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Abstract: This paper presents the results of adding a CCS(Carbon Capture and Storage) plant including an underground CO2 storage to a well described and well documented vision of converting the present Danish fossil based energy system into a future sustainable energy system made by the Danish Society of Engineers. The analyses point in the direction that in such context a CCS investment is not a suitable way to decrease CO2 emissions. Other alternatives are more cost effective and will fit better into the long-term implementation of sustainable energy systems. The reason is that CCS investments involve huge construction costs with the expectation of long lifetimes. Consequently, the CCS has to operate as part of large-scale power or CHP plants with high utilisation hours for the CCS investment to come even close to being feasible. However, seen in the light of transforming to sustainable energy systems, the number of utilisation hours of power and CHP plants will have to decrease substantially due to the energy efficiency measures in combination with the inclusion of renewable energy power inputs from wind and similar resources. Consequently, no power or CHP plants exist in future sustainable energy systems with sufficient utilisation hours to justify a CCS plant. [Copyright &y& Elsevier]

Understanding the patterns of energy usage through simulation and prediction from multiple perspectives is crucial for alleviating energy-environmental conflicts and achieving sustainable energy system development. Despite their importance, multidimensional interactions among the production, demand, and supply sides have not been systematically characterized, thus representing a significant research gap. This paper aims to address this gap by developing a a multidimensional factorial enviro-economic (MFEE) model, which offers an in-depth investigation of Guangdong's energy system. This model, designed for retrospective decomposition (1997–2017) and prospective projections (2035), uniquely links historical and future analysis from systematic and sectoral perspectives through structural decomposition analysis, sectoral evolution analysis, and the Biproportional Scaling RAS method. Our findings reveal that the final demand level and Research & development (R & D) are the principal drivers of increased energy usage. We also found that the wholesale and retail sector have the most significant impact on demand and input sides, accounting for over 70 %. Furthermore, the interaction of key sectors from the production-based perspective notably influences system symbiosis. To effectively manage these dynamics, our study recommends regulating and controlling measures for the circulation sector that consider the benefits of both the energy sector and the accommodation and catering sector. This comprehensive analysis, therefore, offers scientifically-supported guidance for sustainable energy system development. • A multidimensional factorial enviro-economic (MFEE) model from Guangdong perspective is developed. • Approaches of retrospective decomposition and prospective projection for energy systems are conducted. • Interactive effects of various socioeconomic activities on economy and environment are characterized. • The main effects of wholesale and retail sector is the strongest, accounting for more than 70 %. [ABSTRACT FROM AUTHOR]

To establish a sustainable energy system, it is essential to achieve low-carbon and clean utilization of coal. In this study, a novel hydrogen and power cogeneration system with full CO 2 capture that based on coal supercritical water gasification (SCWG) is proposed. Hydrogen is separated from syngas produced by coal SCWG, and the remaining combustible gas is burned to generate power. Moreover, supercritical CO 2 cycle is integrated within the cogeneration system to recover the waste heat with high exergy efficiency. Thermodynamic performances, effects of key operation parameters and off-design performances under part-load conditions of the cogeneration system are analyzed. Under the design condition, the cogeneration system produces 20.26 mol kg−1 hydrogen and generates 8746 kJ kg−1 net power, achieving the high energy efficiency and exergy efficiency of 54.77 % and 52.54 %. The exergy efficiency of cogeneration system can be enhanced by optimizing the operation parameters, which is increased by 0.42 %, 4.03 % and 1.10 % with the optimal coal water slurry concentration (17.5 %), higher gasification temperature (750 °C) and higher gas turbine inlet parameters (1500 °C/3 MPa), respectively. The cogeneration system performance decreases with the power load, and the exergy efficiency decreases by 9.61 % when the system power load reduces from 100 % to 30 %. • A novel hydrogen and power cogeneration system based on coal SCWG is proposed. • Exergy efficiency of the cogeneration system achieves 52.54 % with full CO 2 capture. • Effects of key operation parameters on the system performance are evaluated. • The system off-design performance under part-load conditions is analyzed. [ABSTRACT FROM AUTHOR]

Due to the impacts of climate change, the global energy system must undergo a green transformation. However, this transition process may entail both positive and negative impacts. Therefore, governments must formulate balanced energy policies to establish a secure, accessible, affordable, and environmentally sustainable energy system. To assist decision-makers in evaluating the status of energy systems and formulating rational energy policies to address the complex and dynamic challenges, this study focuses on proposing a method to assess and analyze the equilibrium of a nation's energy system. To achieve these objectives, we propose the Energy Balance Index as a comprehensive method for assessing the equilibrium of a country's energy system. Subsequently, we employ a decision tree-based model to analyze the impact of different factors on the Energy Balance Index. The findings reveal that environmental sustainability holds the most significant influence, followed by energy equity, while energy security has a minor impact. Moreover, the relative influence of these factors varies over time, with energy equity exerting a greater influence prior to 2015, and environmental sustainability emerging as the foremost determinant since then. Through development status analysis of China, this study provides valuable references and recommendations for decision-makers in designing energy policies. • The Energy Balance Index assesses the balance of a nation's energy system. • The index considers energy equity, energy security, and environmental sustainability. • The decision tree-based model provides a systematic methodology for analysis. • Environmental sustainability has the greatest impact on the energy system balance. • The influence of factors on the Energy Balance Index changes dynamically over time. [ABSTRACT FROM AUTHOR]

With the intensification of energy crisis and the aggravation of greenhouse effect, It is particularly essential to develop a sustainable energy system. For this reason, a low-carbon economic dispatch model for a park integrated energy system considering integrated demand response and ladder-type carbon trading is designed. First, a refined model of hydrogen utilization is developed, and hydrogen-enriched natural gas as hybrid energy to extend the scenario of hydrogen utilization. Second, in order to investigate the effect of demand response mechanism and carbon trading mechanism on the system, an integrated demand response model for electricity-heat-gas load and a ladder-type carbon trading model that takes into account the carbon emissions of the whole process are constructed respectively. Finally, based on above models, a low-carbon economic scheduling model is established to optimize the total cost of the system. The simulation results show that the refined modeling and hydrogen-doped operation of the equipment can help reduce the system's carbon emissions. When the integrated demand response mechanism and the ladder-type carbon trading mechanism are considered together, the carbon emissions of the system are greatly reduced, while its total cost can be kept low. • A refined hydrogen utilization model is constructed. • The effect of the IDR and LCT on HIES scheduling is investigated. • An improved low-carbon economic dispatch model for HIES is proposed. • A stepped carbon trading model is constructed based on the consideration of whole life cycle carbon emissions. [ABSTRACT FROM AUTHOR]

Abstract To achieve the EU climate and energy objectives, a transition towards a future sustainable energy system is needed. The integration of the huge potential for industrial waste heat recovery into smart energy system represents a main opportunity to accomplish these goals. To successfully implement this strategy, all the several stakeholders' conflicting objectives should be considered. In this paper an evolutionary multi-objective optimization model is developed to perform a sustainability evaluation of an energy system involving an industrial facility as the waste heat source and the neighbourhood as district heating network end users. An Italian case study of heat recovery from a steel casting facility shows how the model allows to properly select the district heating network set of users to fully exploit the available waste energy. Design directions such as the thermal energy storage capacity can be also provided. Moreover, the model enables the analysis of the trade-off between the stakeholders' different perspectives, allowing to identify possible win-win solutions for both the industrial sector and the citizenship. [ABSTRACT FROM AUTHOR]

The emergence of distributed energy resources (DERs) is expected to result in an increase in the amount of power transmitted through the distribution power grid. If these DERs are not managed properly, the increased power transmission can cause faster degradation of distribution grid assets (pole-top transformers). To prevent this, measures can be taken to manage the DERs connected to a specific pole-top transformer. This paper presents a new coordination framework for home energy management system (HEMS)-integrated peer-to-peer (P2P) trading, with a focus on the impact of such trading on a Distribution Transformer. The proposed framework provides a comprehensive solution to manage the distribution of power within a smart grid environment by enabling HEMS to engage in P2P trading. This paper also examines optimal energy management in a smart neighborhood to minimize the total cost of energy usage. In addition, to prevent power peaks — that could create excessive power transmission and damage the distribution transformer, a cap within the flexibility bound of the household is placed on the total power households can draw/penetrate from/to the power grid. By optimizing P2P energy trading while considering the limitations of the distribution transformer, this approach enables a more efficient, reliable, and sustainable energy system. • Developing a new home energy management system. • Addressing demand-side flexibility with peer-to-peer trading. • Developing a network-aware peer-to-peer trading model. • Analyzing impacts on the distribution transformer. [ABSTRACT FROM AUTHOR]

As a comprehensive energy transition reform strategy, China's new energy demonstration city (NEDC) pilot policy aims to accelerate the transformation from a fossil fuel-based energy system to a more sustainable energy system. Employing unique data on firms' energy consumption from National Tax Survey Database, this paper investigates how NEDC policy affects firms' energy utilization efficiency based on the difference-in-differences model. We observe that NEDC construction reduces firms' energy consumption intensity (ECI) in the pilot cities. After using the instrumental variable approach to deal with endogeneity problems, the conclusions still hold. The mechanism analysis reveals that the decrease in firms' ECI is driven by offering more tax incentives to enterprises and prompting them to pursue technological innovation. Heterogeneity analysis shows that this negative impact is more prominent for SOEs and high-energy-consuming enterprises; we also observe that this effect is more pronounced for firms in resource-based cities and old-industrial-based cities. Our results provide policy implications for initiating policies in other countries to improve firms' energy utilization performance. • NEDC pilot policy affects firms' energy utilization efficiency. • NEDC construction reduces firms' energy consumption intensity (ECI). • Tax incentives and technological innovation are the channels that cut firms' ECI. • This negative impact is more prominent for SOEs and high-energy-consuming firms. • This effect is more pronounced in resource-based and old-industrial-based cities. [ABSTRACT FROM AUTHOR]

One of the effects of climate change is on freshwater availability. The widespread drought in the summer of 2022 impeded access to freshwater, putting into question the reliability of the current and future energy generation and evoking concerns of competition of different industries for water. In response to climate change, energy transition scenarios represent pathways to a more sustainable energy system, but often overlook the water footprint of the energy sector. Therefore, this study uses machine learning for the identification of thermal power plants' cooling systems to estimate the water footprint of the current and future energy system using six energy transition scenarios. It is built on published data on thermal power plants announced globally, with a total capacity of 3277 GW, which are planned to be installed between 2020 and 2050. The results demonstrate that the water consumption of the global power sector may increase by up to 50% until 2050, compared to the 2020 level. The findings also emphasize that every new thermal power plant installed in the future will be associated with a higher average water demand per unit of generated electricity. Hence, the rising stress on water systems becomes another argument supporting the transition towards renewables. • Specific water consumption of thermal plants will increase to 1.7 m3/MWh by 2050 • Specific water consumption of the global energy sector reaches 3.04 m3/MWh by 2050 • Water consumption of the global power sector may increase by up to 50% by 2050 • Water consumption criticality merges water availability and power sector water use • Countries with a high level of water consumption criticality were highlighted [ABSTRACT FROM AUTHOR]

Abstract This review article presents a description of contemporary developments and findings related to the different elements needed in future 4th generation district heating systems (4GDH). Unlike the first three generations of district heating, the development of 4GDH involves meeting the challenge of more energy efficient buildings as well as the integration of district heating into a future smart energy system based on renewable energy sources. Following a review of recent 4GDH research, the article quantifies the costs and benefits of 4GDH in future sustainable energy systems. Costs involve an upgrade of heating systems and of the operation of the distribution grids, while benefits are lower grid losses, a better utilization of low-temperature heat sources and improved efficiency in the production compared to previous district heating systems. It is quantified how benefits exceed costs by a safe margin with the benefits of systems integration being the most important. Highlights • Provides a review of 4th Generation District Heating (4GDH) in scientific papers. • Shows how 4GDH is an important integrated part of future sustainable energy systems. • Quantifies costs and benefits of 4GDH in a future sustainable energy system. • Shows how benefits exceed costs by a safe margin. • Shows the significant benefits of systems integration. [ABSTRACT FROM AUTHOR]

Recent studies show that a high share of district heating is an important part of a future sustainable energy system or smart energy system with a high renewable energy penetration. These studies also show socio-economic benefits of expanding the district heating coverage. However, in order to implement such an expansion, district heating needs to be economically feasible for the heat consumers. This aspect is often not investigated and hence it is unknown if calculations based on consumer-economy, where tax payment is included, will yield the same potential of expansion. This study identifies the differences in the expansion potential of district heating calculated with a socio-economic and a consumer-economic approach, respectively, in a case study of Denmark. By also investigating the consumer-economy of expanding district heating, a deeper insight is obtained of possible locations for expanding district heating under the current framework conditions. [ABSTRACT FROM AUTHOR]

It has been shown that a long term sustainable energy system based on a high penetration of solar photovoltaics requires massive deployment of day charging electric vehicles to make use of the excess solar electricity generation at sun peak hours. In this paper the synergy between these technologies is further explored, determining the minimum penetration levels that allow fulfilling the climate and energy targets. Simulations for a case study of Portugal in 2050 using an electric vehicles smart charging approach show that a 100% renewable energy based electricity supply is possible with certain photovoltaics and electric vehicles combinations and that the environmental targets to reduce carbon dioxide emissions are just reachable with significant electric vehicles market share. The notion that vehicle charging will have to take place during working hours to maximize petroleum displacement is reinforced. [ABSTRACT FROM AUTHOR]

In this study, we analyze the feasibility and impacts of a renewable energy source (RES)-based electricity supply system of future Korea. To achieve this goal, we first developed different scenarios for increasing the contribution of RES by lowering the rate of i) nuclear power, ii) thermal power, iii) both nuclear and thermal power, and iv) these scenarios with real-world constraints. Based on the generated scenarios, we then specified the established systems with practical strategies which encourage different renewable sources (wind, solar photovoltaic, biomass, and waste). Finally, we analyzed the impacts of the established RES-based systems according to various criteria: the total required cost, the dependence on imported energy, CO 2 emissions, and land use. The results show that the RES-based system that utilizes wind energy as its main source by steadily decreasing the rate of thermal power for electricity generation is the most affordable for future Korean electricity system. We also identify the merits and drawbacks of the analyzed systems and provide relevant recommendations for the establishment of a sustainable energy system for Korea. These findings will support policy makers in integrating quantitative assessments into energy-related policy design and implementation. [ABSTRACT FROM AUTHOR]

Photovoltaic energy has become an increasingly competitive source delivering electricity with a steadily cost decline. Alongside the deployment of this sustainable energy system, the power supply stability should be thoroughly examined especially in off-grid systems when electricity storage becomes a constraint. The work presented in this paper proposes a practical solution for the DC bus voltage stabilization in a stand-alone photovoltaic generator devoid of an energy storage system. In order to achieve this objective, a new control strategy applied to the DC/DC converter installed on the PV terminals is investigated. Specifically, the proposed method consists of a modified control in the PWM signal driving the boost converter. Four different modes were considered according to the difference levels between the reference and the measured voltage. Furthermore, this simple and effective technique circumvents the absence of a storage system and ensures the DC bus voltage stability despite the unpredictable operating conditions. An experimental test bench was developed in order to prove the high performance of the proposed control method which is corroborated by the obtained results in particular the DC bus voltage stabilization to the reference value. • A novel control strategy for a stand-alone PV generator is proposed. • The DC bus voltage is regulated without using an energy storage system. • The PWM control signal of the DC/DC converter is adapted according to each load variation. • A correction term of the PWM signal duty cycle is determined according to four modes. [ABSTRACT FROM AUTHOR]

Abstract: The thermochemical production of hydrogen from lignocellulosic biomass is systematically analyzed by developing thermo-environomic models combining thermodynamics with economic analysis, process integration techniques and optimization strategies for the conceptual process design. H2 is produced by biomass gasification and subsequent gas treatment, followed by H2 purification via CO2 removal. It is shown how the overall efficiency is improved by considering process integration and computing the optimal integration of combined heat and power production. In the conversion process, electricity can be generated in steam and gas turbine cycles using the combustion of the off-gases and recovering available process heat. Additional electricity can be produced by burning part of the H2-rich intermediate or of the purified H2 product. The trade-off between H2 and electricity co-production and H2 or electricity only generation is assessed with regard to energy, economic and environmental considerations. Based on multi-objective optimization, the most promising options for the polygeneration of hydrogen, power and heat are identified with regard to different process configurations. The best compromise between efficiency, H2 and/or electricity production cost and CO2 capture is identified. Biomass based H2 and electricity reveal to be a competitive alternative in a future sustainable energy system. [Copyright &y& Elsevier]

Abstract: The Energy Strategy of the Republic of Croatia was adopted by the Croatian Parliament in 2009 for the period until 2020 in order to harmonize national energy goals with goals and time framework of strategic documents of the European Union. The adoption of the Energy Strategy Implementation Program with associated measures is still in process. The goal of the Strategy was to create sustainable energy system that will make a balanced contribution to the security of energy supply, competitiveness and environmental protection in Croatia. In this paper an overview of the energy production, final energy consumption and planned development of energy infrastructure is given. The intention of the paper was to research and stress out the abilities and opportunities of Croatian energy system and to give recommendations for Energy Strategy implementation and practical realization of planned energy infrastructure projects for improvement of security of energy supply and competitiveness of energy system of the Republic of Croatia. [Copyright &y& Elsevier]

Abstract: Assessing the sustainability of urban energy systems and forecasting their development are important topics that have been the focus of recent research. In this paper, an approach for the measurement the sustainability of an urban energy system is introduced. The approach is based on prediction of the future energy needs within the consuming sectors of a city by specification of energy system development scenarios and validation of the scenarios by a multi-criteria decision method. Prediction of energy needs for the area of the city using the simulation model, model for analysis of the energy demands (MAED) is done. Finish the last level of aggregation, using the method of multi-criteria analysis, is getting the General Index of Sustainability (GIS), which shows a measure of the validity or viability, or quality of the investigated scenarios. In this way, the mathematical and graphical made a synthesis of all the indicators that are relevant to sustainable development. The accuracy in determining the mean of the GIS is checked by calculating the standard deviation. Also, a measure of reliability of the preference when watching a few consecutive scenarios was performed. The defined scenarios take into account the utilization of different energy sources, the exploitation of existing energy plants and infrastructure, and the building of new plants. The sustainability criteria are described by a unique set of economic, social and ecological indicators. The new approach was used to forecast the development of sustainable energy system in Belgrade, Serbia. [ABSTRACT FROM AUTHOR]

Developing energy storage techniques is vital to address the variable demand in daily and seasonal cycles. In this study, we propose a power-to-synthetic natural gas (P2SNG) system using hydrogen produced with renewable-based electricity as a valuable complement to the sustainable energy system. The main novelty of this work lies in the comprehensive assessment of the impacts of the hydrogen generation and buffering devices on the operational limits of the P2SNG plant. A time-domain simulation model was developed for the detailed analysis of individual system components, as well as the entire integrated system. The average annual efficiency of hydrogen generation varied from 58.72% to 59.97%. The highest value of the stored energy share in the analyzed range (γ = 0.2297) was obtained for a system with a 4 MW hydrogen generator supplied by a wind farm with 10 MW nominal power. The operational times of the various system components are analyzed for different scenarios and discussed in detail. The results of this study are useful for considering the structural impacts of a P2SNG system on its operation, taking into account the size of the renewable energy source, hydrogen generator, and hydrogen storage capacity. • The dynamic model of P2SNG system was developed. • The time-domain simulations were performed. • Impact of hydrogen buffering on the system operation was evaluated. • Operational times of system components are discussed. [ABSTRACT FROM AUTHOR]

This paper studies an interdisciplinary approach for improving building energy efficiency. In particular, the proposed approach integrates design innovation (DI) techniques, existing energy audit methods (EAM), and data-driven & engineering modeling techniques (DET) in the process of sustainable smart energy system design. From this perspective, DI methods are extended and modified to suit the content of sustainable smart energy system design and a DI 4D (Discover, Define, Develop and Deliver) framework is introduced to guide the design process. The motivation behind and the implementation procedure of each of the DI phases is explained separately, and the process of integrating DI methods, EAM and DET in developing a sustainable smart energy system is demonstrated. The proposed approach is deployed within the campus of a tertiary education institution to show its effectiveness in designing a smart sustainable energy system. • A design innovation (DI) approach is proposed for smart energy system design. • A comprehensive background of the proposed DI framework is provided. • How DI can be used to design smart energy system is demonstrated. • Experimental case studies are provided to show the benefit of the proposed scheme. [ABSTRACT FROM AUTHOR]

The city of Pécs in Hungary has developed an energy strategy to be implemented in the years to come which proposes structural changes in both the supply and demand sides. This paper offers a model based on the proposed system aimed at providing a basis for comparison for decision-makers. The model has been developed with the help of energy system analysis tool energyPRO, and covers the three basic sectors of heat, electricity and transport. It shows the energy system of Pécs in terms of hourly production and demand levels – and these values enable the model to analyse intermittent energy sources. The model is also validated – to ensure that it is satisfactory for the simulation of future energy systems. It analyses two scenarios – one where the city does not implement the changes proposed in the strategy, and one where it does. The paper compares the two scenarios based on sustainability, energy security and affordability. [ABSTRACT FROM AUTHOR]

This study aims to assess and locate the potential for solar power plants (SPP) by utilizing TOPSIS decision analysis and based Fuzzy-Boolean logic based on GIS in Tehran province, Iran. GIS was used as a robust tool for data processing to gather practical and necessary information for effective resources and facilities. Through the multicriteria decision-making method (MCDM), alternative sites were identified and prioritized. The fuzzy logic method was employed to evaluate regions and generate thematic maps, revealing that approximately 95% (14,350 km2) of the region's area was unsuitable for constructing a power plant, while 5% (741 km2) was suitable. From the suitable areas, nine locations were selected for photovoltaic plant construction, totaling 22 km2, occupying 0.15% of the province's total area. Fuzzy TOPSIS was then used to prioritize the alternatives, resulting in the selection of Ghiyeh Naserieh in the southern part of the province as the preferred location for the power generation unit. • Thematic maps that precisely located the solar power plant sites were produced using Fuzzy Logic and ArcGIS. • In this study, the location criteria were divided into five classes and 25 subclasses. • TOPSIS calculates distance between alternative sites and the best one, and it chooses the alternative that comes the closest to the ideal. • Nine regions, totaling 2222 k m 2 , or 0.15% of the region's total area, were selected as a best sites for power plant construction. [ABSTRACT FROM AUTHOR]

Because of economic and environmental issues' importance in the energy field, moving toward smart energy systems and energy hubs (EHs) has accelerated. The impacts of uncertainties, e.g., stochastic behaviors of renewable distributed generations (DGs), on EHs are fundamental challenges that should be considered carefully. Although several studies have been done in the area of EHs, a knowledge gap exists about developing an approach considering uncertainties under different EHs' structures and topologies. This research purposes of responding to such a research gap. In this research, a scenario-based approach for EHs' optimal operation considering wind turbine (WT) and photovoltaic (PV) uncertainties is proposed. The proposed approach is applied to EH under different schemes. Using the k-means clustering algorithm decreases the computational burden, while the appropriate accuracy is achievable. The proposed stochastic optimization problem is solved using the genetic algorithm (GA). The comparative view is considered to investigate the impacts of cooling and heating components like the heat pump (HP), absorption chiller (AC), and heat storage (HS) on EH's optimal operation and energy cost. According to this research findings, the EH's daily energy cost under a scheme using the AC, HP, and HS is approximately 6.5% less than a scheme only using HP. Also, using the HS and HP alongside the AC leads to 5.6% and 6.4% cost-saving, respectively. But for a better comparison, the investment and operation and maintenance (O&M) cost are considered, in which case Structure 3 (AC + HP) is more efficient both in terms of energy consumption and investment costs. • Developing a scenario-based model to consider the renewables uncertainties in an energy hub. • A comparative analysis using different heating and cooling components is considered. • A genetic algorithm is implemented to optimize the operation of the energy hu. • A suitable scheme is determined for the energy hub to obtain the minimum energy cost. • Fossil fuels prices are demonstrated as the essential factor for the energy systems. [ABSTRACT FROM AUTHOR]