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Low or even zero carbon dioxide emissions will be an essential requirement for energy supplies in the near future. Besides transport and electricity generation, industry is another large carbon emitter. Hydrogen produced by renewable energy provides a flexible way of utilizing that energy. Hydrogen, as an energy carrier, could be stored in a large capacity compared to electricity. In Sweden, hydrogen will be used to replace coal for steel production. This paper discusses how the need for electricity to produce hydrogen will affect the electricity supply and power flow in the Swedish power grid, and whether it will result in increased emissions in other regions. Data of the Swedish system will be used to study the feasibility of implementing the hydrogen system from the power system viewpoint, and discuss the electricity price and emission issues caused by the hydrogen production in different scenarios. This paper concludes that the Swedish power grid is feasible for accommodating the additional electricity capacity requirement of producing green hydrogen for the steel industry. The obtained results could be references for decision makers, investors, and power system operators. [ABSTRACT FROM AUTHOR]

Hydrogen is a type of clean secondary energy, and the hydrogen energy supply is vital to regional energy development. Guangdong is at the forefront of hydrogen energy deployment in China, and aims to achieve peak carbon by 2030. However, hydrogen production research is challenging due to complex technical routes, technical maturity levels, life-cycle carbon emissions, and costs. Multi-time-scale research is necessary to explore optimal production paths and their contributions to CO 2 emission reduction. This study discussed key technologies and the technical maturity of five hydrogen production routes: production from industrial byproducts and coal, wind, hydro-, and photovoltaic power. Policy scenarios were designed to investigate the potential of these routes and technology deployment intensity under medium- and long-term scenarios. This paper proposes a roadmap for hydrogen development and provides a reference for hydrogen production planning in Guangdong. This methodology can be applied in other regions for hydrogen energy development research. • Key technology maturity of the hydrogen production routes was evaluated. • Roadmap of hydrogen production in Guangdong Province was designed. • A method for research of hydrogen supply scenarios was proposed. [ABSTRACT FROM AUTHOR]

This paper presents a study that focuses on alleviating the impacts of grid outages in Ethiopia. To deal with grid outages, most industrial customers utilize backup diesel generators (DG) which are environmentally unfriendly and economically not viable. Grid-integration of hybrid renewable energy systems (HRES) might be a possible solution to enhance grid reliability and reduce environmental and economic impacts of utilizing DG. In this study, an optimization of grid integrated HRES is carried out for different dispatch and control strategies. The optimal power supply option is determined by performing comparative analysis of the different configurations of grid integrated HRES. The result of the study shows that grid integrated HRES consisting of photovoltaic and wind turbine as renewable energy sources, and battery and hydrogen as hybrid energy storage systems is found to be the optimal system to supply the load demand. From the hydrogen produced on-site, the FC generator and FCEVs consume 143 620 kg/yr of hydrogen which is equivalent to 394 955 kg/yr gasoline fuel consumption. This corresponds to saving 1 184 865 kg/yr of CO 2 emissions and 605 703 $/yr revenue. Besides, this system yields 547 035.4 $/yr revenue by injecting excess electricity to the grid. The study clearly shows the economic and environmental viability of this new technology for implementation. • Modeling and optimization of grid-integrated HRES including grid-reliability and dispatch control. • Storage of excess electricity produced from renewable energy sources in batteries. • Onsite production of renewable hydrogen with excess electricity produced from renewable energy sources. • The role of renewable hydrogen for simultaneous decarbonization of electricity and transportation sectors. • Minimizing overall operating costs by injecting excess electricity to the grid. [ABSTRACT FROM AUTHOR]

China has pledged to peak its carbon emissions before 2030 and achieve carbon neutrality before 2060. New energy decarbonization will be a major focus area for achieving the 'dual carbon' goals since it accounts for about 20 percent of China' s total energy consumption. The Xiong' an New Area' s geographical advantages and natural endowments have brought abundant wind and solar energy resources and have huge development potential in the field of new energy development. This paper summarizes the Xiong' an New Area' s resource endowment and achievements in developing new energy, and comprehensively analyzes the opportunities and challenges faced by this area in the process of building a national new energy demonstration zone in the context of achieving the 'dual carbon' goals. It sorts out the new energy development policy of the Xiong' an New Area and its history of new energy development and then points out that the current development of new energy in this area lies in power project construction, power grid construction, green energy consumption, energy storage development, and new energy equipment. This study believes that the Xiong' an New Area will experience three development stages of carbon neutrality: initial carbon neutrality, fluctuating carbon neutrality, and stable carbon neutrality, because this area has carried out green power planning simultaneously in the initial construction stage and has more green power supply. With the expansion of population and economic scale, the rapid increase in energy demand would lead to the decline in green power supply ratio, causing carbon neutrality to fluctuate and change over time. With the population and economic structure in a stable development stage, the proportion of high-value-added and high-tech industries would increase, and energy utilization technologies such as green electricity would make progress, resulting in the arrival of the stable carbon neutrality development stage. On the other hand, from the perspective of carbon sink potential corresponding to carbon sources, the planned proportion of the blue-green space and the construction land in the Xiong' an New Area would keep its carbon sink capacity in a relatively stable state for a long period of time. Therefore, in addition to the value-added of the natural carbon sink system, carbon capture, utilization and storage technologies and other means of artificial carbon sink can be used as adjustment tools under the carbon neutrality system. [ABSTRACT FROM AUTHOR]

• A new DPV-5G BS-ES communication and power mutual coupling system is developed. • A BSSCP model is proposed to minimize the number of 5G base station deployments. • The ISOM model is used to optimize the microgrid connection lines in 3D space. • Economically optimal simulation experiments are conducted for different PV systems. The emergence of ultra-dense 5G networks and a large number of connected devices will bring with them significant increases in energy consumption, operating costs, and CO 2 emissions. At the same time, the deployment of distributed photovoltaic (DPV) in megacities plays an important role in promoting the integration of "building-photovoltaic", adjusting the city's clean energy supply system, and building a green, and low-carbon smart city. The development of a new "DPV-5G Base Station-Energy Storage (DPV-5G BS-ES)" coupled DC microgrid system and its pre-deployment investment costs are fundamental factors to be considered when the problem of large-scale DPV and BS deployment in cities has to be addressed. There are almost no published papers on this issue in the literature, which only consider the problem of maximizing the deployment of 5G BS service coverage or only perform optimization analyses for the performance of microgrid systems without considering the economic optimality and low-carbon green issues in the construction of urban utilities. In order to solve the problem of 5G BS deployment and economic optimization of topology in the "DPV-5G BS-ES" coupled DC microgrid system, a novel deployment strategy is proposed in this paper. The strategy is divided into: (a) The Geographic Information System (GIS) for extracting and analyzing 3D data from all buildings in the area. (b) A GIS-based formulation of a mixed integer quadratic constrained planning model (BSSCP) under discrete fixed radius coverage constraints is used to delineate building clusters within the area and determine the optimal deployment location of 5G BS under each sub-cluster. (c) An Improved Self-Organizing Mapping (ISOM) model combines GIS and microgrid performance parameters to address the economically optimal connection of grid lines for DPV in 3D space. (d) Simulation experiments were conducted for the power output and profitability of eight different PV panels and tracking systems to calculate the economically optimal type of DPV generation hardware. The experimental results show that the BSSCP model proposed in this study reduced the 5G BS deployment cost input by up to 35.8974 % compared to that of the control experimental model. Meanwhile, the ISOM model obtained an average reduction of 52.3741 % in the cost of connecting cables for the optimized 25 DPV planning and DC microgrid topology. [ABSTRACT FROM AUTHOR]

Climate change is one of the global issues being combatted in recent times. One of the measures is a worldwide cutdown on carbon emissions. This has brought about the rapid development of technologies that can best actualise this goal. The decentralised energy system is designed to harness the strengths of small power-generating sources such as renewable energy sources in a noncentralised manner to help meet the global need for clean energy. Renewable energy sources are faced with the challenge of intermittency, which brings about instability in the grid. Another source of clean energy is nuclear energy, which is traditionally large and not flexible; however, the recent development of technology has resulted in a scaled-down version of the large nuclear plants that are more flexible yet provide clean and stable electricity. This paper explores the possibility of deploying nuclear microreactors in the decentralised energy system and describes the features and the challenges of a decentralised energy system. The features of the small modular reactor that make it a viable candidate for the generating source in the decentralised energy system are explored. A case study for a DES system with a microreactor was conducted for a rural area in Nigeria. The HOMER software was used in simulating the optimum system, while TOPSIS was used in ranking the systems. The result showed that the PV/nuclear/battery system ranked first, followed by the PV/nuclear/wind and battery system. [ABSTRACT FROM AUTHOR]

As an important energy base in China, Shanxi Province, in its economic development, has depended heavily on coal resources. However, enormous coal consumption produces a large amount of carbon dioxide and an aggravated ecological problem. In this paper, the super efficiency slack-based measure and data envelopment analysis (SBM-DEA) model and Malmquist index were used to calculate the energy consumption and carbon emission efficiency of 11 prefecture-level cities in Shanxi in the period from 2000 to 2020. The results were as follows: (1) The primary form of energy consumption in Shanxi Province is the burning of coal, and the carbon emission efficiencies of the 11 prefecture-level cities are quite different. The technical efficiency, technological progress, and total factor productivity of Taiyuan and Shuozhou were found to be greater than 1 compared to other cities in Shanxi. (2) On the whole, although the carbon emission rate of Shanxi Province has slowed down, it still faces the problems of a large total emission base, high carbon emission intensity, and low efficiency of the unit carbon emission output. Industrial structure is the key factor restricting improvements in the efficiency of carbon emissions in Shanxi Province. (3) From the spatial and temporal evolution of the carbon emission efficiency in Shanxi Province, we can see that the carbon emission efficiency of the whole province gradually dispersed and improved from the central and northern regions to the southern regions during the period of 2000–2020. In order to achieve a low-carbon economy, Shanxi Province must optimize its industrial structure, accelerate research and development in low-carbon technologies, adjust the energy structure, and promote the construction of an energy supply system with clean low-carbon energy as the main source. [ABSTRACT FROM AUTHOR]

Increasing energy consumption rates and concerns over environmental problems like global warming have led researchers to provide new energy supply solutions, one of which is the use of combined energy systems. Combining conventional fossil energy cycles with renewable cycles is one of the most effective ways to improve their performance and also help harvest green energy. To address this solution, in this paper, a hybrid novel energy system including a gas cycle, a steam cycle, two organic Rankine cycles (ORC), and a renewable cycle based on geothermal and solar energy sources using concentrating photovoltaic thermal panels (CPVT) is proposed. A comprehensive study has been conducted on this system from the perspective of energy, efficiency, economy, and the environment. Different fluids have been investigated for use in ORC subsystems in this study. Additionally, a parametric study has been conducted to determine how the cycle's overall performance is affected. Multi-objective optimization using the Non-dominated Sorting Genetic Algorithm second version (NSGA-II) has been performed based on the objective variables of exergy efficiency and capital costs. In this paper, Engineering Equation Solver (EES) and MATLAB are used for modeling and optimization. The results show that the best fluids to use in ORC are R123 in the first cycle and Ammonia in the second cycle, which energy efficiency, exergy efficiency, exergy destruction rate, and generated power in the base state for the whole cycle are 50.59%, 25.44%, 1537.35 kW and 524.66 kW, respectively. Also, the amount of annual capital cost and the amount of carbon dioxide emission from energy and exergy are 107,034 dollars, 11,672, and 35,401 kg per month, respectively. The optimization results indicate a 0.25% improvement in exergy efficiency and a 500$ annual capital cost reduction at the optimal point. • Providing a new combined cycle with a combination of fossil and renewable energies. • Conducting energy, exergy, economic and environmental analyzes (4E). • Performance analysis and selection of the best operating fluids for ORC cycles. • A parametric study of factors affecting cycle efficiency and total cost. • Multi-objective optimization of the cycle using DoE, ANN, and NSGA-II methods. [ABSTRACT FROM AUTHOR]

Summary: This research paper presents the case study results on generating electricity based on solar resources for an existing residential building with conventional electric energy demand located in Cluj‐Napoca, Romania. The solar energy system proposed for analysis has provided the back‐up energy through two types of state‐of‐the‐art energy storage technologies: (a) Tesla batteries and (b) hydrogen vector energy, obtained electrolytically on‐site. Starting from the main imposed condition that all the building's electric energy demand be provided by the solar resource, sustainable technical solutions for renewable energy storage are of crucial importance for the successful implementation of power systems based on clean solar energy. New solar energy storage technologies are imperative for the superior harnessing of solar resources at the production site, whether it is short‐term energy storage such as Tesla batteries or long‐term energy storage such as hydrogen energy vector. The main objective of this work is to assess the feasibility of the proposed grid‐independent energy system, which is pairing solar power to sustainable energy storage technologies within an existing residential building with conventional electric energy demand. This study aims to evaluate the optimal sizing of the solar units implemented in the design along with the optimal back‐up energy storage capacities to fulfil the building's daily electricity demand in an uninterrupted mode. This article investigates the possibility of supplying 100% solar power to the existing residential building with conventional electric energy demand under constraints and limitations conditions due to the stochastic nature of building electricity consumption, volatile and intermittent nature of solar resources, local meteorological conditions specific to the building's placement and space limitations for the positioning of the photovoltaic panels. The average daily load that has been calculated for the building has a value of 6.50 kWh. To reach the proposed target of integral solar power supply, photovoltaic panels with an installed power of 7.84 kWp paired with a Tesla batteries bank with a storage capacity of 7.4 kWh are needed, and in the case of storing solar energy in the form of electrolytic hydrogen it is necessary to pair the photovoltaic panels with an installed power of 15.12 kWp, 3 kW electrolyser, 2 kW fuel cell and H2 tank of 7 kg. The annual energy demand of 2369 kWh is achieved of 43.27% directly from photovoltaic panels and 56.73% through the back‐up energy in case of pairing the batteries as an energy storage medium, and in case of pairing hydrogen as an energy vector, 41.53% is powered directly by photovoltaic panels and 58.46% comes from the energy reserve stored through hydrogen technologies. The environmental analysis highlights an average decrease of up to 85% in carbon dioxide emissions generated by the implementation of clean energy systems analysed compared to the grid electricity. Also, the results of this study show that the investment costs in photovoltaic panels and storage systems are still high, limiting their use in residential buildings, but we are witnessing technological developments to improve the performance and durability of these electricity storage solutions at low costs, which will allow them to be marketed on a large scale, particularly widespread for residential applications. [ABSTRACT FROM AUTHOR]

The acceleration of distributed energy resources and carbon pricing policies have compelled utilities to act and to prioritize carbon-constrained infrastructure augmentation in their capital programs. To implement various carbon emission reduction policies, power system transmission planning has become more challenging. The existing energy system will face massive retirement of coal-fired power plants (CFPPs), large scale integration of renewable energy and network expansion. In this paper, an electricity network planning and transformation roadmap, which has two milestones, is put forward. In the first stage, a mathematical model is proposed based on the average cost of carbon emission reduction to realize the cooperation of CFPPs retirement and renewable energy investment. It can help the network carry out the transition from a fossil-fuel dominated system to a low-carbon oriented system. Because of the promising prospect of power-to-gas (P2G) technology, in the second milestone, a method based on carbon emission flow (CEF) is employed to help the power-to-gas stations (P2GSes) to select the construction site and capacity. The gas network constraints are modeled to guarantee that P2GSes can work smoothly without energy flow congestion in both electricity and gas networks. According to the simulation results in case studies, our method can reach the emission reduction target more economically and effectively, and the P2GSes can produce and absorb clean energy. [ABSTRACT FROM AUTHOR]

The integration of distributed energy resources (DERs) into contemporary energy communities (ECs) has revolutionized power systems, fostering sustainable and clean energy infrastructures. This paper focuses on the effective load-carrying capability (ELCC) to enhance grid resilience in the presence of DERs. We introduce an innovative network topology-based optimization framework that seamlessly integrates economic and resilience metrics within ECs while reducing carbon emissions. The Pareto front of non-dominated solutions for the proposed three-objective optimization problems is extracted, providing a comprehensive visualization of the trade-off between economic, resilience, and emission objectives, enabling informed decision-making. Analytical results, validated on the IEEE 33-bus test system, demonstrate the effectiveness of DER-based ELCC quantification in managing load supply during emergencies. Case studies show how the synergy between economic and resilience-based metrics significantly enhances grid resilience. The proposed framework has diverse applications, including enhancing grid adaptability to climate change, promoting sustainable energy integration, optimizing demand response strategies, and supporting the transition to a decarbonized energy community. This work addresses the challenges and opportunities in the evolving energy landscape, emphasizing the importance of our approach in achieving a cleaner and more resilient energy future. [ABSTRACT FROM AUTHOR]

Strict climate goals require a rapid reduction of carbon emissions across society. It is a considerable challenge to design decarbonization pathways considering co-operation in energy and carbon emissions across multiple sectors simultaneously. In order to obtain the decarbonization pathway for the whole society, this paper establishes a long-term multi-sector low-carbon transition pathway planning model. Besides inter-sectoral energy supply and demand, this study fully considers the allocation of carbon emissions quotas among different sectors by modified-grandfathering method, which takes into account both equity and efficiency principles. The decarbonization targets of different sectors, corresponding mitigation pathways and energy consumption can be calculated. China is taken as a case study. Results show that China's total energy consumption peaks at 5 billion tces around 2030, then falls below 4 billion in 2060, with the proportion of primary electricity and other clean energy reaching over 50 percent. Besides, the realisation of carbon neutralisation in China depends heavily on the improvement of carbon capture and storage (CCS) and end-use electrification rate. Moreover, the study of different quota allocation ways shows that the increase in the contribution rate of power system mitigation leads to the reduction of the total low-carbon transition costs, which also aggravates administrative difficulties. • A multi-sector model is set up to plan the long-term low-carbon transition pathway. • Modified-grandfathering allocation method can consider multiple indicator factors. • The clean energy consumption of China accounts for about 55% in 2060. • The end-use electrification rate in China is close to 70% in 2060. • The transition pathway with lower cost increases administrative difficulties. [ABSTRACT FROM AUTHOR]

• The study investigates HRES sizes to achieve NZEB status for a hotel building. • An optimization analysis of a hotel's grid-connected HRES is presented. • The PV/wind grid-connected system has the lowest NPC and LCOE. • The electricity price of the proposed HRES, at 2.1 ¢/kWh. • The Egypt's retail electricity prices of 6.9 ¢/kWh. The tourism sector is a key source of national income, and the use of renewable energy resources promotes green and sustainable tourism. In addition, ensuring a reliable supply and efficient use of clean energy is a primary objective of Egypt's Vision 2030, as it has a significant impact on the sustainable development and growth of the tourism sector in Egypt. Net-zero energy buildings (NZEBs) are a promising decarbonization effort as they reduce energy consumption while increasing the share of renewable energy. Therefore, it is worth investigating the opportunities for NZEBs applications in tourism sector. This paper presents an optimization analysis of a hotel's grid-connected hybrid renewable energy system (HRES) based on its technical, economical, and environmental prospects. Seven scenarios are considered for on-site generation to match the energy requirements of the specific hotel building. The proposed hybrid systems incorporate photovoltaic (PV), wind turbine (WT), and biogas generators into a grid-connected system for supplying power to a tourist hotel. The size of the microgrid system is optimized to decrease the net present cost (NPC) and levelized cost of electricity (LCOE). The results reveal that the PV/wind grid-connected system, with renewable energy generators consisting of 143 kW of photovoltaic modules and one 20 kW wind turbine with a hub height of 18 m, has the lowest NPC and LCOE. This hybrid energy system has a net present cost of 388 k$, which is significantly lower compared to the electricity grid's cost of 873 k$. The electricity price of the proposed HRES, at 2.1 ¢/kWh, is highly competitive with Egypt's retail electricity prices of 6.9 ¢/kWh. Moreover, grid-connected HRES can lower the pressure on the electricity grid arising from the feed-in of electricity from HRES. Furthermore, the proposed HRES will help slow climate change by reducing GHG emissions and fossil fuel usage. Finally, this study will provide valuable guidance for the practical application of NZEBs in Egypt as well as similar global zones. [ABSTRACT FROM AUTHOR]

Clean offshore energy hubs may become pivotal for efficient offshore wind power generation and distribution. In addition, offshore energy hubs may provide decarbonised energy supply for maritime transport, oil and gas recovery, and offshore farming, while also enabling conversion and storage of liquefied decarbonised energy carriers for export. In this paper, the role of offshore energy hubs is investigated in the transition of an offshore energy system towards zero-emission energy supply. A mixed-integer linear programming model is developed for investment planning and operational optimisation to achieve decarbonisation at minimum cost. We consider offshore wind, solar, energy hubs and subsea cables. A sensitivity analysis is conducted on CO 2 tax, CO 2 budget and the capacity of power from shore. The results show that: (a) a hard carbon cap is necessary for stimulating a zero-emission offshore energy system, (b) offshore wind integration and power from shore can more than halve current emissions, but offshore energy hubs with storage may be necessary for zero-emission production, and (c) at certain CO 2 tax levels, the system with offshore energy hubs can potentially reduce CO 2 emissions by 49% and energy losses by 10%, compared to a system with only offshore renewables, gas turbines and power from shore. • A mixed-integer linear program for large-scale offshore energy system planning. • Investment planning with operational details of offshore oil and gas fields. • Sensitivity analysis on CO 2 tax, carbon budget and onshore power capacity. • Offshore energy hubs show value in emission reduction, energy losses and costs. [ABSTRACT FROM AUTHOR]

Edge computing places cloudlets with high computational capabilities near mobile devices to reduce the latency and network congestion encountered in cloud server-based task offloading. However, many cloudlets are required in such an edge computing network, leading to a tremendous increase in carbon emissions of computing networks globally. This increase in carbon emission envisages the need to employ green energy resources to power these cloudlets. This need has led to the concept of Green Cloudlet Networks (GCNs). But GCNs must deal with the problem of the unpredictability of green energy available to them while optimizing the performance (in terms of latency) delivered to the mobile user. This paper proposes a novel task-assignment called Green Energy and Latency Aware Task Assignment (Ge-LATA) for GCNs to address this issue. The primary aim of Ge-LATA is to optimize the latency and the green energy consumed in processing the offloaded tasks from the mobile devices. In this GCN, the cloudlets are connected in a network to process the incoming tasks cooperatively to ensure load-balancing at the cloudlets. Ge-LATA considers various factors like the current load, available green energy, service rate offered by cloudlets, and the distance from the mobile user, leading to optimal decisions in terms of latency and green energy consumed. Simulations are performed using the actual solar insolation data taken from the NREL database. Ge-LATA is tested with other offloading schemes for latency in processing the offloaded tasks and green-energy consumed under different solar insolation scenarios in these simulations. Simulation results show that Ge-LATA achieves up to 31.87% of reduction in the latency while ensuring up to 50.15% of reduction in the energy consumption than other comparable task-assignment schemes.Thus, Ge-LATA suggests that it leads to an optimal task assignment by considering the various factors mentioned above during the task assignment process. Thus, Ge-LATA considers the above-mentioned extensive set of parameters during the task allotment process. It also proposes an efficient green energy allotment scheme that adapts itself to actual weather and network conditions, leading to optimal task assignment decisions in GCNs. [ABSTRACT FROM AUTHOR]