Managed by Ignitis Gamyba, Kruonis Pumped Storage Hydroelectric Plant (KPSHP) is situated north of the town of Kruonis in Kaišiadorys district and is the only power plant of its type in the Baltic region. It is one of the new-generation energy units.
KPSHP is used primarily to balance electricity supply and demand. It helps to prevent energy system accidents and liquidates their aftermath. Currently, KPSHP can ensure 94% of the total necessary energy reserves for Lithuania in case of emergency.
During periods of low demand, usually at night, the KPSHP is operated in pump mode and uses cheap surplus energy. It raises water from the lower Kaunas Lagoon to the upper 303 ha reservoir that is 100 m above Kaunas Lagoon water level. During peak-demand periods (daytime) with regular energy demands, it operates like a traditional hydroelectric plant. In order to prevent and liquidate system accidents, it is important for units to ensure a rapid reserved capacity. KPSHP can be switched on at full power in less than 2 minutes, if necessary. The KPSHP units can be started automatically by the anti-accident system and can cover any deficit in power. Other equally important functions of KPSHP are the ability to level the system load balance, to regulate voltage and frequency, and to start the system after a total system blackout.
The KPSHP generated 0,72 TWh electricity in 2020.
The decision to build a powerful thermal power plant was made on 18 April 1960. When planning the construction of a nuclear power plant for the future, it became obvious, that a pumped storage plant, which would regulate the operation of the energy system and level load balance (eg by improving the quality of electricity supply and compensating energy deficiency in case of an accident), was essential. After considering six sites for the construction of the plant, Kruonis appeared to be the most suitable location for a potential power plant with potential to generate 1600 MW of eletricity. The main advantage of Kruonis PSHP was the opportunity to use the 63.5 km² Kaunas Lagoon for the lower pool.
Four years were spent on detailed designing. The technical project was accepted in 1978, and the cornerstone of the KPSHP building was completed in 1984. Eight units of 200 MW were planned for the initially designed electrical capacity of 1600 MW, but later this amount was reduced to four units, but with increased capacity of 225 MW. The first unit began operating in 1992, while the fourth one – in 1998.