Water energy

In Slovakia, water energy is the most widely used renewable energy source for electricity production.

Water covers a larger part of the Earth’s surface. Its condition is not static and its movement can be observed in various forms (kinetic movement, evaporation), which is caused by the space in which this energy can be converted to electric energy, a so-called water cycle. This process of conversion is not possible in all stages of the water cycle. The most efficient process of conversion of the water energy to electric energy is the conversion of kinetic, pressure and potential water energy to mechanic energy and subsequently to electric energy. Electric energy produced from water is relatively highly available and uncomplicated.

Energy can be obtained from water by changing the flow (kinetic energy), pressure (potential energy), or both of these types of energy in parallel in a suitable part of the flow. This conversion shall be performed by the water power plant. Thus, water power plants work on the principle of conversion of mechanic energy of the water to electric energy. Energy from water is usually obtained by development of dams on the river and creation of a water reservoir that keeps the water and passes it to the turbine through a feeding channel. Using the water pressure, the turbine powers the generators which produce electric energy. The mechanic energy of the water is converted to the mechanic energy of the shaft which is then converted to electric energy with the help of electric generators. The electric generator of a water power plant very efficiently converts mechanic energy to electric energy. Based on the output, we divide water power plants into small (up to 10 MW) and large (above 10 MW). More attention should be paid to small water power plants which are considered RES. The location of a water power plant with relation to the river flow may be either direct (directly on the flow), or indirect (outside the flow), a so-called derivation power plant.