Editorial special issue on "Energetic Complementarity"

This editorial presents the motivations that were the focus of the papers that make up this Special Issue on energetic complementarity. The articles deal with the application of the concept of energetic complementarity in time under certain conditions and with the proposition of new means to evaluate complementarity in time between more than two renewable energy resources. An article further proposes a method for establishing energetic complementarity in space, a concept that is important and necessary for management and planning of energy resources but does not yet have tools that allow it to be quantified and handled appropriately. In addition, two letters to the editor discuss issues that still need to be matured for a better understanding and application of the concept of energetic complementarity, both in time and space

Modeling NYSE Composite US 100 Index with a Hybrid SOM and MLP-BP Neural Model

Neural networks are well suited to predict future results of time series for various data types. This paper proposes a hybrid neural network model to describe the results of the database of the New York Stock Exchange (NYSE). This hybrid model brings together a self organizing map (SOM) with a multilayer perceptron with back propagation algorithm (MLP-BP). The SOM aims to segment the database into different clusters, where the differences between them are highlighted. The MLP-BP is used to construct a descriptive mathematical model that describes the relationship between the indicators and the closing value of each cluster. The model was developed from a database consisting of the NYSE Composite US 100 Index over the period of 2 April 2004 to 31 December 2015. As input variables for neural networks, ten technical financial indicators were used. The model results were fairly accurate, with a mean absolute percentage error varying between 0.16% and 0.38%

Bases for a methodology assessing time complementarity in space

Energetic complementarity has been studied in recent years and can be an important tool for managers to decide on the design and operation of hybrid systems based on renewable energy resources. Complementarity is an ability presented by two or more energy resources to complement each other over time. Complementarity can be verified in one place or at different places. This second case can be termed as spatial complementarity and is more complex than the complementarity in the same place, requiring a specific approach for its quantification This paper discusses concepts related to energetic complementarity and presents the basis for a method to evaluate energetic timecomplementarity across space, applying the concepts presented to the northern coast of the state of Rio Grande do Sul, the southernmost state of Brazil

A 'feasibility space' as a goal to be achieved in the development of new technologies for converting renewable energies

This method article proposes the establishment of a feasibility space as an objective to be achieved during the development of new technologies to convert energy from renewable resources. The feasibility space can also be a reference when designing an energy system based on renewable resources. The feasibility space is a set of parameter values for the design stage that define the economic and technical feasibility of an energy system or a new technology, which must be satisfied when the energy system comes into operation or when the new technology for converting power goes into operation. The study of possible feasibility spaces allows characterizing energy systems or new technologies as attractive investments, or on the other hand, as unfeasible ventures

Simulating hybrid energy systems based on complementary renewable resources

The complementarity between energy resources can influence the performance of hybrid generation and storage systems, and can also decisively influence their design. Renewable resources may have intermittent characteristics that make the study of the influence of complementarity on the performance of hybrid systems quite difficult. The establishment of a performance limit of hybrid systems based on renewable resources and the study of the effects of complementarity considering this limit can provide interesting results. This performance limit can be established with an idealization of the mathematical functions describing the energy availability of the explored renewable resources. This article presents a method for analyzing the performance of hybrid systems based on complementary resources. The method allows to evaluate the influence of different levels of complementarity between the exploited resources on the cost of energy and capacity shortage. Utilizing idealized energy availability, the result sets a performance limit

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

A ’feasibility space’ as a goal to be achieved in the development of new technologies for converting renewable energies

This method article proposes the establishment of a feasibility space as an objective to be achieved during the development of new technologies to convert energy from renewable resources. The feasibility space can also be a reference when designing an energy system based on renewable resources. The feasibility space is a set of parameter values for the design stage that define the economic and technical feasibility of an energy system or a new technology, which must be satisfied when the energy system comes into operation or when the new technology for converting power goes into operation. The study of possible feasibility spaces allows characterizing energy systems or new technologies as attractive investments, or on the other hand, as unfeasible ventures. - The method proposes to establish a goal to achieve during the development of technologies for energy conversion. - The method provides a benchmark for both the stages of design and development of generation systems and new technologies. - The feasibility space constitutes a planning tool for power systems based on renewable resources of any size