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Abstract: In the mainframe of a research contract, a feasibility pre-design study of a hydrogen-fuelled Laboratory-Village has been carried out: the goals are the design and the simulation of a demonstration plant based on hydrogen as primary fuel. The hydrogen is produced by electrolysis, from electric power produced by a mix of hydroelectric and solar photovoltaic plants. The plant will be located in a small remote village in Valle d’Aosta (Italy). This country has large water availability from glaciers and mountains, so electricity production from fluent water hydroelectric plants is abundant and cheap. Therefore, the production of hydrogen during the night (instead of selling the electricity to the grid at very low prices) could become a good economic choice, and hydrogen could be a competitive local fuel in term of costs, if compared to oil or gas. The H2 will be produced and stored, and used to feed a hydrogen vehicle and for thermal purposes (heating requirement of three buildings), allowing a real field test (Village-Laboratory). Due to the high level of pressure requested for H2 storage on-board in the vehicle, the choice has been the experimental test of a prototype laboratory-scale high-pressure PEM electrolyzer: a test laboratory has been designed, to investigate the energy savings related to this technology. In the paper, the description of the dynamic simulation of the plant (developed with TRNSYS) together with a detailed design and an economic analysis (proving the technical and economical feasibility of the installation) has been carried out. Moreover, the design of the high-pressure PEM electrolyzer is described. [Copyright &y& Elsevier]

Abstract: The objectives and methodology of the EU-funded research project HYVOLUTION devoted to hydrogen production from biomass are reviewed. The main scientific objective of this project is the development of a novel two-stage bioprocess employing thermophilic and phototrophic bacteria, for the cost-effective production of pure hydrogen from multiple biomass feedstocks in small-scale, cost-effective industries. Results are summarised of the work on pretreatment technologies for optimal biodegradation of energy crops and bio-residues, conditions for maximum efficiency in conversion of fermentable biomass to hydrogen and CO2, concepts of dedicated installations for optimal gas cleaning and gas quality protocols, as well as innovative system integration aimed at minimizing energy demand and maximizing product output. The main technological objective is the construction of prototype modules of the plant which, when assembled, form the basis of a blueprint for the whole chain for converting biomass to pure hydrogen. A brief outline is presented of the progress made towards developing reactors for thermophilic hydrogen production, reactors for photoheterotrophic hydrogen production and equipment for optimal gas cleaning procedures. [ABSTRACT FROM AUTHOR]

Portugal, in line with the European Union, is aiming for carbon neutrality by 2050 (Net Zero), which implies a transition to sustainable energy sources. Climate change is all too evident, as extreme weather periods are occurring in a cyclical manner with greater brevity to such an extent that the grid operator must deal with production scenarios where it can no longer rely on hydroelectric production given the recurring drought situation. This situation increases dependence on thermal production using natural gas and imports. This has significant economic implications. Portugal has exploited its onshore wind potential, reaching an installed capacity of 5.671 MW by 2022. However, the expansion of onshore wind energy is limited to reinforcing the existing infrastructure. To overcome these challenges, it is necessary to expand the exploitation of the offshore wind potential that is already underway. This article proposes the location of offshore wind production platforms along the Portuguese coast. This allows for an analysis of offshore production and its optimization according to the minimum cost per MWh in the face of extreme scenarios, i.e., in periods of extreme drought where the hydroelectric production capacity is practically non-existent. The model is fed by using market price indications and the amount of energy needed for the following day. Using forecast data, the model adapts offshore wind production for the following day according to the minimization of the average market price. This study presents an optimization model adapted to combat the unpredictability of extreme weather conditions. This strategic framework significantly increases the resilience and reliability of offshore wind energy production, marking a significant advance in the management of renewable energy under the pressure of climate variability. The results of the simulations allow us to conclude that despite the high cost of offshore technology (in deep waters), in extreme climate scenarios, it enables cost reduction and a clear decrease in imports. [ABSTRACT FROM AUTHOR]

This study examines the optimal energy mix for industrial complexes by incorporating renewable energy systems, decarbonization strategies, and sector coupling technologies. Using data from the Balan Industrial Complex in Korea, five energy scenarios were evaluated, ranging from conventional systems (Scenario 1) to advanced renewable configurations (Scenario 5). The results show that Scenario 5, which integrates sector coupling systems and decarbonization technologies, is the most cost-effective and environmentally sustainable. Scenario 5 achieves the lowest Net Present Cost (NPC), and significantly reduces CO2 emissions. Furthermore, an analysis of electricity prices and CO2 costs from Korea, the United States, and Germany highlights the critical role of regional electricity tariffs and carbon pricing in determining the economic feasibility of energy systems. While renewable setups require higher initial investments, Scenario 5 proves to be the most economically viable over time, offering both cost savings and environmental benefits. These findings provide valuable insights for policymakers and industry leaders, emphasizing the importance of customized strategies to optimize energy systems in industrial applications. [ABSTRACT FROM AUTHOR]

Profit maximization is crucial for both producers and customers in power grids, particularly in deregulated energy markets. By focusing on profit maximization measures, power grids can improve economic viability and sustainability for all stakeholders. The growing demand for electricity in modern civilization poses a significant challenge to the power grid's ability to meet it. To address these difficulties, the power industry is attempting to integrate renewable sources into existing power facilities. Because of its unpredictable character, the presence of renewable energy in the electricity system becomes increasingly important and adds complexity to the grid. Given the intermittent nature of renewable sources, an energy storage device is required in this scenario. During the low-power use phase, the grid has ample power. Meanwhile, energy storage devices can be utilized to store extra power in the low power demand phase while maintaining the safety and stability of the power network during peak demand periods. V2G (Vehicle-to-Grid) technology is commonly employed to address the uncertainty of renewable resources while maintaining system stability. By using automobiles as transportable storage devices, V2G can make the best use of excess electricity during low-energy hours. Wind energy's volatility causes imbalances, lowering system profitability. With wind energy integration, power system profitability can be improved by analyzing uncertainties and employing mitigation strategies. To overcome the issue, the research optimizes the use of V2G and TCSC (thyristor-controlled series compensator). V2G permits bidirectional power flow, lowering imbalance pricing (IP) while considering power demand. TCSC can increase the transient stability of transmission lines, hence reducing line faults. TCSC's involvement in the system increases profitability by lowering congestion expenses. Strategic TCSC placement increases overall profitability. The approach strives to offer efficient, environmentally friendly power at a reasonable price while addressing the needs of both power providers and customers. This study also looks into the effects of V2G mixing on voltage stability, LMP (locational marginal price), and the effectiveness of a TCSC in a deregulated electrical system. MiPower software is used to simulate operation and find the optimal placement of the storage unit within the IEEE 14-bus system. [ABSTRACT FROM AUTHOR]

The traditional mathematical models for solving the economic dispatch problem at the generation level primarily focus on minimizing overall operational costs while ensuring demand is met across various periods. However, contemporary power systems integrate a diverse mix of generators from both conventional and renewable energy sources, contributing to economically efficient energy production and playing a pivotal role in reducing greenhouse gas emissions. As the complexity of power systems increases, the scope of economic dispatch must expand to address demand across multiple regions, incorporating a range of objective functions that optimize energy resource utilization, reduce costs, and achieve superior economic and technical outcomes. This paper, therefore, proposes an advanced optimization model designed to determine the hourly power output of various generation units distributed across multiple areas within the power system. The model satisfies the dual objective functions and adheres to stringent technical constraints, effectively framing the problem as a nonlinear programming challenge. Furthermore, an in-depth analysis of the resulting and exchanged energy quantities demonstrates that the model guarantees the hourly demand. Significantly, the system's efficiency can be further enhanced by increasing the capacity of the interconnection links between areas, thereby generating additional savings that can be reinvested into expanding the links' capacity. Moreover, the multi-objective model excels not only in meeting the proposed objective functions but also in optimizing energy exchange across the system. This optimization is applicable to various types of energy, including thermal and renewable sources, even those characterized by uncertainty in their primary resources. The model's ability to effectively manage such uncertainties underscores its robustness, instilling confidence in its applicability and reliability across diverse energy scenarios. This adaptability makes the model a significant contribution to the field, offering a sophisticated tool for optimizing multi-area power systems in a way that balances economic, technical, and environmental considerations. [ABSTRACT FROM AUTHOR]

The global transportation electrification commerce sector is now booming. Stakeholders are paying an increased attention to the integration of electric vehicles and electric buses into the transportation networks. As a result, there is an urgent need to invest in public charging infrastructure, particularly for fast charging facilities. Consequently, and to complete the portfolio of the green environment, these fast-charging stations (FCSs) are designed using 100% of renewable energy sources (RESs). Thus, this paper proposes an optimization model for the techno-economic assessment of FCSs comprising photovoltaic and wind turbines with various energy storage devices (ESDs). In this regard, the FCS performance is evaluated using flywheels and super capacitors due to their high-power density and charging/discharging cycles and rates. Then, optimal sizing of these distributed generators is attained considering diverse technical and economical key performance indicators. Afterwards, the problem gets more sophisticated by investigating the effect of RES's uncertainties on the selection criterion of the FCS's components, design and capacity. Eventually, as an effort dedicated to an online energy management approach, a deep learning methodology based on radial basis network (RBN) is implemented, validated, and carried out. In stark contrast to conventional optimization approaches, RBN demonstrates its superiority by obtaining the optimum solutions in a relatively short amount of time. [ABSTRACT FROM AUTHOR]

Today, many factors, especially the increasing world population and developing technology, increase the energy needs of people and societies day by day. The fact that fossil resources are both in danger of depletion and have negative environmental impacts has directed countries to new resources. The study focuses on the effective use of renewable energy sources (RES) and the evaluation of waste to meet the electricity and heat energy needs of Yiğit Harman Village, located in the Solhan district of Bingöl Province. For this purpose, a renewable-energy-based combined heat and power system (CHP) was designed using HOMER Pro software (version 3.14.2, Homer Energy LLC, Boulder, CO, USA). Solar, wind, biomass, and hydrogen energy sources were used, considering the resources of the region. Using the designed model, the entire electricity energy requirement and half of the heat energy were completely met by the region's available RESs. In addition to the technical analysis, economic and environmental analyses were also conducted, and LCOE, NPC, and CO2 emission values were obtained as 0.271 USD/kWh, USD 739,772, and 37,958 kg/yr, respectively. These results indicate that with an investment of approximately USD 7000 per household, the electrical and thermal energy needs for 25 years can be met. [ABSTRACT FROM AUTHOR]

A promising energy carrier and storage solution for integrating renewable energies into the power grid currently being investigated is hydrogen produced via electrolysis. It already serves various purposes, but it might also enable the development of hydrogen-based electricity storage systems made up of electrolyzers, hydrogen storage systems, and generators (fuel cells or engines). The adoption of hydrogen-based technologies is strictly linked to the electrification of end uses and to multicarrier energy grids. This study introduces a generic method to integrate and optimize the sizing and operation phases of hydrogen-based power systems using an energy hub optimization model, which can manage and coordinate multiple energy carriers and equipment. Furthermore, the uncertainty related to renewables and final demands was carefully assessed. A case study on an urban microgrid with high hydrogen demand for mobility demonstrates the method's applicability, showing how the multi-objective optimization of hydrogen-based power systems can reduce total costs, primary energy demand, and carbon equivalent emissions for both power grids and mobility down to −145%. Furthermore, the adoption of the uncertainty assessment can give additional benefits, allowing a downsizing of the equipment. [ABSTRACT FROM AUTHOR]

There is a serious need for reducing the carbon dioxide emissions due to the increase in the global warming. Besides, owing to the unavailability of clean energy sources throughout an entire the year, hybrid renewable energy systems (HRESs) are required. On other hand, the importance of optimal HRES design is to achieve a low cost with using a high green energy. Helioscope and HOMER Pro software were used to design a small grid-connected model and estimate the consumption energy for optimization. The analysis of the system showed how a grid-connected PV system with a battery backup affected on the total energy costs. In addition, the role of power supply irregularity from the national grid was highlighted by calculating the likelihood of a power outage and its impact on HRES. The results showed the internal rate of return (IRR) is 13%, and the return on investment (ROI) is around 9%. Also, the value of renewable fraction was around 63.4%. In conclusion, the proposed system was an efficient according to the energy consumption. This case study can extend to be applied in any country, especially the countries have longer summer like Iraq. [ABSTRACT FROM AUTHOR]

Biomass has been the only renewable energy that can be directly converted into fuel. The full utilization of biomass can effectively alleviate energy needs in an eco-friendly way. It is also an important path for China to achieve the goal of "carbon neutrality". Therefore, this study aims to focus mainly on the general goal of clean energy production and high-value utilization for straw-based biomass resources in recent years. A systematic analysis was made to evaluate the comprehensive utilization technology and mode of producing gas, liquid, and solid clean energy in the biological or thermo-chemical way. The development status and research progress were concentrated upon the anaerobic digestion for biogas, hydrothermal catalysis for alcohol and hydrocarbon fuel, pyrolysis liquefaction and bio-oil upgrading, and solid fuel production. Particularly, an attempt was addressed on the prospect of biogas, liquid fuel, and solid fuel. More importantly, no matter what biomass conversion technology was adopted, biomass resources utilization should be comprehensive and of high value. Correspondingly, the large-scale application required at least three basic elements. The first was the scale collection and disposal of biomass raw materials at a low cost. The second was the efficient and stable transformation, as well as quality improvement technology. The last was that the terminal fuel products needed to connect smoothly with the current application. Among them, anaerobic digestion for biogas presented the highest level of industrialization in recent years, due mainly to effectively solving raw materials collection in large breeding farms. It infers that the anaerobic digestion and biogas purification technology were relatively mature during this time. As such, biogas was directly used as a source of fuel, power, and thermal production. By contrast, hydrothermal catalysis for alcohol and hydrocarbon fuel, together with pyrolysis liquefaction for bio-oil was relatively difficult to connect with the current application, due mainly to the high conversion cost, difficult product separation, low-quality improvement efficiency, and unstable products. Therefore, the large-scale development level of the two technologies was relatively low during this time. Nevertheless, the technology of biomass preparation was relatively mature for solid fuels. The research and development of supporting stoves also effectively implemented the application of molding fuel. But the biggest difficulty in the scale application lay in the collection and storage of raw materials. Finally, the development prospects were proposed for the biomass conversion technologies. In terms of biogas, the anaerobic digestion was enhanced by multi-ingredients and bio-strengthen to improve biogas production efficiency. A precise control system should be established for the high concentration anaerobic digestion for better stability. Particularly, the comprehensive utilization of biogas slurry was carried out to realize the nutrient recycling, and biological organic fertilizer, or carbon-based fertilizer for nitrogen and carbon fixation, with emphasis on the efficiency of desulfurization and decarbonization. In terms of liquid fuel, the unpolluted depolymerization can be explored from lignocellulose to platform compounds, especially how to realize the efficient separation and quality improvement of platform compounds. During the quality upgrading process, the multi-step reaction combined catalyzer can be used to shorten the process and improve the reaction efficiency. In addition, the efficient conversion of biomass resources into fuel, chemicals, and materials should be developed synchronously for higher-value products. In terms of solid fuel, the heat transfer and bonding mechanism of torrefaction straw should be studied during the molding process, further to realize the low energy consumption and high quality. New efficient molding and combustion equipment needed to be improved the reliability of solid fuel production, particularly on the standardization, series, and package of torrefaction, molding, and combustion equipment. Consequently, the standard production of biomass collection, storage, and combustion should be improved to form biomass solid fuel industry chain from collection, storage, transportation, molding, and distribution. This research can provide a strong reference for the efficient preparation of clean energy and high-value utilization in rural biomass. [ABSTRACT FROM AUTHOR]

The constant attention to sustainability aimed at reconciling economic and social development with environmental protection is the driving force of the continuous growth of renewable energy in the energy sector. Among the numerous actions taken by the European Commission (EC) in this direction, an important initiative towards the complete decarbonization is represented by the Renewable Energy Communities (RECs). According to the EC, "energy communities enable collective and citizen-driven energy actions to support the clean energy transition. They can contribute to increasing public acceptance of renewable energy projects and make it easier to attract private investments in the clean energy transition". At the European level, numerous energy communities are emerging, although they are all based on photovoltaic production and, consequently, focus only on electricity flows. The aim of this paper is to define a thermal energy community in which thermal energy sharing can be achieved by exploiting the concept of the smart district heating network. Starting from a small existing district heating network, its conversion into a smart one will be analyzed and optimized with the aim of studying the sharing of thermal energy between the various prosumer and non-prosumer users connected to the district heating network. [ABSTRACT FROM AUTHOR]

Morocco’s exploration of nuclear energy aligns with both climate goals and national energy ambitions, offering a promising low-carbon alternative to conventional fossil fuels. Despite the nation’s significant strides in renewable energy, nuclear power remains understudied, revealing a critical literature gap. This research underscores the global imperative to transition to net-zero emissions and the pivotal role nuclear energy plays in addressing climate change. Within the context of Morocco’s 2030 plan, which prioritizes renewable energy, nuclear energy stands as an underexplored aspect, lacking comprehensive research. To bridge this gap, the study employs a PESTLE analysis to examine the political, economic, societal, technological, legal, and environmental factors influencing Morocco’s nuclear energy landscape. The integration of insights from various sources, including press releases, reports, and scientific publications, ensures a holistic and well-informed perspective on Morocco’s nuclear industry. The paper concludes by providing an overview of nuclear energy use on different scales, accompanied by a detailed discussion of the PESTLE analysis outcomes. This approach seeks to contribute valuable insights for informed decision-making and strategic planning in the realm of nuclear energy development. [ABSTRACT FROM AUTHOR]

Amidst a growing global focus on sustainable energy, this study investigates the underutilization of renewable resources in the southern region of Saudi Arabia, with a specific emphasis on the Najran Secondary Industrial Institute (NSII). This research presents an in-depth analysis of installing a hybrid microgrid (MG) system on the roofs of NSII buildings, exploring six cases with varying tilt and azimuth angles. The study innovatively integrates architectural design and system administration, a novel approach for this location, and benchmarks the optimal angles against Hybrid Optimization of Multiple Energy Resources (HOMER) software defaults. The proposed system consists of solar photovoltaic (PV) panels, a battery storage system (BSS), a converter, a diesel generator (DG), and a grid. The selected model balances technological and economic viability with environmental considerations, ensuring a reliable power supply within the NSII's roof area constraints. An extensive sensitivity analysis evaluates the system's resilience across different scenarios. The current system, which is grid-only, has an estimated Net Present Cost (NPC) of about USD 7.02M and emits 1.81M kg/yr of CO2. The findings point to installing a microgrid with a 20.97° tilt and 50° azimuth angle as optimal, demonstrating 54.69% lower NPC and 92% lower CO2 emissions, along with zero kWh/year unmet electrical load when applying the resilience assessments. This outcome highlights Saudi Arabia's southern region's renewable energy potential, aligning with national mega-projects and energy initiatives. [ABSTRACT FROM AUTHOR]

Despite renewable energy source integration being a well-established requirement in international policies, energy systems still face some unresolved issues, including the intermittence of production. To tackle this problem, a viable solution could comprise the off-peak storage of electricity production excess, to be consumed later during peak-load hours. The transition from the diffuse pattern of centralized generation to the distributed model, involving energy communities, suggests an additional aspect to manage: the spatial constraints of systems for domestic applications. Compressed-air energy storage represents a promising Power-to-Power technology for small-scale energy integration. This study proposes the application of a gas–liquid energy storage system (GLES) in a residential building, using renewable energy excess from a photovoltaic (PV) array. The performance of the proposed system, whose operation involves the compression of the gaseous mass through a piston operated by mineral oil, was evaluated through energy analysis performed simulating the devices and their coupling with the load profiles of the building. The thermodynamic model of storage was validated using data from an experimental campaign on a prototype. A sensitivity study, acting on the features of the system, such as the compression rate and vessel size, allowed us to compare the absorbed PV energy excess, the coverage of the building energy demand during the expansion phase, and the electrical efficiency of a daily cycle. The results obtained, together with the related economic analysis, were used to quantify the market potential of the proposed solution, to be exploited as a mechanical alternative to conventional electric batteries in dwellings. [ABSTRACT FROM AUTHOR]

This paper presents a quantitative assessment of the value of hydroelectric power plants (HPPs) in power systems with a significant penetration of variable renewable energy sources (VRESs). Through a capacity expansion planning (CEP) model that incorporates a detailed representation of HPP operating principles, the study investigates the construction and application of HPP rule curves essential for seasonal operation. A comparative analysis is also conducted between the proposed rule curve formulation and alternative modeling techniques from the literature. The CEP model optimizes installed capacities per technology to achieve predefined VRES penetration targets, considering hourly granularity and separate rule curves for each HPP. A case study involving twelve reservoir hydropower stations and two open-loop pumped hydro stations is examined, accounting for standalone plants and cascaded hydro systems across six river basins. The study evaluates the additional generation and storage required to replace the hydropower fleet under high VRES penetration levels, assessing the resulting increases in total system cost emanating from introducing such new investments. Furthermore, the study approximates the storage capabilities of HPPs and investigates the impact of simplified HPP modeling on system operation and investment decisions. Overall, the findings underscore the importance of reevaluating hydro rule curves for future high VRES penetration conditions and highlight the significance of HPPs in the energy transition towards carbon neutrality. [ABSTRACT FROM AUTHOR]

To achieve an energy sector independent from fossil fuels, a significant increase in the penetration of variable renewable energy sources, such as solar and wind power, is imperative. However, these sources lack the inertia provided by conventional thermo-electric power stations, which is essential for maintaining grid frequency stability. In this study, a grid resembling Madeira Island's power generation mix was modeled using the Matlab/Simulink platform. The model included solar, wind, hydro, and thermo-electric generation to accurately represent the energy landscape of Madeira Island. Three scenarios were examined: one reflecting the current power generation on Madeira Island, a future scenario with a substantial rise in the percentage of photovoltaic (PV) generation, and the same future scenario but incorporating a battery energy storage system (BESS). Various analyses were conducted to assess the impact on frequency stability during a ground fault and rapid load/generation changes. In the future scenario without a BESS, the thermoelectric power plant generator desynchronized, leading to system collapse in several simulations. However, with the addition of a BESS, a significant improvement in frequency stability was observed. The thermoelectric power plant generator could return to a steady state after each disturbance. Furthermore, both the maximum frequency deviation and the absolute value of the Rate of Change of Frequency (ROCOF) were reduced, indicating enhanced system performance and stability. [ABSTRACT FROM AUTHOR]

Woody biomass has gained increased attention as a source of renewable energy. However, its categorization as a sustainable source of energy remains controversial, as its carbon neutrality depends on its end use, moisture content, bulk density, and the distance between the source of biomass and its end use. Due to these mediating factors, policies largely shape its sustainability and ability to mitigate emissions. This paper organizes and evaluates the current state of research through a systematic review of global literature from 2011 to 2021 (n = 345) on the governance of the production, transportation, sale, and use of woody biomass for energy. Peer-reviewed literature emphasizes the role of woody biomass as a decentralized energy source for individual households and communities, focusing on its harvest, transport, and localized energy conversion. Policies primarily address land management and energy infrastructure rather than direct emissions reduction. Research gaps in policy within the Global South underscore the need to examine biomass regulation in regions with limited energy diversity. The key factors that drive the sustainable uptake of woody biomass include strict sustainability criteria, fiscal incentives, technological development, and wood utilization from across its value chain. Effective policy implementation increases rural employment, boosts rural economies, provides energy security to remote areas, improves overall environmental sustainability, reduces emissions, and improves land management practices. Our systematic review reveals that future research should focus on improving conversion efficiencies in small-scale systems, reducing emissions in the international trade of woody biomass, and using the wood value chain to increase the profitability of bioenergy products. [ABSTRACT FROM AUTHOR]

Climate change and the energy crisis forced industrialized countries to contain CO2 emissions and use indigenous renewable energy sources. Geothermal energy undoubtedly has great potential, particularly thermal energy, given that 48% of the final energy consumption in the EU20 countries in 2021 was related to heating and cooling systems. The present study verifies and compares the feasibility of realizing district heating systems in two different contexts: (i) depleted hydrocarbon fields with the repurposing of existing hydrocarbon wells into geothermal wells and (ii) areas with documented geothermal resources. The two selected case studies are located, respectively, near Romentino (Northern Italy, province of Novara) and Tuscania (Central Italy, province of Viterbo). Following an assessment of the geothermal resources in the two selected case studies, specific methodological tools have been developed to evaluate the energy demand in the municipalities and determine the projects' economics. Both case studies show positive economic indices assuming heat tariffs aligned with the values recorded in the 2020–2021 period. However, our results show how reusing hydrocarbon wells in geothermal wells constitutes an excellent opportunity to access geothermal resources, significantly reducing the necessary investment and the mining risk and strongly improving the economics of the projects. [ABSTRACT FROM AUTHOR]

Abstract Geothermal energy from hot dry rock is considered to be a source of clean renewable energy. This energy resource in the Gonghe basin of Northwest China is equivalent to 630.3 billion tons of standard coal and represents a massive potential source of geothermal energy. In particular, the Qiabuqia geothermal field located in the eastern part of the basin holds an average geothermal gradient in a granite stratum of 7.1 °C/100 m and reaches a temperature of 236 °C at 3705 m depth in its GR1 well. This major breakthrough in geothermal exploration technology is promising for accelerating the construction of the enhanced geothermal system demonstration power plant in China. Firstly, we initially used actual geological, field, and laboratory data pertaining to the Qiabuqia site to investigate the temperature, rock properties, and in situ stress state of the geothermal reservoir through laboratory analysis and numerical calculation methods. Secondly, a probable reservoir stimulation scheme for the GR1 well in Qiabuqia site on the basis of laboratory experiments and numerical simulation was explored. Finally, we designed a possible enhanced geothermal system and numerically investigated the effects of injection rate, well spacing, and injection temperature on the system performance, providing useful insight into hydraulic pressure, thermal production, and power generation processes for the Qiabuqia geothermal field. Results indicate that the Qiabuqia site is suitable for the development of a demonstration power plant with an installed capacity of 4.02–4.74 MW if a three-vertical-well system is used. Highlights • The characteristics of a dry hot rock reservoir are analysed. • Reservoir stimulation is investigated by laboratory testing and numerical simulation. • Key parameters affecting EGS performance are numerically investigated. • An optimised EGS system with three-vertical-wells is proposed for power generation. [ABSTRACT FROM AUTHOR]

• Modelling of an integral collector storage with phase change material. • Model validation by means of experimental data. • Yearly domestic hot water production simulation and global performance evaluation. Solar Domestic Hot Water (SDHW) systems represent a constantly evolving technology in today's applications. With the new directives promoted by the European Union the renewable energy share produced in buildings will tend to increase further. Research on how to increase the efficiency of the thermal production from renewable energy are therefore of the foremost importance. This study aims to investigate the energy performance of an integral collector storage (ICS) prototype for DHW production. This ICS represents a new concept technology, integrating inside the same device a flat plate absorber and a storage section with phase change material (PCM) connected by heat pipes filled with methanol. An objective of this study was to investigate a possible alternative to conventional solar systems, with the aim of reducing investment costs and improving system reliability without compromising energy performance. The energy assessment was carried out using a numerical model in the Engineering Equation Solver (EES) environment, following an electrical analogy scheme. After a validation process by means of experimental data, a yearly simulation was launched in order to estimate the productivity and the solar fraction of the prototype. The results obtained allowed a global energy evaluation and a comparison with similar systems and to identify the pros and cons of this new technology. [ABSTRACT FROM AUTHOR]

The integration of a CSP tower system with a PV solar field, sharing a thermal energy storage, is modeled and discussed. The tower system uses a new-design solid particle fluidized bed receiver integrated with a thermal storage, where hot particles are directly collected to store daily energy for overnight production of electricity. The PV solar field is aimed to supply the daily energy demand; when there is a surplus of PV energy production, the electric energy is converted to heat and accumulated in the thermal storage too. The integration of the two energy systems is modeled, building efficiency functions for all the sub-components of the integrated plant (heliostat field, receiver, storage, power block, PV field). Yearly simulations are performed for two different locations, Spain and Australia, obtaining that a system with a peak power of 10 MWe CSP + 15 MWe PV can supply—with a limited curtailment—a fraction of more than 60% (respectively, 62% and 68%) of a realistic electric load with a peak demand around 10 MW, to be compared with the 45/47% of the same load obtained adopting a PV-only system with the same overall peak power. In the integrated system, PV directly supplies 40/41% of the load, the remaining 23/28% being produced by the power block (mainly fed by the CSP). [ABSTRACT FROM AUTHOR]

The rapid rise in industrial and human energy consumption has caused a significant increase in global energy demand. In order to meet simultaneously the increasing energy demand and protect the environment, researchers have put more effort into the development of new more sustainable energy sources. One of the promising alternatives for energy production in Pneumatic industrial sector is the integration of a hybrid power system, and making value to their produced waste and collected (tire waste) to use as an alternative energy sources. Considering the above‐mentioned facts, this study shows a techno‐economic and environmental assessment of a novel hybrid waste‐solar system configuration composed of an external depolymerization plant fueled by tires waste producing fuel for a co‐generator and a photovoltaic solar power plant ensuring the complement of the electrical need of our industrial. The novelty of this work is the development of the research methodology and innovative Solar/Waste hybrid power system from the existing system. The simulation is carried out in the HOMER software, the integrated system results in a Cost of Energy evaluated as 0.062 $/kWh, and 25.89% of avoided Greenhouse gasses emissions with an annual carbon credit of 32,422 $. [ABSTRACT FROM AUTHOR]

Many electricity markets use capacity mechanisms to support producers. Capacity payments can mitigate imperfections associated with "missing money" in the spot market and solve transitory capacity shortages caused by investment cycles, regulatory changes, or technology shifts. We discuss capacity mechanisms used in electricity markets around the world. We argue that correctly designed strategic reserves are likely to be more efficient than market-wide capacity mechanisms in jurisdictions that rely on substantial amounts of variable renewable energy and hydro power for electricity supply, such as Sweden. [ABSTRACT FROM AUTHOR]

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The growing demand for electricity driven by population growth and industrialization is met by integrating hybrid renewable energy sources (HRESs) into the grid. HRES integration improves reliability, reduces losses, and addresses power quality issues for safe and effective microgrid (MG) operation, requiring efficient controllers. In this regard, this article proposes a prairie dog optimization (PDO) algorithm for the photovoltaic (PV)-, fuel cell (FC)-, and battery-based HRESs designed in MATLAB/Simulink architecture. The proposed PDO method optimally tunes the proportional integral (PI) controller gain parameters to achieve effective compensation of load demand and mitigation of PQ problems. The MG system has been applied to various intentional PQ issues such as swell, unbalanced load, oscillatory transient, and notch conditions to study the response of the proposed PDO controller. For evaluating the efficacy of the proposed PDO algorithm, the simulation results obtained are compared with those of earlier popular methodologies utilized in the current literature such as bee colony optimization (BCO), thermal exchange optimization, and PI techniques. A detailed analysis of the results found emphasizes the efficiency, robustness, and potential of the suggested PDO controller in significantly improving the overall system operation by minimizing the THD, improving the control of active and reactive power, enhancing the power factor, lowering the voltage deviation, and keeping the terminal voltage, DC-link voltage, grid voltage, and grid current almost constant in the event of PQ fault occurrence. As a result, the proposed PDO method paves the way for real-time employment in the MG system. [ABSTRACT FROM AUTHOR]

This paper presents an optimization approach for Micro-cogeneration systems with internal combustion engines integrated into residential grids, addressing power demand failures caused by intermittent renewable energy sources. The proposed method leverages machine learning techniques, control strategies, and grid data to improve system flexibility and efficiency in meeting electricity and domestic hot water demands. Historical residential grid data were analysed to develop a machine learning-based demand prediction model for electricity and hot water. Thermal energy storage was integrated into the Micro-cogeneration system to enhance flexibility. An optimization model was created, considering efficiency, emissions, and cost while adapting to real-time demand changes. A control strategy was designed for the flexible operation of the Micro-cogeneration system, addressing excess thermal energy storage and resource allocation. The proposed solution's effectiveness was validated through simulations, with results demonstrating the Micro-cogeneration system's ability to efficiently address high electricity and hot water demand periods while mitigating power demand failures from renewable energy sources. The research presents a novel approach with the potential to significantly improve grid resilience, energy efficiency, and renewable energy integration in residential grids, contributing to more sustainable and reliable energy systems. [ABSTRACT FROM AUTHOR]

Integrating renewable resources with existing power system are rapidly increasing day by day, becoming an effective way to rural electrification where distribution system extension is not economically feasible. This research aims to design such an optimal grid-connected hybrid renewable energy system (HRES) modelled using solar, wind energy, diesel generator, battery storage, thermal loads, thermal load controller, and boiler. This system is designed to meet the load demand requirement of chintalayapalle village, Andhra Pradesh, India. The techno-economic, sensitivity analysis and cost-effective optimal configuration of this system have been performed using HOMER software. Totally eight configurations have been designed here and the optimal configuration have been identified based on the minimum net present cost (NPC), lowest cost of energy (COE), and the highest renewable fraction (RF). Results obtained shows that the optimally configured system is more environmentally friendly because of less carbon emission. Also, it would be more cost-effective when wind power becomes the main energy source and combined with moderate capacity of solar photovoltaic and battery. [ABSTRACT FROM AUTHOR]

This study aimed to quantify and evaluate the main environmental impacts generated in each phase of tofu production as well as its main co-products (soy milk, food integrators, etc.) and by-products (straw, hulls, etc.) from organic and conventional soybean cropping and to compare them with the impacts of conventional protein sources (e.g., livestock meat and snails). The starting case study was the tofu production company "Tigusto SA" located in Cugnasco-Locarno (Switzerland). The analysis was performed by means of the life cycle assessment (LCA) method, applying a systematic cradle-to-gate approach, from cultivation and extraction of raw materials to the final products. The aim of the analysis was to identify the phases that cause the main environmental burdens and to propose alternative solutions to minimize the impacts. Results show the importance of applying circularity-based scenarios, such as reuse/recycling of residues and the use of renewable energy, which could increase the sustainability of the investigated system, providing environmental and economic benefits. [ABSTRACT FROM AUTHOR]

At the local level, energy communities are at the forefront of the European Green Deal strategy offering new opportunities for citizens to get actively involved in energy markets. The scope of this study is to apply a multi-objective optimization framework to minimize both carbon dioxide emissions and total annual costs in an energy community, considering, within different constraints, a wide availability of decision variables including local renewable energy sources, sector coupling, storage and hydrogen. The methodology involves the coupling of the software EnergyPLAN with a multi-objective evolutionary algorithm, considering 2030 and 2050 as target years and modelling a set of eight types of scenarios, each consisting of 100 optimal systems out of 10,000. The case study is an energy community in the European Alps. The results show, on the one hand, the key role of sector coupling technologies such as cogeneration, heat pumps and electric vehicles in exploiting local renewable energy sources and, on the other hand, the higher costs in introducing both electricity storage to achieve a complete decarbonisation and hydrogen as an alternative strategy in the electricity, thermal and transport sectors. More specifically, it has been identified that, by 2030 a complete decarbonisation cannot be achieved considering the replacement rates of the technologies included in the Baseline 2018, but nevertheless the European target of -55% of CO2 emissions can be reached with costs similar to those of the Business As Usual trajectory, while, by 2050 a complete decarbonisation is possible with costs within 24% higher than those of the Business As Usual trajectory. [ABSTRACT FROM AUTHOR]

The European Union aims for its existing building stock to be highly energy-efficient and decarbonized by 2050 through long-term renovation strategies so that all residential buildings are nearly zero-energy buildings. The objective of this work is to determine the optimal energy renovation solution for rural residential buildings located in cold climate zones of Spain to achieve nearly zero-energy buildings. For this purpose, the energy, environmental and economic impacts of 48 energy renovation proposals in three different climate zones are assessed, taking La Rioja as a case study. Considering these impacts, the optimal solution is a solution that improves the thermal envelope, applying the life cycle cost analysis, and that uses renewable energy sources to meet thermal needs and a portion of the electrical energy needs. Under the optimal solution, overall savings of up to EUR 2.4 can be achieved for each euro invested, resulting in reductions in non-renewable primary energy consumption by up to 97%, total primary energy consumption by up to 81% and CO2 emissions by up to 97%. The methodology followed and the results obtained can serve as a guide for establishing energy renovation policies in other cold rural Mediterranean zones. [ABSTRACT FROM AUTHOR]

Tapping the full potential of clean, renewable energy resources to effectively meet the steadily increasing energy demand is the critical need of the hour and an important proactive step towards achieving sustainability. India's solar energy consumption has witnessed a nearly twofold increase from 6.76 GW in 2015–16 to 12.28 in 2016–17. Since India enjoys the advantage of high solar insolation, increasing the efficiency of solar power systems can tremendously boost clean energy generation. The escalating energy crisis currently faced by India has compelled scientists and researchers to focus on identifying novel economical and efficient technologies for large-scale energy production. Direct utilization of solar energy for fuel conversion has attained greater importance. In this context, generation of hydrogen from industrial wastewater by using solar energy offers significant economic as well as environmental benefits. This investigative review paper focuses on the importance of the solar photocatalytic process to recover the clean energy H2 from sulphide containing industrial wastewater. [ABSTRACT FROM AUTHOR]

Power-to-heat technology represents a promising solution for the decarbonization of the energy sector. The installation of large-scale heat pumps within district heating systems is widely recognized to be a cost-effective and competitive way to provide flexibility to the electric system, enhancing the use of intermittent renewable energy sources. The goal of this paper is to show how the economic and environmental benefits provided by the installation of a large-scale heat pump in existing district heating systems vary according to the installation location in different scenarios. To do that, an integrated methodology is developed. This includes a physical model of the thermo-fluid dynamic of the district heating network and a detailed modeling of the heat pump. To compare the different positions and also the different operating conditions, an approach based on exergy analysis is adopted. Moreover, a specific control strategy of the mass-flow rate is analyzed to further reduce greenhouse gas emissions. The application to a real large-scale district heating network shows that reductions in CO2 emissions of almost 4% can be obtained by installing a single heat pump of about 4 MWe (over a total thermal load of about 305 MWt), while this positive effect can be reduced by up to 63% if placing the heat pump at non-optimal locations. [ABSTRACT FROM AUTHOR]

Hybrid renewable energy systems (HRES) combine two or more renewable energy systems and are an interesting solution for decentralized renewable energy generation. The exergy and exergo-economic approach have proven to be useful methods to analyze hybrid renewable energy systems. The aim of this paper is to present a review of exergy and exergy-economic approaches to evaluate hybrid renewable energy systems in buildings. In the first part of the paper, the methodology of the exergy and exergo-economic analysis is introduced as well as the main performance indicators. The influence of the reference environment is analyzed, and results show that the selection of the reference environment has a high impact on the results of the exergy analysis. In the last part of the paper, different literature studies based on exergy and exergo-economic analysis applied to the photovoltaic-thermal collectors, fuel-fired micro-cogeneration systems and hybrid renewable energy systems are reviewed. It is shown that the dynamic exergy analysis is the best way to evaluate hybrid renewable energy systems if they are operating under a dynamic environment caused by climatic conditions and/or energy demand. [ABSTRACT FROM AUTHOR]

The energy crisis and its far-reaching effects have led to a significant change in political priorities in EU. Important countries from EU have turned to coal to increase security of electricity supply. The EU electricity demand is expected to recover slightly from 2023 with an average annual growth rate of 1,4% based on expectations of lower energy prices and a boost to electrification. [ABSTRACT FROM AUTHOR]

Solar energy offers a renewable source of power but its fluctuating nature raises concerns about the electrical grid balancing. Network regulators have to estimate the upcoming production to match supply with demand; consequently, power plant operators may be asked to provide accurate forecasts. Planning the thermal or electrical output of solar power plants is thus highly required to ensure a stable power chain supply. This paper presents a solution that couples a meteorological model with a solar power plant performance model. The power output is predicted 24 h ahead in the case of a solar Fresnel power plant. The required Direct Normal Irradiance is inferred from the global horizontal irradiance; the thermal production is evaluated from an optical and thermal model. Our approach has been validated on a 1000 m 2 Fresnel power plant, paving the way for model-based storage strategy. [ABSTRACT FROM AUTHOR]

Micro-district heating networks based on cogeneration plants and renewable energy technologies are considered efficient, viable and environmentally-friendly solutions to realizing smart multi-energy microgrids. Nonetheless, the energy production from renewable sources is intermittent and stochastic, and cogeneration units are characterized by fixed power-to-heat ratios, which are incompatible with fluctuating thermal and electric demands. These drawbacks can be partially overcome by smart operational controls that are capable of maximizing the energy system performance. Moreover, electrically driven heat pumps may add flexibility to the system, by shifting thermal loads into electric loads. In this paper, a novel configuration for smart multi-energy microgrids, which combines centralized and distributed energy units is proposed. A centralized cogeneration system, consisting of an internal combustion engine is connected to a micro-district heating network. Distributed electric heat pumps assist the thermal production at the building level, giving operational flexibility to the system and supporting the integration of renewable energy technologies, i.e., wind turbines, photovoltaic panels, and solar thermal collectors. The proposed configuration was tested in a hypothetical case study, namely, a University Campus located in Trieste, Italy. The system operation is based on a cost-optimal control strategy and the effect of the size of the cogeneration unit and heat pumps was investigated. A comparison with a conventional configuration, without distributed heat pumps, was also performed. The results show that the proposed configuration outperformed the conventional one, leading to a total-cost saving of around 8%, a carbon emission reduction of 11%, and a primary energy saving of 8%. [ABSTRACT FROM AUTHOR]

This paper aims to solve the state's hydropower dependence, build energy security and reduce greenhouse gas emissions through a hybrid renewable energy system and its implementation in Willingdon Island. Hybrid Optimisation of Multiple Energy Resources (HOMER) is used to find the optimal solution for two grid-connected and off-grid scenarios. Of the 19 solutions, an optimal off-grid, an optimal grid-connected, a 100% variable renewable energy, and a diversified energy portfolio option are selected, analyzed, and ranked based on their techno-economic and emissions characteristics. The results suggest the combination of PV/Wind/Grid with a cost of energy of $0.044 as an optimal solution for the Island. The diversified energy solution takes the second position, having 51.4% and 38.8% solar and wind, respectively. [ABSTRACT FROM AUTHOR]

This work aims to find an optimal hybrid renewable system design using solar, wind energy, battery storage, thermal loads, thermal load controller (TLC), boiler, and a diesel generator (DG) for the considered site. The prefeasibility techno-economic analysis has been carried out using HOMER software to meet the load demand requirement of the village. For identifying winning system architecture, minimum net present cost (NPC), lowest cost of energy (COE), and the highest renewable fraction (RF) are used as the criteria. The obtained results show that the least cost-optimal hybrid system consists of 614kW-PV,850kW-WT,800kW-DG, 1212 no. of batteries and 591 kW converter along with TLC-2000kW, having minimum NPC: $5.48M, least COE: $0.272/kWh and highest RF:91.6% can provide 92% reliable power supply to onsite load demand of 4502.95kWh/day with 70% renewable sources in the considered site. This paper also presents a sensitivity analysis of the hybrid system with variations in load demand, diesel fuel price, project lifetime, and interest rate. [ABSTRACT FROM AUTHOR]

Mining sites that combine energy-intensive operations with community living in areas remote from the electricity grid are increasingly developing dedicated micro-grids. Fossil oil gensets hybridization with renewable energy resources has gained momentum. Difficulties in assessing performance are experienced by operators who wish to benefit from improved performances. The designers of such systems also need additional knowledge to anticipate the solutions of the particular problems related to the power plant's implementation area characteristics. The proposed approach gives more suitable tools on the effectiveness evaluation of hybridized microgrid, combining a Heavy Fuel Oil (HFO) thermal power station with photovoltaic generator powering mine activities in the Sahelian area. The authors provide key analyses and improvement factors by seasonal behavioral modelling (SBM) of the fuel consumption of the gensets related to the overall irradiance dynamics of the PV array. Several years of data analysis results have been integrated for sharper considerations on the transient interactions impact of the PV/Diesel Hybrid Power Plant operation. The results of simulations carried out using the proposed new models, including the case of an extended system with storage unit, have been used to evaluate the levelized cost of energy, and to discuss competitiveness. This very relevant approach provides additional knowledge for designers and energetic effectiveness analysts. [ABSTRACT FROM AUTHOR]

This paper estimates the seasonal and zonal CO 2 marginal emissions factors (MEFs) from electricity production in the Italian electricity system. The inclusion of the zonal configuration of the Italian wholesale power market leads to a complete measurement of marginal emission factors which takes into account the heterogeneous distribution of RES power plants, their penetration rate and their variability within the zonal power generation mix. This article relies on a flexible econometric approach that includes the fractional cointegration methodology to incorporate the typical features of long-memory processes into the estimation of MEFs. We find high variability in annual MEFs estimated at the zonal level. Sardinia reports the highest MEF (0.7189 tCO 2 /MWh), followed by the Center South (0.7022 tCO 2 /MWh), the Center North (0.4236 tCO 2 /MWh), the North (0.2018 tCO 2 /MWh) and Sicily (0.146 tCO 2 /MWh). The seasonal analysis also shows a large variability of MEFs in each zone across time. The heterogeneity of results leads us to recommend that policymakers consider the zonal configuration of the power market and the large seasonal variability related to carbon emissions and electricity generation when designing incentives for renewable energy sources expansion and for achieving emission reduction targets. [ABSTRACT FROM AUTHOR]

Renewable energy communities are catalysts of social innovation, the citizens' engagement in energy actions, and the exploitation of local resources. Thus, this paper defines a model for analyzing and optimally sizing energy systems serving renewable energy communities. Then, the proposed and replicable model was tailored to the economic feasibility analysis of a renewable energy community in the municipality of Tirano (Northern Italy). An energy audit was carried out to identify the electricity production and consumption within the perimeter of the primary substation and the thermal energy demand of the existing district heating network. The technical features of the energy conversion systems serving the renewable energy community were determined: an organic Rankine cycle biomass-based cogeneration plant, a mini-hydro plant, and a distributed photovoltaic system. Moreover, several different scenarios have been identified, in terms of cogeneration operating mode, photovoltaic penetration, and thermal energy economic value. The results show that, moving from 4.22 MW to 5.22 MW of photovoltaic peak power, the annual renewable electricity production increases by 10.1%. In particular, the simple pay back ranges between 4.90 and 4.98 years and the net present value between EUR 12.4 and 13.3 M for CHP operating at full power mode, considering that thermal energy available from the cogeneration unit is sold at EUR 49.2/MWh. These outcomes demonstrate the economic feasibility of wood-biomass-based renewable energy communities, which may help to enlarge the contribution of renewable technologies other than photovoltaic. [ABSTRACT FROM AUTHOR]

The EU endeavors to stimulate the use of renewable energy cooperation mechanisms. These cooperation mechanisms can significantly reduce the policy cost for meeting renewable targets. Several authors, however, have raised concerns that such cooperation mechanisms can be subject to efficiency losses due to different national regulatory conditions, and due to an ill-advised selection of cross-border support instruments. A quantitative evaluation of these effects remains missing. To address this gap, we first introduce a unifying analytical framework to show how optimal cross-border renewable energy trade should be organized and how these mechanisms could be distorted. We then develop a partial equilibrium model, formulated as a large-scale mathematical program with equilibrium constraints, to assess the impact of (i) different national grid cost allocation regimes and (ii) different cross-border feed-in premium implementations. Our results indicate that EU-wide auctions for renewable electricity should (i) not be based on sliding feed-in premiums and should (ii) ideally be discriminatory if national regulatory conditions differ across Member States. We also consider country-level distributional effects and confirm that Member States can lose when engaging in renewable cooperation. [ABSTRACT FROM AUTHOR]

A microgrid concept for the thermal and electrical energy supply of a Sport-Recreation Center Ajdinovići (S.R.C.A.) has been proposed in this paper. A self-contained and intelligent power distribution grid has been developed for this case, taking into account the location, locally available renewable energy sources and the very purpose of this center. Comparative analyses between independent power supply through the proposed hybrid power system and the supply over the transmission and distribution network were performed. Technical and economical optimization of an energy system with distributed power generation was done by applying HOMER and DIgSILENT PowerFactory professional software tools. As a result, hybrid power system is more cost-effective than the conventional supply by the power distribution network, microgrid meets the technical criteria based on the analysis of power flows and the stability of the network has been achieved. Establishment of energy independence for the existing S.R.C.A. besides economic factor will show several benefits regarding better use of locally available resources, reduction of CO2 emissions and energy efficiency increment as well as an employment opportunity to the local people, thus contributing to the sustainability of the region. [ABSTRACT FROM AUTHOR]

The standard flat-plate solar collector utilises a single copper tube to remove the absorber plate’s heat. This type of collector’s primary purpose is to provide hot water for a single application. Hot water can be required for different applications at different temperatures. Besides, using the standard collector’s configuration may increase thermal demand and increase the collector’s size. Therefore, this study proposes a novel solar water heating configuration that uses three in-line fluid passages. The goal is to design a single collector that provides hot water for various uses: Sterilisation, washing, and postnatal care. Thus, the proposed system was modelled, and a numerical simulation conducted. This analysis compares the proposed system’s output and the standard collector’s output. The results showed that the thermal load demand was reduced by 27% when the hot water demand for these services was generated using three separate tanks. The serpentine collector’s efficiency with three fluid passages is increased by 20% compared to the traditional serpentine collector. The thermal energy delivered to meet load was 30% higher than that of the traditional serpentine system. The experimental and simulated system performance is in near agreement with an average percentage error Cv(RMSE) of 8.75% and confidence level NSE of about 87%. Since the proposed serpentine collector has a higher overall thermal production, it is recommended for use with hot water, which has to be heated to different temperatures.

The COVID-19 pandemic has had a significant impact on the supply chains of traditional fossil fuels. According to a report by the International Energy Agency (IEA) from 2020, oil-refining activity fell by more than the IEA had anticipated. It was also assumed that the demand in 2021 would likely be 2.6 million bpd below the 2019 levels. However, renewable markets have shown strong resilience during the crisis. It was determined that renewables are on track to meet 80% of the growth in electricity demand over the next 10 years and that sustainable energy will act as the primary source of electricity production instead of coal. On the other hand, the report also emphasized that measures for reducing environmental pollution and CO2 emissions are still insufficient and that significant current investments should be further expanded. The Sustainable Development of Energy, Water and Environment Systems (SDEWES) conference series is dedicated to the advancement and dissemination of knowledge on methods, policies and technologies for improving the sustainability of development by decoupling growth from the use of natural resources. The 15th SDEWES conference was held online from 1–5 September 2020; more than 300 reports with 7 special sections were organized on the virtual conference platform. This paper presents the major achievements of the recommended papers in the Special Issue of Energies. Additionally, related studies connected to the above papers published in the SDEWES series are also introduced, including the four main research fields of energy saving and emission reduction, renewable energy applications, the development of district heating systems, and the economic assessment of sustainable energy. [ABSTRACT FROM AUTHOR]

This paper proposes an economical-environmental-technical dispatch (EETD) model for adjusted IEEE 30-bus and IEEE 57-bus systems, including thermal and high penetration of renewable energy sources (RESs). Total fuel costs, emissions level, power losses, voltage deviation, and voltage stability are the five objectives addressed in this work. A large set of equality and inequality constraints are included in the problem formulation. Metaheuristic optimization approaches—Coronavirus herd immunity optimizer (CHIO), salp swarm algorithm (SSA), and ant lion optimizer (ALO)—are used to identify the optimal cost of generation, emissions, voltage deviation, losses, and voltage stability solutions. Several scenarios are reviewed to validate the problem-solving competency of the defined optimisation model. Numerous scenarios are studied to verify the proficiency of the optimisation model in problem-solving. The multi-objective problem is converted into a normalized one-objective issue through a weighted sum-approach utilizing the analytical hierarchy process (AHP). Additionally, the technique for order preference by similarity to ideal solution (TOPSIS) is presented for identifying the optimal value of Pareto alternatives. Ultimately, the results achieved reveal that the proposed CHIO performs the other approaches in the EETD problem-solving. [ABSTRACT FROM AUTHOR]

Abstract: Within several projects we investigated grid structures and management strategies for active grids with high penetration of renewable energy resources and distributed generation (RES & DG). Those ”smart grids” should be designed and managed by model based methods, which are elaborated within these projects. Cogeneration plants (CHP) can reduce the greenhouse gas emissions by locally producing heat and electricity. The integration of thermal storage devices is suitable to get more flexibility for the cogeneration operation. If several power plants are bound to centrally managed clusters, it is called “virtual power plant”. To operate smart grids optimally, new optimisation and model reduction techniques are necessary to get rid with the complexity. There is a great potential for the optimised management of CHPs, which is not yet used. Due to the fact that electrical and thermal demands do not occur simultaneously, a thermally driven CHP cannot supply electrical peak loads when needed. With the usage of thermal storage systems it is possible to decouple electric and thermal production. We developed an optimisation method based on mixed integer linear programming (MILP) for the management of local heat supply systems with CHPs, heating boilers and thermal storages. The algorithm allows the production of thermal and electric energy with a maximal benefit. In addition to fuel and maintenance costs it is assumed that the produced electricity of the CHP is sold at dynamic prices. This developed optimisation algorithm was used for an existing local heat system with 5 CHP units of the same type. An analysis of the potential showed that about 10% increase in benefit is possible compared to a typical thermally driven CHP system under current German boundary conditions. The quality of the optimisation result depends on an accurate prognosis of the thermal load which is realised with an empiric formula fitted with measured data by a multiple regression method. The key functionality of a virtual power plant is to increase the value of the produced power by clustering different plants. The first step of the optimisation concerns the local operation of the individual power generator, the second step is to calculate the contribution to the virtual power plant. With small extensions the suggested MILP algorithm can be used for an overall EEX (European Energy Exchange) optimised management of clustered CHP systems in form of the virtual power plant. This algorithm has been used to control cogeneration plants within a distribution grid. [Copyright &y& Elsevier]