Wind Hydro Research Articles

Complementarity in Time between Wind and Water Resources in Northeastern Brazil

The world is in a time when the energy resources have been under increasing pressure from a growing demand with higher quality requirements. At the same time, our world, largely based on non-renewables, see these resources approaching scarcity. In this context, it is important to get energy supplies from renewable resources and seek ways to leverage these resources as well as possible. The complementarity between energy resources can be a way to make better use of available resources, enabling a greater supply of energy and facilitating the management of devices for energy storage. This paper presents preliminary results of the identification of complementarity between water and wind resources in a portion of northeastern Brazil. The effects of complementarity for the benefit of the feasibility of a wind hydro hybrid system will prove more effective in conditions of scarce energy resources, contributing to the reduction of the cost per kWh of supplied energy. The map provided in this article can indicate areas where investments in wind hydro hybrid systems will lead to energy supplies with lower specific costs. The map of complementarity indicates that about 40% of the studied area has high levels of complementarity in time.

Power Management Based Current Control Technique for Photovoltaic-Battery Assisted Wind–Hydro Hybrid System

Abstract This article proposes new power management based current control strategy for integrated wind–solar–hydro system equipped with battery storage mechanism. In this control technique, an indirect estimation of load current is done, through energy balance model, DC-link voltage control and droop control. This system features simpler energy management strategy and necessitates few power electronic converters, thereby minimizing the cost of the system. The generation–demand (G–D) management diagram is formulated based on the stochastic weather conditions and demand, which would likely moderate the gap between both. The features of management strategy deploying energy balance model include (1) regulating DC-link voltage within specified tolerances, (2) isolated operation without relying on external electric power transmission network, (3) indirect current control of hydro turbine driven induction generator and (4) seamless transition between grid-connected and off-grid operation modes. Furthermore, structuring of the hybrid system with appropriate selection of control variables enables power sharing among each energy conversion systems and battery storage mechanism. By addressing these intricacies, it is viable to regulate the frequency and voltage of the remote network at load end. The performance of the proposed composite scheme is demonstrated through time-domain simulation in MATLAB/Simulink environment.

Transmission‐constrained intrahour coordination of wind and pumped‐storage hydro units

This study proposes a coordination methodology for wind and pumped-storage hydro (PS) units in the day-ahead operation planning of power systems. PS units that can store the extra wind energy will improve the dispatchability of variable wind energy for delivering hourly firmed energy to a power grid. With coordination, the PS unit can offset intrahour wind energy imbalances (i.e. deviations from hourly schedules) and minimise wind energy curtailments. The proposed coordination, which is incorporated into the transmission-constrained unit commitment, can be used by a vertically integrated utility or an independent system operator. The concept of intrahour wind energy imbalances and the wind-PS coordination is illustrated using two case studies. The numerical results for the 6-bus and the IEEE 118-bus system include case studies with and without the coordination of PS and wind generation units. The results that include the intrahour variability of real-time wind speed show the applicability of the proposed wind-PS coordination approach to the short-term power system operation.

Comparison study between a Renewable Energy Supply System and a supergrid for achieving 100% from renewable energy sources in Islands

Numerous efforts have been done for achieving the maximum penetration of renewable energy sources (RESs) in the autonomous grids of Greek islands, which never exceeded 10%, despite the exceptional wind and solar potential. Large fluctuations on demand during summer, winter, and 24-h period in combination with the technical restrictions of diesel generators of the existing conventional power stations are a major concern of power supply system. Reversing the roles of diesel generators and wind farms (WFs), to use WF as the basic energy source and diesel generators as stand-by system changed in fact the whole philosophy of energy supply systems in islands and created perspectives for the fundamental reformation of the conventional energy supply systems in autonomous grids. In fact, methods of contemporary interim medium term energy storage are investigated for hybrid systems in order to adjust the stochastic behavior of wind energy to the demand, to provide the system with guaranteed power. This Wind–Hydro Plants in combination with the most adequate RES forming an Renewable Energy Supply System (RESS), increase further the economical penetration of RES into autonomous grids up to 90% or even 100% and simultaneously reduce drastically the fuel costs. Furthermore, a supergrid is examined and compared with RESS as another efficient way for achieving higher penetration of RES.

Determining optimum electricity generation technology under the reference and the 450 scenario in an emerging economy: The case of Turkey

Energy vulnerability and security have become top issues for all countries. As an emerging economy, Turkey’s electricity consumption has increased significantly and is expected to follow the same trend in the future. Turkey should start to install new power plants in 2010 to prevent a probable electricity energy deficiency in 2014. Therefore, Turkey is faced with the problem of ranking and selecting the optimum electricity generation technology from natural gas combined cycle power plants, coal power combined heat plants, wind onshore power plants, hydro power plants, nuclear power plants and solar PV power plants by taking into account cost efficiency, cost volatility risk, supply security, climate change & other pollution, and supply-demand mismatch. Grey Relational Analysis is utilized to propose solution to this multiple attribute decision making problem by carrying out sensitivity analyses as well. The empirical results reveal that Turkey should install wind onshore, hydro, and nuclear power plants to transform the structure of her current electricity energy sector into a low-cost, environment-friendly and reliable structure. Turkey has also an immense untapped potential for wind power and hydro power resources.

Isolated Wind–Hydro Hybrid System Using Cage Generators and Battery Storage

This paper deals with a new isolated wind-hydro hybrid generation system employing one squirrel-cage induction generator (SCIG) driven by a variable-speed wind turbine and another SCIG driven by a constant-power hydro turbine feeding three-phase four-wire local loads. The proposed system utilizes two back-to-back-connected pulsewidth modulationcontrolled insulated-gate-bipolar-transistor-based voltage-source converters (VSCs) with a battery energy storage system at their dc link. The main objectives of the control algorithm for the VSCs are to achieve maximum power tracking (MPT) through rotor speed control of a wind-turbine-driven SCIG under varying wind speeds and control of the magnitude and the frequency of the load voltage. The proposed wind-hydro hybrid system has a capability of bidirectional active- and reactive-power flow, by which it controls the magnitude and the frequency of the load voltage. The proposed electromechanical system using SCIGs, an MPT controller, and a voltage and frequency controller are modeled and simulated in MATLAB using Simulink and Sim Power System set toolboxes, and different aspects of the proposed system are studied for various types of linear, nonlinear, and dynamic loads, and under varying wind-speed conditions. The performance of the proposed system is presented to demonstrate its capability of MPT, voltage and frequency control (VFC), harmonic elimination, and load balancing.

Application of Wind and Small Hydro Energy Sources for Rural Electric Power Supply in Nigeria

The paper looks into the possibilities of using available renewable resources in rural areas for electric power generation for remote consumers. Based on meteorological data (the hourly wind speed) collected and analyzed for Dapchi, a north eastern rural settlement of Nigeria, coupled with hydrological data of River Kamadougu Gena, the hourly power produced from a hybrid power system comprising of wind and small hydro power systems is evaluated and considered as a supply source to electrical loads of the settlement.

Automatic Gain Controller for Variable Speed Wind Turbines

This paper presents a novel controller for DFIG based wind parks, designed to achieve more efficient voltage regulation, reactive power compensation and to enhance the transient stability margin of the interconnected power system. The supervisory-secondary voltage control is used to generate the local voltage reference, providing an improved overall voltage profile, while combining an automatic gain controller (AGC) to improve the transient response of the primary control loop. The controller is implemented and tested with a power system comprising of a lumped, fundamental frequency model of a DFIG based wind park, and hydro and diesel generators connected to the electric grid. The performance of the controller was investigated for both steady-state improvements as well as under extreme contingencies to demonstrate its benefits.

Simulation and size optimization of a pumped–storage power plant for the recovery of wind-farms rejected energy

The hybrid wind–hydro power generation appears to be an attractive solution for isolated, autonomous electric grids in order to increase the wind energy penetration and cost-effectiveness. This work presents a numerical methodology for optimum sizing of the various components of a reversible hydraulic system designed to recover the electric energy that is rejected from wind farms due to imposed grid limitations. The algorithm is applied to study a practical case using time variation data of rejected power from a number of wind farms installed in the island of Crete, Greece. The free design parameters of the system include the turbine size, the size and the number of the pumps, the penstock diameter and thickness, and the reservoirs’ capacity, whereas some critical financial parameters are also considered. The numerical procedure combines an evaluation algorithm that simulates in detail the plant operation during a 12-month period, and an automated optimization software based on evolutionary algorithms. The economic analysis uses dynamic evaluation methods and the attainability of various objectives is examined using single or multi-objective optimizations. In addition, the developed numerical tool is used to perform several parametric studies and sensitivity tests in order to analyse in depth the influence of the most important parameters on the plant operation and economic behaviour. The results showed that a well optimized design may be crucial for the technical and economic viability of the examined system.

Novel STATCOM Controllers for Voltage Stabilization of Stand Alone Hybrid (Wind/Small Hydro) Schemes

This paper presents Three novel error driven dynamic controllers for the Static Synchronous Compensator (STATCOM) Facts device to stabilize both Wind Energy Conversion stand alone systems (SWECS) as well as hybrid scheme of wind plus small hydro with employing self excited induction generator. The unified AC system of standalone wind energy conversion scheme and hybrid wind/small hydro scheme are connected to a hybrid electric load. Three novel error driven dynamic controllers are validated for the STATCOM as a voltage stabilization scheme. Two novel controller are error driven dynamic controllers with auxiliary tracking control loop. The first controller is tri loop dynamic error driven controller using the RMS Load bus voltage, RMS-Load Current and the instantaneous AC load power. The second controller is DC voltage dynamic tracking controller using the dc link capacitor voltage. The third dynamic controller is based on the decoupled (d-q) current control strategy, namely the direct and quadrature current component for the STATCOM current. The dynamic response results demonstrated the effectiveness of the STATCOM-Facts device in stabilizing both AC wind energy system and the hybrid wind/hydro scheme by ensuring effective generator/load bus voltage regulation and dynamic reactive power compensation under load, wind and other prime mover excursions.

Wind, Photovoltaic anD Mini-Hydro Hybrid Generation in Bolivia: A Case Study at a Mountainous Village

This paper investigates the most feasible configuration for hybrid generation by indigenous renewable energy sources in Chachacomani village at 4,220 meters elevation in Bolivia. Site monitoring of wind, solar irradiation and the water level of the Jarma River was conducted for a year. The data enabled potential power output from Wind, PV and Micro Hydro generation system to be estimated. Energy balance calculations for different configuration of hybrid generation system were made. The results show that the three energy supplies would be complementary for integrated power.

An integrated system framework for fuel cell-based distributed green energy applications

The environmental pollution and diminishing conventional fuel sources and global warming problems make it more attractive for considering renewables as alternative energy sources, such as solar, wind and micro hydro, etc. Recent advances in hydrogen and fuel cell technologies further facilitate these energy options to supply electrical power to various communities. Hydrogen fuel cell systems coupled with renewable energy sources stand out as a promising solution. This paper presents an integrated system framework for fuel cell-based distributed energy applications. Five components are included in this framework: a physical energy system application, a virtual simulation model, a distributed coordination and control, a human system interface and a database. The integrated system framework provides a means to optimize system design, evaluate its performance and balance supplies and demands in a hydrogen assisted renewable energy application. It can either be applied to a distributed energy node that fulfills a local energy demand or to an energy-network that coordinates distributed energy nodes in a region, such as a hydrogen highway. The proposed system framework has been applied in the first phase of our multi-phases project to investigate and analyze the feasibility and suitability of hydrogen fuel assisted renewable power for a remote community. Through integration with an available renewable energy profile database, the developed system efficiently assists in selecting, integrating, and evaluating different system configurations and various operational scenarios at the application site. The simulation results provide a solid basis for the next phase of our demonstration projects.

Optimal operation and hydro storage sizing of a wind–hydro power plant

Ambitious targets for renewable power production have been defined for the electric power systems in Europe. The accomplishment of these targets requires the increase in renewable energy production, namely from wind power generation. However, the intermittent nature of wind creates several problems to the power system operation and new approaches based on the combined use of wind power and energy storage technologies need to be developed. In this paper, the concept of the combined use of wind power production and hydro storage/production is exploited, through the development of an operational optimisation approach applied to a wind generator park with little water storage ability. The optimisation model defines the operational strategy to be followed for the hours ahead by a pump station and an hydraulic generator embedded in a wind/hydro pumping facility, using the Portuguese energy remuneration rules. The proposed methodology leads to considerable yearly profits for the wind generator production.

Energy in Sudan

Sudan is an agricultural country with fertile land, plenty of water resources, livestock, forestry resources, and agricultural residues. An overview of the energy situation in Sudan is introduced with reference to the end uses and regional distribution. Energy sources are divided into two main types: conventional energy (biomass, petroleum products, and electricity); and non-conventional energy (solar, wind, hydro, etc.). Sudan possesses a relatively high abundance of sunshine, solar radiation, and moderate wind speeds, hydro, and biomass energy resources. Application of new and renewable sources of energy available in Sudan is now a major issue in the future energy strategic planning for the alternative to the fossil conventional energy to provide part of the local energy demand. Sudan is an important case study in the context of renewable energy. It has a long history of meeting its energy needs through renewables. Sudan's renewables portfolio is broad and diverse, due in part to the country's wide range of climates and landscapes. Like many of the African leaders in renewable energy utilisation, Sudan has a well-defined commitment to continue research, development, and implementation of new technologies. Sustainable low-carbon energy scenarios for the new century emphasise the untapped potential of renewable resources. Rural areas of Sudan can benefit from this transition. The increased availability of reliable and efficient energy services stimulates new development alternatives. It is concluded that renewable environmentally friendly energy must be encouraged, promoted, invested, implemented, and demonstrated by full-scale plant especially for use in remote rural areas of Sudan.

Evaluation of the wind—hydro energy solution for remote islands

Evaluation of the wind—hydro energy solution for remote islands

Energy supply potentials and needs, and the environmental impact of their use in Sudan.

Sudan is an agricultural country with fertile land, plenty of water resources, livestock, forestry resources, and agricultural residues. An overview of the energy situation in Sudan is introduced with reference to the end uses and regional distribution. Energy sources are divided into two main types; conventional energy (biomass, petroleum products, and electricity); and non-conventional energy (solar, wind, hydro-electricity, etc.). Sudan possesses a relatively high abundance of solar radiation, and moderate wind speeds, hydro, and biomass energy resources. The application of the new and renewable sources of energy available in Sudan is now a major issue in future energy strategic planning and for an alternative to fossil conventional energy. Sudan is an important case study in the context of renewable energy. It has a long history of meeting its energy needs through renewables. Sudan's renewables' portfolio is broad and diverse, due in part to the country's wide range of climates and landscapes. Like many of the African leaders in renewable energy utilization, Sudan has a well-defined commitment to continue research, development, and implementation of new technologies. Sustainable low-carbon energy scenarios for the new century emphasize the untapped potential of renewable resources. Rural areas of Sudan can benefit from this transition. The increased availability of reliable and efficient energy services stimulates new development alternatives. It is concluded that renewable, environmentally friendly, energy must be encouraged, promoted, invested, implemented, and demonstrated by full-scale plants, especially for use in the remote rural areas of Sudan.

Parametrical investigation of the wind–hydro electricity production solution for Aegean Archipelago

The development of a combined wind–hydro electricity production system is found to be the supreme method of handling energy shortage and excessive electricity production cost problems for the remote Aegean Sea islands, taking also advantage of the existing high quality local wind potential. In the present study, a parametrical investigation concerning the applicability of the recommended solution for several different cases is conducted. Among the most important parameters affecting the energy behavior of the proposed configuration are the number of wind turbines used, the selected water reservoirs size, the corresponding water pumps rated power and the local wind potential quality, along with the system electricity consumption characteristics. Throughout the parametrical analysis, the impact of all the above mentioned parameters on the system energy autonomy and electrical efficiency is examined. On top of that, detailed energy balance profiles on an hourly basis are also included. Finally, the simulation results obtained strongly support the suggested solution, especially when the conclusions of the present work are taken into consideration.

Evaluation of the wind–hydro energy solution for remote islands

The possibility to create a combined wind–hydro energy station in a medium size island of the Aegean Archipelago is investigated on a techno-economic basis. The proposed solution may be used to face the extremely high electricity production cost in these regions, taking also advantage of the excellent local wind potential. Additionally, a parametrical analysis is performed on a techno-economic basis in order to select the appropriate number of wind turbines and the optimum size of water reservoirs. The calculation results obtained, based on real measurements and on experimental data, validate the proposed solution. More precisely, the electricity demand of the remote system is covered in any case, the imported fuel is minimized, the renewable energy sources penetration exceeds 90%, and the negative environmental effects are remarkably reduced.

Sudan energy background; An overview

This paper discussed briefly the potential of renewable energy resources in Sudan. Sudan possessed a relatively high abundance of sunshine, solar radiation, and moderate wind speeds. Sudan is also viewed as one of the potentially richest countries especially in water, land, agriculture and livestock. Sudan is blessed with abundant solar, wind hydro and biomass energy resources. Results, suggest that, renewable energy must be encouraged, promoted, invested, implemented, and demonstrated, but especially for remote rural areas.

Reply to the Comments on "An Investigation of Renewable Resourcesand Renewable Technology Applications in Bulgaria"

The authors of a paper about the reserve solar and wind energies about Bulgaria comment at length to the objections to their preliminary results of a survey of renewable energy resources (wind solar, biomass, geothermal, and hydro) in the frame of the investigation of the country Study Program supported by US DOE. Included are additional comments on technology which could be used including passive heating, active heating, photovoltaic flat plate collectors, wind Power systems. 5 refs.