Simulation Studies for a Multi-MW Hybrid Wind-Solar PV System for Desalination Plants

This paper presents a power system configuration and control schemes for a Multi-MW wind-solar hybrid system, which includes multiple wind turbines and solar panels to support a desalination plant. The wind and solar systems are sized such that the desalination plant obtains, as far as possible, its power from the renewable sources, to minimize the dependence on the utility grid. Each section of the wind turbine system includes a variable speed permanent magnet synchronous generator connected to the grid via a back-to-back voltage source converter. The rectifier operates the wind system at the maximum power point, and the inverter provides power to the desalination plant. The solar plant has multiple panels connected to the grid via a three phase converter, performing the dual functions of power transformation and maximum power point tracking. The modeling and validation of this system is performed with the PSCAD/EMTDC, a software typically employed for transient analysis

A review of microgrid energy systems

Microgrid combined cooling, heating and power energy systems are under intensive investigation owing to expansion of renewable energy generation and development of advanced technologies in distributed energy generation. Multi-generation systems serve as one of the core parts in any microgrid energy systems. This review paper presents the summary of state-of-the-art technologies in these multi-generation systems. The first part introduces the energy structure based on energy sources and the latest renewable energy harvesting technologies for solar, biomass and geothermal energy. In the second part, prime movers, including small-scale ones used in a microgrid energy system, are summarized. The third part shows the expanded microgrid system configurations mainly for desalination. The fourth part describes the control and operation strategies for complex multi-generation systems. In the first three parts, insufficient investigation or research gaps are also pointed out. Overall, this paper systematically summaries recent progress in microgrid multigeneration system, and suggest future researches for designing and optimizing a microgrid energy system

Control systems of offshore hydrogen production by renewable energies

Esta tesis trata sobre un proyecto de diseño de un Sistema de Gestión de Energía (SGE) que utiliza Modelo de Control Predictivo (MPC) para equilibrar el consumo de energía renovable con electrolizadores productores de hidrógeno. La energía generada se equilibra regulando el punto de operación y las conexiones de los electrolizadores usando un MPC basado en un algoritmo de Programación Mixta-Entera Cuadrática. Este algoritmo MPC permite tener en cuenta previsiones de energía, mejorando así el equilibrio y reduciendo el número de encendidos de los equipos. Se han realizado diferentes casos de estudio en instalaciones compuestas por unidades de generación de energía eléctrica a partir de energía renovable. Se considera la técnica de ósmosis inversa como paso intermedio para la producción de agua que alimenta a los electrolizadores. La validación se realiza utilizando datos meteorológicos medidos en un lugar propuesto para el sistema, mostrando el funcionamiento adecuado del SGE desarrollado.Departamento de Ingeniería de Sistemas y AutomáticaDoctorado en Ingeniería Industria

Smart power management of a hybrid photovoltaic/wind stand-alone system coupling battery storage and hydraulic network

An off-grid energy system based on renewable photovoltaics (PV) and wind turbines (WT) generators is coupled via converters to electric and hydraulic networks. The electric network is composed of consumers and of a battery bank for electrical storage,while the hydraulic part is made of motor-pumps and hydraulic tanks for water production and desalination. Both battery and water tanks are used to optimize the power management of both electric and hydraulic subsystems by ensuring electric load demand and by reducing at the same time water deficit following the operation of the renewable intermittent source. Thus, both electric and hydraulic subsystems are strongly coupled in terms of energy making necessary to manage the power flows provided by renewable sources to optimize the overall system performance. In this paper, two kinds of management strategies are then compared in the way they share the hybrid power sources between the storage devices (battery and tanks) and the electrical/hydraulic loads. The first approach deals with an “uncoupled power management” in which the operation of electrical and hydraulic loads does not depend on the state of the intermittent renewable sources: in particular, hydraulic pumps are operated only taking account of water demand and tank filling but without considering power sources. On the contrary, given the available power produced by the sources, the second class of strategy (i.e. the “coupled management strategy”) consists of a “smart” power sharing between the electrical and hydraulic networks with regard to the battery SOC and the tank L1 and L2. A dynamic simulator of the hybrid energy system has been developed and tested using a MATLAB environment. The system performance is shown under the two investigated approaches (uncoupled vs coupled). Several tests are carried out using real meteorological data of a remote area and a practical load demand profile. The simulation results show that the “coupled strategy” clearly outperforms the classical “uncoupled” management strategies

Reviewing energy system modelling of decentralized energy autonomy

Research attention on decentralized autonomous energy systems has increased exponentially in the past three decades, as demonstrated by the absolute number of publications and the share of these studies in the corpus of energy system modelling literature. This paper shows the status quo and future modelling needs for research on local autonomous energy systems. A total of 359 studies are roughly investigated, of which a subset of 123 in detail. The studies are assessed with respect to the characteristics of their methodology and applications, in order to derive common trends and insights. Most case studies apply to middle-income countries and only focus on the supply of electricity in the residential sector. Furthermore, many of the studies are comparable regarding objectives and applied methods. Local energy autonomy is associated with high costs, leading to levelized costs of electricity of 0.41 $/kWh on average. By analysing the studies, many improvements for future studies could be identified: the studies lack an analysis of the impact of autonomous energy systems on surrounding energy systems. In addition, the robust design of autonomous energy systems requires higher time resolutions and extreme conditions. Future research should also develop methodologies to consider local stakeholders and their preferences for energy systems

Incorporating renewable energy in a desalination plant : case study in El Paso, Texas

El Paso is located in the westernmost part of Texas along the Rio Grande across from Ciudad Juarez, Mexico. Water supplies are a paramount concern for El Paso given its location in an arid climate. Although the Rio Grande runs past the city, prior appropriations for farming coupled with obligations to provide water to Mexico for agriculture limit the city’s use of the river in dry years. As a result, groundwater from the Hueco Bolson and Mesilla aquifers plays a pivotal role in El Paso’s water supplies. Both aquifers flow into Mexico and also primarily supply Ciudad Juarez’s water needs. The Hueco Bolson’s proximity to the Tularosa Basin, an enclosed prehistoric oceanic valley, causes the aquifer to have sizable supplies of freshwater and even larger amounts of brackish water. El Paso and Ciudad Juarez’s rapid population growth has led to accelerated drawdowns of the Hueco Bolson’s freshwater supplies, leaving both cities with increasingly brackish groundwater. In response to this problem, El Paso Water, El Paso’s water utility, constructed the Kay Bailey Hutchison Desalination Plant in a joint project with Fort Bliss. The plant uses reverse osmosis to desalinate brackish water and serves as a buffer against brackish water intrusion from the Tularosa Basin. Reverse osmosis is an expensive, energy-intense desalination process. El Paso’s sunny climate provides a perfect opportunity to reduce the plant’s long-term energy expenses through a solar-powered microgrid interconnected with the grid. Based on calculations from the HOMER model using the plant’s energy consumption data, a solar-powered microgrid could be a viable energy source that partially supplies the plant. The primary obstacles involve costs to build the microgrid and concerns from the grid administrator about potential damage to the grid. Therefore, it is important to look to the brisk decline in solar technology costs as well as to work with the grid administrator to increase the viability of such an endeavor. Given that desalination will play a greater role in El Paso’s water supplies and those of the world, scholars and policymakers from El Paso and Ciudad Juarez have an excellent opportunity to make this binational region a world leader in desalination with renewable energy.Geography and the Environmen

Microgrid Application in Algeria Saharian Remote Areas

This paper presents a model and simulation for the development of microgrids in remote areas of the Algerian Sahara, including micro power plants, photovoltaic panels, wind farms, diesel energy and storage facilities. The climate of the Algerian Sahara, located on both sides of a tropical region, is hot, sunny and arid. Daytime temperatures are very high and can exceed 50°C, while the thermal amplitude between day and night is often above 350 or 400°C. In addition, there are many microclimates that are characterised by very high wind speeds. This means that wind energy and photovoltaic energy are both widely appropriate in this field, especially if we assume that the distribution of the population is very dispersed. The creation of microgrids for consumption will be an interesting solution to provide energy to the local population. The microgrid is part of the electrical system and is very dynamic. Production and supply forecasts will lead to reshipment, demand and price effects on regional markets. These feedback effects must be modelled and understood to achieve a stable energy system based on renewable energy

Optimal techno-economic sizing of wind/solar/battery hybrid microgrid system using the forever power method

Advancement in power electronics, energy storage, control, and renewable energy sources has led to the use of integrated renewable energy sources in islanded microgrids (MG). Also, the uses of integrated renewable energy sources have become more technically applicable, more economically feasible, and more environmentally friendly than conventional sources. As a result, electrification of rural villages using renewable energy technologies has started to become widely adopted around the world. Since generating power from renewable energy sources is highly intermittent and difficult to predict, the use of proper energy storage technology is important to eliminate mismatches between the load demand and generation. Obtaining proper unit sizing for energy sources and storage is critical in determining the cost and reliability of the system. It is challenging to properly optimize the size of hybrid micro-sources for islanded MGs with minimum capital and operational cost while still achieving the targeted availability of the power supply. In this research, typical meteorological data is used with the Forever Power method to generate all possible combinations of PV modules and wind turbines along with the corresponding availability of the power supply. The goal of the study is to allow the designer of the system to select the size that best fits the targeted availability of the power supply with the most economical cost. As a case study, this method has been applied to an isolated MG for four homes in a rural area outside of Yanbu City, Saudi Arabia. A techno-economic analysis was applied using MATLAB to find the optimal size of the hybrid micro-sources. --Abstract, page iii