Open Access
An energy management system design using fuzzy logic control: smoothing the grid power profile of a residential electro-thermal microgrid
(IEEE, 2021) Arcos Avilés, Diego; Pascual Miqueleiz, Julio María; Guinjoan Gispert, Francesc; Marroyo Palomo, Luis; García Gutiérrez, Gabriel; Gordillo, Rodolfo; Llanos, Jacqueline; Sanchis Gúrpide, Pablo; Motoasca, Emilia; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
This work deals with the design of a Fuzzy Logic Control (FLC) based Energy Management System (EMS) for smoothing the grid power prole of a grid-connected electro-thermal microgrid. The case study aims to design an Energy Management System (EMS) to reduce the impact on the grid power when renewable energy sources are incorporated to pre-existing grid-connected household appliances. The scenario considers a residential microgrid comprising photovoltaic and wind generators, at-plate collectors, electric and thermal loads and electrical and thermal energy storage systems and assumes that neither renewable generation nor the electrical and thermal load demands are controllable. The EMS is built through two low-complexity FLC blocks of only 25 rules each. The first one is in charge of smoothing the power prfile exchanged with the grid, whereas the second FLC block drives the power of the Electrical Water Heater (EWH). The EMS uses the forecast of the electrical and thermal power balance between generation and consumption to predict the microgrid behavior, for each 15-minute interval, over the next 12 hours. Simulations results, using real one-year measured data show that the proposed EMS design achieves 11.4% reduction of the maximum power absorbed from the grid and an outstanding reduction of the grid power profile ramp-rates when compared with other state-of-the-art studies.
Open Access
Fuzzy-based power exchange management between grid-tied interconnected residential microgrids
(IEEE, 2020) Arcos Avilés, Diego; García Gutiérrez, Gabriel; Guinjoan Gispert, Francesc; Ayala, Paúl; Ibarra, Alexander; Motoasca, Emilia; Llanos, Jacqueline; Pascual Miqueleiz, Julio María; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
This paper presents a fuzzy-based power exchange management between two neighboring residential grid-connected microgrids comprising both photovoltaic generation and battery energy storage system (BESS). The proposed power exchange management accounts for the magnitude of the energy rate-of-change of each microgrid and the charge difference between the BESSs of both microgrids to charge the ESS that has an energy deficit. As such, the proposed power exchange management can reduce the amount of power absorbed from the mains of each microgrid by operating jointly with each other rather than separately, and it also synchronizes the ESS of both microgrids, improving the behavior of ESSs. A comparison of the simulated results for a scenario with and without power exchange is presented in order to demonstrate the adequate behavior of the proposed power exchange management.
Open Access
Fuzzy logic-based energy management system design for residential grid-connected microgrids
(IEEE, 2018) Arcos Avilés, Diego; Pascual Miqueleiz, Julio María; Marroyo Palomo, Luis; Sanchis Gúrpide, Pablo; Guinjoan Gispert, Francesc; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Gobierno de Navarra / Nafarroako Gobernua
This paper presents the design of a low complexity fuzzy logic controller of only 25-rules to be embedded in an energy management system for a residential grid-connected microgrid including renewable energy sources and storage capability. The system assumes that neither the renewable generation nor the load demand is controllable. The main goal of the design is to minimize the grid power profile fluctuations while keeping the battery state of charge within secure limits. Instead of using forecasting-based methods, the proposed approach use both the microgrid energy rate-of-change and the battery state of charge to increase, decrease, or maintain the power delivered/absorbed by the mains. The controller design parameters (membership functions and rule-base) are adjusted to optimize a pre-defined set of quality criteria of the microgrid behavior. A comparison with other proposals seeking the same goal is presented at simulation level, whereas the features of the proposed design are experimentally tested on a real residential microgrid implemented at the Public University of Navarre.
Open Access
Integration of wind and PV power in the spanish electric system using existing hydroelectric power
(IEEE, 2024-08-30) Garwa, Asheem; Pascual Miqueleiz, Julio María; Marroyo Palomo, Luis; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
This paper analyses the potential reduction of electric energy generated with fossil fuels with 40 GW of PV power and 40 GW of wind power in the existing Spanish electric system and its integration by making use of existing hydroelectric power and reserves with different levels of flexibility. We use 10-minute data for 2 years and we firstly assume that hydro power remains the same as originally, observing an already high reduction in fossil fuel use in the electric mix. Then we increasingly allow more flexibility in hydro power use, i.e., we allow to use hydro reserves with different time horizons, and we analyze the incremental reduction in fossil fuel generation as we increase this flexibility. We observe that we can obtain notable gains in terms of fossil fuel reduction when increasing flexibility just slightly showing how hydro power can integrate large amounts of variable renewable energy in Spain with only a small change in the reserves profile.
Open Access
Long-term degradation rate of crystalline silicon PV modules at commercial PV plants: an 82-MWp assessment over 10 years
(Wiley, 2021) Pascual Miqueleiz, Julio María; Martínez Moreno, Francisco; García Solano, Miguel; Marcos Álvarez, Javier; Marroyo Palomo, Luis; Lorenzo Pigueiras, Eduardo; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
Due to high competitiveness in the PV sector, despite the low degradation rate of crystalline silicon PV modules (below 0.5%/year), it is still important for utilities to know its actual value due to its impact on energy yield and hence, profitability, over the lifetime of a PV plant. However, uncertainties related to both the influence of downtime periods due to problems that may appear under normal operation of a commercial PV plant and to the measurement of degradation rates at PV plant level make this a challenging task. In order to obtain a significant value, in this paper, three measuring methods with different uncertainty sources are used for 82 MWp of PV modules on different locations in Spain and Portugal over 10 years. According to the different methods used and PV plants analyzed, excluding PV plants with problems, a range of degradation rates between 0.01 and 0.47%/year has been found. The overall average value observed is 0.27%/year. The findings of this work have also revealed the great importance of good operation and maintenance practices in order to keep overall low degradation rates.
Open Access
Intelligent control of wind-assisted PHEVs smart charging station
(MDPI, 2019) Hassan, Syed Zulqadar; Kamal, Tariq; Riaz, Muhammad Hussnain; Shah, Syed Aamir Hussain; Ali, Hina Gohar; Riaz, Muhammad Tanveer; Sarmad, Muhammad; Zahoor, Amir; Khan, Muhammad Abbas; Pascual Miqueleiz, Julio María; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
Two technology opportunities, integration of renewable energy sources and the electrification of vehicles are being encouraged to reduce dependency on fossil fuels and pollution problems. Nevertheless, the huge increase of plug-in hybrid electric vehicles (PHEVs) on roads will cause an additional load in demand, especially at rush hours, and therefore, threatens the stability of existing power grids. Considering PHEV stay for several hours in the workplace, (i.e., university), this may provide an inimitable framework to charge PHEV from wind in the workplace. This paper introduces the possibility of introducing intelligent control of wind power and battery storage units as supplementary power sources for future PHEV charging demands during rush hours. The operation of the proposed algorithm is based on the priority levels of PHEVs charging, and fluctuations in DC link voltage levels due to the variation in wind speed. The priorities of PHEVs charging are developed according to their power requirements, maximum rating of distribution transformer and park duration of PHEVs in the workplace during wind speed. Various non-isolated proportional-integral controllers and improved intelligent fuzzy control are used to keep a minimum critical DC link voltage to permit the power conditioning system to operate a charging station uninterruptedly, even at low wind speed. The improved intelligent fuzzy controller also contributes to minimizing the stress on the DC bus and ensures quality output power. The performance of the proposed charging station is verified for the real PHEV under real-world record of wind speed. All the energy sources, electric charging station and their controllers are designed in MATLAB/Simulink. Finally, the feasibility of proposed charging station is checked experimentally in the laboratory.
Open Access
On the requirements of the power converter for second-life lithium-ion batteries
(IEEE, 2019) Berrueta Irigoyen, Alberto; San Martín Biurrun, Idoia; Pascual Miqueleiz, Julio María; Sanchis Gúrpide, Pablo; Ursúa Rubio, Alfredo; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Gobierno de Navarra / Nafarroako Gobernua
The use of lithium-ion batteries is increasing year after year, especially in the automotive sector. Given the high requirements of electric vehicles, their energy storage systems are discarded when they still have around 70% of its initial capacity. These discarded batteries are being studied as a low-price option for stationary systems, mostly related to renewable energy generation, with lower battery requirements. However, the increasing dispersion of cell capacity detailed in this contribution limits the use of second-life cells if regular battery management systems and power converters. We present in this contribution an experimental comparison of the capacity dispersion between fresh and second-life cells, and detail the relationship between the capacity dispersion and the required BMS functionality. Furthermore, we include the ageing phenomena in the analysis by means of experimental ageing results, given that the capacity dispersion is enlarged as the battery ages. After this, we use this data to quantify advantages and disadvantages of a combined BMS and power converter, based on a multilevel topology, compared to a conventional BMS. The most relevant result, when a 55-cell battery is analysed, is a 65% increase in capacity during its whole second life if the BMS and power converter are combined by means of a multilevel topology. The increased level of complexity required by the combined BMS-power converter architecture is analysed in this contribution, providing a convenient tool for the selection of the most suitable option for each application.
Open Access
Estrategias avanzadas de gestión energética basadas en predicción para microrredes electrotérmicas
(2016) Pascual Miqueleiz, Julio María; Marroyo Palomo, Luis; Sanchis Gúrpide, Pablo; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
El primer objetivo concreto de la tesis consiste en estudiar los perfiles de potencia de los diferentes elementos de la microrred y su interacción, ya sea directa, en el caso de flujos de potencia confluyentes, o indirecta, en el caso de la posible interacción de distintos sistemas (sistema eléctrico y térmico). Este análisis se realiza en el Capítulo 2. El segundo objetivo es el diseño de estrategias de gestión energética para la microrred y evaluación comparativa en base a criterios específicos de calidad. Este objetivo se desarrolla en los Capítulos 3 a 7. En los Capítulos 3 y 4, se desarrollan y analizan estrategias de gestión sin datos de predicción. Las estrategias del Capítulo 3 basan su gestión en el control de la batería en función del balance de potencias instantáneo, mientras que en el Capítulo 4 se desarrollan estrategias de similar estructura, pero basándose en el balance energético diario en la microrred. Consecuencia del análisis de estas primeras estrategias, se verá la necesidad de utilizar predicción de la potencia. Para ello, se analiza en el Capítulo 5 la predicción del consumo y de la generación estudiando por separado los datos medidos por los vatímetros y la estación meteorológica de la microrred, los datos de predicción meteorológica ofrecidos por el servidor utilizado y los modelos físicos que ayudan a transformar los datos de variables ambientales en datos de potencia generada. Posteriormente, en el Capítulo 6 se analizan las ventajas de la utilización de los datos de predicción y cómo utilizarlos, poniéndose en práctica su uso. La estructura del control propuesto es similar a la vista en el Capítulo 4, pero, debido a la naturaleza de los datos de predicción, se desarrolla un nuevo control de la batería basado en el error de la predicción. Este control mejora notablemente los resultados en comparación con los obtenidos en las estrategias previas. No obstante, del análisis de esta estrategia, queda patente la influencia que tiene el sistema térmico sobre el eléctrico, que puede ser negativa si se deja que evolucione de forma independiente. Por el contrario, el sistema térmico puede ser muy beneficioso si la estrategia toma el control del mismo. Así, en el Capítulo 7, se hace uso de una caldera eléctrica gestionable, que hace de nexo entre el sistema eléctrico y el térmico, y un depósito de agua caliente que sirve de almacén de energía térmica. De esta forma, se fusiona la gestión de ambos sistemas creando un único sistema energético, denominado microrred electrotérmica. El tercer objetivo de la tesis es la validación experimental de los resultados obtenidos. Así, realizados los análisis de las distintas estrategias mediante simulación, se prueba su funcionamiento en la microrred instalada en el Laboratorio de Energías Renovables de la UPNA. Su implementación y los resultados obtenidos se detallan en el Capítulo 8. Finalmente, en el Capítulo 9 se repasan las principales conclusiones y se presentan las líneas futuras.
Open Access
Fuzzy-based energy management of a residential electro-thermal microgrid based on power forecasting
(IEEE, 2018) Arcos Avilés, Diego; Gordillo, Rodolfo; Guinjoan Gispert, Francesc; Sanchis Gúrpide, Pablo; Pascual Miqueleiz, Julio María; Marietta, Martin P.; Marroyo Palomo, Luis; Ibarra, Alexander; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
In this paper, an energy management strategy based on microgrid power forecasting is applied to a residential grid-connected electro-thermal microgrid with the aim of smoothing the power profile exchanged with the grid. The microgrid architecture under study considers electrical and thermal renewable generation, energy storage system (ESS), and loads. The proposed strategy manages the energy stored in the ESS to cover part of the energy required by the thermal generation system for supplying domestic hot water to the residence. The simulation results using real data and the comparison with previous strategy have demonstrated the effectiveness of the proposed strategy.
Open Access
Implementation and control of a residential electrothermal microgrid based on renewable energies, a hybrid storage system and demand side management
(MDPI, 2014) Pascual Miqueleiz, Julio María; Sanchis Gúrpide, Pablo; Marroyo Palomo, Luis; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Gobierno de Navarra / Nafarroako Gobernua
This paper proposes an energy management strategy for a residential electrothermal microgrid, based on renewable energy sources. While grid connected, it makes use of a hybrid electrothermal storage system, formed by a battery and a hot water tank along with an electrical water heater as a controllable load, which make possible the energy management within the microgrid. The microgrid emulates the operation of a single family home with domestic hot water (DHW) consumption, a heating, ventilation and air conditioning (HVAC) system as well as the typical electric loads. An energy management strategy has been designed which optimizes the power exchanged with the grid profile in terms of peaks and fluctuations, in applications with high penetration levels of renewables. The proposed energy management strategy has been evaluated and validated experimentally in a full scale residential microgrid built in our Renewable Energy Laboratory, by means of continuous operation under real conditions. The results show that the combination of electric and thermal storage systems with controllable loads is a promising technology that could maximize the penetration level of renewable energies in the electric system.