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The aim of this study was to assess the feasibility of creating a prototype of a self-sufficient houseboat that is capable of prolonged independence from power grids and freshwater sources. In this design, electricity demand is met by a photovoltaic installation, and the energy is stored in batteries. Fresh water for living needs may be obtained from many sources, depending on the environmental conditions, such as through purifying outboard water, desalinating seawater, and collecting and storing rainwater. No waste production of the vessel can be achieved in two ways: waste can be treated and discharged into a body of water, or processed into fertiliser for later use in agriculture. Four possible locations were analysed: Rome, Lisbon, Gdańsk and Stockholm. The findings reveal that the length of time for which the unit is autonomous and emission-free depends on the geographical location of the facility. In periods when there is overproduction of energy, the system can produce hydrogen, donate energy to the grid, use it for the needs of its own movement, or perform other useful work, e.g. cleaning or aerating the water body on which it is floating. [ABSTRACT FROM AUTHOR]

Hybrid microgrids, integrating local energy resources, present a promising but challenging solution, especially in areas with limited or no access to the national grid. Reliable operation of off-grid energy systems necessitates sustainable energy sources, given the intermittent nature of renewables. While fossil fuel diesel generators mitigate risks, they increase carbon emissions. This study assesses the viability of integrating a very small modular renewable energy reactor into a microgrid for replacing conventional diesel generators, substantially curbing greenhouse gas emissions. A comprehensive analysis, including design and economic evaluation, was conducted for an off-grid community microgrid with an annual generation and load of 8.5 GWh and 7.8 GWh, respectively. The proposed microgrid configurations incorporate very small modular reactors, alongside solar, wind, and battery storage systems. MATLAB modeling and simulation across eight cases, accounting for seasonal variations, demonstrate the technical and economic feasibility of case 7. This configuration, integrating modular reactors, photovoltaics, wind turbines, and battery storage, satisfactorily meets load demands. Notably, it boasts a high internal rate of return up to ~31% and a shorter payback period of around 4 years compared to alternative scenarios. [ABSTRACT FROM AUTHOR]

Off‐grid solar systems provide clean and affordable energy sources. Adoption of off‐grid Solar energy is becoming increasingly popular in Kenya as a source of renewable energy, with an estimated 10 million people using off‐grid solar power systems as of the end of year 2022. However, the rising off‐grid solar systems technology uptake comes with a growing amount of solar e‐waste, which can have harmful environmental and health effects if not managed properly. Current data on the exact amount of solar e‐waste being generated in Kenya is unavailable and this amount will continue to rise with the expiry of many of these off‐grid solar systems lifespans. This study through stakeholder's workshop and document review data collection and analysis approaches, established that Kenya just like many countries in the Global South has a robust general waste policy and regulation management framework. However, it lacks specific policies and regulations on off‐grid‐solar electronic waste management a challenge that many countries in the Global North have made considerate steps in addressing. In addition, there is a lack of awareness of the hazardous nature of off‐grid solar systems' e‐waste components to both consumers and institutions of governance. There is a lack of adequate infrastructure and sufficient systems for off‐grid solar e‐waste management in the country. Enforcement and implementation challenges of the existing general waste regulations due to limited resources and capacity and corruption culture are major impending factors. This calls for the development of effective policies and regulations to ensure sustainable off‐grid solar e‐waste management in Kenya against the backdrop of the rising uptake of off‐grid solar systems. [ABSTRACT FROM AUTHOR]

The study determined optimum roof tilt and building azimuth for rooftop-based distributed photovoltaic (PV) energy generation in Ikeja, Lagos State, Nigeria, as strategic technological input to alternative power generation and new housing development in Metropolitan Lagos. The energy planning & foresight analysis methodology was used. The data were obtained via literature, Global Positioning System (GPS) systems, energy models, and site visits and comprised manual and satellite imagery, dimensions, roof angles, and coordinates of the building structures in the study area (Rows between 0 – 60o, Columns between 0 – 180o ; System sizes: 533 kW, 110 kW, and 0.547 kW). The results showed solar array yield varied from 768,944 kWh per annum for a 500 kVA system to 780 kWh per annum for a 0.5 kVA system. A five-tier rooftop generation template of 245 MWp was consequently developed. The systems ' optimal roof tilt and building azimuth angles were estimated to be 5o and 180o, respectively, though combinations of azimuth and tilt angles not exceeding 30o tilt and 90o azimuth gave acceptable yields. The study concluded that the optimum roof tilt and building azimuth for rooftop-based distributed photovoltaic (PV) energy generation in the study area were strategic policy intelligence inputs for the Federal and Lagos State governments' renewable power generation and new housing development programmes. [ABSTRACT FROM AUTHOR]

Copyright of Integrated Intelligent Energy is the property of Editorial Department of Integrated Intelligent Energy and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Electric car charging stations are in high demand as a result of the development of the e-mobility sector and the adoption of electric vehicles in transportation. This study aims to construct and analyze a stand-alone solar PV-powered electric car charging station to fulfil electric vehicle load demand and make recommendations for optimizing its operation. The goal is to achieve 3D’s i.e., Decarbonization, Digitalization and Decentralization in both the transport and power supply (electricity supply). Advancing towards attaining 3D’s goal, an off-grid solar PV-powered EV charging station was built at the University of Sharjah to meet the load demand. The EV charging station includes PV panels, inverters, energy storage devices and EV charging outlets. A solar PV system of 7.4 kWp with an energy storage capacity of 34.56 kWh is installed. A battery inverter of 4.6 kW is incorporated to meet the load demand of three electrical vehicles simultaneously. The performance of the system is monitored over a year. The EV charging station is in off-grid mode; thus, it is following the load demand for PV energy production. The findings reveal that the total energy production by the PV system is 2971.59 kWh from which the direct consumption is 383.77 kWh (12.91 %), and 2587.83 kWh (87.09 %) is stored in the energy storage devices. The total energy consumption by electric vehicles is 2379.01 kWh of which 1995.24 kWh (83.87 %) is taken from the battery bank. The PV system is working at 24.58 % of its full capacity. By elevating the daily load demand to 33 kWh, the full utilization of the solar resource can be achieved. To evaluate the adverse effect of dust, natural dust is allowed to settle down on the surface of PV panels continuously for 322 days. A linear degradation was recorded in the performance ratio from 77.92 % to 27.30 % in 218 days. Thereafter a plateau was attained and insignificant variation (min. 26.36 % and max. 33.78 %) was observed in the next 104 days. It is concluded that once a thick layer of dust forms on the surface of the PV panels, further dust accumulation becomes minimal.

Universal access to electricity is beneficial for the socio-economic development of a country and the development of smart communities. Unfortunately, the electrification of remote off-grid areas, especially in developing countries, is rather slow due to geographic and economic barriers. In the Philippines, specifically, many electrified off-grid areas are underserved, with access to electricity being limited to only a few hours a day. This is mainly due to the high dependence on diesel power plants (DPPs) for electrifying these areas. To address these problems, hybrid renewable energy systems (HRESs) have been considered good electrification alternatives and have been extensively studied for their techno-economic and financial feasibility for Philippine off-grid islands. In this work, articles published from 2012 to 2023 focusing on off-grid Philippine rural electrification were reviewed and classified based on their topic. The taxonomical analysis of collected studies shows that there is a saturation of works focusing on the technical and economic aspects of off-grid electrification. Meanwhile, studies focusing on environmental and socio-political factors affecting HRES off-grid electrification are lagging. A bibliographic analysis of the reviewed articles also showed that there is still a lack of a holistic approach in studying off-grid electrification in the Philippines. There are only a few works that extend beyond the typical techno-economic study. Research works focusing on environmental and socio-political factors are also mainly isolated and do not cross over with technical papers. The gap between topic clusters should be addressed in future works on off-grid electrification.

Abstract The transition to sustainable power infrastructure necessitates integrating various renewable energy sources efficiently. Our study introduces the deterministic balanced method (DBM) for optimizing hybrid energy systems, with a particular focus on using hydrogen for energy balance. The DBM translates the sizing optimization problem into a deterministic one, significantly reducing the number of iterations compared to state-of-the-art methods. Comparative analysis with HOMER Pro demonstrates a strong alignment of results, with deviations limited to a 5% margin, confirming the precision of our method in sizing determinations. Utilizing solar and wind data, our research includes a case study of Cairo International Airport, applying the DBM to actual energy demands.

Off-grid electrification planning increasingly recognizes the importance of productive use of electricity (PUE) to promote community value creation and (financial) project sustainability. To ensure a sustainable and efficient integration in the community and energy system, PUE assets must be carefully evaluated to match both the community needs and the residential electricity demand patterns. We propose a novel methodology interlinking qualitative interviews, statistical analysis and energy system modeling to optimize decision making for PUE integration in off-grid energy systems in rural Madagascar by aligning relevant PUE effectively with anticipated residential electricity demand patterns based on socio-economic determinants of the community. We find that a possible contribution of the PUE to reducing the electricity costs depends significantly on three factors: (1) The residential electricity consumption patterns, which are influenced by the socio-economic composition of the community; (2) The degree of flexibility of (i) PUE assets and (ii) operational preferences of the PUE user; and (3) The capacity of community members to finance and operate PUE assets. Our study demonstrates that significant cost reductions for PUE-integrated off-grid energy systems can be achieved by applying our proposed methodology. When matching PUE and residential consumption patterns, the integration of PUE assets in residential community energy systems can reduce the financial risk for operators, provided the PUE enterprise operates reliably and sustainably. We highlight that the consideration of local value chains and co-creation approaches are essential to ensure the energy system is addressing the community's needs, creates value for the community, enhances the project's financial sustainability and is achieving the overall objectives of decentralized energy system planning. [ABSTRACT FROM AUTHOR]

A properly designed and manufactured autonomous lighting system has an impact on reducing the amount of conflicts between pedestrians and drivers. For pedestrian crossings located outside of urban areas, one of the utilized solutions is PV installations with an electrochemical energy storage bank. So, the question should be asked: is it possible to maintain proper energy and lighting parameters throughout the year? This depends on the technical parameters of the installation, insolation, operating time, and the number and power of lighting luminaires directly prescribed by formal regulations. The purpose of this article is to present a method for evaluating the performance of a lighting installation at isolated pedestrian crossings based on annual power generation data obtained from a photovoltaic installation. This article presents lighting requirements for pedestrian crossing lighting. Based on the developed five lighting scenarios and energy calculations, year-round operation was simulated. Problems and risks that may affect the availability and performance of the lighting system were introduced. Directions for further research on the application of photovoltaic installations in road infrastructure were identified. [ABSTRACT FROM AUTHOR]

The transition to sustainable power infrastructure necessitates integrating various renewable energy sources efficiently. Our study introduces the deterministic balanced method (DBM) for optimizing hybrid energy systems, with a particular focus on using hydrogen for energy balance. The DBM translates the sizing optimization problem into a deterministic one, significantly reducing the number of iterations compared to state-of-the-art methods. Comparative analysis with HOMER Pro demonstrates a strong alignment of results, with deviations limited to a 5% margin, confirming the precision of our method in sizing determinations. Utilizing solar and wind data, our research includes a case study of Cairo International Airport, applying the DBM to actual energy demands. [ABSTRACT FROM AUTHOR]

Hybrid renewable energy sources (HRES) are increasingly being utilized to meet global energy demands, particularly in rural areas that rely on diesel generators and are disconnected from the utility grid, due to their environmental and human health benefits. This study investigates the performance of an off-grid, hybrid PV/diesel generator/battery system for a decentralized power plant in Kuakata, Bangladesh, meeting a load demand of 3000 kWh/day with a 501.61 kW peak load demand. HOMER Pro (hybrid optimization model for electric renewable) software (version 3.11) was used to simulate and optimize system operations utilizing real-time solar radiation and load profile data from that location. This study also includes a sensitivity analysis of the off-grid HRES system under different electrical load demands, project longevity, and derating variables. The results reveal that CO2 emissions have potentially decreased by more than 30% and over 10 tons per year, respectively, when compared to traditional power plants. The optimized system's net present cost (NPC) was determined to be around USD 5.19 million, with a cost of energy (COE) of USD 0.367 per kWh per unit with a 100% renewable component. Furthermore, the current study's findings are compared to previous research that has resulted in an economical hybrid renewable energy system with an affordable COE. The hybrid energy system under consideration might also be applicable to other parts of the world with comparable climate conditions. [ABSTRACT FROM AUTHOR]

Using pumps operating as turbines (PATs) offers the possibility of increasing the sustainability of water and energy systems by recovering the excess energy that would be otherwise lost in pressure-reducing valves or head loss chambers. Regarding on-grid applications, there have been many research works, and PATs have been implemented in several ways. However, more research still needs to be done on optimizing the efficiency and stability of PATs operating in off-grid systems. This work contributes to the development of stable direct current (DC) off-grid electric systems based on PATs using a self-excited induction generator (SEIG). In this context, a methodology is proposed, based on the hydraulic, mechanical, and electric subsystems, to define the PAT-SEIG operational area to maximize energy conversion and system efficiency. These limits depend highly on the capacitor value, rotational speed, and electric load. In addition, an analytical model is proposed to estimate the PAT-SEIG operation under specific conditions. With this, water managers can design and optimize an off-grid PAT-SEIG system and define the best hydraulic machines, electronic equipment, and control elements to maximize energy conversion within the target of operational limits. Two micro PAT-SEIG setups were implemented in the hydraulic laboratory of IST/CERIS under typical operating conditions to validate the proposed methodology. The system's maximum efficiency and operational limits can be adapted using different capacitor values for the excitation of the SEIG. Considering the nominal efficiencies of the system's components, the maximum p.u. efficiency obtained for each PAT-SEIG system was between 0.7 and 0.8 p.u. [ABSTRACT FROM AUTHOR]

This study assesses the viability of employing a hybrid system that combines wind and tidal turbines, connected to a microgrid, to provide electricity to coastal communities that are geographically isolated from the primary power grid. The specific focus of this research is the case study of Stewart Island, where the cost of electricity from a centralized diesel power station is comparatively higher than that of the main grid in New Zealand. While lithium‐ion batteries are generally regarded as more reliable and efficient than lead‐acid batteries, the analysis conducted indicates that, for the off‐grid storage system in Oban, lead‐acid batteries are the preferable choice. Multiple off‐grid configurations are simulated utilizing the HOMER Pro software. While lithium‐ion batteries demonstrate higher charge power and renewable fraction, it is found that lead‐acid batteries, with their longer battery life, offer advantages such as reduced fuel consumption, lower cost of electricity, discounted payback, and increased power production. The annual fuel consumption for lead‐acid battery is 867 L less compared to the lithium‐ion battery. Power generated in this case is 6780 kWh more and COE with lead‐acid battery is $0.213 in compared with lithium‐ion of $0.217. These findings suggest that for the specific context of the Oban off‐grid system, lead‐acid batteries outperform lithium‐ion batteries. [ABSTRACT FROM AUTHOR]

Abstract Off‐grid solar systems provide clean and affordable energy sources. Adoption of off‐grid Solar energy is becoming increasingly popular in Kenya as a source of renewable energy, with an estimated 10 million people using off‐grid solar power systems as of the end of year 2022. However, the rising off‐grid solar systems technology uptake comes with a growing amount of solar e‐waste, which can have harmful environmental and health effects if not managed properly. Current data on the exact amount of solar e‐waste being generated in Kenya is unavailable and this amount will continue to rise with the expiry of many of these off‐grid solar systems lifespans. This study through stakeholder's workshop and document review data collection and analysis approaches, established that Kenya just like many countries in the Global South has a robust general waste policy and regulation management framework. However, it lacks specific policies and regulations on off‐grid‐solar electronic waste management a challenge that many countries in the Global North have made considerate steps in addressing. In addition, there is a lack of awareness of the hazardous nature of off‐grid solar systems' e‐waste components to both consumers and institutions of governance. There is a lack of adequate infrastructure and sufficient systems for off‐grid solar e‐waste management in the country. Enforcement and implementation challenges of the existing general waste regulations due to limited resources and capacity and corruption culture are major impending factors. This calls for the development of effective policies and regulations to ensure sustainable off‐grid solar e‐waste management in Kenya against the backdrop of the rising uptake of off‐grid solar systems.

Hybrid microgrids, integrating local energy resources, present a promising but challenging solution, especially in areas with limited or no access to the national grid. Reliable operation of off-grid energy systems necessitates sustainable energy sources, given the intermittent nature of renewables. While fossil fuel diesel generators mitigate risks, they increase carbon emissions. This study assesses the viability of integrating a very small modular renewable energy reactor into a microgrid for replacing conventional diesel generators, substantially curbing greenhouse gas emissions. A comprehensive analysis, including design and economic evaluation, was conducted for an off-grid community microgrid with an annual generation and load of 8.5 GWh and 7.8 GWh, respectively. The proposed microgrid configurations incorporate very small modular reactors, alongside solar, wind, and battery storage systems. MATLAB modeling and simulation across eight cases, accounting for seasonal variations, demonstrate the technical and economic feasibility of case 7. This configuration, integrating modular reactors, photovoltaics, wind turbines, and battery storage, satisfactorily meets load demands. Notably, it boasts a high internal rate of return up to ∼31% and a shorter payback period of around 4 years compared to alternative scenarios.

Abstract In recent years, Electric Vehicles are becoming more popular. The pollution level in the atmosphere can be effectively minimized by using Electric vehicles for large-scale transportation. A battery station is required for continuous operation; however, the Photovoltaic-based OFF grid charging station can only operate during the day. Therefore, the three-port converters have started to arise from a number of current EV charging station developments. In this study, a unique PWM and Phase Shift Controller are proposed to reduce switching losses and to improve reliability. In addition, for Maximum PowerPoint Tracking, a Fuzzy is added to the PV system. Furthermore, an appropriate interleaved boost converter topology is used to create the various charging voltages required for EV and battery stations. The proposed topology is simulated, and the hardware prototype has been created and tested. The result shows that the proposed topology has a better efficiency than the traditional converters. Article Highlights. A dual composite charging station for electric vehicle charging in environment friendly manner. Optimization of power electronics required in Electric Vehicle charging stations. Maximum utilization of battery for cyclic charging from charger and discharging through Electric Vehicles.

The electricity production from Renewable Energy (RE) in isolated locations requires long-term energy storage systems. To that end, Hybrid Energy Storage Systems (HESS), through a combination of hydrogen and batteries, can benefit from the different advantages of both technologies. This paper presents a hybrid Power-to-Power (PtP) Optimal Power Dispatch (OPD) model for isolated systems with no electric grid access. Currently, the electricity supply in such cases is usually based on a mix of RE as the primary energy source sustained by a diesel genset acting as a backup generator. In this context, the model delivers the hourly energy flows between renewable production sources, energy storage devices and the electrical load, which minimises costs and Green House Gases (GHG) emissions. For validation purposes, the model was tested through its application to a case study in an isolated area in the Canary Islands, Spain. The results show that the algorithm calculates the hourly OPD successfully for a given plant sizing, considering the defined operational states of the different assets. These operational constraints showed a decrease in the PtP round-trip efficiency of 5.4% and a reduction of the hydrogen production of 9.7%. Finally, the techno-economic analysis of the results proves that the combination of hydrogen and batteries with RE production is a feasible alternative to phasing out fossil fuels for the selected case study – reducing the diesel generator usage down to 1.2% of the yearly energy supply. • Novel multi-state optimal power dispatch model for power-to-power energy systems. • Multi-year techno-economic evaluation of an off-grid case study. • Phasing out fossil fuels with renewable energy-based hybrid energy storage systems. • Hydrogen technology contributes to a lower levelized cost of energy. • High initial investment cost was a significant entry barrier to deploying hydrogen. [ABSTRACT FROM AUTHOR]

Growing concerns about the climate change accompanied with energy crisis due to the unrest in the world have pushed the energy market to utilize sustainable and secure alternatives such as solar photovoltaics (PV). However, for residential consumers, the primary concerns are the reliability of the supply and the cost of PV-generated electricity. This study reports on the economic feasibility and technical analysis of PV systems in megacities worldwide. Nine mega cities, Beijing, Berlin, Istanbul, London, New Delhi, New York, Paris, Seoul, and Tokyo, have been selected based on their significant population sizes and the pronounced demand for electricity independence among residents. The annual production, load matching, and PV-electricity and battery dispatch are discussed, with Lazard's levelized cost of electricity (LCOE) and net present value (NPV) employed as economic indicators. While calculated LCOEs ranged from $0.084/kWh to $0.27/kWh across different cities, the NPVs were predominantly negative, varying approximately between –$2,000 and –$20,000, with Berlin as an exception. Finally, a sensitivity analysis was conducted, revealing that the LCOE is more sensitive to financial parameters than to module efficiency and irradiation. [ABSTRACT FROM AUTHOR]

Smart urbanism is an established research area in geography and the social sciences. We draw on 'worlding-provincialising' strategies identified in an Urban Studies Special Issue from February 2021 to explore how smart infrastructures, a form of smart urbanism, disrupt representations of informality and urban development in new and productive ways. Focussing on the disruptive or troublesome implications of smart infrastructures reveals site-level considerations for developing policy and practice, where acknowledging the nuanced context for its use can present opportunities for not only understanding energy transitions in the Global South, but also creates opportunities for cross-learning. Drawing on our collective insights on a solar mini-grid project in Qandu-Qandu, Cape Town, we sketch out three ways the disruptive aspects of solar energy can be helpful for re-building knowledge on the informal city by: (i) re-positioning notions of 'formal' and 'informal' infrastructure(s) in urban planning and policymaking; (ii) highlighting new avenues for citizen autonomy; and (iii) recasting the informal city as a site for continuous innovation and learning. [ABSTRACT FROM AUTHOR]

For an energy transformation project with emerging technologies to be viable and sustainable, it requires community participation, the social appropriation of the knowledge of the technology to be implemented, and the assessment of its social and environmental impact. In this context, this research carried out a diagnostic study on the energy consumption of ethnic communities belonging to National Natural Parks in the Colombian Pacific in order to provide indicators of the potential and relevance of portable photovoltaic solar energy for small-scale energy supply in these communities. For this purpose, four strategic sites in the district of Buenaventura were selected to implement questionnaires to collect technical data on demographic characterization (age, occupation, ethnicity, educational level, residence time), solar exposure, architectural infrastructure, energy sources, use of electrical elements, and energy consumption. The study focused on five sectors of interest: (i) housing, (ii) microenterprises, (iii) schools, (iv) health centers, and (v) boats. Fuelwood and diesel were found to be the main sources of energy in the region; this represents continuous pollution of gases and noise. Electricity is supplied mainly through diesel power generators with a cost per kWh higher by 86% than the average value in the interconnected area. It was identified that the most representative economic activities of these communities are fishing, and other activities associated with tourism; therefore, after diagnosing the use of low-power electrical elements in different types of boats, we propose a portable photovoltaic solar system adjusted to local environmental conditions and the needs of artisanal fishing. [ABSTRACT FROM AUTHOR]

Copyright of Automatisierungstechnik is the property of De Gruyter and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Shanghai Jiaotong University (Science) is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In recent years, Electric Vehicles are becoming more popular. The pollution level in the atmosphere can be effectively minimized by using Electric vehicles for large-scale transportation. A battery station is required for continuous operation; however, the Photovoltaic-based OFF grid charging station can only operate during the day. Therefore, the three-port converters have started to arise from a number of current EV charging station developments. In this study, a unique PWM and Phase Shift Controller are proposed to reduce switching losses and to improve reliability. In addition, for Maximum PowerPoint Tracking, a Fuzzy is added to the PV system. Furthermore, an appropriate interleaved boost converter topology is used to create the various charging voltages required for EV and battery stations. The proposed topology is simulated, and the hardware prototype has been created and tested. The result shows that the proposed topology has a better efficiency than the traditional converters. Article Highlights. A dual composite charging station for electric vehicle charging in environment friendly manner. Optimization of power electronics required in Electric Vehicle charging stations. Maximum utilization of battery for cyclic charging from charger and discharging through Electric Vehicles. [ABSTRACT FROM AUTHOR]

Direction-of-arrival (DOA) estimation problem is one of the most important tasks for array signal processing. Conventional methods are limited by either the computational complexity or the resolution. In this paper, a novel deep learning (DL) framework for super-resolution DOA estimation is developed, where the grid mismatch problem is fully considered into the DL DOA estimation and the offset between the real DOA and the discrete sampling grid is thereby trained as a part of the network output. Specifically, we first model the DOA estimation problem as a multi-classification task and obtain the on-grid estimation result with a resolution of 1° as the first output. Then we designed another regression module to estimate the offset between target angles and the corresponding grids. By combining both on-grid and offset estimation results, the accurate off-grid estimation is achieved. In addition, the method of fusing low-level features and high-level features by skip connection is adopted between the on-grid estimation module and the offset estimation module. The high-level features in the first part of the network are combined with the original input to improve the training speed and the estimation accuracy. Herein, our training dataset contains a large number of off-grid signal data, which is close to the practical application. Also, the utilization of the off-grid part information improves DOA estimation performance compared to existing DL-based methods, achieving more accurate DOA estimations. Numerous simulation results have demonstrated the superiority of the proposed method in DOA estimation precision, and a good performance advantage maintains even when using a limited number of snapshots. Further, we test the proposed method on the real millimeter-wave radar system, and it outperforms the other state-of-the-art methods, especially for two adjacent targets in the same range and Doppler bin. [ABSTRACT FROM AUTHOR]

Recently, deep unfolding networks have been widely used in direction of arrival (DOA) estimation because of their improved estimation accuracy and reduced computational cost. However, few have considered the existence of a nested array (NA) with off-grid DOA estimation. In this study, we present a deep sparse Bayesian learning (DSBL) network to solve this problem. We first establish the signal model for off-grid DOA with NA. Then, we transform the array output into a real domain for neural networks. Finally, we construct and train the DSBL network to determine the on-grid spatial spectrum and off-grid value, where the loss function is calculated using reconstruction error and the sparsity of network output, and the layers correspond to the steps of the sparse Bayesian learning algorithm. We demonstrate that the DSBL network can achieve better generalization ability without training labels and large-scale training data. The simulation results validate the effectiveness of the DSBL network when compared with those of existing methods. [ABSTRACT FROM AUTHOR]

Hydrogen-based Fuel Cells (FCs) hold significant potential as energy conversion technologies. In a previous study, we presented a pump-based hydrogen generator (PHG) that utilizes a catalytic reaction between sodium borohydride (NaBH4) powder and water. The pump circulates the water solution through the powder chamber in a closed-loop reaction. The PHG demonstrated clear advantages over alternative hydrogen sources in terms of both safety and energy density. However, as operating time increases, the solution in the closed-loop PHG becomes saturated, causing the reaction rate to decline. This limitation can be overcome in cases where an external water source is available, such as marine vehicles, drones equipped with water recovery systems from their fuel cells, or systems located near pipelines. In such scenarios, introducing freshwater feeding and product emission offers intriguing possibilities for significantly enhancing the fuel's energy density and extending its effective operation time.Our current research introduces an innovative concept: a dual-cycle generator (DCG) that effectively overcomes the issue of solution saturation over time. It achieves this by combining solution circulation with freshwater feeding and product emission. Our study employed a DCG prototype to examine various operating modes and to demonstrate the effectiveness of this approach. The DCG achieved a calculated energy density for the fuel of 3868 Wh/kg, with 93% H2 extraction yield from the powder. Our findings reveal substantial improvements in terms of extended operation duration (81%), increased hydrogen flow rate (36%), enhanced energy density (33%), and improved H2 yield extraction from the powder (39%). This methodology holds promise for mobile applications or off-grid systems situated in proximity to a water source.

Container Based Sanitation (CBS) is seen, by some, as a sustainable sanitation 'solution' for informal settlements. Presented as a cost-effective form of improved, safely managed, affordable, and water-saving sanitation, proponents argue that it not only enhances safety for vulnerable groups, but that it can also be funded through innovative market and circular economy solutions. The City of Cape Town (CoCT) provides CBS on a large scale to informal settlements for free. Yet residents are notoriously unhappy with CBS. This paper is based on two years of fieldwork in BM Section, Khayelitsha, Cape Town, which included transect walks, participant observation, engagement with community leaders and civil society activists, and in-depth interviews with 42 respondents including BM Section residents, City of Cape Town officials, and private sector contractors. The paper applies the concept of infrastructural citizenship to examine the provision of Portable Flush Toilets (PFTs), a form of CBS, in Khayelitsha. Our data reveals conflicted views in relation to the (non)adoption of CBS, which are deeply entwined with frustration at the unmet promises of the post-apartheid state. At face value, CBS in Cape Town is an acceptable and successful form of sanitation for informal settlements. However, this paper suggests that this is an illusion. Our case study reveals that PFTs are experienced as neither a dignified nor a sustainable sanitation solution. This paper shifts the debate surrounding the adequacy and nature of sanitation provision in informal settlements, from focusing on material technological systems to the complexity of sanitation-related infrastructural citizenship

Abstract Rural electrification is a crucial component of meeting sustainable development goals. In Pakistan, load shedding and power outages are frequent. According to the current data, Pakistan is experiencing a shortfall of power between 6000 and 6500 MW. Microgrid technology has the potential to provide a solution to this problem in an efficient and low‐cost manner. This paper proposes the development of a hybrid microgrid system (HMGS) for rural communities. For that purpose, a technological analysis of the HMGS system for rural electrification is performed. Solar photovoltaic (PV) and wind resource‐based renewable energy systems are considered in this work for the electrification of rural areas of Pakistan. A hybrid PV/wind system is designed using MATLAB software. Simulation results show that a 230‐V sinusoidal output voltage has been produced by the proposed model. The advantage of this model is that it minimizes the impact of transients and provides a sinusoidal output waveform.

This paper describes test results of two sets of VRLA GEL batteries that included various phenomena which might accelerate their degradation process in off-grid PV systems like: incomplete charges (bad recharges), low start current and remaining in partially discharge state. The test shown in the paper included two cycling experiments lasting 45 days and 98 days during which the batteries where constantly charged and discharged in different cycles. The results show strong acceleration of degradation process for incomplete charges (bad recharges) which are specifically difficult to avoid in off-grid systems. In order to avoid the premature destruction of lead–acid battery in off-grid PV systems the hybrid battery system consisting of lithium-iron-phosphate and lead–acid batteries connected with DC/DC converter is proposed.

The off-grid inverter with the inverter side voltage as the feedback parameter has the advantages of a single voltage loop, simple control parameter design, and low cost. But the output voltage accuracy is not enough. A single-stage off-grid inverter with feedforward control is recommended to improve the output voltage accuracy. It has a higher voltage regulation rate compared to the proportional–integral (PI) control and it can track a given AC signal at any frequency compared to the proportional-resonant (PR) control. Bus capacitors can employ thin-film capacitors for improved reliability and higher power density and the voltage stress on power devices can be decreased by controlling the intermediate bus voltage to a non-constant value. The working principle is explained. The design principles of the parameters are provided and the external characteristics and stability of the system are analyzed. A simulation model was built to verify the control strategy for improving voltage accuracy and decreasing voltage stress.

Researchers have recently shown an increased interest in estimating the direction-of-arrival (DOA) of wideband noncircular sources, but existing studies have been restricted to subspace-based methods. An off-grid sparse recovery-based algorithm is proposed in this paper to improve the accuracy of existing algorithms in low signal-to-noise ratio situations. The covariance and pseudo covariance matrices can be jointly represented subject to block sparsity constraints by taking advantage of the joint sparsity between signal components and bias. Furthermore, the estimation problem is transformed into a single measurement vector problem utilizing the focused operation, resulting in a significant reduction in computational complexity. The proposed algorithm's error threshold and the Cramer-Rao bound for wideband noncircular DOA estimation are deduced in detail. The proposed algorithm's effectiveness and feasibility are demonstrated by simulation results.

Liberia, a developing nation, faces significant challenges in its energy sector, with limited access to electricity and heavy reliance on traditional biomass and imported fossil fuels. This review explores Liberia's energy landscape, policies, challenges, and opportunities, aiming to identify ways to improve energy access and foster sustainable development. Our methodology employed a systematic search strategy, examining relevant literature from various sources, encompassing research articles, reports, and studies related to Liberia's energy landscape from 2010 onward. Our findings indicate that Liberia's energy mix is historically dominated by traditional biomass fuels such as firewood and charcoal, accounting for more than 80 % of the country's total energy consumption. Petroleum products, including gasoline and diesel, contribute to about 10 % of energy consumption, while hydroelectric power makes up just over 6 %. The remaining energy comes from various sources, including solar energy. This heavy reliance on traditional biomass and limited access to affordable energy has significant social and economic implications. Efforts have been made in recent years to improve Liberia's energy situation. Yet, significant challenges, including financial constraints, inadequate infrastructure, affordability issues, and an outdated energy policy, continue to hinder progress. However, the review identifies opportunities for improving energy access, including abundant renewable energy resources, international support, public-private partnerships, off-grid solutions, and energy efficiency measures. Additionally, regular reviews and updates of policies, informed by accurate data and forward-looking strategies, are also essential to ensure that the energy sector remains aligned with changing circumstances and technological advancements.

The use of renewable energy resources for off-grid electricity production has gained more importance in recent decades for meeting the energy needs of remote areas, even with limited resources. This research aims to provide an optimized and cost-effective approach for generating electricity in rural areas. By using current methodology, a stand alone energy source of PV is designed for development of NZE village. Solar irradiance of the selected location is 6.16 kWh/m2/day while the estimated electric load data for whole village is 64.259 kWh. Electric load and solar irradiance of the loaction is used in the Hybrid Optimization Model for Electric Renewable (HOMER) to design and analyze the techno-economic feasibility of the stand alone PV system to meet the load requirements. The study obtained the total Net Present Cost (NPC) of $0.511 M and the Cost Of Electricity (COE) is 2.26$/unit through the HOMER analysis, which is further refined by performing sensitivity analysis using parameters such as PV panel price, battery price, solar irradiance, variations in electric load and discount rates. According to the results, system is feasibile by annual electricity production of 30,078 kWh with initial capital investment of $0.434 M. This analysis compared the system performance and showed that it is economically and technically viable to meet the complete electricity needs of the village with a payback period of 7.2 years. Research can be utilized for policy making and implementation of NZE approach in remote areas by the government.

The increased utilization of non-renewable energy during the last century has influenced the climate, with increased carbon dioxide emissions and elevated temperature as a result. Thus, the need to develop and demonstrate new sustainable solutions regarding both energy supply and consumption, but also energy system optimization, is obvious. This case study presents the nano-size off-grid energy system at the Meteoria visitor center in Ostrobothnia, Finland, and the real-time measuring techniques that have been installed to follow up the energy production and consumption. The Meteoria consists of several buildings, which are open to the public from April to October. The case site is operated by energy derived from wind power, solar power, and a diesel generator (as a backup), with batteries for energy storage. The Internet of Things (IoT) has been retrofitted to the existing energy system to enable energy measurements and follow various electrical parameters in real-time. In addition, a graphical visualization platform open to the public has been developed. In this study, the completeness of data sampling and the IoT system was checked, and the results show high availability of data. Furthermore, various errors/limitations regarding the IoT system were identified. The energy supply/demand at the Meteoria in 2021 was monitored and the challenges regarding the existing energy system in a cold climate zone are discussed as well as the potential role of the Meteoria to function as a living lab.

Aiming at the off-grid application of distributed renewable energy, this study proposes a combined hydrogen, heating and power system based on solar energy, which mainly includes alkaline water electrolysis, metal-hydride hydrogen storage and proton exchange membrane fuel cells. To achieve the best combination of electricity, heat, and hydrogen, four energy management strategies based on mass, energy, and information flow are proposed. Taking an ecological community in Ningbo as the application scenario, the system performance under four control strategies in typical summer and winter days is studied, and the best control strategies in summer and winter are given, respectively. Electricity-led and high-led strategies are recommended for summer and winter, and both strategies can achieve a real-time supply of electric power, heating power, and hydrogen. After a day of operation, the two strategies have surpluses of 0 and 221.5 kW h of electricity, 5706 and 102.16 MJ of heat, and 57 and 17.82 kg of hydrogen, respectively. • A coordinated control system based on three-flow theory is proposed. • Four energy management strategies are proposed to achieve load matching. • Fluctuation characteristics of multi-source heat flow are studied. • The optimal control strategies in winter and summer are obtained. [ABSTRACT FROM AUTHOR]

Rural electrification is a crucial component of meeting sustainable development goals. In Pakistan, load shedding and power outages are frequent. According to the current data, Pakistan is experiencing a shortfall of power between 6000 and 6500 MW. Microgrid technology has the potential to provide a solution to this problem in an efficient and low‐cost manner. This paper proposes the development of a hybrid microgrid system (HMGS) for rural communities. For that purpose, a technological analysis of the HMGS system for rural electrification is performed. Solar photovoltaic (PV) and wind resource‐based renewable energy systems are considered in this work for the electrification of rural areas of Pakistan. A hybrid PV/wind system is designed using MATLAB software. Simulation results show that a 230‐V sinusoidal output voltage has been produced by the proposed model. The advantage of this model is that it minimizes the impact of transients and provides a sinusoidal output waveform. [ABSTRACT FROM AUTHOR]

Container Based Sanitation (CBS) is seen, by some, as a sustainable sanitation 'solution' for informal settlements. Presented as a cost-effective form of improved, safely managed, affordable, and water-saving sanitation, proponents argue that it not only enhances safety for vulnerable groups, but that it can also be funded through innovative market and circular economy solutions. The City of Cape Town (CoCT) provides CBS on a large scale to informal settlements for free. Yet residents are notoriously unhappy with CBS. This paper is based on two years of fieldwork in BM Section, Khayelitsha, Cape Town, which included transect walks, participant observation, engagement with community leaders and civil society activists, and in-depth interviews with 42 respondents including BM Section residents, City of Cape Town officials, and private sector contractors. The paper applies the concept of infrastructural citizenship to examine the provision of Portable Flush Toilets (PFTs), a form of CBS, in Khayelitsha. Our data reveals conflicted views in relation to the (non)adoption of CBS, which are deeply entwined with frustration at the unmet promises of the post-apartheid state. At face value, CBS in Cape Town is an acceptable and successful form of sanitation for informal settlements. However, this paper suggests that this is an illusion. Our case study reveals that PFTs are experienced as neither a dignified nor a sustainable sanitation solution. This paper shifts the debate surrounding the adequacy and nature of sanitation provision in informal settlements, from focusing on material technological systems to the complexity of sanitation-related infrastructural citizenship. [ABSTRACT FROM AUTHOR]

Wireless sensor network (WSN) is one of the important systems in remote operations that are necessary in defence and industrial applications. Powering these systems is critical in the monitoring and control of the systems. Normally these systems often operate off-grid. Solar power is one of the clean and abundant energy that can be harvested to power WSN nodes. Hence it can be used to power the system under hostile environment also. Therefore, the defence and industrial WSN systems can be powered using Solar Photovoltaic Module (PM) along with a suitable converter. This paper explores the working of Solar Powered WSN nodes, that uses Non-Inverting Buck Boost Converter (NIBBC). The proposed model is developed and simulated in MATLAB Simulink for Indian climatic conditions. The output power of the PM along with NIBBC connected is found to supply power with 93.27% efficiency to its load (WSN node) at its Maximum Power Point (MPP). [ABSTRACT FROM AUTHOR]

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As renewable energy (RE) costs decrease, private non-subsidized revenue sources, such as power purchase agreements (PPA), will increase in off-grid areas. This paper's objective is to improve policymakers' and utilities' understanding of PPA's role in mitigating private investors' risks in off-grid areas to accelerate the energy transition. The paper built a PPA dataset for the largest off-grid area in the Philippines and developed novel and efficient techniques to evaluate the risk mitigation ability of a PPA. While oil-based technologies are expensive, they are low-capital-intensive, and the fuel, the bulk of the cost, is passed through to consumers and primarily funded by subsidies. In contrast, the most affordable energy source, RE, requires higher upfront capital investments, financed primarily with equity. Investors chose low-capital-intensive technologies (oil), rehabilitated power plants, and utilized old equipment, all investment decisions to mitigate residual PPA risks, i.e., distribution utilities' low creditworthiness and capital recovery uncertainty. Presenting the investment as a PPA residual mitigation tool is one of the paper's contributions to the literature. The distribution utility needs to reduce investors' uncertainty by covering reasonable investors' costs. Policymakers need to level the playing field between fossil fuels and RE by reducing subsidies and strengthening distribution utility creditworthiness. [ABSTRACT FROM AUTHOR]