The Dubnica nad Váhom hydroelectric power plant is a third HPP on the diversion channel and because of maintaining the same flow conditions it is also designed for a flow rate of 2 x 75 m3.sec-1. In case of an urgent need for peak power supply from the whole system of hydroelectric power plants on the Váh river, however, the water needs to be let through at the Ilava and Dubnica HPP´s idly up to 30 m3.sec-1, which together with the flow through these HPP´s yields a maximum flow rate of 180 m3.sec-1 to be used by the downstream HPP´s. The water let through idly, however, will not generate electricity and this is a loss to us.
Slovenské elektrárne operates 31 hydroelectric plants. Their combined output is 1,652.7 MW, representing approximately 38.4% of the Company’s total installed capacity. Majority of the installations is located on the Váh River cascade, or the longest river in Slovakia. On average, the hydroelectric sources generate 2,070 MW annually (consumption of pumped storage power stations excluded), or some 11% of the electricity produced by Slovenské elektrárne.
Because of their very variable power output and operational flexibility, hydroelectric plants are capable to satisfy the swiftly changing demands in the daily-load diagram, pairing nicely with the base load supply covered by nuclear power plants. Slovenské elektrárne has 736.6 MW installed in river hydropower plants and 916.4 MW in pumped storage power stations.