Czech Republic launches its largest energy storage facility. Its role goes beyond storing PV energy

A battery energy storage system with a power output of 37.95 MW and a capacity of 41.7 MWh has begun operating in Modlany, Czech Republic. The facility works alongside a 42.7 MW photovoltaic farm, but it was not built solely to shift solar generation into the evening hours. Its primary task is to balance the power system and stabilize frequency.

The storage system can deliver full power for around 66 minutes

According to CNTE, the storage facility in Modlany consists of 11 STAR T-285 containers. Each provides 3.45 MW of power and 3.793 MWh of capacity.

In total, the system therefore reaches 37.95 MW of power and 41.7 MWh of capacity. The facility uses lithium iron phosphate cells and liquid cooling. According to the manufacturer, round-trip efficiency exceeds 93%. The system can also charge and discharge at a power level corresponding to its capacity.

This means it can operate at full power for around 66 minutes. It is therefore not an energy storage system designed primarily for shifting generation over several hours. CNTE says its equipment supports configurations ranging from one to four hours. However, the configuration used in Modlany clearly favors the rapid delivery of high power.

This is not just a conventional battery for a photovoltaic farm

The storage facility is part of the energy park in Modlany. The project also includes a photovoltaic farm with a capacity of 42.7 MW.

The battery can store surplus solar generation and discharge the energy later. However, its power-to-capacity ratio points to a broader operating model. The system has been connected to a major high-voltage substation. This allows it to respond quickly to the needs of the Czech power grid.

The facility is intended to provide frequency regulation and balancing services. It can also reduce short-term fluctuations in photovoltaic generation. The storage system therefore does not serve solely as a battery for the solar farm. It is also a separate flexibility asset that can provide services to the grid operator.

The solar farm was built on 30 hectares of former mining land

The energy park was developed on around 30 hectares of post-industrial land. In the past, the area was associated with lignite mining. The degraded site has therefore been given a new energy-related purpose.

According to Greenbuddies, the solar farm uses more than 58,300 photovoltaic panels. Each panel has a rated capacity of 720 Wp.

The project investor is Katemo Group, while Česká spořitelna is the financial partner. Greenbuddies was responsible for project delivery under an EPC contract.

The contractor’s data from the construction stage differs slightly from CNTE’s later announcement. Greenbuddies reported a battery power rating of around 35 MW, while the supplier ultimately stated 37.95 MW.

The Czech Republic is already preparing larger energy storage projects

According to CNTE, the facility in Modlany is the largest completed battery energy storage system in the Czech Republic. However, this is a claim made by the technology supplier rather than an official ranking issued by the regulator.

Larger projects are already being developed in the Czech market. Some of them, however, are still at the delivery, construction or commissioning stage.

The key takeaway, however, concerns the direction of development. The Czech Republic is combining a photovoltaic farm, energy storage and access to a high-voltage grid connection. Such a setup makes it possible not only to sell electricity but also to provide grid services. The storage system is therefore becoming a system-level asset rather than merely an addition to renewable energy sources.