Enhancing residential energy access with optimized stand-alone hybrid solar-diesel-battery systems in Buea, Cameroon.

This study examined the optimal size of an autonomous hybrid renewable energy system (HRES) for a residential application in Buea, located in the southwest region of Cameroon. Two hybrid systems, PV-Battery and PV-Battery-Diesel, have been evaluated in order to determine which was the better option. The goal of this research was to propose a dependable, low-cost power source as an alternative to the unreliable and highly unstable electricity grid in Buea. The decision criterion for the proposed HRES was the cost of energy (COE), while the system's dependability constraint was the loss of power supply probability (LPSP). The crayfish optimization algorithm (COA) was used to optimize the component sizes of the proposed HRES, and the results were contrasted to those obtained from the whale optimization algorithm (WOA), sine cosine algorithm (SCA), and grasshopper optimization algorithm (GOA). The MATLAB software was used to model the components, criteria, and constraints of this single-objective optimization problem. The results obtained after simulation for LPSP of less than 1% showed that the COA algorithm outperformed the other three techniques, regardless of the configuration. Indeed, the COE obtained using the COA algorithm was 0.06%, 0.12%, and 1% lower than the COE provided by the WOA, SCA, and GOA algorithms, respectively, for the PV-Battery configuration. Likewise, for the PV-Battery-Diesel configuration, the COE obtained using the COA algorithm was 0.065%, 0.13%, and 0.39% lower than the COE provided by the WOA, SCA, and GOA algorithms, respectively. A comparative analysis of the outcomes obtained for the two configurations indicated that the PV-Battery-Diesel configuration exhibited a COE that was 4.32% lower in comparison to the PV-Battery configuration. Finally, the impact of the LPSP reduction on the COE was assessed in the PV-Battery-Diesel configuration. The decrease in LPSP resulted in an increase in COE owing to the nominal capacity of the diesel generator.

Optimization of hybrid renewable-diesel power plants considering operational cost, battery degradation, and emissions.

Renewable energy sources have immense potential for enhancing environmental sustainability; however, addressing their intermittency and irregularity is vital for optimizing economic benefits within microgrids. Integrating renewable energy systems with energy storage presents a promising solution. This study introduces an innovative energy management system designed for hybrid renewable power stations, incorporating battery energy storage systems and diesel generators. By accounting for battery degradation costs associated with charge depth and lifespan, the study transforms long-term battery expenses into real-time operational costs. The optimization problem is formulated as a mixed integer linear programming framework with the objectives of minimizing operating costs, battery degradation costs, and pollutant gas emissions. Through diverse case studies reflecting various market profiles. The proposed approach demonstrates reductions in overall system costs.

Chemical profiles of PM2.5 emitted from various anthropogenic sources of the Eastern Mediterranean: Cooking, wood burning, and diesel generators.

The chemical profiles of PM2.5 emitted from a non-road diesel generator, wood burning and cooking activities including chicken and beef charcoal grilling and general cooking activities were determined. The characterization included the carbonaceous fraction (OC/EC), water-soluble ions, elements, and organic species comprising n-alkanes, polycyclic aromatic hydrocarbons, carboxylic acids, levoglucosan, dioxins, furans, and dioxin-like polychlorinated biphenyls. The main component in the PM2.5 from the different sources was carbonaceous matter with a mass contribution to PM2.5 of 49% for cooking activities, 53% for wood burning, 66% for beef grilling, 72% for chicken grilling, and 74% for diesel generator with different OC/EC concentration ratios. The analysis of organic compounds contents using diagnostic ratios and indexes showed differences between the sources and revealed specific source markers. The water-soluble ions had the highest contribution in the cooking activities profile with 17% of PM2.5 and the least in the chicken grilling profile (1.1%). Additionally, 29 analyzed elements were identified, and their contribution varied with the sources (ranging from 1% to 11% of PM2.5). These findings could be used to differentiate these sources and could assist in the use of source apportionment methods.

Energy Management Strategy for an Autonomous Hybrid Power Plant Destined to Supply Controllable Loads.

This paper proposes an energy management strategy (EMS) for a hybrid stand-alone plant destined to supply controllable loads. The plant is composed of photovoltaic panels (PV), a wind turbine, a diesel generator, and a battery bank. The set of the power sources supplies controllable electrical loads. The proposed EMS aims to ensure the power supply of the loads by providing the required electrical power. Moreover, the EMS ensures the maximum use of the power generated by the renewable sources and therefore minimizes the use of the genset, and it ensures that the batteries bank operates into the prefixed values of state of charge to ensure their safe operation. The EMS provides the switching control of the switches that link the plant components and decides on the loads' operation. The simulation of the system using measured climatic data of Mostoles (Madrid, Spain) shows that the proposed EMS fulfills the designed objectives.

Modeling of Distributed Generators Resilience Considering Lifeline Dependencies During Extreme Events.

This article derives distributed generators resilience models considering lifeline dependencies during extreme events. The effects on power resilience of storage capacity, fuel delays, and fuel order placements are analyzed. Results indicate that storage capacity has an important role in improving overall power supply resilience as seen by loads. In addition, the presented models provide a quantifiable approach in evaluating fuel delivery resilience. The models facilitate studying fuel scheduling policies and local fuel storage sizing for specified resilience requirements. It is observed that tank autonomy greatly affects the flexibility in employing scheduling policies supplying fuel to generators. Resilience dependence on buffer autonomy is high during the first few days of extreme events, and this could have considerable effects on managing evacuations and rescue operations.

Emissions from a generator fueled by blends of diesel, biodiesel, acetone, and isopropyl alcohol: analyses of emitted PM, particulate carbon, and PAHs.

Biodiesel is one of alternative energies that have been extensively discussed and studied. This research investigates the characteristics of particulate matter (PM), particulate carbon, and polycyclic aromatic hydrocarbons (PAHs) emitted from a generator fueled by waste-edible-oil-biodiesel with acetone and isopropyl alcohol (IPA) addition. The tested biodieselhols consisted of pure diesel oil (D100) with 1-3 vol.% pure acetone (denoted as A), 1-70 vol.% waste-edible-oil-biodiesel (denoted as W), and 1 vol.% pure isopropyl alcohol (the stabilizer, denoted as P). The results show that in comparison to W1D99, W3D97, W5D95, W10D90, and W20D80, the use of biodieselhols achieved additional reduction of PM and particulate organic carbon (OC) emission, and such reduction increased as the addition percentage of pure acetone increased. Regardless of the percentages of added waste-edible-oil-biodiesel, acetone, and isopropyl alcohol, the use of biodieselhol in place of D100 could reduce the emissions of Total-PAHs (by 6.13-42.5% (average = 24.1%)) and Total-BaPeq (by 16.6-74.8% (average = 53.2%)) from the diesel engine generator. Accordingly, the W/D blended fuels (W<20 vol.%) containing acetone (1-3 vol.%) and isopropyl alcohol (1 vol.%) are a potential alternative fuel for diesel engine generators because they substantially reduce emissions of PM, particulate OC, Total-PAHs, and Total-BaPeq.

Discussion on How to Equip Backup Power for Medical Equipment in Hospital / 医疗卫生装备

Backup power should be equipped in hospitals in order to prevent the medical risks.At present,there are three choices of the backup power including UPS,EPS and diesel generator.The principles of three backup powers are introduced.Methods for equipping backup power are also discussed to guarantee the security of power supply system for emergency medical equipment.