{"title":"A global optimization framework for joint generation and transmission expansion planning with AC power flow representation","authors":"Ghazaleh Mozafari , Mahdi Mehrtash , Yankai Cao , Bhushan Gopaluni","doi":"10.1016/j.ref.2025.100725","DOIUrl":"10.1016/j.ref.2025.100725","url":null,"abstract":"<div><div>The integration of renewable energy generating units, often located in remote regions with limited grid connectivity, has created a pressing need for coordinated generation and transmission expansion planning (G&TEP). However, considering full AC network representation, the co-optimization of generation and transmission poses a challenging nonconvex mixed-integer problem that is prone to locally suboptimal solutions. In this study, we propose a tailored global optimization framework to identify the most cost-effective set of generating units and candidate transmission lines while satisfying operational and investment constraints. The proposed solver employs second-order cone relaxation, further enhanced through a set of relaxation-tightening constraints, along with feasibility-based and optimization-based bound tightening techniques to improve relaxation strength. A salient feature of the solver is the integration of a no-good cut technique, which enables efficient exploration of alternative candidate solutions within the feasible region. As demonstrated by numerical results, this technique is specifically tailored to the G&TEP problem and significantly improves solution quality while reducing the runtime required to achieve global optimality. A comparative performance analysis with state-of-the-art global MINLP solvers demonstrates that the proposed approach achieves tighter optimality gaps faster and exhibits superior flexibility and scalability.</div></div>","PeriodicalId":29780,"journal":{"name":"Renewable Energy Focus","volume":"55 ","pages":"Article 100725"},"PeriodicalIF":4.2,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144330419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Renewable Energy FocusPub Date : 2025-12-01Epub Date: 2025-06-08DOI: 10.1016/j.ref.2025.100728
M. Shamsi , M. Sheidaei , B. Karami , A. Cheraghdar , S. Bakhsheshi , A. Afshardoost
{"title":"Development of an off-grid polygeneration system utilizing multi-waste heat recovery from low-grade heat sources for sustainable production of e-methanol, potable water, liquefied CO2, and utilities","authors":"M. Shamsi , M. Sheidaei , B. Karami , A. Cheraghdar , S. Bakhsheshi , A. Afshardoost","doi":"10.1016/j.ref.2025.100728","DOIUrl":"10.1016/j.ref.2025.100728","url":null,"abstract":"<div><div>The multi-waste heat recovery approach represents an innovative solution for harnessing waste heat in industrial sectors. Harnessing and employing waste heat leads to a decrease in adverse environmental effects and improves overall performance. In this study, a near-zero polygeneration system is developed by utilizing cascade heat recovery from geothermal sources and flue gases, and integrating it with key subunits including an absorption chiller, carbon capture and storage, reverse osmosis, water electrolysis, methanol synthesis, and power generation cycles. In the proposed integrated off-grid system, multi-products are generated, including e-methanol, oxygen, drinking water, electricity, natural gas, chilled water, and liquefied CO<sub>2</sub>. Energy, exergy, sustainability, and enviro-exergo-economic analyses were conducted to evaluate the proposed system. The thermodynamic evaluation revealed an energy efficiency of 67.71 % and an exergy efficiency of 42.79<!--> <!--> %. Implementation of the designed system led to annual fuel savings of 6,885.30 L and a reduction in CO<sub>2</sub> emissions by 26,396.81 tonnes, corresponding to an annual carbon tax avoidance of $346,326.09. The sustainability index was calculated to be 1.748, while the LCOP and TUCP were determined to be $0.0926/kWh and $3.4385/GJ, respectively. Additionally, the effects of key operational variables- including seawater flow rate, geofluid flow rate and temperature, methanol synthesis reactor pressure, H<sub>2</sub>/CO<sub>2</sub> ratio, electrolyzer power consumption, and LNG flow rate - on proposed system performance were thoroughly investigated. Finally, based on the results of the parametric study, a sensitivity assessment was performed using the SHAP approach to quantify the influence of key operational parameters on thermodynamic and economic performance indicators.</div></div>","PeriodicalId":29780,"journal":{"name":"Renewable Energy Focus","volume":"55 ","pages":"Article 100728"},"PeriodicalIF":4.2,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144270102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Renewable Energy FocusPub Date : 2025-12-01Epub Date: 2025-07-20DOI: 10.1016/j.ref.2025.100742
Lijun Yang , Baiting Pan , Qinglong Duan
{"title":"An adaptive robust planning method for data center micro-energy system towards flexibility enhancement","authors":"Lijun Yang , Baiting Pan , Qinglong Duan","doi":"10.1016/j.ref.2025.100742","DOIUrl":"10.1016/j.ref.2025.100742","url":null,"abstract":"<div><div>Driven by the economic, flexibility, and sustainability requirements of data center (DC) development, a key challenge lies in optimizing the capacity planning of diverse energy devices within DC micro-energy systems. Thus, to further exploit the flexibility potential and ensure robustness, a two-stage adaptive robust methodology is proposed, based on an innovative architecture for DC micro-energy system. First, to achieve the efficient utilization of energy, dual-condition heat pumps is integrated into the system architecture with seasonal waste heat recovery (WHR) strategy. Second, a novel batch load demand response (DR) model with a differential compensation scheme is proposed, uniquely incorporating users’ fatigue effect and trust process, to incentivize load participation. Finally, a two-stage adaptive robust planning model that accounts for planning flexibility is developed, utilizing gaussian process regression (GPR) to capture key features of forecasted data. Case studies demonstrate that compared to conventional waste heat recovery strategies, carbon emission reductions increased by 79% and investment costs for photovoltaic, gas turbine and energy storage systems were reduced by 9.1%, 14.3% and 8.6%, respectively. And compared to scenarios that omit planning flexibility, the planning costs can be reduced by approximately 0.5% to 4.9%. Through the incorporation of resource and planning flexibility, alongside the refinement of the uncertainty set, the flexibility of the system is unlocked, while the stability and economy of the planning results are guaranteed.</div></div>","PeriodicalId":29780,"journal":{"name":"Renewable Energy Focus","volume":"55 ","pages":"Article 100742"},"PeriodicalIF":4.2,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144687428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Renewable Energy FocusPub Date : 2025-12-01Epub Date: 2025-07-19DOI: 10.1016/j.ref.2025.100741
Timothy King Avordeh , Forson Peprah , Christopher Quaidoo , Rockson Opare-Boateng
{"title":"Engaging the Next Generation: the role of youth in promoting demand response participation in Ghana","authors":"Timothy King Avordeh , Forson Peprah , Christopher Quaidoo , Rockson Opare-Boateng","doi":"10.1016/j.ref.2025.100741","DOIUrl":"10.1016/j.ref.2025.100741","url":null,"abstract":"<div><div>Ghana’s energy sector struggles with power shortages (“dumsor”), increasing demand, and its reliance on fossil fuels. While Demand Response (DR) programs could improve grid stability and renewable integration, low participation persists due to awareness gaps and cultural barriers. This study examines youth (15-35 years) as potential DR catalysts, bridging digital literacy and traditional household decision-making. Through a mixed-methods approach (comprising 400 surveys, six focus group discussions, and 12 interviews), we found that urban youth had higher DR awareness (mean = 3.47) compared to rural youth (mean = 2.67). However, rural areas showed better energy-saving behaviors through community trust networks. Hybrid digital-community approaches (social media + radio) boosted engagement by 18-30%, outperforming top-down policies. Successful models from Kenya (Green Schools) and South Africa (#PowerShiftSA) demonstrate scalability. Key recommendations include integrating the DR curriculum, establishing youth task forces, and implementing mobile enrollment platforms. The research positions youth as active energy stakeholders, offering a framework for sustainable transitions in similar contexts through intergenerational engagement and culturally-adapted policy reforms.</div></div>","PeriodicalId":29780,"journal":{"name":"Renewable Energy Focus","volume":"55 ","pages":"Article 100741"},"PeriodicalIF":4.2,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144680333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Renewable Energy FocusPub Date : 2025-12-01Epub Date: 2025-06-30DOI: 10.1016/j.ref.2025.100736
Florentin Eckl , Ana Moita , Rui Costa Neto
{"title":"Cost optimization of electrolytic oxygen distribution: A mathematical framework with a green steel and hospital case study in Portugal","authors":"Florentin Eckl , Ana Moita , Rui Costa Neto","doi":"10.1016/j.ref.2025.100736","DOIUrl":"10.1016/j.ref.2025.100736","url":null,"abstract":"<div><div>Decarbonizing the steel industry is crucial as it accounts for 7 % of global carbon emissions. Hydrogen-based direct reduced iron with electric arc furnace technology offers a sustainable solution. Both gases, hydrogen and oxygen, from electrolysis are necessary for steel production, however, in a different ratio than the electrolyzer delivers. This study evaluates the economic feasibility of distributing electrolytic excess oxygen from a green steel facility in Portugal to hospitals. Using a capacitated vehicle routing problem model, results show liquefaction (57 %), distribution (39.9 %) as key cost components, emphasizing the need for optimized logistics. Selling 6007 tons of excess oxygen yearly for 0.7 €/kg results in a net present value of €39.1 million over 20 years and a cost-benefit ratio of 8.25 and provides highly profitable application. The internal rate of return of 248 % and a discounted payback period of under half a year further underscore the project’s strong financial viability. This study confirms the economic benefits of valorizing electrolytic oxygen, providing a competitive alternative to conventional production while supporting steel decarbonization and medical oxygen supply.</div></div>","PeriodicalId":29780,"journal":{"name":"Renewable Energy Focus","volume":"55 ","pages":"Article 100736"},"PeriodicalIF":4.2,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144535763","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Renewable Energy FocusPub Date : 2025-12-01Epub Date: 2025-08-05DOI: 10.1016/j.ref.2025.100745
Md.Sazid Khan , Hasan Muhommod Robin , Md Nahid Khan , Sadman Salim Rahman Asif , Md.Sadbin Islam , Mim Mashrur Ahmed
{"title":"Strategic assessment of waste-to-energy pathways for sustainable municipal solid waste management in Bangladesh","authors":"Md.Sazid Khan , Hasan Muhommod Robin , Md Nahid Khan , Sadman Salim Rahman Asif , Md.Sadbin Islam , Mim Mashrur Ahmed","doi":"10.1016/j.ref.2025.100745","DOIUrl":"10.1016/j.ref.2025.100745","url":null,"abstract":"<div><div>Uncontrolled accumulation of municipal solid waste (MSW) in Rajshahi City Corporation (RCC), Bangladesh, poses a critical threat to environmental and public health. With MSW projected to rise by over 320% by 2040 from 2024 levels, there is an urgent need to transition from open dumping to sustainable energy recovery solutions. This study presents a techno-economic and environmental assessment of three waste-to-energy (WtE) pathways anaerobic digestion (AD), incineration (INC), and landfill gas (LFG) recovery over the 2024-2040 period. AD and INC emerged as the most effective, each producing over 700 million kWh annually by 2040, compared to 45 million kWh for LFG. AD and INC showed strong financial viability, with net present values of USD 419 million and USD 392 million and discounted payback periods of 4.2 years. Levelized cost of energy remained low across all options. AD had the lowest acidification and dioxin emissions, while LFG and No Recovery scenarios imposed the highest human health (USD 1.39 million) and ecosystem damages (USD 15 million). Sensitivity analysis confirmed the resilience of AD and INC under varying inflation and electricity price conditions. Overall, an AD-led strategy, supported by selective INC, offers the most balanced energy, economic, and environmental outcomes. The study provides an evidence-based framework for implementing decentralized WtE systems in rapidly urbanizing cities.</div></div>","PeriodicalId":29780,"journal":{"name":"Renewable Energy Focus","volume":"55 ","pages":"Article 100745"},"PeriodicalIF":5.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144770730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Renewable Energy FocusPub Date : 2025-12-01Epub Date: 2025-06-14DOI: 10.1016/j.ref.2025.100735
Minghao Liu , Hongyang Huo , Yiding Xu , Zhonghe Han , Zhiquan Wu
{"title":"Two-stage stochastic robust optimization for the planning and operation of rural integrated energy systems considering source-load uncertainties","authors":"Minghao Liu , Hongyang Huo , Yiding Xu , Zhonghe Han , Zhiquan Wu","doi":"10.1016/j.ref.2025.100735","DOIUrl":"10.1016/j.ref.2025.100735","url":null,"abstract":"<div><div>The transition to renewable energy in rural areas is hindered by the inherent unpredictability of renewable resources and load demand. This study proposes a two-stage stochastic robust optimization (TS-SRO) framework to address the integrated planning and operation of rural energy systems under source-load uncertainties. The optimal capacity allocation for renewable energy generation, storage, and conversion devices is determined in the first stage, while the second stage optimizes multi-energy dispatch under uncertainty. Renewable energy fluctuations are modeled through data-driven stochastic scenarios derived from historical data using a 0–1 programming clustering method. In contrast, load uncertainties are characterized via confidence interval-based box-type uncertainty sets. A Nested Column-and-Constraint Generation (NCCG) algorithm combined with dynamic weighting is introduced to resolve the computational complexity arising from multi-objective optimization and uncertainty coupling. A case study in northern China demonstrates the model’s efficacy: compared to the baseline scenario, the TS-SRO approach reduces total energy costs by 37.62% and carbon emissions by 85.33%. Sensitivity analyses reveal that economic performance deteriorates with increasing uncertainty budgets and confidence intervals while robustness improves. Notably, biogas combined heat and power unit pricing significantly influences system economics, whereas solar water heaters and heat pumps show minimal impact.</div></div>","PeriodicalId":29780,"journal":{"name":"Renewable Energy Focus","volume":"55 ","pages":"Article 100735"},"PeriodicalIF":4.2,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144280506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Microgrids protection: A review of technologies, challenges, and future trends","authors":"Goutam Kumar Yadav, Mukesh Kumar Kirar, S.C. Gupta","doi":"10.1016/j.ref.2025.100720","DOIUrl":"10.1016/j.ref.2025.100720","url":null,"abstract":"<div><div>The proliferation of distributed generation, particularly renewable energy sources, has catalyzed the emergence of microgrids as a pivotal element in contemporary power system architectures. However, the integration of these sources introduces significant complexities in protection system design due to the inherent dynamic characteristics of microgrids, bidirectional power flow, and operational mode transitions between grid-connected or islanded states. Traditional protection paradigms, predicated on static fault current magnitudes prevalent in passive radial distribution networks, exhibit limitations in microgrid environments characterized by substantial fault current variability. Notably, constrained fault current contribution of inverter-interfaced DG units operating in current-limiting mode impedes the efficacy of traditional overcurrent protection. This necessitates the development of adaptive and intelligent protection methodologies. A hybrid microgrid simulation is employed to analyze fault current variations across diverse operational scenarios, underscoring the imperative for advanced protection strategies. This study evaluates the current state of microgrid protection, identifies existing research lacunae, and proposes potential future research directions to improve resilience, reliability, and security. This review examines various microgrid types, including AC and DC systems, with a focus on their operational conditions, configurations, and the diverse fault types they encounter in relation to different protection device frameworks. The study emphasizes the critical need for advanced protection technologies that are continuously evolving to address the increasing complexity of microgrid systems effectively. By presenting a comprehensive analysis of past advancements and future directions in microgrid protection, this paper aims to guide researchers and scientists, emphasizing the significance of their contributions in shaping the development and innovation of protection strategies in this essential domain.</div></div>","PeriodicalId":29780,"journal":{"name":"Renewable Energy Focus","volume":"55 ","pages":"Article 100720"},"PeriodicalIF":4.2,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144262734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Renewable Energy FocusPub Date : 2025-12-01Epub Date: 2025-06-14DOI: 10.1016/j.ref.2025.100721
Mariem Kammoun, Manef Bourogaoui
{"title":"Future-ready power grids: From variability to predictability with scalable AI for PV energy integration","authors":"Mariem Kammoun, Manef Bourogaoui","doi":"10.1016/j.ref.2025.100721","DOIUrl":"10.1016/j.ref.2025.100721","url":null,"abstract":"<div><div>The increasing integration of renewable energy, particularly solar power, presents challenges in maintaining grid stability due to fluctuations in power generation and voltage variations. This issue is especially important because solar energy is highly variable and depends on weather conditions, which makes it difficult to keep the power grid stable and reliable. Therefore, there is a strong need for accurate tools that can help predict these changes and improve the way the grid is managed. This study addresses these challenges by leveraging AI-based methods that combine climate data analysis and power grid simulations. The analysis relies on key environmental variables: solar irradiation, temperature, and wind speed to predict two critical outputs: power and voltage levels across the network. Among the tested models, Support Vector Regression (SVR) gave the best performance for power prediction. On the IEEE 123-bus Network, SVR achieved an RMSE of 183.07 and an MAE of 169.15, remaining well within the acceptable margin of 400 kW. For voltage prediction, the Long Short-Term Memory (LSTM) model performed best by capturing long-term time dependencies. On the IEEE 123-bus Network, LSTM achieved an RMSE of 0.0133 and an MAE of 0.0104 for Bus 64, staying well below the acceptable error threshold of 0.015 pu. Accordingly, through addressing a real-world challenge in electrical network operation, this study helps energy systems become more flexible and efficient. The proposed approach supports the transition toward a more stable, clean, and intelligent energy infrastructure.</div></div>","PeriodicalId":29780,"journal":{"name":"Renewable Energy Focus","volume":"55 ","pages":"Article 100721"},"PeriodicalIF":4.2,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144481270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Renewable Energy FocusPub Date : 2025-12-01Epub Date: 2025-08-19DOI: 10.1016/j.ref.2025.100749
Ashish Shukla, Parul Mathuria
{"title":"Credibility-driven pricing settlements in peer-to-peer energy trading using blockchain technology","authors":"Ashish Shukla, Parul Mathuria","doi":"10.1016/j.ref.2025.100749","DOIUrl":"10.1016/j.ref.2025.100749","url":null,"abstract":"<div><div>Blockchain-enabled peer-to-peer electricity trading using behind-the-meter deployment encourages users to increase their utilisation of renewable energy while consuming energy within the local energy markets (LEMs). Effective pricing settlements can assist mutual trust among users and encourage them to participate in trading. In this work, we focus on pricing settlement and present a novel score-based model aimed at accelerating stable P2P trading by increasing the number of pricing settlements among participants and minimising trading (or power delivery agreements) failures without incurring any financial loss. We present a credibility-based score model to better manage the larger differences in offered prices between sellers and buyers. In particular, the algorithm analyses historical transactions to calculate the credibility score between the seller and buyer. This score falls within the user’s threshold range, allowing for price adjustments during pricing settlement. Simulation results show that more successful trading transactions encourage participation despite wider price differentials between ToU and FiT rates and mitigating financial losses for users.</div></div>","PeriodicalId":29780,"journal":{"name":"Renewable Energy Focus","volume":"55 ","pages":"Article 100749"},"PeriodicalIF":5.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144895136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}