10,569 research outputs found
Technological Innovations and Advances in Hydropower Engineering
It has been more than 140 years since water was used to generate electricity. Especially since the 1970s, with the advancement of science and technology, new technologies, new processes, and new materials have been widely used in hydropower construction. Engineering equipment and technology, as well as cascade development, have become increasingly mature, making possible the construction of many high dams and large reservoirs in the world. However, with the passage of time, hydropower infrastructure such as reservoirs, dams, and power stations built in large numbers in the past are aging. This, coupled with singular use of hydropower, limits the development of hydropower in the future. This book reports the achievements in hydropower construction and the efforts of sustainable hydropower development made by various countries around the globe. These existing innovative studies and applications stimulate new ideas for the renewal of hydropower infrastructure and the further improvement of hydropower development and utilization efficiency
Optimal Short-term Operation of a Cascaded Hydro-Solar Hybrid System: a Case Study in Kenya
In this paper we propose an optimal dispatch scheme for a cascaded hybrid hydro-solar power system, i.e., a hydroelectric system coupled with solar generation, that maximises the head levels of each dam, and minimises the spillage effects. As a result more water is stored in the dams to meet a given amount of energy providing more flexibility to the system in dry months. This dispatch scheme is based on the development of a simplified hydroelectric power system model which has low computational burden and may be implemented for the short-term operation of a cascaded hydro-solar hybrid power system. To this end, the nonconvex relationships that describe the system physical constraints, e.g., hydroelectric power output, are transformed into affine relationships; thus reducing the computational complexity. The transformations are based on the construction of convex envelopes around bilinear functions, piecewise affine functions, and exploitation of optimisation properties. We validate the proposed framework and quantify the benefits of coupling hydroelectric and solar resources in terms of live water volume in dams and amount of solar a system may withstand with the Tana river cascade located in Kenya through an analysis of incorporating actual system data
Modeling of Cascade Dams and Reservoirs Operation for Hydropower Energy Generation
Water Resources Planning and Managemen
Hydropower Scheduling Toolchains:Comparing Experiences in Brazil, Norway,and USA and Implications for Synergistic Research
While hydropower scheduling is a well-defined problem, there are institutional differences that need to be identified to promoteconstructive and synergistic research. We study how established toolchains of computer models are organized to assist operational hydro-power scheduling in Brazil, Norway, and the United States’Colorado River System (CRS). These three systems have vast hydropowerresources, with numerous, geographically widespread, and complex reservoir systems. Although the underlying objective of hydropowerscheduling is essentially the same, the systems are operated in different market contexts and with different alternative uses of water, where thestakeholders’objectives clearly differ. This in turn leads to different approaches when it comes to the scope, organization, and use of modelsfor operational hydropower scheduling and the information flow between the models. We describe these hydropower scheduling toolchains,identify the similarities and differences, and shed light on the original ideas that motivated their creation. We then discuss the need to improveand extend the current toolchains and the opportunities to synergistic research that embrace those contextual differences.Hydropower Scheduling Toolchains:Comparing Experiences in Brazil, Norway,and USA and Implications for Synergistic ResearchacceptedVersio
Water-related modelling in electric power systems: WATERFLEX Exploratory Research Project: version 1
Water is needed for energy. For instance, hydropower is the technology that generates more electricity worldwide after the fossil-fuelled power plants and its production depends on water availability and variability. Additionally, thermal power plants need water for cooling and thus generate electricity. On the other hand, energy is also needed for water. Given the increase of additional hydropower potential worldwide in the coming years, the high dependence of electricity generation with fossil-fuelled power plants, and the implications of the climate change, relevant international organisations have paid attention to the water-energy nexus (or more explicitly within a power system context, the water-power nexus). The Joint Research Centre of the European Commission, the United States Department of Energy, the Institute for Advanced Sustainability Studies, the Midwest Energy Research Consortium and the Water Council, or the Organisation for Economic Co-operation and Development, among others, have raised awareness about this nexus and its analysis as an integrated system. In order to properly analyse such linkages between the power and water sectors, there is a need for appropriate modelling frameworks and mathematical approaches.
This report comprises the water-constrained models in electric power systems developed within the WATERFLEX Exploratory Research Project of the European Commission’s Joint Research Centre in order to analyse the water-power interactions. All these models are deemed modules of the Dispa-SET modelling tool.
The version 1 of the medium-term hydrothermal coordination module is presented with some modelling extensions, namely the incorporation of transmission network constraints, water demands, and ecological flows. Another salient feature of this version of Dispa-SET is the modelling of the stochastic medium-term hydrothermal coordination problem. The stochastic problem is solved by using an efficient scenario-based decomposition technique, the so-called Progressive Hedging algorithm. This technique is an Augmented-Lagrangian-based decomposition method that decomposes the original problem into smaller subproblems per scenario. The Progressive Hedging algorithm has multiple advantages:
— It is easy parallelizable due to its inherent structure.
— It provides solution stability and better computational performance compared to Benders-like decomposition techniques (node-based decomposition).
— It scales better for large-scale stochastic programming problems.
— It has been widely used in the technical literature, thus demonstrating its efficiency.
Its implementation has been carried out through the PySP software package which is part of the Coopr open-source Python repository for optimisation.
This report also describes the cooling-related constraints included in the unit commitment and dispatch module of Dispa-SET. The cooling-related constraints encompass limitations on allowable maximum water withdrawals of thermal power plants and modelling of the power produced in terms of the river water temperature of the power plant inlet. Limitations on thermal releases or water withdrawals could be imposed due to physical or policy reasons.
Finally, an offline and decoupled modelling framework is presented to link such modules with the rainfall-runoff hydrological LISFLOOD model. This modelling framework is able to accurately capture the water-power interactions. Some challenges and barriers to properly address the water-power nexus are also highlighted in the report.JRC.C.7-Knowledge for the Energy Unio
Dams
The construction of large dams is one of the most costly and controversial forms of public infrastructure investment in developing countries, but little is known about their impact. This paper studies the productivity and distributional effects of large dams in India. To account for endogenous placement of dams we use GIS data and the fact that river gradient affects a district's suitability for dams to provide instrumental variable estimates of their impact. We find that, in a district where a dam is built, agricultural production does not increase but poverty does. In contrast, districts located downstream from the dam benefit from increased irrigation and see agricultural production increase and poverty fall. Overall, our estimates suggest that large dam construction in India is a marginally cost-effective investment with significant distributional implications, and has, in aggregate, increased poverty.
Dams
The construction of large dams is one of the most costly and controversial forms of public infrastructure investment in developing countries, but little is known about their impact. This paper studies the productivity and distributional effects of large dams in India. To account for endogenous placement of dams we use GIS data and the fact that river gradient affects a district's suitability for dams to provide instrumental variable estimates of their impact. We find that, in a district where a dam is built, agricultural production does not increase but poverty does. In contrast, districts located downstream from the dam benefit from increased irrigation and see agricultural production increase and poverty fall. Overall, our estimates suggest that large dam construction in India is a marginally cost-effective investment with significant distributional implications, and has, in aggregate, increased poverty.Dams, Development Planning, Program Evaluation, India
Numerical and Experimental Investigation of Performance for Very-Low-Head Micro and Pico Kaplan Hydro-Turbines with Rim-Driven Generators
Renewable energy plays a significant role in new power generation worldwide, and hydropower is contributing to 86% of renewable electricity production within all other renewable energy resources. Simultaneously, hydropower shares 83% of U.S. renewable energy capacity and accounts for 77% of actual renewable electricity generation. However, most of the installed hydropower consists of large plants. Much potential hydro generation remains untapped, particularly at lower power and head levels. There is a substantial opportunity worldwide and across the U.S. in specific to add new hydropower generating capabilities at low-head sites such as non-powered dams, canals, and conduits with a water height of less than 30 meters, especially, where the potential of solar and wind is not available. As stated by the U.S. Department of Energy, there is an estimated potential hydropower capacity of 12,000 MW of the existed 80,000 unpowered dams with at least 3 feet of water head available.
In this research, investigation of power-efficient micro and pico Kaplan hydro turbines at very-low-head with rim-driven generators to be studied and evaluated, specifically, at heads of less than 3 meters (10 ft). Optimization of performance and design for a 3D-printed conventional -with shaft- 7.6 cm (3-inch) Kaplan turbine to be carried out based on an experimental setup in the Hydro Turbines Laboratory of the University of Wisconsin-Milwaukee in addition to the utilization of Computational Fluid Dynamics (CFD). Then a shaftless rim-driven generator-based turbine (RDT) to be introduced and optimized. Such a new hydro turbine perception will increase the efficiency (of power generation) of hydro turbines in general, and the efficiency of low-head turbines in specific.
The design optimization includes; the number of the blades for the turbine’s rotor (runner) and stator, the blade wrap-angle of the rotor, intake and draft tubes angles, lengths and shapes, and the guide vanes. The performance in terms of the power output and the efficiency is evaluated for the conventional turbine by utilizing CFD and by testing a 3D-printed model of the turbine in a custom-built experimental setup at different water heads (from 2.0 m to 2.6 m) and different rotational speeds (0 – 4000 rpm). The CFD setup is based on 3D transient turbulent featuring the Large Eddy Simulation (LES) model, and STAR-CCM+ is the CFD software. In addition, the high-performance computing (HPC) cluster of the University of Wisconsin-Milwaukee is used for solving the complex CFD simulations.
To evaluate the advantage of the RDT over the conventional turbines, the rim-driven shaftless turbine is introduced in this research at the same boundary conditions. The RDT is not expected only to increase the efficiency of hydro turbines. It will also contribute saving the environment by allowing debris or fish to pass through the central area of the turbine, especially in the case of run-a-river hydro turbines applications. Furthermore, some applications of the RDT are presented in this study. The utilization of RDT in wastewater treatment plants (WWTPs) is one example where WWTPs usually have low or very-low head between the discharge point of the plant and the water body where the treated water is supposed to be disposed. At the same time, a significant continuous water flow rate is available all over the year for feasible hydro turbine installations. Such utilization will improve the energy efficiency of WWTPs
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