Self-sufficiency Ratio Research Articles

Hybrid solar-wind renewable energy systems with energy storage for net/nearly zero energy buildings: An uncertainty-based robust design method

Net/nearly zero energy buildings (NZEBs) are recognized as pivotal solutions to reduce building energy consumption and advance sustainable development. Existing studies often used traditional methods to facilitate the design of renewable energy systems (RESs) under deterministic conditions, which may fail to achieve the design targets of NZEBs during their service life. Considering uncertainty correlation and equipment degradation, an uncertainty-based approach was proposed in this study to robustly design RESs in NZEBs. Firstly, scenarios were randomly generated considering correlated uncertainties. A novel scenario reduction technique, which considered correlation loss while reducing scenarios, was then introduced to improve the optimization efficiency. Furthermore, the potential of NZEBs in reducing carbon emissions was explored by evaluating the environmental impact of various RESs using hourly marginal emission factors. Lastly, the optimal design solutions were identified and analyzed based on the specified targets of various NZEB definitions. The results indicated that, compared with the first year, the annual energy supply, net energy, and carbon emission reduction decreased by 28.2 %, 52.2 %, and 51.3 %, respectively, after 20 years of operation. The traditional design scheme failed to consistently achieve the predefined NZEB targets throughout the system's service life. In contrast, the RESs designed using the proposed approach exhibited reliable performance, consistently meeting the requirements under various NZEB definitions and achieving an average self-sufficiency ratio of 89.1 %, validating its energy autonomy throughout the system's operational lifespan. The proposed method can effectively result in robust design of RESs in NZEBs while satisfying the design targets of economic-technical-environmental dimensions under uncertainties.

Food Self-Sufficiency in the Honey Market in Poland

Looking from the perspective of the importance of beekeeping production for agriculture, and its impact on production sustainability, biodiversity and food security, research on food self-sufficiency in the honey market is important. The aim of this article was to assess food self-sufficiency in the honey market in Poland in terms of the sustainability of production. The research covered the years 2002–2023. The research material consisted of secondary sources of information from the FAOSTAT 2024 database, reports of the Institute of Horticulture, Department of Beekeeping in Puławy, and market reports of IERiGŻ-PIB. The research used dynamic indicators, Pearson’s correlation coefficient, self-sufficiency ratios (SSR) and intra-industry trade (IIT) indicators. The analysis showed that Poland is not food self-sufficient in honey production. Environmental issues and related food security will be important for a change in the model of beekeeping in Poland, as this sector plays an important role in maintaining sustainability and biodiversity; hence, the assessment of food self-sufficiency in honey production should be treated broadly, including the benefits for agriculture.

Emergy-Based Evaluation of the Sustainability of Agricultural Ecosystem in Dazhou, China, from 2002 to 2022

Our aim is to analyze the emergy evaluation indicators of the agricultural ecosystem in Dazhou, northeastern Sichuan, and provide practical and effective recommendations for sustainable agricultural development. Using emergy analysis, the emergy inputs and outputs of an agricultural ecosystem from 2002 to 2022 were calculated. Five emergy indicators were selected for evaluation: emergy yield ratio (EYR), emergy self-sufficiency ratio (ESR), emergy input ratio (EIR), environmental load ratio (ELR), and emergy sustainable indices (ESI). The total emergy input of the agricultural ecosystem showed an upward trend from 2002 to 2017, thus the industrial auxiliary emergy input decreased, somewhat curbing its continued rise from 2017 to 2022. The structure of emergy inputs, in descending order, is as follows: industrial auxiliary > organic emergy > renewable environmental resources > non-renewable environmental resources. The total emergy output of the agricultural ecosystem was highest in 2007, reaching 2.31 × 1022 Sej, and lowest in 2012, at 1.83 × 1022 Sej. The structure of emergy outputs, in descending order, is as follows: livestock > planting > fishery > forestry. The emergy yield ratio fluctuated down from 3.12 to 2.51, with an average of 2.88, below the provincial average of 3.07. The emergy self-sufficiency ratio fluctuated down from 0.30 to 0.26, with an average of 0.27, above the provincial average of 0.13. The emergy input ratio fluctuated up from 2.31 to 2.91, with an average of 2.66, above the provincial average of 1.86. The environmental load ratio fluctuated from 3.8 to 4.75, with an average of 4.40, which is higher than the provincial average of 1.68. The emergy sustainable indices fluctuated down from 0.81 to 0.53, with an average of 0.67, below the provincial average of 1.17. The efficiency of resource utilization in the agricultural ecosystem of Dazhou has decreased, economic inputs have increased, and it is in a consumptive production process. The pressure on the local natural environment is increasing, and the capacity for sustainable development remains at a low level over the long term.

Resource-optimized cnns for real-time rice disease detection with ARM cortex-M microprocessors

This study explores the application of Artificial Intelligence (AI), specifically Convolutional Neural Networks (CNNs), for detecting rice plant diseases using ARM Cortex-M microprocessors. Given the significant role of rice as a staple food, particularly in Malaysia where the rice self-sufficiency ratio dropped from 65.2% in 2021 to 62.6% in 2022, there is a pressing need for advanced disease detection methods to enhance agricultural productivity and sustainability. The research utilizes two extensive datasets for model training and validation: the first dataset includes 5932 images across four rice disease classes, and the second comprises 10,407 images across ten classes. These datasets facilitate comprehensive disease detection analysis, leveraging MobileNetV2 and FD-MobileNet models optimized for the ARM Cortex-M4 microprocessor. The performance of these models is rigorously evaluated in terms of accuracy and computational efficiency. MobileNetV2, for instance, demonstrates a high accuracy rate of 97.5%, significantly outperforming FD-MobileNet, especially in detecting complex disease patterns such as tungro with a 93% accuracy rate. Despite FD-MobileNet’s lower resource consumption, its accuracy is limited to 90% across varied testing conditions. Resource optimization strategies highlight that even slight adjustments, such as a 0.5% reduction in RAM usage and a 1.14% decrease in flash memory, can result in a notable 9% increase in validation accuracy. This underscores the critical balance between computational resource management and model performance, particularly in resource-constrained settings like those provided by microcontrollers. In summary, the deployment of CNNs on microcontrollers presents a viable solution for real-time, on-site plant disease detection, demonstrating potential improvements in detection accuracy and operational efficiency. This study advances the field of smart agriculture by integrating cutting-edge AI with practical agricultural needs, aiming to address the challenges of food security in vulnerable regions.

Virtual energy dispatching method for hybrid microgrid demand response based on Lyapunov optimization

Abstract The hybrid microgrid (HMG) possesses power generation, storage, and distribution capabilities, serving as an integrated foundational structure for advanced localized distribution networks. However, due to significant discrepancies in load demands and energy consumption among different users, the photovoltaic (PV) generation output and end-user load requirements exhibit unpredictability, resulting in relatively low self-sufficiency ratio (SSR) and self-consumption ratio (SCR) of the HMG PV system. To address this issue, this study proposes a virtual energy dispatching method for hybrid microgrid demand response based on Lyapunov optimization. Initially, a bidirectional virtual energy dispatching system model based on energy provider/buyer classification is constructed, optimizing load demands and energy management of both the load side and the main utility grid (MUG) while considering demand response. Subsequently, a Lyapunov optimization-based bidirectional virtual energy dispatching algorithm (LOBVED) is introduced, optimizing queueing systems in stochastic networks based on drift-plus-penalty technique to resolve the dynamic interactions among stability, performance, and energy self-sufficiency in the HMG environment, aiming to maximize the PV SSR and SCR of the HMG while ensuring the reliability of battery energy storage (BES) energy queues. Finally, the effectiveness of the proposed method is validated through MATLAB simulations.

An Assessment of the Production Potential and Food Self-Sufficiency of Ukraine against the Background of the European Union and Poland

Rapidly changing external conditions, such as the COVID-19 pandemic and the war in Ukraine, which are pure crisis phenomena, not only determine the geopolitical and geoeconomic situation in the global markets but also cause structural changes in individual countries. Under these conditions, the level of food self-sufficiency becomes particularly important, as it is one of the factors determining the food security of any country. The aim of this research is to assess Ukraine’s food self-sufficiency compared to the European Union and Poland. The self-sufficiency ratio (SSR) index was used to assess food self-sufficiency. This is the ratio of the volume of production of the most important products of plant and animal origin to the volume of domestic consumption. Domestic consumption was defined as the volume of domestic production plus the volume of imports minus the volume of exports, and it also included changes in domestic stock levels. The surveyed time frame is 2019–2021. The analyzed data were taken from the State Statistics Service of Ukraine, FAOSTAT, USDA, and Statistics Poland. A comparative analysis of self-sufficiency for the main agri-food sectors of Ukraine, the EU, and Poland showed significant differences. Taking into account the production potential and food self-sufficiency indicators of Ukraine, Ukraine’s possible accession to the EU can be expected to have a major impact on the EU’s supply and demand situation, as it may pose a threat to many EU agri-food sectors.

Competitiveness and Cereal Self-Sufficiency in Western Balkan Countries

Crises like the COVID-19 pandemic, the Russian-Ukrainian war, and challenges associated with sustainable development have emphasized the need for local food to increase the food system’s resilience. Therefore, this research analyzes the food self-sufficiency ratio (SSR) and revealed comparative advantage (RCA) of cereals in Western Balkan countries (Serbia, Bosnia and Herzegovina, Montenegro, Albania, and North Macedonia) and compares them with the same indicators for all European countries. The methodological framework of this research examined the food self-sufficiency and macro-level competitiveness for cereals in Western Balkan countries, as well as in Europe. The results of the research showed that all European countries have higher self-sufficiency in cereals (109.12%) and higher revealed comparative advantage (2.21) compared to the group of Western Balkans countries (71.89%; 1.53), which have lower values of the mentioned indicators. The results of econometric modeling for the Western Balkan countries showed that GDP per capita negatively influences the SSR of cereals, and agriculture value added per worker and area harvested under cereals positively influence the SSR of cereals. When it comes to the influence on the RCA of cereals in the Western Balkan region, the critical influence is GDP per capita, political stability, and agriculture value added per worker, all of which positively influence the RCA.

Assessing Scotland’s self-sufficiency of major food commodities

BackgroundAnalysis of food self-sufficiency at the regional level helps to better understand its dependency on, and vulnerability to, the food system. Moreover, achieving food self-sufficiency has gained prominence in the present policy agenda to increase resilience to adverse events and lower food resource footprint. Using a novel method, we estimated the food balance sheets of Scotland, the second-largest region in the United Kingdom, and assessed the self-sufficiency of major food commodities for the first time.MethodsData from 2003 to 2019 were obtained from Economic Reports on Scottish Agriculture and the Department for Environment, Food and Rural Affairs (DEFRA)’s family food statistics. Food import and export data are not readily available for Scotland. Therefore, we developed a consumption-based approach to estimate the net trade values of each commodity. We also assessed the contribution of domestic production toward nutrient security.ResultsAccording to our estimates, Scotland is a net exporter of beef, exporting an average of 51.3 thousand tons per year. It is also a net exporter of cereal (wheat, barley, oats) and potatoes, although this was not always the case between 2003 and 2019. Scotland has a strong level of self-sufficiency in cereals, potatoes, lamb, beef, dairy, and eggs. However, there is room for improvement in achieving self-sufficiency in poultry and pork, where the self-sufficiency ratio is relatively low. Our analysis of nutrient security indicates that wheat and dairy sourced from Scotland play crucial roles in the food supply chain, markedly influencing total energy, dietary protein, and primary dietary fat sources.ConclusionsOur assessment can serve as a foundation for evidence-based decision-making in Scotland's agricultural and food policy. It offers insights into where investments and support may be needed to enhance domestic production and promote a resilient and sustainable food system. Estimated self-sufficiency ratios provide a more accurate assessment of the extent of food localization in Scotland. The method we developed in this study has the potential to be a valuable tool for future research studies, allowing for the estimation of regional-level food self-sufficiency even when trade data and food balance sheets are unavailable.

Economic impact and food security effects of trade disruptions in agricultural products for Sweden

The COVID-19 pandemic and geopolitical conditions in 2022–2023 highlighted the vulnerabilities of food supply chains to trade disruptions in agricultural inputs and foods, with the ensuing economic effects on producers and consumers. This study calculated the impact of various disruptions in the trade of agricultural inputs and outputs for Swedish producers and consumers and for food security. To this end, a mathematical programming model of the food sector with a spatial dimension was applied, which accounts for adjustments and interactions between producers and consumers of food. Food security is measured in terms of the self-sufficiency ratio, the ability to produce minimum dietary needs, and economic access for low-income households. The trade scenarios included disruptions to imports of agricultural inputs (fertilisers, fuel, feed, pesticides and foreign labour) and foods. The results showed that the economic effects for producers can be considerable, with a reduction in producer surplus by up to 75%. The decrease in consumer surplus is smaller, amounting to a maximum decrease of 21%. The self-sufficiency ratio and the ability to produce minimum dietary needs can be reduced by 55% and 61%, respectively, but may rise if the disruption to feed imports increases. Economic access to foods is slightly decreased in all scenarios. These results showing different impacts of trade disruptions on producers and consumers and food security metrics highlight the need to undertake extensive assessments to determine whether and how to prevent and mitigate their effects. The economic effects on producers and consumers and the associated impacts on food security are likely to differ, which affects the selection and targeting of policies, such as compensation for economic losses and promotion of food security.

Performance assessment of large-scale rooftop solar PV system: a case study in a Malaysian Public University

Adopting rooftop solar PV systems in various domestic and non-domestic sectors (including commercial, industrial, and agricultural) exhibits their commitment to green energy ventures. This study intends to evaluate the effectiveness of a grid-connected solar system that has been installed so far: a 6.9 MWp photovoltaic (PV) system implemented at University Tun Hussein Onn (UTHM) in Batu Pahat, Johor. This green energy system was installed as a part of the Self-Consumption (SELCO) program utilizing a Supply Agreement for Renewable Energy (SARE) contract. To assess the mounted energy system's efficiency, performance monitoring was carried out between December 2021 and November 2022. By evaluating the enactment of the 6.9 MWp solar system at UTHM, this present work has attempted to compile the achievement of implementation of self-consumption in terms of performance analysis and financial benefits to consumer. Based on International Electrotechnical Commission (IEC) 61724 standard, this study also investigates several performance characteristics of the PV system, such as final yield, clearness index (CI), array yield, PV module efficiency, inverter efficiency, reference yield, and capacity factor (CF) performance ratio (PR). Moreover, an assessment of Carbon Dioxide (CO2)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${CO}_{2})$$\\end{document} avoidance was also conducted to quantify the amount of CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${CO}_{2}$$\\end{document} reduction achieved. In addition, the self-consumption ratio and self-sufficiency ratio pattern for solar power plant in UTHM has been assessed. The monthly clearness index at the project location from December 2021 to November 2022 ranges from 0.63 to 0.66. The PV system was monitored throughout this time and generated 8529 MWh of energy. The installed PV system has shown an efficiency of 11.86%, a final yield of 108.28%, and a PR of 0.78, respectively. Further, the installed 6.9 MWp PV system at UTHM will cut CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${CO}_{2}$$\\end{document} emissions by 5450 tons annually. The 6.9 MWp solar PV system is also estimated to reduce 25.1 RM mil in 25 years. Making the system larger to 6.9 MWp would reduce the consumption from the grid during the week, makes it possible to achieve self-consumption levels of up to 100% and self-sufficiency of this solar plant is relatively low ranges from 22 to 35%. The research finding bridges the gap between policy makers, investors, and the public regarding acceptance of the large-scale Self-Consumption (SELCO) and strengthen the strategic collaborations between solar service provider and educational bodies to support of the government’s agenda to achieve carbon emission intensity reduction in Malaysia.Graphical

Multi-criteria evaluation of poly-generation system applied to commercial buildings with various prime movers and building types

The present study evaluates the performance of a poly-generation system applied to commercial buildings. An internal combustion engine (ICE) and solid oxide fuel cell (SOFC) used as prime movers represent different efficiency distributions according to part load ratio variation. Accordingly, discrete results are found in terms of energy, environment, and economy depending on the prime mover type applied to each building. A renewable energy system is combined with the poly-generation system, and the outputs produced from the energy generation units are transferred to the energy storage system and supplied to the demand sources. Through the parametric study and hybrid control method, the stored energy is optimally distributed to the cooling and heating system to maximize the primary energy saving ratio. The major components constituting the poly-generation system are modeled and validated based on experiments and literature to enhance the reliability of the dynamic simulation model. The monthly amounts of replenished and wasted energy are examined, and the magnitude of produced energy contribution to the building self-sufficiency ratio is also identified. When ICE- and SOFC-based poly-generations are applied to the hospital, 30.2% and 45.2% of the primary energy consumption is saved, respectively, compared with the conventional system. For the office, the corresponding systems reduce primary energy consumption by 1.8% and 37.2%, respectively. The economic feasibility of the poly-generation systems is examined considering the current energy project in South Korea.

Vulnerability assessment of food imports—Conceptual framework and empirical application to the case of Switzerland

The world's food supply is becoming increasingly vulnerable because of rising political and climatic crises. To identify food supply vulnerabilities at an early stage, this paper proposes a multifactorial and standardized import vulnerability index (IVI). The IVI encompasses (i) an exporter vulnerability index (EVI) consisting of four exporter-specific factors and (ii) a product vulnerability index (PVI) consisting of three product-specific factors. We applied a robust principal component analysis to derive weights to combine these individual factors into a standardized IVI. The IVI was applied to food import-dependent Switzerland from 2014 to 2019 as an empirical case study. The results showed that a large share of Swiss food imports mainly originated from neighboring countries, indicating a very low to moderate EVI. Regarding the PVI, only product groups that were imported from a small number of countries (e.g., oilseeds) or that showed a low self-sufficiency ratio (e.g., coffee) or high price volatility (e.g., meat) exhibited a high value. Moreover, the findings demonstrate that the IVI showed neither large fluctuations nor a decreasing or increasing trend. With regular updates, the proposed indicator can become a valuable monitoring tool for food supply security.

Санкции Японии и ЕС против российского энергетического сектора в условиях кризиса 2022 г.

The aim of this article is to compare the measures taken by Japan and the European Union in response to the Ukrainian crisis escalation and subsequent world energy crisis. The article focuses on the sanctions policy of the two actors in the energy sphere, and the consequences from a socio-economic viewpoint. The volume of this study is limited to anti-Russian sanctions against basic fossil fuels – coal, crude oil, and natural gas. Under investigation are import restrictions, import diversification directions and EU–Japanese joint initiatives, taken to overcome the crisis under the US leadership. The study rests upon detailed statistical information from Japan’s and the EU’s, as well as international databases. Special attention is attributed to the problem of Russian gas import: Japan’s ongoing participation in the Sakhalin‑1 and 2 oil and gas projects, the routes of EU gas supplies alternative to Nord Stream‑1. The choice of actors is explained by the common situation which the EU and Japan found themselves in. Among the nations that introduced sanctions, they suffer the most, being short of natural resources and highly dependent on fossil fuel imports. Both imposed a wide range of sanctions in the energy sphere, following the hard line of the energy-independent United States. The paradox is that the EU, which is much more dependent on Russian fossil fuels, introduced much more severe sanctions than Japan. The author offers the following suggestion for this situation. First, Japan’s energy selfsufficiency ratio is lower than that of the EU, which is recognised by the G7 partners. Second, Japan, demonstrating full solidarity with Western countries, in contrast to the EU, still considers the Ukrainian crisis to be geographically distant, with relatively little effect on its domestic policy, except for the potential impact on the Taiwan Strait crisis escalation. Meanwhile, the energy crisis hits Japan directly, putting it into a situation where it must choose whether to follow the US’ and EU’s rigid approach, or to protect its own economic interests as much as possible. The study shows that, while the EU is putting democratic values protection ahead of the member states’ economic and social situation, Japan shows a more pragmatic approach in the energy sphere, trying to protect its industry and households from the devastating influence of the energy crisis, even if it goes against the G7 basic line and needs special approval. The degree of EU–Japan cooperation in solving common problems is seen as low. The absence of common proposals to overcome the crisis is explained by strategic dependence on the US, which is acting as the thought leader of the sanctions campaign under the G7 framework.

Economic Analysis of Policies to Improve Food and Feed Crop Self-sufficiency Ratios under the Strategy to Expand Exports of Agricultural, Fishery and Food Products in Japan: Utilizing the Nine Interregional Computable General Equilibrium Model

Economic Analysis of Policies to Improve Food and Feed Crop Self-sufficiency Ratios under the Strategy to Expand Exports of Agricultural, Fishery and Food Products in Japan: Utilizing the Nine Interregional Computable General Equilibrium Model

Optimal Sizing of Renewable Energy Communities: A Multiple Swarms Multi-Objective Particle Swarm Optimization Approach

Renewable energy communities have gained popularity as a means of reducing carbon emissions and enhancing energy independence. However, determining the optimal sizing for each production and storage unit within these communities poses challenges due to conflicting objectives, such as minimizing costs while maximizing energy production. To address this issue, this paper employs a Multi-Objective Particle Swarm Optimization (MOPSO) algorithm with multiple swarms. This approach aims to foster a broader diversity of solutions while concurrently ensuring a good plurality of nondominant solutions that define a Pareto frontier. To evaluate the effectiveness and reliability of this approach, four case studies with different energy management strategies focused on real-world operations were evaluated, aiming to replicate the practical challenges encountered in actual renewable energy communities. The results demonstrate the effectiveness of the proposed approach in determining the optimal size of production and storage units within renewable energy communities, while simultaneously addressing multiple conflicting objectives, including economic viability and flexibility, specifically Levelized Cost of Energy (LCOE), Self-Consumption Ratio (SCR) and Self-Sufficiency Ratio (SSR). The findings also provide valuable insights that clarify which energy management strategies are most suitable for this type of community.

Performance analysis of zero-emission integrated energy system for low-density residential building clusters

The low-density residential building clusters exist widely in Chinese towns and rural areas, and have advantages to achieve zero emission with lower energy density and larger available space. However, the path for these areas to achieve zero emission is not clear yet and needs to be investigated. This study attempts to explore the approaches that the low-density residential communities achieve carbon neutrality considering local and external energy resources comprehensively. Regional zero-emission energy systems are designed and optimized to meet users' multiple energy demands. Five scenarios are established and compared based on the different combinations of energy resources. Results show that the regional self-sufficiency ratio can be 72.9%, and external energy supply is required even for the low-density areas. The PV installation area can be up to 100%, and the utilization of the local municipal waste can significantly increase the self-sufficiency ratio, about 24% of the power generation. The systems' economic performance is not attractive yet, with the minimum payback period about 8 years. If the carbon tax is adopted and the external fuels’ price decreases, applications of the systems could be feasible. This paper would provide guidelines and suggestions to promote the zero-emission energy systems in the low-density areas.

The irrigated wheat initiative of Ethiopia: a new paradigm emulating Asia’s green revolution in Africa

AbstractThe aim of this paper is to assess and document the experience of the successful irrigated wheat initiative in Ethiopia, identify potential limitations, and suggest alternative options that contribute towards the sustainability of the program. In the past decades, Ethiopia has initiated several projects to ensure food and wheat security but did not achieve the anticipated impact as planned. In 2019, however, the current government of Ethiopia put in place structural, economic, and sectorial reforms, with wheat chosen as a strategic commodity for food security, raw material for the agroindustry, import substitution that transits to export, and job creation along the value chain. With a total of 2.6 million ha of land cultivated under both rain-fed and irrigated systems, followed by a record amount of wheat harvest (8.2 million tons) in 2022, Ethiopia achieved a wheat self-sufficiency ratio of 100% and more than 1 million tons of surplus for export, indicating that the new irrigated wheat initiative of Ethiopia has been found transformational and is becoming a game changer. Moreover, modest case scenario projections revealed that Ethiopia will become a net exporter of wheat by 2023, indicating that the country is achieving not only wheat security but also championing the possibility of replicating Asia’s Green Revolution in Africa. Yet, the sustainability of the current initiative relies on an efficient water management system, private sector engagement, sustainable input supply, well-established input and output marketing systems, and leadership commitment at all levels.

On a new method to design solar photovoltaic systems in renewable energy communities: The case of Culatra Island (Ria Formosa, Portugal)

Islands must reach sustainable lifestyles by improving resources management and by getting accustomed to renewable energy sources. Culatra, a small Portuguese island, is actively increasing renewable energy penetration into local processes in order to be the first 100% sustainable Portuguese territory by 2030. Based on the electric consumption of Culatra, the objective of the present study is to project a photovoltaic unit composed of several sub-fields, each with a distinct orientation, in order to increase the self-consumption ratio while at the same time reducing the surplus of energy production, assessed by the self-sufficiency ratio criteria, resulting in a lower levelised cost of energy of the power system. To achieve this, MATLAB’s implementation of a genetic algorithm was used to find the optimised set of orientations for a given load profile. The results indicate that it is possible to optimise the photovoltaic plant to reach a more continuous electricity generation through daytime, reducing the storage needs and increasing the value of photovoltaic systems. The method can be extended to other locations or demand curves, assisting on comparing different energy management strategies, and their respective advantages and disadvantages.

Assessment of Potential of Forest Wood Biomass in Terms of Sustainable Development

Forest wood biomass is one of the basic renewable resources used in the bioeconomy as a raw material for industrial products and fuel. The forest also plays an important role in the global carbon cycle. The increasing demand for wood biomass due to the growing population, as well as the required strategies to face climate change, force us to look at the use of forest wood biomass from a different angle. The European Commission has made a decision about the European Green Deal strategy. The new EU Forestry Strategy, as an element of the European Green Deal, promotes the sustainable use of wood-based resources. Therefore, it is important to know what is the sustainable potential of forest wood biomass and how it can be assessed. This study aimed to assess the potential of forest wood biomass in terms of sustainable development in the European Union. Five estimates were applied, the self-sufficiency ratio, imports-dependence ratio, logging residues rate, recovery rate, and the ratio between annual fellings and the net annual increment of forest wood biomass. The findings indicate that the self-sufficiency in primary wood biomass is quite high, and the ratio between annual fellings and net annual increment of wood biomass is sustainable in total in the EU. However, in separate countries, there are opportunities to increase domestic fuelwood potential and reduce fuelwood imports by using logging residues. The basic idea is that the biomass potential of forest wood has more sustainable use opportunities. This study can provide insight for political direction into how to increase self-sufficiency in wood biomass and maintain a balance between harvesting and the increment of wood biomass at the same time. Future research on the potential of forest wood biomass should consider the distribution potential by countries and counties. The principal conclusions of this study are important for the development of a sustainable bioeconomy and the need to sustainably use the potential of forest wood biomass.

A Nash bargaining model for energy sharing between micro-energy grids and energy storage

Micro-energy grids (MEGs) play a crucial role in achieving diverse energy utilization and promoting low-carbon economies. However, the intermittent nature of distributed generation and the inter-coupling of multiple energy types pose challenges to efficient energy management in MEGs. In this paper, we propose a novel Nash bargaining game-based electricity-gas energy-sharing model for MEGs. Our model incorporates bus structure-based energy storage combined with power-to-gas technology, which enables MEGs to establish an integrated electricity-gas energy-sharing network. This network facilitates both direct sharing and buffered sharing of energy, addressing the limitations of intermittent generation and enhancing overall energy management. To address the issue of computational complexity, the proposed Nash bargaining game model is decomposed into two sub-problems: social energy cost minimization and benefits sharing. Through optimization, we obtain optimal energy-sharing profiles and energy-sharing payments. Moreover, we consider the investment payback period of energy storage and adjust the initial benefit-sharing results accordingly. Case studies demonstrate that our model significantly improves economic performance, increasing the self-sufficiency ratio of MEGs to 64% and energy storage efficiency to 63% compared to operating independently. Additionally, the multiplayer Nash bargaining game model facilitates Pareto optimal benefits for MEGs and energy storage by capturing their interactive dynamics.