Cairo University Faculty of Engineering Electrical Power Department Fourth Year Technical specification report Hydroelectric power plant Name Ahmed Essam Abd rabou Ahmed Mohamed Ahmed Ahmed Mohamed Farouk George Hany Fahim Mahmoud Sayed Ahmed Mahmoud Shami Said Mahmoud Abdelnasser Ashour Youssef Mohamed Helmy Section 1 1 1 1 4 4 4 4 B.N 17 19 22 50 7 9 12 49 Submitted to: Dr/Ahmed Ali Suleiman Huzain 18/1/2021 Table of Contents Introduction ................................................................................................................................5 Historical review .........................................................................................................................5 Classification of hydropower plants ............................................................................................5 1. River power plants............................................................................................................6 2. Storage Power Plants ........................................................................................................7 2.1 Operation of Pumped Storage Power Plants ...................................................................7 3. Oceanic Power Plants .......................................................................................................8 3.1. The tidal power plant: ................................................................................................8 3.2. Wave power plant:.....................................................................................................8 3.3. The oceanic heat power plant:....................................................................................9 3.4. Ocean Current Power Plants: .....................................................................................9 3.5. Osmotic power plant:.................................................................................................9 Classification based on capacity of hydropower plants ................................................................9 Classifications according to load .................................................................................................9 1. Base load plants. ...............................................................................................................9 2. Peak load plants .............................................................................................................. 10 Classifications according to Head .............................................................................................. 10 1. Low head plants ............................................................................................................. 10 2. Medium head plants ....................................................................................................... 10 3. High head plants. ............................................................................................................ 10 Construction of hydropower plant ............................................................................................. 10 1. 2. Main Parts ...................................................................................................................... 10 1.1. Turbine .................................................................................................................... 10 1.2. Electric Generator.................................................................................................... 10 1.3. Transformer and Powerhouse .................................................................................. 11 1.4. Upper and Lower Reservoir ..................................................................................... 11 Structural Parts ............................................................................................................... 11 2.1 Dam and Spillway ....................................................................................................... 11 2.2 Surge Chambers .......................................................................................................... 12 2.3 Stilling Basins ............................................................................................................. 12 2.4 Penstock and Spiral Casing .......................................................................................... 12 2|Page 2.5 Tailrace ....................................................................................................................... 13 2.6 Pressure Pipes .............................................................................................................. 13 Hydraulic turbines: .................................................................................................................... 13 1. Peloton wheel turbine ..................................................................................................... 14 2. Francis turbine ................................................................................................................ 14 3. Propeller and Kaplan turbines ......................................................................................... 15 Advantages of Hydropower ....................................................................................................... 16 Disadvantages of Hydropower .................................................................................................. 16 Economics of hydropower plant ................................................................................................ 16 1. Introduction ...................................................................................................................... 16 2. Framework of economic analysis of hydro power ............................................................. 17 2.1 Cost-benefit analysis:................................................................................................... 18 2.2 Economic impact assessment ....................................................................................... 18 2.3 Cost effectiveness analysis........................................................................................... 18 2.4 Risk-benefit analysis .................................................................................................... 18 3. Economics of small hydro power plant ............................................................................. 18 4. Economic analysis of pumped storage hydropower plant .................................................. 19 References ................................................................................................................................ 20 3|Page List of figures: Figure 1: Classifications of hydropower plants. [3] ......................................................................5 Figure 2: Scheme of diversion canal fed river power plant [3]. ....................................................6 Figure 3: River power plant in southern Germany in wintertime [3]. ...........................................6 Figure 4: Scheme of storage power plant [3]. ..............................................................................7 Figure 5: Operation diagram of a tidal power plant [3]. ...............................................................8 Figure 7: Schemes of wave power plants [3]. ..............................................................................8 Figure 6: Scheme of the LIMPET power plant [3]. ......................................................................8 Figure 8: Seagen ocean current power plant [3]. ..........................................................................9 Figure 9: Shaft of 70 MW hydropower plant [3]. ....................................................................... 11 Figure 10: Sludge deposited in reservoir of 1,000 MW storage power plant [3]. ........................ 11 Figure 11: Stilling basin with pillar [3]. ..................................................................................... 12 Figure 12: Pressure pipes of a storage power plant [3]. .............................................................. 13 Figure 15: Peloton turbine [5].................................................................................................... 14 Figure 16: Francis turbine [5]. ................................................................................................... 15 Figure 17: kaplan turbine [5]. .................................................................................................... 15 Figure 18: indicative cost per MW for a selection of existing, approved and proposed hydro projects. (Modified from [8])..................................................................................................... 17 Figure 19: typical installed costs and LCOE of hydro power project (modified from [8]) .......... 17 Figure 20: distribution investment in small hydro scheme (modified from [9]) .......................... 18 4|Page Introduction The term ‘hydro’ is the Greek word for water and hydropower is the energy contained in water. Hydroelectric plants provide a clean and renewable source of electrical energy. The principle of hydroelectric power plant is simply explained as shown: [Potential Energy Kinetic Energy Mechanical Energy Electrical Energy]. Stored water contains Potential energy, due to head of the dam. When it flows towards turbine, the Kinetic Energy is converted into Mechanical Energy. The turbine is mechanically coupled with generator. Whenever turbine starts to rotate with the help of high-pressure water, generator starts to rotate, and electrical energy is produced. [1] Historical review In 1882, the world’s first hydroelectric power plant began operation on the Fox River in Appleton, Wisconsin. The plant was initiated by Appleton paper manufacturer H.J. Rogers, who had been inspired by Thomas Edison's plans for an electricity-producing station in New York. Unlike Edison's New York plant which used steam power to drive its generators, the Appleton plant used the natural energy of the Fox River. When the plant opened, it produced enough electricity to light Rogers's home, the plant itself, and a nearby building. [2] Today, a vast expansion of hydropower’s potential is possible through new technologies for conventional, pumped storage, and hydrokinetic projects, for modernizing existing hydropower facilities and adding generation to existing non-powered dams. [2] Classification of hydropower plants Different classifications exist for hydropower plants. They are classified according to their operation, construction, or type of turbine used as shown in figure 1. This figure shows different classifications of hydropower plants, and the connection between them. [3] Figure 1: Classifications of hydropower plants. [3] 5|Page 1. River power plants River power plants use the natural flow of the river, and the drop in height to produce electricity. They are fed by a river, or a diversion canal. Canal power plants usually have less capacity due to the limitation of water flow in the canal. Figure 2 shows the scheme of diversion canal feeding river power plant, while figure 3 shows a river power plant in southern Germany of capacity 4 MW [3]. River power plants have three different operating modes. In the first mode, “it can work with a weir and without a slack flow in which the river water streams directly through the turbine without being stopped by a dam”. [3] Figure 2: Scheme of diversion canal fed river power plant [3]. Figure 3: River power plant in southern Germany in wintertime [3]. The second mode of operation uses small storage, which has a weir, and slack flow. The water is stored in a small reservoir. Two main reasons to store water, the first reason is to provide a certain depth of water to make the river navigable for ships. The second reason is to use the reserved water in peak load duration. Capacity of these reservoirs is much smaller than the reservoirs of storage type hydro power plants. The third mode of operation in small river power plants lacks both weir and slack flow. [3] Referring to turbines in figure 1, water wheel does not require weir or slack flow because it runs by the streaming water of a river only. The turbines that are used for the first two operating modes are Kaplan turbines, Propeller turbines, and Francis turbines. They are perfect for small heights of fall, huge masses of water and low pressure. River power plant delivers energy for the base load, its capacity may range from a few kilowatts to several hundred megawatts depending on the volume of water and the height for its fall. [3] 6|Page The main advantage of river power plant that it lacks a reservoir, so people living near the river do not have to leave their house and relocate which reduces the environmental impact [3]. “The output power depends on the river run-off, which may not satisfy the power demand, but still it may be the only choice if a river flows from one country to another country and by agreement, stoppage of flow is not allowed by one country for safety, security, irrigation or drinking water availability in the other country”. [3] 2. Storage Power Plants Storage Power Plants have a natural or abnormal influx of water. Its scheme is shown in figure 5. Two types of turbines are used, Francis turbines are used for fall heights of about 15 to 500 meters, and they can manage a huge amount of water flow. Pelton turbines are also used for fall heights of up to 2000 meters, but they work with a relatively much smaller flow [3]. The pressure of water is very high as the height is high, which means that the plant can generate a large amount of power. Kaplan turbines are not used in storage power plants as the maximum allowed height for them is nearly 25 meters. [3] Storage power plants have two main functions, the first one is to store the electric energy as the potential energy of water and use it when needed as peak load hours. The second one is to compensate for the availability of water caused by seasonal fluctuations. The base load can be delivered only when enough water is available in the reservoir. Storage power plants can deliver a base load for a few months because they can store the winter’s melt water until summer in the reservoir behind a dam. [3] Figure 4: Scheme of storage power plant [3]. 2.1 Operation of Pumped Storage Power Plants Pumped-storage power plants are structured around two reservoirs of water, an upper and a lower reservoir as shown in figure 4. During high power demand, the control gate opens and the water from the upper reservoir goes throw penstock to drive a turbine and a generator to produce electricity, which is used to meet the increased demand. [5] 7|Page When demand is low, electricity is taken from the grid to feed a pump that pumps water from the lower reservoir back up to the upper reservoir. In this way, the water in the upper reservoir stores the electrical energy as potential energy ready to be used when needed. The reservoir acts as a battery. ‘‘The stored energy is proportional to the volume of water and the height from which its falls’’. [5] 3. Oceanic Power Plants This type of hydropower plant has different categories. 3.1. The tidal power plant: It looks as a river power plant but with a dam. However, the water from the ocean side can be stored behind a dam during the high tide. The used turbines are Kaplan or Propeller turbines. The tidal power plant produces a variable amount of energy due to changing the position of earth, moon and sun. [3] Figure 5: Operation diagram of a tidal power plant. [3] 3.2. Wave power plant: Potential energy of waves is converted mechanically through some mechanisms as shown in Figure 7. It uses the energy of waves to pressurize the fluid using a pendulum door (left scheme). Another principle is that the waves press air, which is going through a wind propeller (right scheme) [3]. Figure 7: Scheme of the LIMPET power plant [3]. Figure 6: Schemes of wave power plants [3]. 8|Page 3.3. The oceanic heat power plant: It uses the difference in temperature between the surface of water and deep water to run a circuit, which produces electric energy. However, it is not used in commercial applications nowadays. [3] 3.4. Ocean Current Power Plants: It works as a wind power plant but under water. It converts the energy of the streaming water by rotors similar to wind offshore converters. The movement of water in oceans, which comes from differences of water densities due to temperature differences, is used to drive a turbine. [3] Figure 8: Seagen ocean current power plant [3]. 3.5. Osmotic power plant: The difference in salinity of ocean water and river water is used to produce energy by producing pressure in the water. The pressure is converted by an expansion engine to a rotating energy, which drives the generator. [3] Classification based on capacity of hydropower plants 1. Large hydropower: It has a capacity of more than 15-20 MW up to several GW. 2. Small hydropower: It has a capacity in the range of 0.1 to 15–20 MW. 3. Micro hydropower: It has a capacity of less than 100 KW. [3] Classifications according to load 1. Base load plants. They supply almost constant load, operate at high load factor, and have large capacity. Run off river plants without poundage, and reservoir plants are used as base load plants with low unit cost of energy [5]. 9|Page 2. Peak load plants Run off plants with poundage and reservoir plants can be used as peak loads during lean flow periods. These plants store the water during off peak then, run at peak load periods [5]. Classifications according to Head 1. Low head plants The low head plant operates at head less than 30 m. This needs a dam or a barrage across the river to get the required head. The power plant is located near the dam, so no surge tank is needed. The barrage should have regulating gates to discharge the surplus of water [5]. 2. Medium head plants These plants operate at heads between 30 and 100 meters. An open channel gets the water from the main reservoir to the fore bay where the penstocks carry the water to the turbines [5]. 3. High head plants. The plants operating at heads above 100 m and these plants requires dam, reservoir, tunnel, surge tank and penstock [5]. Construction of hydropower plant 1. Main Parts 1.1. Turbine The turbine is the cornerstone of any hydropower project as it turns water's power into a mechanical energy. Hydraulic turbines have the rotating shaft fitted with a series of blades. The water flowing hits the blades of the turbine, and causes the rotation of the shaft because of its impact, or change of velocity, and pressure change . “While ο¬owing through the hydraulic turbine the velocity and pressure of water diminish resulting in the development of torque and rotation of the turbine shaft” [3]. Depending on the operating criteria, there are various types, or designs of hydraulic turbines in use. [3] 1.2. Electric Generator For a hydropower station, the main purpose of a generator is to transform shaft rotation to electric power, and Error! Reference source not found. shows the construction of the generator. “The basic process of generating electricity in this manner is to rotate a series of coils inside a magnetic ο¬eld, or vice versa” [3]. “This process leads to the movement of electrons inside conductors, which produces electrical current” [3]. In practice, large hydro turbines' speed does not usually exceed 500 rpm and needs a generator of about eight pole pairs, or more. [3] 10 | P a g e 1.3. Transformer and Powerhouse A hydropower plant's transformers and powerhouse establish a connection between the power transmission lines, and the electric generator. It is needed because high voltage is preferred as technical losses are reduced for transmitting power over long distances [3]. Figure 9: Shaft of 70 MW hydropower plant [3]. Figure 10: Sludge deposited in reservoir of 1,000 MW storage power plant [3]. 1.4. Upper and Lower Reservoir Storage hydro power plant have an upper and lower water level with the equipment in between. Until it meets the turbine, the water is contained in a reservoir. “Water is stored in upper reservoir because during the course of the day, or with seasonal changes, different amounts of electricity are demanded from the grid and the availability of water in the river feeding water to the hydropower plant may not match the requirement of power governing the requirement of water for the turbine” [3]. These reservoirs can naturally be available near the power generation site; however, they are often just man-made reservoirs. Figure 10 shows an emptied upper reservoir of a 1,000 MW pumped storage power plant. 2. Structural Parts 2.1 Dam and Spillway Dams are constructed over rivers to avoid the over flow of water, and to create a reservoir, then it is diverted to hydroelectric turbines. For rainy days, the dams capture, and store water to get stable flow across the turbines over the year [3]. The dam should be able to withstand the 11 | P a g e pressure caused by the massive amount of water stored behind it [3]. “There are different types of dams depending upon the shape of their structure such as arch dams, gravity dams and buttress dams” [3]. Spillway is used to allow flood water to be released from a dam to prevent dams from overflowing which may damage, or dam failure [3]. 2.2 Surge Chambers The surge chambers provide reserve space for storage, or supply water in the event of a sudden increase, or decrease in turbine loading [3]. “The role of surge chambers in each case is to prevent damage of equipment, and structure against the effect of change in equipment loading” [3]. 2.3 Stilling Basins The task of the stilling basin is something to do with the spillway. Water can unleash immense powers when flowing over the spillway, which depend on the amount of flow, and it may be difficult to control the harm it does. A stilling basin has the purpose of reducing the danger, directing the water in a calculable, simple way, and making it simpler to control [3]. “One possibility to control the ο¬ooding water is using a regular basin with a pillar in the middle as shown in Figure 11” [3]. Figure 11: Stilling basin with pillar [3]. 2.4 Penstock and Spiral Casing Penstocks are pipes that pass water to the turbines from the reservoir within the station. The water pressure which flows through the penstock is very high. “In some locations where an obstruction is present between the dam, and power station such as a mountain, the tunnel connecting the reservoir, and the power station itself serves the purpose of a penstock” [3]. After passing the grill to prevent large solid objects from entering, the water faces the trumpet-shaped inlet, which is also known as the spiral casing [3]. 12 | P a g e 2.5 Tailrace The tailrace is the lower part of a dam where water flows back into the flow. The tail race extends towards the end as the energetic losses in the constant section tail race should be minimized for an enlarging section. “This loss of energy in outgoing water helps to reduce the back pressure on the upstream side and consequently helps in operating the turbine more efο¬ciently” [3]. 2.6 Pressure Pipes Pressure pipes enable water to reach the system under pressure, and usually prevent any air in. The main function is to move water to the power plant from the reservoir. Figure 12 “shows long pressure pipes of a storage power plant in the Black-Forest region, Germany” [3]. Figure 12: Pressure pipes of a storage power plant [3]. Hydraulic turbines: Hydraulic turbines are responsible for converting the mechanical power produced from water into a rotating motion, which will drive the alternator, they got high efficiency, simple construction, and easy control, they are built in all sizes up to 106 hp and speed varying from 100 rpm to 1000 rpm. [5] They may be horizontal or vertical, the vertical configuration makes the machine require a thrust bearing to carry the heavy load and withstand the runaway speed of the turbine. The horizontal configuration requires a lighter alternator as the turbine runs at high speeds and keeps the turbine house floor above the highest tail race level that’s in case of the tail race level suffer from great variations, thus the vertical configuration is used more. [5] Hydraulic turbines are classified as the following: 1) Impulse type as peloton wheel turbine. 2) Reaction type as francis and propeller turbines. [5] 13 | P a g e 1. Peloton wheel turbine This type operates depending on the difference in velocity of the water, so it is a pure impulse type turbine. It is used with low flow rate of water, large head and usually in a horizontal alignment. The water is converted into kinetic energy using a jet and it hit the buckets that are fixed on the rotor causing it to spin [5]. A spear is placed on the outlet of the jet to control the speed of the rotor, it controls the flow of water coming out of the jet, and a speed governor controls the spear [5]. The number and design of the buckets are an important aspect. The buckets are divided into two symmetrical parts with a splitter in the middle. This configuration enables that the two axial forces produced cancel each other. The bottom part of the bucket is removed, so the water jet will not be interrupted by the incoming bucket achieving the max speed. The number of buckets on the rotor is important as if it is enough that will result in loss of water jet, hence loss of power and lower efficiency [5]. The buckets are made of cast iron, bronze or stainless steel and casted as one piece to avoid fatigue failure. The rotor of the runner is made of cast steel. It is used for 200 m heads and above to avoid using big runner diameters [5]. Figure 13: Peloton turbine [5]. 2. Francis turbine This type is mostly in vertical alignment and operates depending on the difference in both pressure and velocity in the water, so it is not a pure reaction type. It is used with medium flow, and medium head. The runner is placed in the middle of a spiral casing, the casing area decreases starting from the inlet to the outlet to ensure that the water enters to the runner at a uniform speed [5]. The casing is fitted with stay vanes and guide vanes (wicket gates). The stay vanes are used to direct the water from the casing into the runner and reduce water swirling, so they are fixed. The guide vanes are moved to control the flow rate and angle of water entering the runner to provide enough power with load variations and ensure maximum power output [5]. 14 | P a g e The blades of the runner are made in complex shape. As the water enters the runner, it will cause the pressure on one side to be higher than the other, which will exert force on the runner. The bucket shape at the bottom of the blades, will cause a force to be exerted on the blades due to difference of speed, both forces will move the runner [5]. The water is then discharged axially through a draft tube. The tube cross section increases gradually while the end of the tube in submerged under trail race water. This design reduces the effect of cavitation [5]. The runners are made of cast iron for low heads, but in case of above, 100 m the runners are made of cast steel or bronze [5]. Figure 14: Francis turbine [5]. 3. Propeller and Kaplan turbines Propeller turbine is suitable for low heads, large quantity of water, and mostly used in a vertical alignment. Kaplan is like propeller turbine but with adjustable blade runners that makes water able to hit the blades with the maximum angle of attack. This produces maximum lift force, thus increases the efficiency if not operating at full load. This turbine is capable of reverse operation, so it can be used in pump storage systems [5]. The construction of the turbine is almost the same as Francis turbine, draft tube, guide vanes, and spiral casting. The difference is in the shape of the runner, and the shape and number of the blades. The blades are curve shaped allowing water to hit the blades axially. This produces a lift force with a tangential component causing the rotation of the runner. Also there is a continuous twist in the blades from rotor to tip to ensure optimum angle of attack for the whole cross section of the blade. Although it suffers from cavitation problem even more than Francis type [5]. Figure 15: Kaplan turbine. [5] 15 | P a g e Advantages of Hydropower 1. 2. 3. 4. 5. 6. 7. 8. It is a renewable source of energy, and it saves reserved fossil fuel. It is a clean power source, as there is no air pollution or nuclear emission. It is carbon dioxide free, so there are no problems with global warming. It is good for use in the peak demand, due to ability for instantaneous starting, stopping, varying loads, and increasing reliability. Its lifetime is 50 years. The operation, generation, and maintenance costs are lower than other plants. The cost of generation is free from inflationary effects after the initial installation. It helps people in remote areas to make their schools, medical services, road communication, telecommunication, etc.) [3]. Disadvantages of Hydropower 1. hilly or foothill areas are the best choices for constructing hydropower plants, these areas are undeveloped areas, so this requires long transmission lines and leads to large losses. 2. Due to large dams (which are a heavily concentrated load on the earth), the earth may suffer from seismic effects. 3. There is a risk to the safety of the dam during rains. However, the release of large amounts creates floods in the downstream side. 4. At some locations, silt in the water due to soil erosion causes damage to the turbine blades requiring frequent maintenance during rains [3]. Economics of hydropower plant 1. Introduction As the electricity market is always searching for the best choice of generation source to a specific site, which can fulfill the target. The target is that the returning form electricity sales must be equal to operational cost and depreciation, besides providing an acceptable return on the capital invested. Electricity market has different terminology for comparing between different form of generation as LCOE (levelized cost of electricity), cost per MW, etc. The following tables give calculated example for both method (LCOE, cost per MW) 16 | P a g e Figure 18: indicative cost per MW for a selection of existing, approved and proposed hydro projects. (Modified from [8]) Figure 19: typical installed costs and LCOE of hydro power project (modified from [8]) Many software programs as EMPS and Reopt can be used to compare between different generation sources. 2. Framework of economic analysis of hydro power After this brief introduction, economic analysis framework is a tool, which provides guidance to conduct analysis. An example of hydro power economic analysis framework can include cost-benefit analysis, economic impact assessment, cost effectiveness analysis, and risk-benefit analysis [8]. 17 | P a g e 2.1. Cost-benefit analysis: The major benefits and cost components are defined below: 1. Gross power benefits: it reflects the benefits of selling the power, in case of a hydropower plant didn’t exist, and the power has taken from a costly source. 2. Costs of operation: “it reflects the project investment cost, operation and maintenance costs, and anticipated future reinvestment costs” [3]. 3. Costs of environmental measures: “Many licensing decisions enforce operating requirements intended to protect, minimize harm, or enhance the environmental quality”. 4. Benefits of environmental measures: “Environmental initiatives, such as fish screens or, improvements in minimum flow standards, can enhance habitat for fish and wildlife, leisure opportunities, and other environmental quality concerns” [3]. 2.2 Economic impact assessment It just looks at the gross benefits of a particular project and determines the magnitude of activity generated by a particular project [8]. 2.3 Cost effectiveness analysis It identifies the lowest cost option for delivering a particular outcome [8]. 2.4 Risk-benefit analysis The decision rule for this analysis is that: [πππππππ‘π − πππ π‘π − πππ ππ ]>0 Besides, the implementation of economic analysis in two type of hydropower, will take place. [8] 3. Economics of small hydro power plant In the following figure, Figure 20: distribution investment in small hydro scheme (modified from [9]) It generalizes the most investment distribution in small hydro, which can be divide into: 1. Civil works: In the SHP project, the civil works mainly concern with diversion channels, spillways, and powerhouse buildings. 18 | P a g e 2. Electro-mechanical equipment: It considers the basic portion of the total project cost and consists mainly of control, protection devices, turbine, draft tube, etc. Finally, there are many different ways for cost determination depend mainly in collection of data, we will give one of the mathematical models used (in India) for these costs. πΆ (π, π, π ) = π ∗ (π)π ∗ (π»)π Where: a, b, c are coefficients, P= installed capacity in kilowatt (KW), H= head in meter (m) [6]. 4. Economic analysis of pumped storage hydropower plant It can be categorized into four main cost: 1.1. Capital investment cost. 1.1.1. It can be divided into two main part: 1.1.1.1. Total fixed capital cost contains: 1.1.1.2. Electromechanical system, which contains turbines, actuators, generators. 1.1.1.3. Control and monitoring system, as SCADA. 1.1.1.4. Water supply system, as the total cost of water required, can be calculated from the above formula. π€ππ‘πππππ π‘ = (ππ πΆ + π ∗ ππ‘ ) ∗ ππ€ Where: ππ πΆ = upper reservoir capacity of water in cubic meter, N=no. of construction in year discarding the year for filling, ππ‘ =annual loss of water due to evaporation, ππ€ =price of 1 cubic meter of water 1.1.2. Extra costs: It includes, both loans from local and foreign banks. 1.2. Civil works: It depends on the topography of the site. Moreover, it considers as a lion's share of the project cost. 1.3. Operation and maintenance costs are divided into two parts: 1.3.1. Fixed O&M costs: They include the wages and salaries as well as the spare parts. 1.3.2. Back up water cost: The cost includes the operational cost of recovering the evaporated water. 1.4. Pumping cost: The cost of electricity that will be needed in pumping mode to lift water from a low-level reservoir to a high-level reservoir [6]. 19 | P a g e References [1] S. Patil, N., 2021. Electrical Engineering Department Sanjay Ghodawat.... Nitin S. Patil Electrical Engineering Department Sanjay Ghodawat Polytechnic, Atigre Hydro-Electric Power Plant. [Online] dokumen.tips. Available at: <https://dokumen.tips/documents/electrical-engineering-department-sanjay-ghodawatnitin-s-patil-electrical.html> [Accessed 14 January 2021]. [2] National Hydropower Association. History - National Hydropower Association. [Online] Available at: <https://www.hydro.org/about/history/> [Accessed 14 Jan 2021]. [3] Wagner, H. and Mathur, J., 2011. Introduction to Hydro Energy Systems. 2nd ed. Berlin: Springer-Verlag. [4] Planète Énergies. How They Work: Pumped-Storage Power Plants. [Online] Available at: <https://www.planete-energies.com/en/medias/close/how-they-workpumped-storage-power-plants> [Accessed 18 Jan 2021]. [5] GUPTA, B.R., 2017. GENERATION OF ELECTRICAL ENERGY, Eurasia publication house (PVT.) LTD. [6] Abdellatif, D., AbdelHady, R., M.Ibrahim, A. and Abu El-Zahab, E., 2018. Conditions for economic competitiveness of pumped storage hydroelectric power plants in Egypt. Renewables: Wind, Water, and Solar, [online] 5(1). Available at: <https://link.springer.com/article/10.1186/s40807-018-0048-1> [Accessed 14 January 2021]. [7] Førsund, F.n., 2015. Hydropower Economics. 2nd Ed. New York, NY: Springer US, pp.183-199. [8] Knowles, T., 2014. Training Manual Hydropower and Economic Development. [Online] Giz.de. Available at: <https://www.giz.de/de/downloads/giz2014-enhydropower-economic-development-mekong.pdf> [Accessed 13 Jan 2021]. [9] Mishra, S. and Khatod, D., 2012. Costing Of a Small Hydropower Projects. [Online] Ijetch.org. Available at: <http://www.ijetch.org/papers/357-P013.pdf> [Accessed 14 Jan 2021]. 20 | P a g e