Technological gem in the middle of a nature park
Čierny Váh has two primacies. It is our biggest pumped storage power plant and the largest Slovak hydro power plant with installed output t of 735,16 MW. It is called a technical wonder of the country. It is composed of the upper and lower reservoirs interconnected with three underground pipes. They descend almost half a kilometre.
Both reservoirs are attractive for tourism. You can admire the panorama of the High Tatras too from the upper one, situated in the Low Tatras National Park 1,160 meters above sea level. There is cycle route from Svarín going here; you can turn to Východná village roughly in the mid of the route.
If you get a permit from Lesy SR (Forests of the Slovak Republic, a state enterprise), you can drive your car to the upper reservoir. Forget about your car in winter, you can get there walking or skiing only. The personnel from the power plant only may use the lift hidden in the hill. There is a second alternative. To go upstairs. However, there are 2,320 stairs!
The Danube River, with an average flow of 2,025 m3 per second would need 30 minutes to fill the reservoir. The same capacity could feed the Niagara Falls for over half hour.
Slovenské elektrárne take care of the environment. The lower reservoir is an official bio-corridor for some species of migrant birds which fly over it. At the same time it is home for brown trout, SE together with fishermen from Lesy SR have brought the trout in order to obtain an extra increase of its population.
Important for the power grid
The power plant itself is situated nearby the lower reservoir. It has an irreplaceable role in the sector of power generation for regulating deviations in the grid. When there is a shortage of electricity it is able to start up the turbine and operation, hence to generate electricity in record-breaking 70 seconds. We can generate as much as 3,800 MWh of electricity in 5 and half hours from the water in the upper reservoir.
During the night when, on the other hand, there is sufficiency or surplus of electricity in the course of 8 hours we pump the water back to the upper reservoir.
We may shut down Čierny Váh pumped storage hydro power plant only in the period when none of our four nuclear units is in outage. This measure is for the sake of the safe and reliable power supply.
Čierny Váh is able to cover for a potential shut-down of one reactor unit for up to five hours without any problem.
In summer 2017 we completely drained the reservoir because of the two-month outage during august and September. Planning of the outage of that kind takes one year. “In the past this kind of outage with emptying of the upper reservoir was done every two years. Measuring, though showed us that is sufficient to do it once in five years”, Vlastimil Majerčák, hydro power plants director, explains.
At present, pumped storage power plants are the most common, the cheapest and the most reliable energy repositories.