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Rapid growth in population and economic development in Iran and its neighboring countries has resulted in a dramatic increase in electricity demand over the past few years. A substantial amount of electricity must be produced to meet this growing demand in this region. By installing conventional fossil power plants, using renewable energy, and interconnecting with neighboring countries, this growing demand can be accomplished. The main aim of this research is to identify prospects and challenges in the electrical sector around Iran. To this end, this paper evaluates the existing and future state of the electrical sector in Iran and its neighboring countries. Despite the fact that there is still a long way to go in terms of renewable energy in this region, there are some promising targets for the future that will allow fossil fuels to be replaced effectively. Notwithstanding this, we should point out that a number of cross-border interconnection projects are being pursued by Iran and its neighbors in order to integrate their networks and supply this growing demand. Finally, this study presents an overview of the future prospects and challenges of electricity capacity expansion, cross-border interconnections, and electricity transmission corridors in this region. The review results provide comprehensive background knowledge to all the researchers in order to investigate further into the field. This paper assists energy policy makers regarding the development of sustainable energy planning. • •In addition to providing a general overview of the geographical location, population growth, and economic indicators of Iran and its neighboring countries, this paper presents the current state of the Iranian electricity sector and its neighboring countries in light of the trends in electricity production, energy mix, price, and exports and imports. • •This paper explores the existing and future states of electricity capacity expansion in the region, specifically focusing on renewable energy sources. • •The existing and future states of cross-border electricity interconnections are examined to present a comprehensive overview of the cross-border interconnections in this region. • •This region's potential electricity transmission corridors are proposed to create the opportunity to transmit electricity across countries. [ABSTRACT FROM AUTHOR]

Brazil is a case of the achievement of a high share of wind energy integration to an interconnected power system in an emerging market. A series of successful energy supply programmes and a strong renewable-oriented finance framework implemented since 2002, have promoted alternative renewables – wind installed capacity increased over 22-fold from 927 MW in 2011 to 21 GW in 2022, reaching 11.77% of total procured power. From this, about 90% are concentrated in Brazil's least developed region, the Northeast, where wind investment should create jobs and propel socioeconomic development. Despite that, there is no studies specific assessing the regional and economy-wide effects of those programmes, gap that this paper aims to fill by applying the regional Computable General Equilibrium (CGE) model TERM-BR10. We assess that by modelling an alternative scenario for the period 2010-19 based on an official electricity matrix built in 2010, that projected 3.4 additional GW of wind power while not considering all the success of renewable policies, against the observed installed capacity expansion, where wind power was 3.7 times higher than what had been planned. Our results show that in the absence of renewable policies, Brazil would have faced economic losses such as GDP (−0.27%) and investment (−4.76%). The Northeast region would have been the most impacted in terms of GDP (−1.3%), real wage (−2.99%) and employment creation (−0.1%). We propose that such socioeconomic co-benefits are incorporated in energy planning, which could promote regional equality through renewable energy expansion. • Wind power capacity increased over 20-fold from 2011 to 2022. • 90% are in the poorest region where policies propel development and job creation. • Policy absence would entail a GDP loss of 0.27% nationally and of 1.3% in the region. • Negative impacts to labour market are mostly over skilled jobs. [ABSTRACT FROM AUTHOR]

Over the past decade, energy storage in renewable energy-dominated systems has received increasing interest. Effective energy storage has the potential to enhance the global hosting capacity of renewable energy in power systems, accelerate the global energy transition, and reduce our reliance on fossil fuel-based generation. Pumped hydro storage (PHS) is the most common storage technology due to its high maturity, reliability, and effective contribution to the integration of renewables into power systems. Accordingly, it is essential to achieve the optimal operation of energy systems combined with PHS. Therefore, this paper comprehensively reviews recent efforts toward the optimal operation of PHS-based energy systems (PHS-BES), considering the diversified energy sources, configurations, grid connectivity, and research directions. The evaluation criteria for the optimal operation of these systems are mathematically addressed and discussed. Moreover, methods of solving the studied problem are categorized and several improvements are suggested. It is observed that more flexible energy policies are urgently needed to encourage new investments in PHS, and the existing environmental and social criteria require further research. Moreover, the hybridization of PHS with other storage devices should be further investigated, and the development of robust hybrid methods for solving the optimal operation of PHS-BES, especially for real-time applications, is highly promising. Based on an in-depth analysis, this paper provides a compendium of real-world research and industry-oriented challenges, and presents future research and industry trends for the optimal operation of PHS-BES. • The latest studies on the optimal operation of PHS-BES are reviewed. • PHS-BES are categorized based on the number and type of integrated energy sources. • The evaluation criteria and solving methods for the optimal operation of PHS-BES are discussed. • A compendium of real-world research and challenges is presented. • Future research on PHS-BES is concluded. [ABSTRACT FROM AUTHOR]

Virtual power plants possess the capability to effectively manage the inherent conflict between dispersed electricity generation and user demand, hence optimising market advantages. Nevertheless, the presence of severe weather conditions, geopolitical factors, the phenomenon of global warming, and several other global concerns greatly enhance the level of uncertainty related to the establishment of sustainable energy sources and the corresponding demand from users. Consequently, these factors expose the limitations of virtual power plants in effectively controlling power supply. The active involvement of community members has the potential to invigorate the process of development. This study presents a novel model, referred to as the CE-based cVPP (CE-cVPP) model, that combines the principles of circular economy (CE) and community-based virtual power plant (cVPP). The objective of this model is to enhance the effectiveness of sustainable development efforts. This research redefines the concept of a CE-cVPP, elucidates its defining features, scopes, and classification, and constructs a technological framework, together with an explanatory community case structure. The CE-cVPP energy life cycle framework is constructed based on the principles of the circular economy paradigm. This study investigates the enduring and sustainable benefits of the CE-cVPP across four dimensions: energy, environment, economics, and society. In conclusion, this paper provides a comprehensive examination of the energy, digital, and circular economy perspectives, encompassing critical analysis, problems, prospective analysis, and future directions. • Circular economy and community-based Virtual Power Plant (CE-cVPP) is a paradigm for the future energy sector. • CE-cVPP is a novel sustainable pattern that combines circular economy and community virtual power plants. • CE-cVPP features renewable energy, electricity, gas, cold, heat, and biodegradable waste. • CE-cVPP promotes economic, social, and ecological sustainability. • CE-cVPPs enhance the power and energy system's adaptability, versatility, and stability. [ABSTRACT FROM AUTHOR]

Coal-fired power plants still dominate the electricity market in Southeast Asia, supplying around 30 % of the total demand, and the demand trend for this sector will continue to be high for decades to come. As a result, coal fly ash (CFA) production has also increased rapidly. However, most countries in this region consider them hazardous waste due to the immense potential for destroying living things and the environment. An increase in the utilization rate of CFA will undoubtedly result in numerous economic and environmental benefits. This article provides an intensive update regarding the current development of CFA utilization research and its realization. This article also provides a specific summary of its use as a medium for valuable materials. Recent studies have proven that CFAs have significant potential due to their physical and chemical characteristics. CFA can be further utilized as an adsorbent, catalyst, mesoporous, and synthesis material for high-efficiency zeolite. By working out the strategies proposed in this paper and the latest research results, the possibility of their utilization can be increased. Thus, the potential of CFA can be utilized to its fullest extent as one of the instruments for Southeast Asia to become a better and more sustainable region. [Display omitted] • Intensive updates regarding the current research developments on using coal fly ash and its realization in Southeast Asia. • Provide information on the potential utilization of coal fly ash due to its physical and chemical properties. • Coal fly ash can be further utilized as adsorbents, catalysts, and in the synthesis of high-efficiency zeolites. • The potential for optimal utilization of coal fly ash can make Southeast Asia a better and more sustainable region. [ABSTRACT FROM AUTHOR]

The current paper presents a numerical analysis of a multi-source renewable energy system for building air conditioning aiming at decarbonising the building envelope. The thermal management of the building is pursued through a radiant floor fed by a heat pump and integrated with phase change materials for thermal inertia enhancement. A fan coil is foreseen for humidity control. The heat pump can be fed through three parallel circuits involving different thermal sources: air with an ordinary air-to-water heat exchanger, sun through photovoltaic thermal solar collectors, and ground using shallow ground flat-panel heat exchangers. At need, the ground can be exploited for thermal energy storage when the heat pump is idle. A set of dedicated control rules chooses the optimal source or mix of sources to exploit at any time. Simulations of a reference building, namely a large single-room snack bar, are performed for various plant configurations, hypothesising the building as located in distinct climate zones and characterised by different thermal transmittance. The thermal performance of the building is given in terms of primary energy needs per year and compared to that of an analogous single-source plant. Results show that the proposed system can lead to primary energy savings of up to 16% compared to the corresponding state-of-the-art single-source plant, being more effective if the geothermal field is large enough and the building heating and cooling needs are comparable. The relevance of a proper control algorithm for plant performance optimisation is highlighted: a thermal power-based approach is proposed and successfully tested. • A multi-source renewable energy system for buildings thermal management is proposed. • Air, sun, and ground can be exploited as thermal sources by means of heat exchangers. • A phase change materials integrated radiant floor covers the building thermal needs. • A control algorithm selects the sources to be used for the optimal plant operation. • TRNSYS simulations foresee energy savings up to 16% in different operating conditions. [ABSTRACT FROM AUTHOR]

Sugarcane mills currently use sugarcane bagasse to cogenerate heat and electricity, supplying the process with mechanical, thermal and electrical energy. Some of these plants are able to produce surplus electricity to export to the national grid. With the improvement in collection techniques, sugarcane straw has also become available and has been used in some mills as fuel for steam boilers, mixed with sugarcane bagasse. However, due to different traits compared to bagasse, the use of sugarcane straw may pose additional problems of incrustation and corrosion on heat exchange surfaces. Several alternatives and technologies have been studied and tried out in order to increase the production of surplus electricity. Among others, biomass integrated gasifier–gas turbine combined cycle (BIGCC) is a promising technology. However, several attempts have resulted in failure, whether on a pilot or industrial scale. Biomass gasification integrated with internal combustion engines can become an opportunity for generation of small power capacity (<15 MW) and integrated to sugarcane mills. This paper analyzes the difficulties and barriers to increasing electricity generation in the sugarcane industry through studies, projects and experimental and industrial-scale installations that have already been carried out. • Bagasse and cane straw show great potential for electricity generation. • Sugarcane industry in Brazil accounts for 6.4% of the electricity generated. • Biomass integrated gasification and combined cycle can increase electricity generation. • Technological and economic challenges are major barriers to the development of BIGCC. • No BIGCC project already implemented is currently in commercial operation. [ABSTRACT FROM AUTHOR]

This paper provides a review of negative carbon capture technologies. Based on these technologies, here it is proposed an innovative negative emissions power plant combining the generation and storage of energy from biomass, photovoltaic, and concentrated solar power, capturing and recovering CO 2 by producing H 2 or CH 4 as green energy carriers. The main features of the system are i) large-scale energy production system with negative CO 2 emissions; ii) 100% renewable system based on biomass and solar energy with the possibility of integrating other renewables; iii) synergistic integration of processes and systems; iv) recovery of O 2 generated by photovoltaic-driven electrolysis within the process of partial biomass oxycombustion and v) solar-driven limestone calcination. A detailed model of the entire plant is developed to evaluate the integration of the process. The model performance is assessed on an hourly basis throughout the whole year. The base case results show an energy consumption from 1 to 2.1 MJ/kg CO 2 to capture 60–77% of CO 2 emitted from the biomass plant and green methane production of more than 7500 tons/year. The negative emissions associated with the process are -612 kg CO 2 /MWh. It justifies the interest in the proposed negative emissions power plant. [Display omitted] • A synergetic integration of CO2 capture, energy storage and methane production is proposed. • A biomass power plant is considered, resulting in -612 kg CO2/MWh negative emissions. • Solar PV and CSP are integrated into the process to reduce the SPECCA to 1–2.1 kg CO2/MWh. • A large amount of solids storage is required to achieve 70–90% CO2 capture capacity. [ABSTRACT FROM AUTHOR]

Modernization in the area of smart energy equipment, are forming the perception of an interlinked energy network in subsequent times. This energy network is contemplated to govern real-time energy consumption and optimization in the future. Traversing a prolonged period of development, the energy industry has reached the landmark of Virtual Power Plant (VPP) and still going onward to this newfangled energy network, also can be called the next generation VPP. This paper demonstrates the challenges and opportunities in executing the transpiring aspects of the next generation VPP. Based on essential components and requisites, detailed descriptions are depicted from different technological viewpoints such as electrical and communication, computing technologies, energy management, economic profit, geographical factors, and adoption of emerging technologies. We also present the recent updates of existing VPP projects. Finally, considerations towards implementing the next generation VPP are marked out, along with necessary frameworks, regulations, and policies. This paper can provide prudent support for researchers and practitioners in the field of VPP. [Display omitted] • Review of development aspects in virtual power plants (VPP). • Critical requirements and necessary components for VPPs are presented. • Emerging technologies that can be integrated with next generation VPP are discussed. • Challenges and opportunities in the road of developing the next generation VPP are characterized. • Next generation VPP's framework, policies, and regulations are outlined. [ABSTRACT FROM AUTHOR]

Control algorithms for wave energy conversion technologies with air turbines require contingency tools to prevent the rated power and maximum rotational speed from being exceeded. Survival problems limit energy conversion when the available power is too large compared to the turbo-generator-rated power. Short-term predictions require information from local wave-measuring buoys, which raises reliability concerns. Wave groups in the ocean result in extremely high wave power peaks that cannot be smoothed by low-inertia power-take-off (PTO) systems, leading to survival problems. The most common strategy to cope with this situation is to set the rated power of the PTO several times more than the annual average produced electrical power. The PTO is shut-down when the available power is excessive. These two engineering decisions have a detrimental impact on the capacity factor and the energy cost. The paper shows a new control algorithm for wave energy oscillating-water-column (OWC) devices that can control the shutter position of a fast-acting valve to dissipate the pneumatic energy excess. Hence, the PTO can operate even when the available power is significantly larger than the generator's rated power. The algorithm was validated with the 30 kW biradial turbine prototype from the OPERA H2020 European project under real sea conditions at Mutriku's wave power plant. Results show the algorithm's effectiveness in real situations and during a generator failure simulated during the experimental campaign. This new concept may reduce the energy cost from wave energy and open a new field of design possibilities for OWC wave energy converters. • First-of-a-kind hardware to perform peak shaving in OWC wave energy devices. • Algorithm tested at Mutriku's wave power plant in real sea conditions. • Generator's rated power and maximum rotational speed are prevented from being exceeded. • The algorithm protects the power take-off system in the case of a generator failure. • Novel peak shaving control can reduce the OWC WECs energy costs. [ABSTRACT FROM AUTHOR]

Many places are dealing with the problem of water scarcity, especially in the summer months. This occurs mostly in the dry areas with hot climates that are exposed to intensive solar insolation which are the main driver for the evaporation of water. Some companies that are in charge of water service, and are operating open water reservoirs, have developed a solution to cover the water with floating balls to limit the solar insolation and to mitigate the evaporation of water. Another good approach is using floating solar panels for the same cause, which will provide an additional power source. It can enhance the productivity of hydropower plants with reservoirs. An additional benefit of the solution is the amount of the available water surfaces for placing the solar panels, instead of potentially useful areas for other purposes (agriculture, buildings ...). This paper reviews the current development of the technology, potentials, and best practices. It shows that this technology is feasible and can compete with other power sources, considering the cheapest LCOE being 46 USD/MWh for a 50 MW power plant in Uttar Pradesh, India. [Display omitted] • FPV is feasible, with LCOE as low as 46 USD/MWh for a 50 MW power plant in Uttar Pradesh, India. • FPV improves water retention in open reservoirs while improving efficiency of PV panels. • Asian countries have recognized potentials of FPV and have the largest plants (150 MW construction in Huainan, China). • Developers from EU have key knowledge for development of FPV projects, why their development should be supported there. [ABSTRACT FROM AUTHOR]

Carbon Capture and Storage is a technology of paramount importance for the fulfillment of the Sustainable Development Goal 7 (Affordable and Clean Energy) and the Sustainable Development Goal 5 (Climate Action). The European Union is moving rapidly towards low carbon technologies, for instance via the Energy Union Strategy. Coupling biofuels and carbon capture and storage to decarbonize the power and the industrial sector can be done through the development of BECCS (Bioenergy with Carbon Capture and Storage). Chemical Looping combustion is one of the cheapest way to capture CO 2. A Chemical Looping Combustion (CLC) plant can be coupled with a turbo expander to convert energy to power, but it has to work in pressurised conditions. The effect of pressure on the chemical reactions and on fluidised bed hydrodynamics, at the moment, is not completely clear. The aim of this review is to summarize the most important highlights in this field and also provide an original method to optimize power plant efficiency. The main objective of our research is that to design a pressurised Chemical Looping Combustion plant which can be coupled to a turbo expander. To achieve this we need to start from the characteristics of the turbo expander itself (eg. the Turbine Inlet Temperature and the compression ratio) and then design the chemical looping combustor with a top down approach. Once the air and the fuel reactor have been dimensioned and the oxygen carrier inventory and circulation rate have been identified, the paper proposes a final optimization procedure based on two energy balances applied to the two reactors. The results of this work propose an optimization methodology and guidelines to be used for the design of pressurised chemical looping reactors to be coupled with turbo expanders for the production of power with carbon negative emissions. • BECCS technology can be developed by coupling PCLC with a gas turbine. • Efficiency of a chemical looping combined cycle plant can range between 42.1% and 52.4%. • Pressure can affect minimum fluidization velocity in the fluidised bed reactor. • The influence of pressure is dependent on the type of bed particles and their dimension. • Circulation rate is one of the most critical factors in PCLC design. [ABSTRACT FROM AUTHOR]

In deregulated power markets, electricity suppliers have the option to trade in the spot market, derivatives market, and bilateral contract market. The spot market is always available and open to competition, but the variability and risk incurred need to be carefully handled. The suppliers might allocate their capacity in the derivatives and bilateral contract market if these alternatives are more viable. The strike price, bilateral contract price, and spot market prices need to be used to decide the capacity allocation problem considering the generation cost of the supplier. This paper first examines the market design and electricity trading in the Turkish electricity market. Then three problems were proposed for a coal-fired coal unit that aims to allocate its capacity to spot, derivative, and bilateral contract markets to maximize its expected profit. A Monte Carlo method is used for allocated electricity capacities, spot market, strike, and bilateral contract price scenarios. A simulation methodology is then proposed that includes capacities allocated to each market and price scenarios. The best capacity allocation strategy is determined that return the highest expected profits for all market price samples. The model is illustrated for a coal unit in the Turkish electricity market. The results are presented for the case, including 100 spot price samples, 100 capacity scenarios, 3 scenarios for the strike, and bilateral contract prices. The sensitivity analysis for spot price volatility on the profit is also presented with 20% volatility increase. It is shown that allocating the capacity to more than one market can increase the total expected profit for a power supplier and the rate of increase varies depending on the scenario set. • Electricity trading of a thermal generator in different markets is discussed. • Capacity allocation to spot, derivative and bilateral contract market is modeled. • Price and capacity scenarios for the Monte carlo simulation is developed. • It is shown that capacity allocation to different markets can increase total profit. • A supplier can determine its strategy based on the price expectations. [ABSTRACT FROM AUTHOR]

This paper presents two different scenarios for the energy system of the Netherlands that achieve the Dutch government's national target of near net-zero greenhouse gas emissions in 2050. Using the system optimisation model OPERA, the authors have analysed the technology, sector and cost implications of the assumptions underlying these scenarios. While the roles of a number of key energy technology and emission mitigation options are strongly dependent on the scenario and cost assumptions, the analysis yields several common elements that appear in both scenarios and that consistently appear under differing cost assumptions. For example, one of the main options for the decarbonisation of the Dutch energy system is electrification of energy use in end-use sectors and for the production of renewable hydrogen with electrolysers. As a result the level of electricity generation in 2050 will be three to four times higher than present generation levels. Ultimately, renewable energy – particularly from wind turbines and solar panels – is projected to account for the vast majority of electricity generation, around 99% in 2050. Imbalances between supply and demand resulting from this variable renewable electricity production can be managed via flexibility options, including demand response and energy storage. Hydrogen also becomes an important energy carrier, notably for transportation and in industry. If import prices are lower than costs of domestic production from natural gas with CCS or through electrolysis from renewable electricity (2.4–2.7 €/kgH 2), the use of hydrogen increases, especially in the built environment. • We explore two scenarios for a near climate-neutral energy system in the Netherlands. • With the OPERA model we determine their technology, sector and cost implications. • The electricity share in primary energy increases from 19% today to 41–71% in 2050. • Hydrogen becomes another important energy carrier, notably in transport and industry. • Biomass use increases, mostly as fuel in transport and industry. [ABSTRACT FROM AUTHOR]

With the exponential penetration of Photovoltaic (PV) plants into the power grid, protection has gained exceptional importance in recent years for ensuring stability, reliability, security, and power quality of the power systems. Thus, to address these issues many countries have established new requirements in the form of grid codes for grid connection of PV plants. One of the main requirements of grid codes is Fault Ride Through (FRT) capability. FRT describes the power generator performance during and in post-fault circumstances. In this paper, an in-depth review is carried out on various scientific aspects of faults and FRT strategies available in the literature. First, various faults occurring in the grid-connected PV system are classified and compared along with a critical and analytical assessment of grid codes especially FRT requirements i.e., Low Voltage Ride Through (LVRT) and High Voltage Ride Through (HVRT) for various countries. Then, FRT approaches and strategies are classified and compared based on improved controller-based methods and external devices methods in detail. The existing FRT strategies are compared based on various aspects i.e., complexity, economically, and technically. After that, a case study that explains the complete design and implementation of conventional Crowbar, Bridge Type Fault Current Limiter (BFCL), and Switch Type Fault Current Limiter (STFCL) as an FRT strategies for 100 kW three-phase grid-connected PV system in MATLAB/Simulink is presented. A comparative assessment is also carried out among these strategies that validate the robust performance of BFCL and STFCL. Lastly, the conclusion is presented along with a brief proposal for future work. • Faults classification and investigation for PV systems. • Analysis of requirements for modern grid codes. • Categorization and comparison of various FRT strategies for grid connected PV system. • Design and evaluation of three FRT strategies for 100 kW three phase grid connected PV system. [ABSTRACT FROM AUTHOR]

With the exponential penetration of Photovoltaic (PV) plants into the power grid, protection has gained exceptional importance in recent years for ensuring stability, reliability, security, and power quality of the power systems. Thus, to address these issues many countries have established new requirements in the form of grid codes for grid connection of PV plants. One of the main requirements of grid codes is Fault Ride Through (FRT) capability. FRT describes the power generator performance during and in post-fault circumstances. In this paper, an in-depth review is carried out on various scientific aspects of faults and FRT strategies available in the literature. First, various faults occurring in the grid-connected PV system are classified and compared along with a critical and analytical assessment of grid codes especially FRT requirements i.e., Low Voltage Ride Through (LVRT) and High Voltage Ride Through (HVRT) for various countries. Then, FRT approaches and strategies are classified and compared based on improved controller-based methods and external devices methods in detail. The existing FRT strategies are compared based on various aspects i.e., complexity, economically, and technically. After that, a case study that explains the complete design and implementation of conventional Crowbar, Bridge Type Fault Current Limiter (BFCL), and Switch Type Fault Current Limiter (STFCL) as an FRT strategies for 100 kW three-phase grid-connected PV system in MATLAB/Simulink is presented. A comparative assessment is also carried out among these strategies that validate the robust performance of BFCL and STFCL. Lastly, the conclusion is presented along with a brief proposal for future work. • Faults classification and investigation for PV systems. • Analysis of requirements for modern grid codes. • Categorization and comparison of various FRT strategies for grid connected PV system. • Design and evaluation of three FRT strategies for 100 kW three phase grid connected PV system. [ABSTRACT FROM AUTHOR]

This paper presents two different scenarios for the energy system of the Netherlands that achieve the Dutch government's national target of near net-zero greenhouse gas emissions in 2050. Using the system optimisation model OPERA, the authors have analysed the technology, sector and cost implications of the assumptions underlying these scenarios. While the roles of a number of key energy technology and emission mitigation options are strongly dependent on the scenario and cost assumptions, the analysis yields several common elements that appear in both scenarios and that consistently appear under differing cost assumptions. For example, one of the main options for the decarbonisation of the Dutch energy system is electrification of energy use in end-use sectors and for the production of renewable hydrogen with electrolysers. As a result the level of electricity generation in 2050 will be three to four times higher than present generation levels. Ultimately, renewable energy – particularly from wind turbines and solar panels – is projected to account for the vast majority of electricity generation, around 99% in 2050. Imbalances between supply and demand resulting from this variable renewable electricity production can be managed via flexibility options, including demand response and energy storage. Hydrogen also becomes an important energy carrier, notably for transportation and in industry. If import prices are lower than costs of domestic production from natural gas with CCS or through electrolysis from renewable electricity (2.4–2.7 €/kgH 2), the use of hydrogen increases, especially in the built environment. • We explore two scenarios for a near climate-neutral energy system in the Netherlands. • With the OPERA model we determine their technology, sector and cost implications. • The electricity share in primary energy increases from 19% today to 41–71% in 2050. • Hydrogen becomes another important energy carrier, notably in transport and industry. • Biomass use increases, mostly as fuel in transport and industry. [ABSTRACT FROM AUTHOR]

Hybrid polygeneration systems offer a great opportunity to meet growing energy demands with cost efficiency and environmental benefits. The identification of the optimal solution (configuration and operational strategy) is strongly affected by the relationship between the system and its surroundings. Previous studies have analyzed the influence of boundary conditions on the synthesis of polygeneration systems for buildings. However, local regulations are often disregarded or oversimplified in those studies. Therefore, this paper aims to evaluate the influence of legal conditions on the integration of renewable energy technologies in polygeneration systems for buildings. A comprehensive synthesis model is developed, including different types of legal conditions, such as power exchange modalities, subsidies/surcharges on energy prices and investment costs, and total ban on fossil fuels. Then, the model is applied to the case study of a Brazilian hospital. The current Brazilian net metering scheme is implemented. Results show that natural gas cogeneration is an attractive solution to cover the hospital's energy demands with or without the possibility of selling/exporting electricity. Also, the Brazilian net metering scheme, by itself, is not enough to ensure renewable energy deployment. An in-depth discussion about the conditions that would promote renewable energy integration is reported and recommendations are made on how current policies can be improved, including the need to explicitly address renewable technologies, the application of minimum renewable fractions, and the role of renewable heat/cooling. While the case study considers the specific circumstances in Brazil, it provides insights that can be extended to other countries or applications. • Synthesis model of hybrid renewable polygeneration systems for buildings. • Influence of legal constraints on the integration of renewable energy technologies. • Power exchange modalities, subsidies/surcharges, and fossil fuel ban are considered. • Technical, economic, and environmental analysis of a Brazilian hospital case study. • The Brazilian net metering scheme did not promote renewable energy technologies. [ABSTRACT FROM AUTHOR]