Water is a condition for life, life on Earth would be impossible without it, and only 2.5% of the total amount of water on Earth is freshwater. Considering that a large percentage of water is trapped in glaciers or is located deep below the surface, water is the most valuable resource today. Also, we must not forget that freshwater ecosystems are the environment of 50% of all fish in the world and 10% of all animals. The importance and role of water today is reflected in today’s trend of resource use. Hydropower plants, pollution and other harmful activities endanger freshwater habitats and are a threat to the population and the economy. However, water energy (hydropower) is the most important renewable energy source, and at the same time the only one that is economically competitive with fossil fuels and nuclear energy. In the last thirty years, the share of hydropower is 3.3% of total energy from renewable sources, because the use of hydropower has its limitations. These limitations are the presence of fairly fast running water throughout the year, the construction of dams and reservoirs, the cost of building a hydroelectric power plant, and special attention is drawn to raising groundwater levels in the vicinity of the reservoir and the negative impact on flora and fauna. However, despite numerous obstacles, hydropower is increasingly being given importance in the world. Innovative solutions of hydro engineers are being sought, which will annul the harmful effects of the use of water power, and increase the number and capacity of hydro power plants. What is a hydroelectric power plant? Hydropower plants are plants (places) for the production of electricity from water energy. The main parts of the hydroelectric power plant are the accumulation basin, dam, catchment, pipeline, machine building and drain.

In Serbia, the hydro potential contributes with 30% of electricity. Our largest hydroelectric power plant Djerdap is actually a system of one accumulation and one flow hydroelectric power plant, Djerdap I and Djerdap II built on the river Danube, at the exit from the Djerdap gorge. Djerdap I is our largest hydroelectric power plant and represent a strategic element of Serbia’s energy. The plant of 6 hydro units of 171MW each, or 1026MW, provides about 200MW per each unit. The highest energy per year is produced in the hydroelectric power plant Djerdap 1, in just 7 months 3,238,642 MWh, while the other Danube power plant Djerdap II for the same period produces about 938,928 MWh. Djerdap II consists of two power plants with 20 units with a capacity of 540MW. This is not the end, because the construction of the Djerdap III hydroelectric power plant, an accumulation power plant with a total capacity of 4,200 MW, is planned. There are also mini hydroelectric power plants, great potential for electricity production for the needs of mountain facilities, rural households, etc. Although a lot of dust has been raised about the damage to the environment, a lot of space has opened up for innovative solutions in the field of hydropower. The future of engineers is guaranteed as the growing global pollution caused by the use of fossil fuels needs to be replaced by the sustainable use of renewable energy sources.