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Introduction
Published in Amitava Sil, Saikat Maity, Industrial Power Systems, 2022
The location of hydropower plants is usually predetermined by: (i) the availability of water, (ii) the water must be available at a usable head. The head is the vertical height from the top of the penstock to the bottom of the penstock. (iii) The water must be available in sufficient quantity and (iv) if the flow is not regular enough for continuous supply, there must be accommodation for a reservoir at a reasonable cost; the lower the head, the larger the reservoir must be. The three types of hydropower facilities are as follows: (i) impoundment – which is typically a large hydropower system where water is released from the dam that stores the water and flows through a turbine, spinning it, which in turn activates a generator to produce electricity. (ii) Diversion – which is called run-of-river type that channels a portion of a river through a canal or penstock dispensing the requirement of a dam and the natural flow rate is used to generate the power. Run-of-river type can be classified as micro – generation limited to less than 100 KW, mini – generation limited to less than 1 MW, and small – generation limited to less than 50 MW; (iii) pumped storage – where water is pumped to a higher elevation reservoir when there is a surplus of electricity and the stored water is then released into lower elevation reservoirs to generate electricity when needed.
Today’s Renewable Energy Market: Innovations, Commercialization, and Impact on Market
Published in Amritanshu Shukla, Atul Sharma, Pascal Henry Biwolé, Latent Heat-Based Thermal Energy Storage Systems, 2020
Rohit Bansal, Vikas Bansal, Rachit Jaiswal
There are some challenges imposed by hydropower projects like submerging of large areas of land, substantial alterations to river ecosystems, resettlement of communities, and so on. These challenges must be judiciously considered and alleviated. The World Bank has continued its support to hydropower projects for both climate mitigation and local development. In Paris Climate Conference 2015, the World Bank emphasized on the significance of using hydropower along with other renewable power technologies in its efforts to escalate climate-resilient and low-carbon development in sub-Saharan Africa. There has been an increase in the demand for additional storage capacity caused by growing shares of renewable energy. Many new projects for pumped storage, which is one of major sources of large-scale energy storage, are under development. The global pumped storage capacity rose by approximately 6 GW in the year 2016 with new additional capacity installation in South Africa, China, and Europe. The installation of three turbines of 333 MW each of the 1.3 GW Ingula Plant for pumped storage in South Africa was completed in 2016, while the remaining two turbines became operational in January 2017.36
Energy Resources
Published in Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough, Earth Materials, 2019
Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough
Impoundment dams, like the Hoover Dam, stop all, or most, natural flow and funnel water through turbines. Diversion dams, also called run-of-river dams, only partially block river flow. Diversion dams generate electricity similarly to impoundment dams, but because they do not block the river completely, a constant flow of water continues downstream. Pumped storage dam systems, variants of impoundment dams, release water to generate electricity during periods of high demand and pump water back uphill into the reservoir during periods of low demand. So, during the day, when demand is highest, the dam produces electricity by allowing water to flow through turbines and power a generator. At night, when demand is low, electricity from another source is used, so the flow of water is reversed, refilling the reservoir.
Cavitation mechanism in turbine runaway process of a pump-turbine
Published in Journal of Hydraulic Research, 2022
Xiaolong Fu, Deyou Li, Hongjie Wang, Guanghui Zhang, Xianzhu Wei
Pumped-storage power generation is an energy storage and generation technology that is widely used on a power grid scale (Zuo et al., 2015). In a power grid, it serves as a storage battery for coordinating and supporting the production of clean but intermittent renewable energy, such as wind and solar power (Tarroja et al., 2019). To balance the load and regulate the frequency in a power grid, a pump-turbine, which is a key component of a pumped storage power system, frequently switches the operation modes among power generation, pump, power generation phase modulation, and spinning reserves. Moreover, it inevitably undergoes various transitions such as load acceptance and rejection, start-up, shutdown, runaway, and pump power-off transients (Ye et al., 2020). During the transitions of a pumped-storage power plant, the guide vane/valve closure and rotational speed fluctuations of the runner cause pressure variations in the pump-turbine. The pressure variation occurs owing to various reasons such as water hammer in the penstocks before the guide vanes/valves, water column separation, rejoining as well as collision of the separated water columns, cavity collapse, or reverse water hammer in the runner and draft tube behind the guide vanes/valves (Li et al., 2019; Wang & Yang, 2015). The severe pressure variations during transitions of a pumped-storage power plant have an extremely adverse effect on the operation of the pump-turbine. Therefore, studies related to the hydraulic transients of pump-turbines are important to achieve normal operation.
Industrial Heritage Assessment and Guidelines for the Architectural Conservation of Hydroelectric Plants
Published in International Journal of Architectural Heritage, 2021
According to the method they use in the production of electricity, plants are categorized as run-of-river plants, storage plants, pumped-storage plants and off-shore plants. The type of the hydroelectric facility is determined based on the environment it is constructed in or the various demands for energy. Run-of-river plants: In run-of-river facilities, turbines are turned by the power of naturally flowing water to provide energy. In these cases, water is not stored and the production changes according to daily and seasonal fluctuations.Storage plants: In storage hydropower facilities, a dam is constructed on the river in order to create a reservoir behind it, and water is released through tunnels into turbines which activate generators for the production of electricity. At storage hydropower facilities, the system can be controlled according to the demand, and it can be operated independently for long periods of time.Pumped-storage plants: In pumped-storage plants, water is cycled between an upper and a lower reservoir by making use of pumps. Such plants are utilized to overcome seasonal fluctuations and changing power demands.Off-shore hydropower plants: As facilities of a more recent technology, off-shore plants make use of tidal currents or the power of waves in order to produce electricity.
Computational research on the formation mechanism of double humps in pump–turbines
Published in Engineering Applications of Computational Fluid Mechanics, 2021
Yong Liu, Dezhong Wang, Hongjuan Ran
As the key energy conversion component of pumped-storage power stations, pump–turbines have the functions of both pump and turbine. Owing to their special structure, pump–turbines have hump problems under pump mode. During the process of pump starting, stopping, and working conditions changing, severe vibration and noise appear when passing through the hump region, and the loop flowrate oscillates hugely, even leading to pump surge. Humps not only threaten the safety, reliability, and service life of pumps, but also lead to operational failure (Lu, 2018; Yin, 2012). With the continuous large-scale production of renewable energy by means such as nuclear power, solar power, and wind power, the power grid system increasingly relies on pumped storage technology to cope with load changes, and pump–turbines need to be started and stopped more frequently. Thus, hump problems are even more critical (Capelo et al., 2017; Li, 2017; Li et al., 2020; Sampedro et al., 2021). Pump–turbines have always developed rapidly in the direction of higher heads, and the maximum head of a single-stage pump–turbine has reached about 800 m. How to deal with humps is becoming more and more important (Li, 2017; Li et al., 2017). Hump problems are key to restricting the development of pumped storage technology, and it has always been a research hotspot, but the hump formation mechanism has not been fully understood.