What are some disadvantages of hydroelectric power plant? The disadvantages of the hydroelectric power plant are as follows. The hydroelectric power plant can be developed only where the large quantity of water is available. The hydroelectric power plant cannot be used where there is lack of water supply. Dams may fail which may cause flooding. The capital cost of the generator is high. The distance between the hydroelectric power plant and load center is more so the longer transmission line is required which increases costs. Initial civil engineering costs may be high. These are some disadvantages of the hydroelectric power plant.