Poland entered August with renewable integration already under visible pressure. PSE had ordered photovoltaic installations to reduce generation on every day from July 20 to 27. Then, in early August, capacity market call periods were announced on August 4 from 17:00 to 19:00 and again on August 6 from 17:00 to 22:00. (PSE) (Money.pl) (Radio ZET)
At first glance, the combination invites a simple explanation: too much solar at one point, followed by too little power later. The evidence points to a more complicated picture. Redispatch and capacity market calls respond to different operating conditions, and there is no basis for assuming that photovoltaic generation reduced during earlier periods would necessarily have prevented a later capacity call.
Together, however, they illustrate a broader challenge. A power system with a growing share of variable renewables has to cope with conditions that can change substantially from one hour to another. At some times it needs generation to fall or consumption to rise. At others, dependable capacity and sufficient reserve have to remain available.
Solar redispatch is becoming a recurring operating issue
The July sequence was part of a longer pattern. According to Poland’s Energy Regulatory Office, URE, PSE ordered 597.26 GWh of non-market photovoltaic generation reductions in 2024. Of that total, 595.17 GWh was attributed to balancing the national power system and only 2.09 GWh to network constraints. The total PV reduction volume was 2,362% higher than in 2023. PSE also ordered nearly 125.1 GWh of wind-generation reductions, with 118.05 GWh related to balancing and 7.03 GWh to network constraints. (URE)
That distinction matters. Renewable curtailment is often associated primarily with transmission congestion, yet the Polish data show that system balancing has been the much larger driver of PSE-ordered PV reductions.
PSE explains that electricity production and consumption must remain continuously balanced. When high potential renewable output coincides with relatively low demand, the system can face an excess of available generation while running short of downward flexibility — the ability to reduce output or otherwise absorb the surplus. Non-market renewable redispatch is used only after other available balancing measures are insufficient. Repeated PV reductions are therefore better understood as a flexibility problem than simply as evidence of “too much solar.” (PSE)
Capacity market calls reflect a different system need
The capacity market operates on another side of the system. Its purpose is to ensure that sufficient dependable capacity is available when reserve conditions become tighter.
On August 4, PSE announced a call period from 17:00 to 19:00. Two days later, another call extended from 17:00 to 22:00. These events require resources carrying capacity obligations to deliver on those commitments; they are not equivalent to household blackouts. (Money.pl) (Radio ZET)
The mechanism had also been activated on June 30, when PSE announced four consecutive one-hour call periods from 18:00 to 22:00. PSE stated that entities covered by capacity obligations had to make the contracted capacity available during those hours. (PSE)
PV redispatch and capacity calls therefore represent different operating conditions rather than two halves of a proven daily cause-and-effect sequence. One highlights the need to manage periods of excess available renewable generation; the other focuses on dependable capacity and reserve when system conditions become tighter. Their common feature is flexibility. More installed generation alone does not guarantee that the right type of resource will be available at the right time.
Poland’s flexibility assessment is part of a wider EU shift
This is no longer only an interpretation of a few summer events. On July 29, PSE published Poland’s assessment of estimated electricity-system flexibility needs for 2030 and 2035. PSE said the report had been approved by URE and submitted to the European Commission and ACER. (PSE)
The European context makes that development more significant. ACER approved a common EU methodology for national flexibility-needs assessments in July 2025. The framework requires Member States to assess how much non-fossil flexibility their systems need and distinguishes between network flexibility and broader system flexibility. National results are intended to inform indicative targets for resources such as storage and demand response. (ACER)
Poland’s report is therefore part of a wider shift in European electricity-market planning: flexibility is being treated as something that can be assessed and supported through market design, rather than as a general benefit that simply appears when more renewables are built.
Flexibility can come from several sources — flexible generation, demand response, cross-border exchange, storage and network measures. PSE itself identifies flexible consumption and energy storage among the options for making better use of periods of surplus electricity, while specifically noting thermal storage in that context. Batteries are one part of this wider toolkit, not a single answer to every constraint. (PSE)
Where batteries fit — and where projects become more complicated
A BESS can respond in both directions. It can charge when electricity is abundant and discharge when electricity becomes more valuable to the system. That makes energy shifting an intuitive response to increasing variability, but the commercial case goes beyond a simple “charge at noon, discharge in the evening” model.
A real project needs suitable grid access, adequate power and energy duration, state-of-charge management and access to markets that reward the services it can provide. Duration changes what a battery can realistically do, while committing capacity to one service can restrict what remains available for another. More intensive cycling also affects degradation and long-term performance.
This is why optimisation is becoming part of the Polish BESS story.
Greenvolt Power’s 200 MW / 800 MWh Turośń Kościelna battery project entered commercial operation in July 2026, according to Entrix. Energy-Storage.News reported that the four-hour project is connected at 110 kV and forms part of Greenvolt’s Polish capacity-market portfolio. Entrix, which is responsible for optimisation and trading, says the battery will be dispatched using a multi-market strategy and is due to participate in Poland’s capacity market from 2028. (Entrix) (Energy-Storage.News)
That project provides a real-world counterpart to the system discussion. It shows how the value of a large BESS can depend on allocating battery capability across several markets rather than relying on a single arbitrage opportunity.
Entrix and Greenvolt have also agreed to optimise and trade a wider 1.3 GW / 5.2 GWh Polish BESS portfolio across markets including FCR, aFRR, day-ahead and intraday trading. Because this information comes from companies directly involved in the projects, it should be read as commercial evidence rather than an independent market forecast. (Entrix)
The next question is whether flexibility becomes bankable
The physical case for flexibility is becoming clearer. Repeated PV redispatch shows that periods of high renewable availability can create real balancing pressure. Capacity-market calls highlight a different requirement: dependable resources still matter when reserve conditions tighten. Poland’s formal 2030–2035 assessment, together with the EU-wide framework approved by ACER, shows that this is moving into long-term system and market planning.
For storage developers and investors, the harder question is how much of that system need can be converted into predictable project revenue. Capacity payments, balancing services, wholesale trading, grid access, storage duration and optimisation strategy can all affect project economics. Turośń Kościelna provides an early example of how that value may be spread across more than one market.
Poland’s next challenge is broader than adding more renewable or battery megawatts. The system has to absorb electricity when renewable production is abundant, maintain dependable capacity when conditions tighten, and create market signals that reward resources capable of moving between those needs.
For the Polish storage market, the key signal to watch is whether this growing need for flexibility develops into revenue structures strong and predictable enough to make the next wave of BESS projects bankable.
