4 TYNDP 2026 Scenario Framework //

In previous cycles, the TYNDP Scenario framework consisted of a fully bottom-up NT+ Scenario alongside with two deviation Scenarios – Distributed Energy (DE) and Global Ambition (GA) – which illustrated alternative decarbonisation pathways toward 2050.

Under the new ACER’s TYNDP Scenario Framework Guidelines, this structure has been streamlined: the NT+ Scenario serves as a Central Scenario with the core reference aligned with national and EU policy targets.

The previously defined additional deviation scenarios are no longer maintained in their original form; instead, the framework introduces two Economic Variants: a High Economic Variant (HEV) and a Low Economic Variant (LEV). These variants are designed as stress tests applied to the Central Scenario and should not be interpreted as directly comparable stand-alone scenarios. The following section details the framework upon which the TYNDP 2026 Scenarios are based.

The TYNDP 2026 Scenarios are built on a two-step approach, distinguishing between the National Trends (NT) data collection and the Central Scenario National Trends + (NT+).

The National Trends (NT) data collection reflects energy demand and supply data submitted by electricity and gas TSOs based on national policies, including National Energy and Climate Plans (NECPs) complemented by relevant national strategies and EU policies. As such, NT represents a bottom-up view of the energy system derived from nationally reported inputs, without further adjustments.

According to the European Commission’s latest communication on the EU-wide assessment of the final updated NECPs (28 May 2025), the latest available NECPs demonstrate improved alignment with EU’s 2030 targets compared to the draft updated NECPs. However, some gaps with respect to EU-wide targets remain at aggregated level.

To ensure consistency with EU targets, a gap-filling methodology is applied to the NT dataset. This methodology introduces additional adjustments at EU level, while applying proportional corrections at country level.

The outcome of this process is the Central Scenario (NT+), which represents the target-compliant scenario used as the main reference for the TYNDP 2026 analysis.

The methodology follows a transparent and harmonised framework, ensuring neutrality and equal treatment across all countries. It formed an integral part of the consultation process, offering stakeholders the opportunity to give feedback on the approach. While efforts have been made to improve the methodology, there is still room for further improvement; however, this would require a more significant revision of the bottom-up data, which is based on the NECP complemented by relevant national strategies and EU policies.

Further information on the gap-filling methodology is provided in the “TYNDP 2026 Scenarios Methodology Report”, Chapter 9. Impacts of the gap-filling methodology application are presented in chapter 9.2.2 Final Energy Demand in the NT+ Scenario after the gap-filling methodology and chapter 10.4 Assessment of carbon budget and targets. More information on alignment of the NT data collection provided by TSOs and national climate and energy policies is available in Annex I.

While supply and demand inputs are based on NECPs, the electricity and hydrogen grids are based on TYNDP projects (ENTSO-E TYNDP 2026 and ENTSOG TYNDP 2024 Project Collections). For further information, see Chapter 8 in the TYNDP 2026 Scenarios Methodology Report.

The 2026 scenario framework includes one Central Scenario (NT+) reflecting the latest updated national strategies, following the application of the gap-filling methodology described in Chapter 9 of the TYNDP 2026 Scenarios Methodology Report, and two Economic Variants, representing higher and lower economic growth trajectories respectively.

For the current 2026 cycle, the economic variants exercise is applied to the 2035 and 2040 target horizons. It thus complies with Regulation (EU) 2022/869 (“TEN-E Regulation”) and the ACER TYNDP Scenarios Framework Guidelines. Figure 1 illustrates the scenario time horizon framework used in the TYNDP 2026 cycle.

The Central Scenario (or NT+) represents the core reference for the TYNDP 2026 scenarios and is derived from the National Trends (NT) data collection following the application of the gap-filling methodology described above. As such, it reflects a target-compliant scenario that combines nationally reported inputs with adjustments to achieve alignment with EU climate and energy objectives.

The NT dataset is based on data collected from electricity and gas TSOs, reflecting the latest available national and European energy and climate policies and strategies. By the cut-off date (24 December 2024), 24 NECPs out of 27 had been updated.

Some differences between the updated NECPs and the submitted datasets were identified. These mainly relate to differences in data granularity, the need to provide information beyond the NECP time horizon, and the application of fallback solutions where requested data were not available. Further details on data alignment and fallback approaches are provided in Chapter 11.

In order to ensure consistency with national policy developments, 80% of EU27 electricity and gas TSOs validated the submitted datasets with NRA/Ministry in their respective Member States (see TSO Survey Outcomes, Annex I). Where datasets were incomplete for certain energy carriers and additional sources or assumptions were required, the applied methodologies and resulting data were subject to stakeholder feedback through public consultation and the SRG.

In addition to the Central Scenario (NT+), two Economic Variants (HEV and LEV) are developed to assess the sensitivity of the energy system to alternative economic conditions.

These variants represent higher and lower economic growth pathways and are not intended as standalone scenarios with separate storylines, but as targeted stress tests of the scenario framework.

The Economic Variants are derived from the underlying National Trends dataset (NT), prior to the application of the gap-filling methodology. This ensures that the variants reflect alternative macroeconomic conditions based on national inputs.

The variants deviate from the reference assumptions through a limited set of selected parameters, chosen for their relevance and impact on system outcomes. Parameter changes are applied symmetrically across both variants to ensure balanced comparison and interpretability of results (e.g. + x % in one variant, – x % in the other).

The HEV represents a higher Gross Domestic Product (GDP) growth than NECPs indicate, including higher sectoral activity, purchasing power or willingness to pay, stronger focus on innovation and risky investments, and a stronger focus on sustainability as well as long-term views on investment decisions.

The LEV represents a lower GDP than NECPs indicate. It includes a more moderate or lower levels of sectoral activity, purchasing power or spending opportunities, less focus on innovation and a more business-as-usual approach. It involves stronger focus on cost and affordability, and a short-term view on investment decisions.

The Economic Variants are developed for the 2035- and 2040-time horizons , and the methodologies used for their construction were subject to stakeholder consultation.