DME system loses its economic feasibility when the on-grid tariff of renewable energy exceeds 0.06 kWh. [Display omitted] • Three SOEC-assisted MSW gasification to methane/methanol/DME routes are simulated. • A comparative techno-economic and carbon emission analysis are accomplished. • The methane system owns the highest exergy efficiency with 60.60%. • The carbon emission of methanol system is lower than other pathways. • The NPV of SOEC-assisted MSW-to-DME system is the highest with 771.59 $/t. [ABSTRACT FROM AUTHOR]

[Display omitted] • Plant-level methane losses at 69 biogas plants varied between 0.3 and 40.6%. • Pressure relief valves were an often seen source of emission (53% of plants). • A national emission factor was determined at 2.5% for the Danish biogas production. • Leak search and emission quantification can lead to reduced methane emission. • Mitigation actions can sometimes be fully financed through increase in energy sales. In total, 69 biogas plants representing 59 % of Danish biogas production participated in a national effort to reduce methane (CH 4) emission. Measurements in terms of total plant CH 4 emissions, quantification of emissions from point sources, leak surveys and conceptual design plans to mitigate emissions were performed. Plant-level CH 4 emission rates varied between 1.3 and 81.2 kg CH 4 h−1, and CH 4 losses expressed in percentages of production varied between 0.3 and 40.6 %. Agricultural plants generally had lower CH 4 loss rates compared to wastewater treatment plants. Biogas plants with a smaller gas production emitted a larger fraction of their production compared to larger plants, which was partly explained by the absence of gas collection from digestate storage tanks at smaller plants. A very commonly observed source of emission was pressure relief valves, where this source of leakage was observed at 53 % of the plants. A national emission factor (sum of CH 4 emissions/sum of CH 4 productions) was determined at 2.5 % for the Danish biogas production, whereof it was 2.1 % for agricultural biogas production and 6.7 % for biogas production at wastewater treatment plants. Measurements of total CH 4 emissions at six plants performed before and after implementation of mitigating actions showed that emissions were reduced by 46 % by carrying out relatively minor technical fixes and adjustments. An economic evaluation showed that, in some cases, mitigating actions could be economically beneficial for the biogas plant (positive net present value over a 10 year time frame), due to an increase in revenue. [ABSTRACT FROM AUTHOR]

Conventionally, project managers schedule the activities first; later prepare for materials management, procurement, and supplier selection in project planning. This disjointed process leads in a loss of expected profit for the company owing to a lack of planning coordination. In this paper, a mixed integer programming model is developed for resource constrained multi-project scheduling, materials ordering (MO), and supplier selection (SS) problems to maximize the net profit of the organization. Since the resource constraint multi-project scheduling with MO and SS belongs to the class of problems that are NP-hard. Thus, a genetic algorithm-based memetic algorithm (MA) is proposed to solve the proposed model. The proposed MA utilizes the basic components of genetic algorithm (GA) like selection, crossover, and mutation with a local search. The proposed algorithm is tested on self-generated 16 instances with a range of 2 to 5 projects in a multi-project set with 30 to 90 activities in a project with 6 to 8 suppliers. The results revealed that the suggested MA generates better solutions than the GA by achieving projects higher net present value (NPV). The findings of this paper provide managerial insights for the project managers to secure organizations' profitability. [ABSTRACT FROM AUTHOR]

[Display omitted] • The economic feasibility and environmental impact of PBS from food waste were investigated. • Sensitivity analysis was conducted, and critical factors were investigated. • In this study, the minimum selling price of PBS was 3.5 $/kg. • In this study, GHG emission was 5.19 kg CO 2 -eq/kg of PBS. In this present study, the production of poly (butylene succinate) (PBS) from food waste was investigated and critical factors were evaluated. The economic feasibility of the process was investigated, as well as the minimum selling price (MSP) of PBS and sensitivity analysis of economic factors based on critical input parameters. 1,4-butanediol price and solvent usage in PBS purification significantly impacted economics during the process. In this process, the MSP of PBS was 3.5 $/kg. The Monte Carlo simulation technique was used to determine the uncertainty in the MSP of PBS. The plant's return on investment (ROI), payback period, internal rate of return (IRR), and net present value (NPV) were 15.79 %, 6.33 years, 16.48 %, and 58,879,000 USD, respectively. The environmental impact factors were evaluated. The results showed the GHG emission from the process was 5.19 kg CO 2 -eq/kg of PBS which is low than conventional PBS production. [ABSTRACT FROM AUTHOR]