EN - ZTC Group

Among renewable energy sources in the Czech Republic are dominated water power plants.CEZ obtains majority share of energy from renewable sources from dam water power plants, not from farms with solar power stations or wind power plants. Currently CEZ has 21 water cannons, that produce about 83% of renewable energy of CEZ (830 MWh)

Hydroelectric power stations have been used since antiquity. Firstly it was to transport (boats and rafts floating downstream rivers), later to drive mechanisms (mills, pumps). First water plant was built in Appleton, Wisconsin in the U.S. in 1882. A large proportion of the total production of electricity produce water power plants in Norway, Switzerland or Canada.

The advantages of water power plants:

Water power plants dont pollute the air, dont destroy landscape and surfacewater or groundwater extraction.Water power plants are highly safe. Ability, that are able to accumulate energy, make water power plants  more efficiency of energy storage.Thanks for high degree of automatic, they contribute to offsetting changes in flows and create new opportunities for revitalizing the environment.

Types of turbines:

Turbines, that are used today, have been developed by gradually increasing improvement of water wheels. Today they have an efficiency about 90%. Today, we often use three basic type of turbines.

Pelton turbine is appropriate, where are big differences in level of surface and low flow. By nozzle is water sprayed under pressure on the vanes of turbine and thus it is fueled.

Francis turbine is suitable for places where you can ensure a constant diference sufrace and level of flow for which is turbine designed.

Kaplan turbine has a fundamental advantage that you can set position of the vanes of turbine. This turbine is widely used where it can provide constant flow and contrast level of surface. These are the most common turbines in the Czech Republic.

Types of water power plants:

 Water power plants as a whole, can be divided into three basic types: Classical water power station, Pumped storager power plant, Tidal power plant

Classical water power plants can be divided into small and large. Small water power stations mean installations of up to 10 MW. Large classical water power plants are primarily on dams in our conditions. The largest classical power plant in Czech Republic is on the Orlik dam with a maximum output 364 MW.

Pumped storage power plant is type of hydroelectric serves as a storage of electrical energy, which goes through the gravitational potential energy of water. Pumped storage hydroelectric power system consists of two tanks, that lie above them. In energy peak is electricity produced by water from the upper tank, that go through a turbine, which impel the generator, to the lower tank. On the contrary, when is surplus of energy for example during night,  the water is drawn from the lower tank back to the upper tank and thus create a supply of water for production in energy peak. Only this technically feasible method, we can storage electricity for longer time by which electricity can be produced on a large scale for longer storage.

Pumped storage power plants are used in The Czech Republic is used: Black Lake with output 1.5 MW, Štěchovice with 45 MW, Dalešice with 480 MW and Long Hillsides with output 650 MW.

Tidal power plants use changing of level of surfice during inflow and outflow. Normally this is the dammed bay with turbines in the dam, which is spinned by influent water during inflow and runoff water during outflow. This kind of power is not still too widespread. For example, in France, was built several experimental devices. The largest is located in Saint Malo. Here is one of the biggest differences in sea level in the world, which reaches up to 14 meters. In France there is a tidal power plant at the mouth of the River Rance, which has 24 turbines with a diameter of 5.8 meters and its maximum power is 240 MW. Other facilities are also located in the U. S. and Canada. Tidal power plants have not proved very effective and often destroy a unique part of the coast and they threat many species of animals.