Croatia’s energy regulator said on 23 July that negative-price hours on CROPEX rose from 196 in 2024 to 257 in 2025. The regulator linked the increase, reported as about 31%, to the growing influence of renewable generation and more frequent periods when supply exceeds demand. The report also quantified the scale of exposure across the year.
The 257 hours equate to roughly 2.9% of the year, or about 10.7 full days of continuously negative pricing. These hours were concentrated mainly in spring and on sunny Sundays. During those periods, electricity demand was weak and photovoltaic output was strong. Some subsidised generators continued operating under mandatory offtake obligations or legacy support arrangements.
Beyond negative pricing: capture-price pressure for solar projects
The commercial effects described by the regulator extend beyond intervals when prices fall below zero. Solar developers face a larger set of periods in which prices remain positive but drop below project operating assumptions. A plant selling at €5–€20/MWh during its highest-output hours can experience capture-price erosion even if it does not run during a negative-price event.
Newer Croatian market-premium contracts include provisions that can suspend support when prices remain negative under specified conditions. This shifts more of the market signal to generators. The same contract design can also increase revenue volatility for lenders and equity investors unless projects have storage, curtailment rights, or more sophisticated power-offtake arrangements.
Battery capacity and regulatory timeline for wider deployment
Croatia had approximately 11 MW of battery storage capacity in March 2026. The country’s first large-scale system entered trial operation early in the year. The regulatory framework needed for broader deployment is still being completed, with more substantial additions expected from 2027.
The regulator’s assessment frames a growing mismatch between market exposure and flexibility availability. Negative-price exposure is described as becoming structural, while utility-scale storage remains at an early stage of development. Early battery projects could face less crowded balancing and arbitrage conditions, but they also encounter unresolved issues including network tariffs, charging status, licensing requirements, and how potential double grid fees would be treated.
Implications for capture-rate modelling under CROPEX price patterns
The regulator’s data is presented as relevant to solar investment screening based on CROPEX outcomes. It highlights that capture-rate forecasts need to incorporate at least 257 negative-price hours, along with additional near-zero-price periods. The same modelling should also reflect the possibility that continued photovoltaic expansion will deepen the midday price discount before sufficient storage capacity becomes available.
The reported trend also points to a shift in how electricity value is determined as solar capacity expands faster than flexibility resources. In that setting, the value of generation depends not only on output levels but also on timing relative to when power reaches the market.
