Water Quality and Trophic Status of Koto Panjang Reservoir, Indonesia

Koto Panjang Reservoir is one of the hydroelectric power plants in Indonesia, located in Kampar Regency, Riau Province. This paper aims to determine the water quality and tropic status of the Koto Panjang Reservoir. The research was carried out along the Koto Panjang Reservoir, covering the floating net cages area, inlet, outlet, and the center of the reservoir. Water samples were collected twice a year, February and September 2017. The results showed that the water quality of Koto Panjang reservoir is still within the tolerance range for the aquatic organisms' life, including fish. Based on the TSI analysis, the Koto Panjang Reservoir throphic status was categorized as eutrophic to heavy eutrophic. This study recommends that relocating floating net cages is necessary so that the nutrient load will not only be concentrated in one location. The efficiency of using the feed for floating net cages could minimize the waste.

Availability Projections of Hydroelectric Power Plants through Monte Carlo Simulation

The present work proposes a Monte Carlo Simulation (MCS) to obtain availability projections for Hydroelectric Power Plants (HPP), based mainly on regulatory aspects involving the Availability Factor (AFA). The main purpose of the simulation is to generate scenarios to obtain statistics for risk analysis and decision-making in relation to the HPP. The proposed methodology consists of two steps, firstly, the optimization of the maintenance schedule of the hydroelectric plant is carried out, in order to allocate the mandatory maintenance in the simulation horizon. Then, for the MCS, scenarios of forced shutdowns of the Generating Units (GU) will be generated, which directly influence the operation and, consequently, the availability of the HPP. The scenarios will be inserted into an operation optimization model, which considers the impact of forced shutdown samples on the MCS. The proposed modeling was applied using real data from the Santo Antônio HPP, which is one of the largest hydroelectric plants in Brazil.

Technology of welding and repair works of hydropower plants units

In the course of long-term operation of hydroelectric units, they are subject to wear and tear, which negatively affects the power generating capacity of the hydroelectric power station. The existing repair technology provides the restoration of the geometric dimensions of the impeller chamber of the hydraulic unit using an austenitic cladding layer. However, this technology is characterized by the occurrence of cracks and delamination of the deposited layer during post-repair operation, which is negatively reflected in the production cycle of electricity. A new technology and welding consumables have been proposed for repair and restoration works of hydroelectric units at hydroelectric power plants, providing an increase in the quality level, high characteristics of hydroabrasive and cavitation resistance, and increasing of working period of hydroelectric power plants. Inspection of the body of the hydraulic unit was carried out, defects were identified and classified, the reasons for their occurrence were analyzed. The research results make possible to optimize the alloying system of the deposited metal, to determine the optimal welding mode, to reduce the amount of the martensite component and to develop new filler materials and the technology for welding and repair works of hydroelectric power plants.

Hydroelectric power plants for small rivers

Comparative analysis of methods of obtaining electricity from a renewable energy source is carried out. Various designs and op-tions for small hydroelectric power plants have been proposed. Positive and negative factors of structures under consideration and their impact on the environment are analyzed. The main characteristics of the flow (speed, head) for the choice of the optimal variant of hydroelectric power plant have been determined. Three variants of impellers for free-flow hydroelectric power plants are proposed with a comparison of the efficien-cy of each variant. An analysis was carried out and an impeller based on a Darrieus rotor was selected for further research. Simulation was performed in the Flow Simulation program. The initial data for the design of Darrieus rotor operating in a liquid were the diameter and width of the impeller. The calculations involved a rotor with straight and swirling blades. The swirling blades rotor is self-starting. In the course of the calcula-tion, the speed of the liquid flow approaching the rotor and the rotor speed were changed. As a result of cal-culation, the value of the positive moment for self-starting was determined, which occurs at an incident flow velocity of at least 1.3 m/s.

Influence of digital technologies on the quality of life by modelling the risk of flooding of territories by flood waters

Every year, there are many floods on the planet, which have a significant impact on ensuring the safety of people and affects the quality of life. The development of modern modelling technologies makes it possible to predict various scenarios for the development of the situation and reduce the likelihood of negative consequences. This issue is especially relevant for settlements located in the immediate vicinity of hydroelectric power plants, since by regulating discharge costs from hydroelectric power plants, it is possible to safely pass flood waters avoiding flooding of residential buildings and infrastructure, but this requires knowing the flooding zones at different water levels and discharge costs. This paper presents the results of solving the problem of modelling the dynamics of flood waters within the boundaries of the settlement of Krasnoyarsk. To calculate the flooded areas, the TUFLOW program was used in the Surface-water Modelling System modelling environment, as well as neural network forecasting using the NeuroPro software product. The simulation results made it possible to predict local flooding of the settlement during the flood of 2021 and take preventive measures to reduce the risk of flooding.

Floating photovoltaic system for Indian artificial reservoirs—an effective approach to reduce evaporation and carbon emission

Floating photovoltaic system for reservoirs is a recent innovative technology that is highly advantageous in reducing evaporation while generating solar power. In addition, the integration of floating photovoltaic systems with the existing hydroelectric power plants will increase renewable power production. The present study aims to assess the electrical performance of floating photovoltaic systems in major reservoirs with existing hydroelectric power plants in India. The reservoirs with large water surface area were selected for the study, and a model floating photovoltaic system with a 5-MW capacity was designed for the selected reservoirs. The numerical analysis showed that installing floating photovoltaic systems will result in an annual energy yield of 160 GWh. Further, the systems also save 1.40 million cubic meters of water per day and also help in generating additional energy of 514.80 MWh/day from the saved water through its integration with hydroelectric power plants. A single-axis tracking mechanism to the floating photovoltaic systems will increase the annual energy generation by 11%. The detailed cost analysis and carbon emission analysis were also carried out. The results indicate that the tracking mechanisms increase the total installation cost of the systems. The annual carbon emission reduction from the floating photovoltaic systems accounts for about 3.30 million tons of CO2. The obtained results highlight the suitability of this innovative technology for installation in Indian reservoirs and its effectiveness in reducing evaporation and carbon emission. Graphic abstract