Simplified evaluation of energetic complementarity based on monthly average data

Energetic complementarity is a subject that has been holding more and more attention from researchers in recent years, being a concept that can be applied both in energy planning stages and in phases of operation of energy systems based on renewable energy resources. The complementarity between two renewable sources of energy has three components: time-complementarity, energy-complementarity and amplitude-complementarity, and can be determined between raw energy availabilities or between energy generated by power plants. Complementarity can be evaluated between two renewable resources in the same place or between two renewable resources in different places and these two types can be denominated respectively as temporal and spatial complementarity. This method allows simplified evaluation of the energy complementarity between two renewable resources by comparing basic parameters obtained from series of monthly average values that characterize these resources. Finally, an application example clarifies the application of the method

River Model Calibration Based on Design of Experiments Theory. A Case Study: Meta River, Colombia

Numerical models are important tools for analyzing and solving water resources problems; however, a model’s reliability heavily depends on its calibration. This paper presents a method based on Design of Experiments theory for calibrating numerical models of rivers by considering the interaction between different calibration parameters, identifying the most sensitive parameters and finding a value or a range of values for which the calibration parameters produces an adequate performance of the model in terms of accuracy. The method consists of a systematic process for assessing the qualitative and quantitative performance of a hydromorphological numeric model. A 75 km reach of the Meta River, in Colombia, was used as case study for validating the method. The modeling was conducted by using the software package MIKE-21C, a two-dimensional flow model. The calibration is assessed by means of an Overall Weighted Indicator, based on the coefficient of determination of the calibration parameters and within a range from 0 to 1. For the case study, the most significant calibration parameters were the sediment transport equation, the riverbed load factor and the suspended load factor. The optimal calibration produced an Overall Weighted Indicator equal to 0.857. The method can be applied to any type of morphological models

Factors and interactions that influence the pressure drop across an air volume reducing device on low-pressure water distribution networks

Efficient water supply systems are necessary for the development and sustainability of human societies. One relevant aspect of these systems is the metering function, recorded employing water meters, which determines the charges levied to the clients and estimates the water losses in the network. Inaccurate measurements are detrimental for both the client and the supplier. For allowing more precise metering, one option is to use an air volume reducing device, an accessory similar to a check valve that minimizes the air volume entrapped in the pipelines, thus improving metering accuracy. This research used an experimental design to determine the influence of four factors and their interactions on the pressure drop across these devices as a preliminary step for allowing their extended use on low-pressure water supply systems. The results showed that the diameter, the spring stiffness, and the flow rate are significant factors in the pressure drop. The shape of the valve stem is statistically significant only when interacting with other factors

Analysis of delays and cost overruns of road construction projects in the Colombian Caribbean Region

Construction projects are constantly threatened by delays and cost overruns that might compromise their viability. Th us, identifying the leading causes of these issues based on the experience of experienced professionals is essential to planning and reducing these risks. This research evaluates the frequency and severity of variables causing delays and cost overruns in Colombian Caribbean Region road projects. Th e nine causes studied in this research were defined through a literature review, preliminary discussion and a pilot  test. A survey directed to 42 road construction engineers allowed the authors to characterise these professionals’ perceptions regarding the frequency and severity of these variables in terms of delay and cost overruns, with a confi dence level of 80%. Statistical analyses were applied to the results of the survey to establish which variables generate the most signifi cant impacts when building roads and related works in the Colombian Caribbean Regio

Analysis of delays and cost overruns of road construction projects in the Colombian Caribbean Region

Construction projects are constantly threatened by delays and cost overruns that might compromise their viability. Th us, identifying the leading causes of these issues based on the experience of experienced professionals is essential to planning and reducing these risks. Th is research evaluates the frequency and severity of variables causing delays and cost overruns in Colombian Caribbean Region road projects. Th e nine causes studied in this research were defined through a literature review, preliminary discussion and a pilot test. A survey directed to 42 road construction engineers allowed the authors to characterise these professionals’ perceptions regarding the frequency and severity of these variables in terms of delay and cost overruns, with a confidence level of 80%. Statistical analyses were applied to the results of the survey to establish which variables generate the most significant impacts when building roads and related works in the Colombian Caribbean Region.Revisión por pare

Economic analysis and optimization of a renewable energy based power supply system with different energy storages for a remote island

This study investigates and compares the various combinations of renewable energies (solar, wind) and storage technologies (battery, pumped hydro storage, hybrid storage) for an off-grid power supply system. Four configurations (i.e., single RE source system, double RE source system, single storage, and double storage system) based on two scenarios (self-discharge equal to 0% and 1%) are considered, and their operational performance is compared and analyzed. The energy management strategy created for the hybrid pumped battery storage (HPBS) considers that batteries cover low energy surplus/shortages while pumped hydro storage (PHS) is the primary energy storage device for serving high-energy generations/deficits. The developed mathematical model is optimized using Particle Swarm Optimization and the performance and results of the optimizer are discussed in particular detail. The results evidence that self-discharge has a significant impact on the cost of energy (13%–50%) for all configurations due to the substantial increase in renewable energy (RE) generators size compared to the energy storage capacity. Even though solar-wind-PHS is the cost-optimal arrangement, it exhibits lower reliability when compared to solar-wind-HPBS. The study reveals the significance of HPBS in the off-grid RE environment, allowing more flexible energy management, enabling to guarantee a 100% power supply with minimum cost and reducing energy curtailment. Additionally, this study presents and discuss the results of a sensitivity analysis conducted by varying load demand and energy balance of all considered configurations is performed, which reveals the effectiveness of the supplementary functionality of both storages in hybrid mode. Overall, the role of energy storage in hybrid mode improved, and the total energy covered by hybrid storage increased (48%), which reduced the direct dependency on variable RE generation

Roads of the Caribbean: regional analysis from Environmental Impact Assessments in Colombia

The road infrastructure produces several impacts on the environment. In the Colombian Caribbean region, the growing road infrastructure threatens systems equilibrium in diverse and not well-known ways. Despite the several administrative tools available in Colombian legislation to manage every project impact, the big picture of the interconnected regional ecosystems falls out of scope. To study the large-scale problems in landscape, we analyzed eight Environmental Impact Studies of road construction projects in the region. We did a scientific and institutional literature review to shed light on the possible unseen problems and future challenges. Results suggest that Environmental Impact Assessments for each project focus on construction processes, ignore accumulative and residual effects, and use typified measures to cover a broad set of impacts. We offer recommendations from an integrated analysis perspective for future projects to understand landscape and water systems alteration at the regional scale

Dataset after seven years simulating hybrid energy systems with Homer Legacy

Homer Legacy software is a well-known software for simulation of small hybrid systems that can be used for both design and research. This dataset is a set of files generated by Homer Legacy bringing the simulation results of hybrid energy systems over the last seven years, as a consequence of the research work led by Dr. Alexandre Beluco, Federal University of Rio Grande do Sul, in southern Brazil. The data correspond to twelve papers published in the last seven years. Two of them describe hydro PV hybrid systems with photovoltaic panels operating on the water surface of reservoirs. One of these twelve papers suggests the modeling of hydropower plants with reservoirs and the other the modeling of pumped hydro storage, and a third still uses these models in a place that could receive both the two types of hydroelectric power plant. The other simulated hybrid systems include wind turbines, diesel generators, batteries, among other components. This data article describes the files that integrate this dataset and the papers that have been published presenting the hybrid systems under study and discussing the results. The files that make up this dataset are available on Mendeley Data repository at https://doi.org/10.17632/ybxsttf2by.2