Multi-energy Complementary System Research Articles

Collaborative development model and strategies of multi-energy industry clusters: Multi-indicators analysis affecting the development of coastal energy clusters

The paper explores Coastal Energy-Based Industrial Clusters (EBICs) and their role in advancing energy efficiency and sustainability through collaborative innovation. Economic growth theory and energy sustainability have been introduced into industrial clusters to illustrate indicators that have a greater impact on the development of EBICs. This paper proposes an EBICs development model based on the Cobb-Douglas function, in which accounts for various factors that drive the progress of such clusters. The outcomes of the economic model also provide insights into how the interaction of various factors affects the economic growth of EBICs and their eventual dominance in the energy market of coastal regions, dependent on gradually investing in areas such as research and development (R&D). Different development strategies demonstrate that the final development of a cluster has low dependence on the cluster's initial advantages. The study also illustrates how clusters can gradually monopolize the energy market, even with initial disadvantages. Through quantitative analysis, it showcases the transformation process of developing advantageous clusters into sub-clusters. Next, an energy symbiosis framework for coastal is proposed, which places greater emphasis on the multi-energy complementary system and reduces production costs. Finally, this paper also sheds light on shaping energy strategies for public authorities who shape economic policies at various levels of aggregation and in diverse dimensions.

Comprehensive evaluation of the working mode of multi-energy complementary heating systems in rural areas based on the entropy-TOPSIS model

BackgroundThe establishment of a multi-energy complementary heating system (MECHS) using abundant renewable energy is currently an effective way to solve the rapid growth of heating demands in rural areas. However, coupling schemes for different energy sources have become a critical barrier to the MECHS development. ObjectivesThe entropy-TOPSIS method was used to conduct a comprehensive evaluation of MECHS, which provided a basis for optimizing system operation strategy. MethodsWe built a test platform for MECHS based on solar-biomass-electricity energy in Tumxuk, Northwest China. Frist, six working modes were established according to the system operation control strategy. Second, we constructed the evaluation indexes of MECHS considering energy, environment and economy and determined their weights using entropy weight method. Third, the TOPSIS model was used to perform a comprehensive evaluation of the different working modes to identify optimal energy supply schemes. ResultsOur case study showed that the MECHS operated stably and met the indoor temperature demands of rural houses in cold regions. To maximize the heating efficiency of the system, it is necessary to reduce the types of energy appropriately. Next, based on entropy-TOPSIS model, the recommended order of energy supply mode for heating systems were solar-biomass energy (0.6202), solar-biomass-electric energy (0.6152), solar-electric energy (0.5895), biomass energy (0.4075), biomass-electric energy (0.3680), and electrical energy (0.3603). We found that the optimal energy supply mode was solar-biomass. ConclusionOur results indicated that the entropy-TOPSIS model could provide practical recommendations for the design and operation strategies of MECHS in cold rural areas.

A case study of multi-energy complementary systems for the building based on Modelica simulations

The utilization of renewable energy sources and the development of energy storage technologies have enhanced the interconversion of various energy sources to slow down global warming. The building sector, as the main bearer of energy consumption, is essential for its energy saving and emission reduction. Integrating natural gas-based combined cooling, heating, and power systems with renewable energy generation facilities is an effective solution. For that, different scenarios are designed to provide energy for a specific office building and compared with the current scenario of depending only on the municipal grid. Equipment models for photovoltaic, battery, gas engine, absorption chiller-heater, and electric heat pump are created. The results show that the multi-energy complementary system has better economic and environmental characteristics, with a primary energy ratio of over 80 % and emission reduction of over 17 %; the advantages of configuring the unit capacity to meet the cooling and heating loads for 80 % of the year are obvious, and in this scenario abandoning battery storage has higher economics for users, with a static payback period from 7.3 years to 4.4 years, but the primary energy ratio decreased by 3 % and carbon emissions increased by 7.2 tCO2. It is recommended to consider the principle of gas-electricity complementarity, relying on the combined cooling, heating, and power system to meet part of the loads, with the remaining loads being supplemented by the municipal grid. The installation of batteries should be considered comprehensively based on the price of the batteries and the requirement for energy-saving and emission-reduction.

Research on multi-time scale optimal scheduling of integrated energy system based on digital twinning

Due to the differences in time scales of different units in integrated energy systems, the adaptability of dispatching to load fluctuation is low, and the corresponding cost input is large. Therefore, the research on multi-time scale optimal dispatching of integrated energy systems based on digital twinning is proposed. Based on FPGA and multiple constraints such as timing, resources, and algorithms, a digital twin model of a multi-energy integrated energy system is constructed to address the dynamic changes of various components in the time scale of the multi-energy complementary system. In the scheduling stage, the scheduling interval is determined based on the output and load parameters of each unit module in the integrated energy system, and the specific scheduling parameters are determined with the goal of digital twin mirror equivalence. In the test results, the fluctuation cost under different operation scenarios is stable below 700 yuan, and the operation cost is stable below 1, 400 yuan, both of which are at a low level.

A review on research and application of multi-energy complementary system containing high proportion of renewable energy based on different attributes

To better understand the latest development of renewable energy systems, recent studies on multi-energy complementary power systems with a high proportion of renewable energy are reviewed in this paper. The connection modes of power grids and economic system analysis are summarized and discussed respectively, putting forward some suggestions on the system design and operation optimization. Firstly, the characteristics and differences between an integrated system and an off-grid system are reviewed, concluding that an integrated system is more reliable and costeffective based on a few case studies. Secondly, the commonly used economic parameters and cost evaluation methods of the hybrid power system are reviewed. Those methods offer crucial tools to optimize the system, and they are able to analyze the system feasibility, enabling the most economical configuration. The results of several cases prove that the hybrid multi-energy system is more economical than the single-energy system. Finally, there are few articles focusing on technical details assessments and environmental impacts, which leaves room for future study.

Performance analysis and multi-objective optimization of the offshore renewable energy powered integrated energy supply system

Offshore renewable energy technologies offer a promising prospect for energy supply on offshore islands. However, traditional wind and solar energy sources exhibit strong variability and cannot fully meet the energy demands of users. At the same time, the energy demand of users also has great volatility, so the supply side and demand side of energy cannot match well. Existing renewable energy systems often utilize thermal power generation as a stabilizer for the system, however, this approach is difficult to apply in offshore conditions. This study introduces an innovative multi-energy complementary system that integrates seawater freezing desalination, refrigeration and power-hydrogen-ammonia co-generation, driven by ocean thermal energy, wind energy, and solar energy. The system incorporates the use of a new developed small temperature difference ejector refrigeration cycle to stabilize the entire system and produce low-temperature refrigeration. By utilizing the seawater freezing desalination process to minimize energy conversion losses and balancing fluctuations in multiple energy inputs and user demands through ammonia-hydrogen co-production, this approach effectively minimizes energy waste, enhances energy utilization efficiency, and reduces excess power handling. The purpose is to optimize the configuration of the energy conversion subsystem within the multi-energy complementary multi-effect co-generation system, thus improving the economic feasibility and reliability of the system in providing energy and freshwater supply, ultimately achieving the goals of reducing energy waste, achieving high conversion efficiency, and minimizing equipment investment. This study conducts an economic analysis and optimization of a multi-energy complementary system, utilizing a 2 MW-level OTEC subsystem as a stabilizer. Both equipment investment and operating costs are considered in the economy analysis. The carbon emission reduction performance of this system is evaluated. The performance optimization results show that the system achieves an energy storage efficiency of 65.96 %, and the curtailment rate of this system is only 3.99 %, significantly lower than the 10 % curtailment rate in traditional system. The proposed system can meet the annual electricity demand of 33.09 million kWh, as well as a cooling demand of 546.81 million kWh. Under typical conditions, the ocean thermal energy conversion cycle exhibits a power efficiency of 0.85 % and a refrigeration efficiency of 29.10 %. Meanwhile, it annually reduces CO2 emissions by 2.54 million tons, demonstrating significant environmental benefits. This proposed system is mainly applicable to tropical waters with high surface water temperatures and depths of no less than 600 m worldwide. This study offers a practical and economically beneficial solution for energy and freshwater supply on offshore islands.

Method of Multi-Energy Complementary System Participating in Auxiliary Frequency Regulation of Power Systems

This research investigates a grid with two areas interconnected by a high-voltage direct-current (DC) link. One of the areas, called the sending-end region, has intermittent renewable generation and frequency stability issues. To address the lack of frequency-regulation (FR) resources in the sending-end region of the interconnected grid, the participation of hydroelectricity–photovoltaics and pumped storage complementary systems (HPPCSs) in auxiliary frequency-regulation (AFR) services is studied in the context of the construction of the electricity market. Firstly, the HPPCS participating in AFR services considering DC modulation is modeled by combining the operational characteristics of the actual power station. Taking the purchase cost of auxiliary service as the objective function, the optimum allocation of FR scheduling demand is achieved by the proposed method. The simulations confirm that the proposed method of HPPCS participation in the AFR service of the sending-end grid can effectively maintain the frequency stability of the regional interconnected grid while ensuring optimal economic efficiency. The proposed method provides the optimal scheduling solution for multiple energy resources participating in the AFR service of the grid.

Exergy and exergoeconomic analyses of multi-energy complementary system based on different natural gas and biogas co-firing ratios considering carbon tax

This study analyzes the exergy and exergoeconomic performances of a combined cooling, heating, and power (CCHP) system powered by natural gas and biogas. First, the exergy of the energy and material flows in the investigated co-firing CCHP system is obtained. In addition, the exergy loss and exergy loss distribution ratios of each component as well as the exergy efficiency of the entire system are investigated. Furthermore, the effects of the co-firing ratio of natural gas and biogas on the exergy and exergoeconomic performances are analyzed. Meanwhile, a carbon tax is considered in the exergoeconomic analysis. The results show that the gasifier, two-stage LiBr-H2O absorption chiller, and internal combustion engine indicate the largest exergy loss and exergy loss distribution ratios under different co-firing ratios. The exergy efficiency of the entire system decreases by 3.81% and 4.93% as the co-firing ratio decreases from 1:1–1:10 (natural gas: biogas) in the summer and winter, respectively. The unit exergoeconomic cost (UEC) of multiple products decrease with the co-firing ratio. Finally, a sensitivity analysis is performed to reveal the effects of the co-firing ratio and natural gas price on the UEC of multiple products.

Study on the Application of a Multi-Energy Complementary Distributed Energy System Integrating Waste Heat and Surplus Electricity for Hydrogen Production

To improve the recovery of waste heat and avoid the problem of abandoning wind and solar energy, a multi-energy complementary distributed energy system (MECDES) is proposed, integrating waste heat and surplus electricity for hydrogen storage. The system comprises a combined cooling, heating, and power (CCHP) system with a gas engine (GE), solar and wind power generation, and miniaturized natural gas hydrogen production equipment (MNGHPE). In this novel system, the GE’s waste heat is recycled as water vapor for hydrogen production in the waste heat boiler, while surplus electricity from renewable sources powers the MNGHPE. A mathematical model was developed to simulate hydrogen production in three building types: offices, hotels, and hospitals. Simulation results demonstrate the system’s ability to store waste heat and surplus electricity as hydrogen, thereby providing economic benefit, energy savings, and carbon reduction. Compared with traditional energy supply methods, the integrated system achieves maximum energy savings and carbon emission reduction in office buildings, with an annual primary energy reduction rate of 49.42–85.10% and an annual carbon emission reduction rate of 34.88–47.00%. The hydrogen production’s profit rate is approximately 70%. If the produced hydrogen is supplied to building through a hydrogen fuel cell, the primary energy reduction rate is further decreased by 2.86–3.04%, and the carbon emission reduction rate is further decreased by 12.67–14.26%. This research solves the problem of waste heat and surplus energy in MECDESs by the method of hydrogen storage and system integration. The economic benefits, energy savings, and carbon reduction effects of different building types and different energy allocation scenarios were compared, as well as the profitability of hydrogen production and the factors affecting it. This has a positive technical guidance role for the practical application of MECDESs.

Grid aided combined heat and power generation system for rural village in north China plain using improved PSO algorithm

The rural areas of North China Plain, an important grain producer in China, are endowed with abundant new energy resources such as biomass, solar, and wind energy. The revitalization of the rural villages is confronted with the shortage of clean and low carbon energy supply. This work proposes a multi-energy complementary distributed energy system (DES) tailored for daily energy consumption in a typical scattered village on the basis of the field survey results. The geothermal heat pump, photovoltaic system (PV), biomass gasification equipment, and other energy conversion devices are integrated in the DES model. The state grid is used as a fundamental ensuring resource to improve the robustness of the system. The improved particle swarm optimization (PSO) algorithm is employed to determine the optimal unit capacity configuration by examining investment cost, payback period, system self-sufficiency, accommodation rate, and annual CO2 emissions. The main available renewable energy resources are biomass and solar energy with the annual amount of 1608.9 tons and 1679 kW h/m2. The heat, gas, and electricity load account for 76.84%, 3.14%, and 20.02%, respectively. Based on the daily peak-to-valley price differentials in Beijing of over $0.15/kWh, DES optimization was carried out with PSO module in MATLAB software. The cost of the energy supply with DES, Scenario 3, was compared with that of the mere grid and renewable systems, Scenario 1 and Scenario 2. The direct DES cost is $0.52 million with the internal rate of return of 8.46%, resulting in a payback period of 6.15 years. The overall system self-sufficiency index except for grid achieved a value of 0.42. The application of the DES lead to energy costs of residents and annual carbon emission reduction by 32.5% and more than 3800 tons, respectively, compared to grid-only energy consumption, showcasing the feasibility of grid-aided combined heat and electricity production in rural areas.

Operating characteristics analysis and capacity configuration optimization of wind-solar-hydrogen hybrid multi-energy complementary system

Wind and solar energy are the important renewable energy sources, while their inherent natures of random and intermittent also exert negative effect on the electrical grid connection. As one of multiple energy complementary route by adopting the electrolysis technology, the wind-solar-hydrogen hybrid system contributes to improving green power utilization and reducing its fluctuation. Therefore, the moving average method and the hybrid energy storage module are proposed, which can smooth the wind-solar power generation and enhance the system energy management. Moreover, the optimization of system capacity configuration and the sensitive analysis are implemented by the MATLAB program platform. The results indicate that the 10-min grid-connected volatility is reduced by 38.7% based on the smoothing strategy, and the internal investment return rate can reach 13.67% when the electricity price is 0.04 $/kWh. In addition, the annual coordinated power and cycle proportion of the hybrid energy storage module are 80.5% and 90%, respectively. The developed hybrid energy storage module can well meet the annual coordination requirements, and has lower levelized cost of electricity. This method provides reasonable reference for designing and optimizing the wind-solar-hydrogen complementary system.

Optimal operation regulation strategy of multi-energy complementary system considering source load storage dynamic characteristics in oilfield well sites

Optimal operation regulation strategy of multi-energy complementary system considering source load storage dynamic characteristics in oilfield well sites

Multi-objective optimization of multi-energy complementary system based on cascade utilization of heat storage

A multi-energy complementary system driven by solar energy and central grid is proposed to supply electricity and cooling/heating, in which a dual-tank thermal storage system is integrated to achieve cascaded solar heat energy utilization. The system integrates parabolic trough solar collectors, high-temperature and low-temperature thermal storage tanks, and an organic Rankine cycle to form an operational loop. The low-temperature thermal storage tank drives an absorption heat pump independently. Excess photovoltaic power drives the ground source heat pump for heating/cooling. Three indicators are defined and compared to show the renewable energy penetration rate in the complementary system. A multi-objective optimization model considering economic performance and renewable energy rate is constructed to optimize the system configurations. Three sets of objective functions are compared through the optimization Pareto frontiers. Then, the TOPSIS method is employed to select the optimum configuration through setting different weights of optimization objectives. Compared with the reference system, the proposed multi-energy complementary system improves the energy, economic and environmental benefits by 59.21%, 24.27% and 11.31%, respectively. Through a variety of equipment (PV, ORC, AHP, TES), solar energy supplies 86.2% and 72.2% of total electricity and heat loads, respectively.

Evaluation of Biogas and Solar Energy Coupling on Phase-Change Energy-Storage Heating Systems: Optimization of Supply and Demand Coordination

Biogas heating plays a crucial role in the transition to clean energy and the mitigation of agricultural pollution. To address the issue of low biogas production during winter, the implementation of a multi-energy complementary system has become essential for ensuring heating stability. To guarantee the economy, stability, and energy-saving operation of the heating system, this study proposes coupling biogas and solar energy with a phase-change energy-storage heating system. The mathematical model of the heating system was developed, taking an office building in Xilin Hot, Inner Mongolia (43.96000° N, 116.03000° E) as a case study. Additionally, the Sparrow Search Algorithm (SSA) was employed to determine equipment selection and optimize the dynamic operation strategy, considering the minimum cost and the balance between the supply and demand of the building load. The operating economy was evaluated using metrics such as payback period, load ratio, and daily rate of return. The results demonstrate that the multi-energy complementary heating system, with a balanced supply and demand, yields significant economic benefits compared to the central heating system, with a payback period of 4.15 years and a daily return rate of 32.97% under the most unfavorable working conditions. Moreover, the development of a daily optimization strategy holds practical engineering significance, and the optimal scheduling of the multi-energy complementary system, with a balance of supply and demand, is realized.

Real-time operational optimization for flexible multi-energy complementary integrated energy systems

Multi-energy complementary integrated energy system (MCIES) has gained widespread attentions due to its utilization of diverse energy sources, enhancing energy efficiency, and reducing carbon emissions. The scheduling optimization of MCIESs needs to address multiple factors, including solar/wind energy potential, fluctuating load demand, and prediction errors, to maintain its highly flexible and decarbonized operation. This study presents a scheduling optimization model based on a mixed integer nonlinear programming model (MINLP) with a novel flexibility index as the objective function. A case study of a MCIES in a swimming pool in Changsha is provided. The results demonstrate that real-time operational scheduling considering flexibility enhances the system flexibility of the MCIESs from 0.608 to 0.623 comparing with the day-ahead scheduling, maintaining superior performance across multiple dimensions. The coupling between the power grid and the natural gas network is also improved, significantly reducing the carbon dioxide emissions of the MCIES by 127.67kgCO2 per day. Furthermore, the study reveals that the flexibility-aware real-time operational scheduling for MCIES outperforms day-ahead scheduling in responding to weather and equipment failures, sustaining high flexibility operation, economic viability, and notably improved environmental performance. CO2 emissions are reduced by 21.088% and 14.638%, respectively. The proposed operational optimization approach in this study can enhance the flexibility and coordinated operation of MCIESs, leading to reduced carbon emissions.

Research on optimal configuration of park-level multi-energy complementary system with multiple evaluation indexes

At present, energy shortages are becoming increasingly severe, and the concept of park level multi energy complementary systems (MECS) has provided direction for sustainable energy development. In recent years, how to improve the economy and reliability of multi energy complementary systems has become a research hotspot in this field. In this paper, a two-layer optimal scheduling strategy is proposed to allocate the capacity of various energy equipment in the park, considering the comprehensive energy self-sufficiency rate, comprehensive energy utilization rate and energy shortage expectation. The proposed capacity allocation scheme can effectively improve the economy of MECS in the park. Finally, the effectiveness and practicability of the algorithm are verified by simulation analysis.

Multi-energy Complementary Power System Economic Dispatch Considering Carbon Emission and Regional User Coordination

The integration of multi-energy complementarity and source-grid-load-storage is an important initiative to promote energy transformation and the high-quality development of power systems. This paper proposes a two-tier day-ahead multi-energy complementary power system economic dispatch model from the perspective of clean and low-carbon, taking into account carbon emissions and multi-regional user synergy. The model optimises the production and purchase of electricity through different decisions between the upper generation side and the lower user side, which minimises the energy production cost in the upper tier and the energy purchase cost in the lower tier, and achieves mutual benefits between the upper and lower tiers. This paper validates the algorithm and model with an improved IEEE 39-node system.

Preface

This Proceedings contains the selected papers of the 2023 2nd International Conference on Smart Grid and Green Energy (ICSGGE 2023), which was held in Qingyuan, China from April 24th to 26th, 2023.The 2nd ICSGGE is aimed at the academic and scientific community and the productive sectors of the region, with the aim of disseminating academic and research work; moreover, promotes the exchange of experiences between researchers as well as the participation of the productive sectors in research, extension, technological development, and innovation activities, contributing to strengthening the relationship between universities, enterprises and institutions.This Conference was articulated with different topics around the theme of Smart Grid and Green Energy to discuss on the research findings, their possibilities as well as challenges. The relevance of the ICSGGE 2023 conference themed on a wide range of disciplines is reflected in the papers that have been submitted for publication. The topics covered in the Proceedings includes: Smart Grid Architectures and Models, Energy Transfer and Interactive Technology, Smart Grid Networking and Communications, Electric Vehicles and Vehicle-to-Grid (V2G), Fault Monitoring and Predictive Maintenance, etc.. All the papers, having been reviewed through a double-blind review process, are original contributions to the topics and shown the research works that are doing in the field of the described theme.We had about 80 participants all around the world. The scientific program of the Conference was composed of keynote speech, oral presentation, and academic investigation. Professor Weiliang Wang (Jinan University, China), combing his own professional knowledge and research experience, performed a keynote speech. He is mainly engaged in research on “carbon neutral” and energy development strategy, efficient utilization of new generation basic energy, new energy technology development, key technology of large-scale energy storage, and multi-energy complementary integrated energy system. The brilliant speeches of each speaker provided a feast of knowledge for all the participants, bringing reflections and enlightenment to them and allowing them to communicate with each other and get some academic advice or suggestion.Our sincere thanks and gratitude to all the participants for making such a comprehensive ICSGGE conference and Proceedings and thus contributed to the enhancement and development in related fields. We are grateful to the Technical Program Committee for their valuable time and advice. Special thanks to the members of the Journal of Physics: Conference Series for making this Proceedings published. We appreciate the effort from those involved and look forward to a more successful conference next year.The Committee of ICSGGE 2023List of Committee Member are available in this pdf.

Thoughts on the development of CO2-EGR under the background of carbon peak and carbon neutrality

In September 2020, the Chinese government proposed the goals to reach carbon dioxide emissions peak by 2030 and achieve carbon neutrality by 2060 (“two-carbon goals”). This brings opportunities to the development and application of CO2-enhanced gas recovery (CO2-EGR) in China. To obtain an overall understanding of the development of CO2-EGR under the two-carbon goals, this paper analyzes the significance, potential, status quo and challenges of CO2-EGR, and makes suggestions on the development of CO2-EGR in China. The research results are obtained as follows. First, the development of CO2-EGR plays a crucial role in ensuring China's energy security, accelerating the construction of the clean energy system to promote energy transition and realizing the two-carbon goals as early as possible. Second, China should clarify a path for CO2-EGR development, build a spatial layout of CO2-EGR, and promote digital inclusion in CO2-EGR, enhance the emission reduction role of CO2-EGR in the multi-energy complementary system, boost large scale application of renewable energy and deep decarbonization in the traditional coal industry, which is difficult to reduce carbon emissions. Third, China should draw lessons from European and American tax credit and innovation funds policies to accelerate the construction of a CO2-EGR policy support system. Fourth, China should carry out research on key CO2-EGR technologies to accelerate the construction of a CO2-EGR methodology and standard system and promote rapid and standardized development of the CO2-EGR industry. It is suggested to establish a CO2-EGR demonstration area in the Sichuan Basin and popularize it across China, so as to improve comprehensive economic benefits through the establishment of large-scale industrial clusters. It is concluded that the two-carbon goals bring opportunities to the development of CO2-EGR in China, which will promote gas production and demonstration of CO2 sequestration in gas reservoirs and have positive significance in ensuring energy security and realizing carbon peak and carbon neutrality in China.

Combining integrated solar combined cycle with wind-PV plants to provide stable power: Operation strategy and dynamic performance study

Building a multi-energy complementary power generation system is a viable way to encourage the use of renewable energy and decarbonize power generation. However, the intermittent nature of renewable power generation, such as photovoltaic and wind power, has prompted concerns regarding power grid stability. To balance such fluctuations, energy storage systems or other flexible power generation technologies should be integrated. In this paper, the peak regulation ability of integrated solar combined-cycle has been enhanced via employing a gas/oil exchanger between the top and bottom cycle. When integrating high penetration intermittent renewable energy, an appropriate operational strategy towards high-quality steady power output regulation is proposed. Dynamic performance analysis of the system, coupled characteristic of heat and mass transfer between subsystems have been highlighted. The case study demonstrates that fluctuations of the multi-energy complementary system power output can be controlled below 0.3 MW without renewable energy curtailment, even though wind-PV power generation fluctuates from 0.3 MW to 26.1 MW with variations per second reaching −2.8/3.7 MW. Furthermore, the system's levelized cost of electricity is down to 0.0512 $/kWh, which is cost-competitive with conventional power generation technologies.