FNA CZ 2026: Czech grid can handle RES growth, but will require more batteries and new gas capacity

If the ERAA 2025 reference scenario is fulfilled, the Czech Republic should not need to develop flexibility beyond its scope in 2030 and 2035 under the FNA methodology. This is one of the main conclusions of the Assessment of the Flexibility Needs and Potential of the Czech Electricity System through 2035, published by ČEPS. However, the result cannot be interpreted as meaning that the Czech system already has sufficient flexibility today. The modelled scenario itself assumes a major transformation of the generation mix, the deployment of battery storage and greater use of demand-side response.

The FNA study, or Flexibility Needs Assessment, was prepared in line with the European regulation on the internal electricity market and using a methodology approved by the European Union Agency for the Cooperation of Energy Regulators (ACER). The common methodology is intended to enable Member States to assess flexibility needs on a comparable basis. ACER approved the methodology in 2025, and the national assessments are subsequently intended, among other things, to provide a basis for setting indicative national targets for non-fossil flexibility.

The Czech FNA assesses 2030 and 2035 and is based on the reference scenario of the ERAA 2025 European resource adequacy assessment. According to ČEPS, this scenario includes forecasts by transmission system operators, reflects current national and European policies (particularly National Energy and Climate Plans and Fit for 55 targets), and is supplemented by studies and expert estimates. Electricity consumption is expected to rise from 69 TWh in 2030 to 74 TWh in 2035, or by approximately 7.2%.

The largest capacity category in the chart is solar photovoltaics. Its installed capacity is expected to reach 9 999 MW in 2030 and 11 065 MW in 2035. Over five years, the scenario thus envisages an increase of 1 066 MW, or approximately 10.7%. A more pronounced relative change occurs in wind power: from 1 485 MW to 2 475 MW, representing an increase of 990 MW, or 66.7%.

Together, solar and wind power are expected to increase installed capacity from 11 484 MW in 2030 to 13 540 MW in 2035, or by around 17.9%. As weather-dependent generation grows, so does the importance of the electricity system’s ability to respond to differences between instantaneous generation and consumption. This ability is precisely what the FNA assesses. Among other things, ČEPS evaluates how much flexibility the system needs to balance differences between consumption and generation from sources dependent on current weather conditions.

Battery storage is a significant component of the scenario. Its capacity reaches 1 723 MW in 2030 and 2 031 MW in 2035, an increase of 308 MW or approximately 17.9%. However, one limitation of this figure is important: the ČEPS chart gives installed capacity in MW, rather than energy capacity in MWh. These figures therefore do not indicate how long batteries will be able to provide their rated output. Information on energy capacity would be needed to assess their ability to bridge longer periods of generation shortage or surplus.

The scenario also envisages substantial growth in gas-fired capacity. Installed capacity of gas sources rises from 3 396 MW in 2030 to 4 754 MW in 2035. This is an increase of 1 358 MW, or virtually exactly 40%.

This development takes place alongside the phase-out of coal. While the chart still shows 932 MW of coal-fired capacity for 2030, it does not envisage any coal in 2035. The scenario therefore cannot be described as a simple replacement of coal with renewable energy sources. It combines growth in solar and wind power with higher gas-fired capacity, batteries, nuclear and hydropower, as well as demand-side response.

Nuclear capacity rises between the two modelled years from 4 099 MW to 4 384 MW, or around 7%, while hydropower increases from 2 174 MW to 2 267 MW, roughly 4.3%. The category of other RES, by contrast, declines from 1 298 MW to 1 120 MW, while electrolyser capacity remains at 128 MW. Demand-side response, referred to as DSR (Demand Side Response), increases from 150 MW to 190 MW, or by approximately 26.7%.

FNA does not track installed megawatts alone

However, the capacity of individual technologies is not the main outcome of the FNA. ČEPS assesses flexibility using four interrelated indicators: residual load, RES integration, rapid changes in output, or ramping, and short-term flexibility. For short-term flexibility, it further distinguishes a commercial component, provided by short-term wholesale electricity markets, and a technical component in the form of balancing services for ČEPS. According to ČEPS, batteries or demand management can help in all of these areas.

The main result must therefore be interpreted precisely. ČEPS states that if the ERAA 2025 scenario is fulfilled, there is no need to develop flexibility beyond its scope from the perspective of the FNA methodology. This is therefore not a claim that the system can manage with its current state, nor that 2 031 MW of batteries or 4 754 MW of gas-fired capacity represent calculated minimum required capacities. They are parameters of the reference scenario on which the assessment was carried out.

This is an important distinction. If the future structure of the Czech power sector were to deviate significantly from the ERAA 2025 scenario, the FNA conclusion could not automatically be applied to such a different development. ČEPS likewise explicitly acknowledges that additional flexibility may be useful even beyond the scenario’s scope – for example, by reducing the volume of curtailed RES generation or enabling their greater deployment.

Moreover, the FNA is not a standalone resource adequacy assessment. ČEPS notes that its results complement the European Ten-Year Network Development Plan (TYNDP), the European ERAA resource adequacy assessment and the Czech MAF CZ, and that these analyses need to be considered together. In other words, a positive FNA result in itself does not mean that the issue of sufficient capacity or security of supply has been resolved in all circumstances.

FNA CZ 2026 can be understood as a test of a specific transformation scenario, rather than confirmation that Czechia has already resolved the issue of flexibility. The 2035 scenario already includes 13,54 GW of solar and wind power, 2,03 GW of batteries, 4,75 GW of gas-fired capacity and 190 MW of demand-side response. The key will be to monitor not only whether these capacities are actually built, but also whether their flexibility is technically and commercially available when the system needs it.

The next article will address precisely this second condition – tariffs, metering, aggregation, data and the twelve measures proposed by the FNA to develop flexibility.