In Lithuania, the recent expansion of renewable capacity has increasingly led developers to combine solar, wind and battery storage within shared control frameworks. On paper, this convergence promises operational efficiency. In practice, however, it exposes a series of familiar constraints: bringing multiple assets into a single balancing unit is rarely straightforward.
When multiple facilities are brought together, variations in control capability, metering equipment or data interfaces quickly become apparent. Projects that appear routine at the outset can take significantly longer. In one case, a two-month schedule extended to four due to system incompatibilities and weather-related testing delays.
Slower procedures and shifting requirements
Both operators and developers continue to climb the learning curve. Processes that once took a few days can now take up to 40 working days. Mathematical model verification alone has expanded from two weeks to two months, driven by a surge in project submissions and new regulatory checks. As a result, commissioning now typically requires four to five months instead of two.
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Manufacturers frequently promote new controllers and inverters with advanced storage functions. However, many of these features remain incomplete or require extended testing and additional programming. Developers should confirm that every function listed in a datasheet is not only necessary but operational before relying on it in project design.
Operating challenges in battery systems
Uneven cell balancing is a common issue. Individual cells may charge or discharge at different rates, leading to false state‑of‑charge readings and gradual capacity loss. Automated or scheduled balancing is therefore essential to maintain performance.
Thermal management presents similar challenges. In one case, a storage system located in an unheated warehouse repeatedly failed to charge during low winter temperatures. In another, unnecessary continuous heating consumed nearly as much power as the system generated. Effective temperature control must consider both heating and cooling across seasonal conditions.
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Since May 2025, all new energy projects in Lithuania, including solar, wind and battery storage, must comply with cybersecurity standards. Previously, compliance was often deferred, but since September the distribution operator ESO has required verified cybersecurity reports before granting permission for grid operation. As a result, these requirements now need to be integrated into project planning from the outset.
Outlook
The Lithuanian experience indicates that integrating renewable generation and storage involves more than technical capability alone. It depends on coordination between developers, manufacturers and grid operators, supported by clear communication and a degree of flexibility as projects progress. Each project contributes to this shared learning process, while gradually moving the system towards a more stable, data‑driven energy future.
By Dr. Šarūnas Stanaitis and Manfred Gorgus
