Kruonis Hydro Pumped Storage Power Plant is located north of the town of Kruonis in Kaišiadorys district of Lithuania. With an installed capacity of 900MW, the project primarily helps in maintaining electricity supplies by providing a grid energy storage.

The power plant is managed by Ignitis Gamyba, a subsidiary of state-controlled energy holding company Ignitis Group.

Kruonis Power Plant features four hydro units of 225MW each. The first unit of the project started operations in 1992, while the fourth unit was launched in 1998.

As part of an expansion, a fifth unit is being constructed at the power plant. It is expected to become operational by the end of 2026.

In 2020, the Kruonis Pumped Storage Project generated 0.72 terra watt hours (TWh) of electricity.

According to Ignitis Gamyba, the project ensures 94% of the total energy reserves for Lithuania necessary during emergencies.

History of Kruonis Hydro Pumped Storage Project

A decision to develop a thermal power plant was taken in April 1960. Subsequently, the need for a pumped storage plant was recognised while planning the construction of a future nuclear plant.

The pumped storage plant will help in regulating the operation of the energy system and level load balance.

The Kruonis site, which offers advantage of using the 63.5km2 Kaunas Lagoon for the lower pool, was selected out of six potential sites.

Detailed designing of the project took four years, which was followed by its technical acceptance in 1978.

The cornerstone of the hydro pumped storage power plant project building was completed in 1984.

Initially, eight units of 200MW each were planned providing the project with a total capacity of 1,600MW.

However, the number was reduced to four units with increased capacity of 225MW each.

To promote energy production from renewable sources, the Kruonis Project has started using solar energy.

A battery of solar collectors is used to heat water to meet the hot water demand for the plant‘s internal consumption.

Kruonis Pumped Storage Hydro Project details

The pumped storage project consists of four units of 225MW capacity each, with overall efficiency factor of 0.74.

Each unit has operational range of 0-225MW in generator mode and 220MW in pump mode.

The project operates in pump mode, during periods of low demand at night, and uses surplus energy to raise water from the lower Kaunas Lagoon to the upper 303hectare reservoir situated 100m above the lagoon’s water level.

During peak demand periods, it operates like a traditional hydroelectric plant allowing water to flow from the upper pool to the lower one to generate additional electricity.

The plant can generate 900MW for about 12 hours with a completely filled upper reservoir. It supplies electricity via a 330kV electricity line to a power plant in Elektrėnai and Kaunas.

In case of systemic failures, the plant can be connected to the grid in less than two minutes and can compensate the power deficit.

Kruonis Hydro Pumped Storage Power Plant is the only power plant of its type in the Baltic region.

Project expansion details

The expansion of the Kruonis Pumped Storage Hydro Project is underway which includes the construction of the flexible fifth 225MW unit.

The fifth unit will operate at range of 110-225MW in pump mode and at 55-225MW in generation mode.

The target overall efficiency factor of the fifth unit cycle is 78%, which is four units higher than the current units.

Feasibility and environmental assessment studies were conducted successfully for the expansion and technical specifications have been prepared.

The addition of the new unit will ensure the largest share of the secondary active power reserve, amid increasing production capacities. The construction of the new unit will involve an investment of around €150m.

Key Contractors involved

In April 2023, Voith Hydro won a contract to deliver the flexible pump turbine unit needed for the expansion of Kruonis Pumped Storage Project.

Voith will be the general contractor responsible for the design, manufacturing, transport, assembly, and commissioning of the unit on site.

HOLO Projects was selected to modernise the electrical protection systems of all four power generators of the Kruonis Project, main transformers, and a 330-kW bus bar in 2012.