Alexandre Barin

Multicriteria decision making for management of storage energy technologies on renewable hybrid systems - the analytic hierarchy process and the fuzzy logic

Worldwide, several studies have investigated many proposals for the use of hybrid systems as alternative energy sources, operating together with energy storage technologies. Accordingly, there are large concerns about the use of appropriate methods to evaluate the application of renewable energy sources and storage energy systems. Thus, it is important to observe that the renewable hybrid systems are environmental friendly, having as consequence governmental incentives for their development in many countries, like Brazil. This paper presents a methodology taking as basis the theory developed by Saaty -- the Analytic Hierarchy Process (AHP method) - and multi-rulesbased decision and multi-sets considerations applied using fuzzy logic. By exploiting a multi-criteria decision making, this methodology evaluates the operation of storage energy systems such as: compressed air energy storage (CAES), pumped hydro storage (PHS), H2 storage, flywheel and super-capacitors. In addition, different scenarios are investigated concerning environment impacts and costs. For the purpose of the study, these five different energy storage technologies are evaluated objectifying to find the most appropriate storage energy system for different scenarios, always considering the desirable criteria, namely: efficiency, costs, technical maturity, environmental impacts, power application range and lifecycle.

Selection of storage energy technologies in a power quality scenario — the AHP and the fuzzy logic

In response to the escalating energy crisis and related pollution problems verified worldwide, it is essential to assume new energy technologies that use renewable energy sources in an efficient and environmentally friendly manner. However, widespread implementation of these sources will be more attractive only if they operate together with energy storage technologies. Besides, a successful storage energy selection is essential to deal with some mismatches among costs, efficiency and power quality constrains. This paper presents a methodology taking as basis the AHP (Analytic Hierarchy Process) and fuzzy logic. By exploiting a multi-criteria decision making, this methodology evaluates the operation of storage energy systems such as: pumped hydro storage (PHS), compressed air energy storage (CAES), H2 storage, flywheel and super-capacitors. The main objective of the study is to develop a multicriteria analysis to find the most appropriate storage energy system concerning a power quality scenario. For this, the criteria in analysis are: efficiency, load management, technical maturity, costs, lifecycle and power quality. Considerations and results described in this paper are part of the Research & Development Program undertaken by the Federal University of Santa Maria, Brazil.

Methodology for placement of Dispersed Generation Systems by analyzing its Impacts in Distribution Networks

The Brazilian electric systems need the development of new researches and tools, in order to obtain a logic solution to maintain and improve the reliability and the quality of the power delivered to customers. The study of the appropriate connection of dispersed generation sources is an essential topic to be analyzed, since this process may provide positive impacts along the feeders. The main effects of the DG operation inside a distribution system model are here analyzed through the software DigSilent®, considering power losses and voltage levels. Moreover, a multi-objective methodology - Bellman-Zadeh algorithm and membership fuzzy functions - is used for evaluating quantitative and qualitative parameters. The main objective of the paper is finding the appropriate DG placement inside a distribution system model. It is important to observe that the methodology presented in this study can be applied to distribution system feeders to find in which feeder will be the most appropriate DG location, as well to any node inside a determined feeder providing a specific place for the appropriate DG site.

Storage energy management with power quality concerns the analytic hierarchy process and the fuzzy logic

In view of current and foreseeable energy shortage and environmental scenario, the exploitation of renewable energy sources offer great potential to satisfy the energy lack and to decrease the dependence on fossil fuel, also reducing global warming caused by CO2 emissions. However, widespread implementation of these sources will be more attractive only if they operate together with energy storage technologies. Besides, an effective storage energy management is essential to deal with some mismatches among power quality, efficiency, costs and environmental constrains. This paper presents a methodology taking as basis the analytic hierarchy process and fuzzy multi-rules and multi-sets. By exploiting a multi-criteria decision making, this methodology evaluates the operation of energy storage systems such as: pumped hydro storage (PHS), compressed air energy storage (CAES), H2 storage, flywheel, super-capacitors, lithium-ion and NaS advanced batteries and VRB flow battery. The main objective of the study is to develop a multicriteria analysis to find the most appropriate energy storage system concerning a power quality priority. For this, the criteria in analysis are: efficiency, load management, technical maturity, costs, environment impacts and power quality. Considerations and results described in this paper are part of the Research & Development Program undertaken by the Federal University of Santa Maria, Brazil.

Assessment of the smart grids applied in reducing the cost of distribution system losses

The distribution systems need to adjust and intensify the use of new available technologies and incorporate intelligence to combat non-technical loss processes. Its detection is one of the greatest challenges to energy distribution companies. Studies and research involving load modeling or load estimation (LM/LE) on power system distribution combined with smart grid functionality will help control commercial loses in electric power distribution systems. The use of algorithms is proposed for LM/LE using monthly energy consumption data converted to hourly demand. This information and the remote monitoring consumption data via smart meters will be processed by a computational tool that will indicate the feeder with the greater probability of presenting non-technical losses, with the objective of locating energy fraud, directing companys investment on combating non-technical losses.

Seleção de fontes alternativas de geração distribuída utilizando uma análise multicriterial baseada no método AHP e na lógica fuzzy

This paper presents a methodology for renewable energy sources selection according to the evaluation of the main operational characteristics related with social, economic and environmental aspects. Accordingly, the proposed methodology taking as basis the theory developed by Saaty in the AHP method and multi-rules-based decision and multi-sets considerations applied in the fuzzy logic. By exploiting a multi-criteria decision making, this methodology evaluates the most important energy technologies that make use of renewable primary resources, such as - wind generators, microturbines, photovoltaic cells and fuel cells. For the purpose of the study, these technologies are evaluated with the intention to find the most appropriate renewable energy system for different scenarios, according to the selected criteria, namely: efficiency, costs, technical maturity, environmental impacts, power application range and lifecycle. In conclusion, it is presented a comparison of the final results - renewable energy sources ranking - achieved by the fuzzy logic and the AHP method for environment impacts and costs scenarios.

A Novel Fuzzy-Based Methodology for Biogas Fuelled Hybrid Energy Systems Decision Making

In response to the soaring energy crisis and the related pollution problems worldwide, it is essential to apply new technologies that use renewable energy sources in both an efficient and environmentally friendly manner. In this way, biomass offers one of the largest potential among renewable energy sources. The aim of this work is to demonstrate a novel fuzzy-based methodology for selecting hybrid energy systems fuelled by biogas. Fuzzy multi-rules and fuzzy multi-sets are used to evaluate the main operational characteristics of five types of renewable sources fuelled by biogas. The possibility of using the methodology for energy storage system evaluation is also assessed. The construction of the fuzzy multi-rules and fuzzy multi-sets is based on the following methods: Mamdani (fuzzification process), Max-Min (inference process), and Center of Gravity (defuzzification process). Several criteria are used: costs, efficiency, cogeneration, life-cycle, technical maturity, power application range, and environmental impacts. The methodology considers three different settings with two different constraints: costs and environment. One of the most relevant aspects presented by this work is about the previous classification of the criteria. It was created according to the different relevance observed among the attributes. The purpose of the proposed arrangement is to facilitate the understanding of the methodology and to increase the possibility of incorporating the decision makers’ preferences on the decision-aid process. These aspects are essential to strengthen the final decision.

Fuzzy Multi-Sets and Multi-Rules: Analysis of Hybrid Systems Concerning Renewable Sources with Conventional and Flow Batteries

The increasing market penetration of intermittent renewable resources – as a solution to green power energy production has been resulting in the development of several types of storage technologies, such as: PHS, CAES, Flywheel, and supercapacitors. However, the constant development of different types of batteries both conventional and by flow turns this type of storage system one of the most useful to be applied together with renewable energy sources. This paper uses multi-rules-based decision and multi-sets considerations applied in the fuzzy logic to evaluate the main characteristics of the operation of intermittent renewable sources and batteries. The renewable sources analyzed in this work are wind generators and photovoltaic cells, while the analyzed batteries are Lead Acid, Nickel Cadmium, Lithium ion, Sodium-Sulphur, Vanadium Redox and Polysulphide bromide (flow batteries). These analyses are developed according to the desirable criteria defined to find the most appropriate renewable hybrid system, considering two different scenarios: costs and environment. The selected criteria are: environmental impacts, efficiency, costs, lifecycle, technical maturity and power application range. Index Terms — batteries, fuzzy logic, renewable hybrid system, intermittent renewable sources.

Analysis of the impacts of distributed generation sources considering the appropriate choice of parameters in a multi-objective approach for distribution system planning

Presence of the distributed generation (DG) in electric systems can represent a significant impact on the operational characteristics of distribution networks. This paper presents a study aimed at the appropriate choice of parameters used in a multi-objective analysis considering the optimal DG placement. Thus, this paper develops a multi-objective approach to define qualitative and quantitative parameters using the fuzzy logic and the Bellman-Zadeh algorithm to determine optimal DG location in distribution systems. Therefore, this study allows the energy supplying companies may guarantee an appropriate selection of their own parameters according to an optimal DG location. This also allows a structural rethinking of the electric utility, diversifying and deploying electrical energy sources at many generation sites, thus providing increased planning flexibilities. These locations are determined both for the distribution system feeders, as well as for nodes inside of a given feeder. Considerations and results described in this paper are part of the Research & Development Program developed by the State Company of Electric Energy (CEEE) and the Federal University of Santa Maria (UFSM), Brazil.

Simulation of Transient State Impacts from Low Power DG Aiming at Improving Power Quality and Reliability of Distribution Networks

Presence of independent and self producers in the electric system can represent significant impact on the operational characteristics of distribution networks. Many of these sources, even at low power, may cause significant impacts on the transient state because of switching operations. The main problem is that these effects are not well known yet. New sources connected at the grid will alter the short circuit levels, and may cause bad operation of the protective devices. Thus, it is important to determine precisely these effects originated in the Distributed Generation (DG). In this way, the electric energy companies, independent or self producers, can decide for a standard protection system, to minimize the impacts. The considerations and results described in this paper are integrant parts of the Research & Development Program developed for the State Company of Electric Energy (CEEE) and the Federal University of Santa Maria (UFSM).