7 Grid //

It is important to note that the electricity and hydrogen grids used in the scenarios draw upon project data originating from different TYNDP cycles. This is a consequence of the fact that ENTSO-E and ENTSOG conduct their project collection according to the timelines established for their respective TYNDP processes, which, although broadly coordinated, do not follow an identical calendar. As a result, the project information available for the electricity system reflects the TYNDP2026 collection conducted in the first half of 2025, whereas the hydrogen system relies on the project list assembled for TYNDP2024 conducted in Q4 of 2023, complemented by a review to ensure the continued relevance of the data.

In addition to the formal TYNDP project collections, ENTSO-E and ENTSOG carried out a joint request in Q2 2025 for the submission of long term “conceptual capacity increases”, corresponding to potential new interconnections for which preliminary investigations had already been conducted.

These conceptual submissions—required to be technically sound, aligned with EU 2050 climate objectives and jointly agreed between the relevant countries – underwent a dedicated screening process and are used exclusively in the Scenario Grid for the 2050 horizon in both vectors. They are not considered in the TYNDP processes outside the ­scenario framework (including Identification of System Needs, Cost-Benefit Analysis, or the project lists associated with those processes).

Under this approach, the Scenario Grid forms the infrastructural backbone for the modelling of the 2030, 2035, 2040 and 2050 horizons. Its role is not to anticipate system needs nor to prejudge the outcomes of ongoing network development processes, but rather to provide a technically credible, policy consistent and maturity constrained representation of the European transmission system, ensuring that cross vector interactions and long term dynamics are assessed within a coherent and operationally meaningful network environment.

The electricity transmission grid represented in the TYNDP 2026 Scenarios constitutes a critical input to the market modelling framework. Its configuration directly influences simulated cross-border exchange capacities and generation dispatch patterns across all target years. The Scenario Grid is therefore constructed with the objective of reflecting the most plausible evolution of European transmission infrastructure over the planning horizons considered.

The grid representation is derived from the ENTSO-E TYNDP 2026 project collection, which constitutes the most ­comprehensive and up-to-date dataset of planned transmission ­infrastructure available at the time of modelling. This dataset is compiled through a structured data-­collection process involving all ENTSO-E member TSOs and, where applicable, third-party project promoters. It captures both internal reinforcement projects and cross-border interconnection investments across the ENTSO-E perimeter and its neighbouring systems.

To ensure that the scenarios reflect credible infrastructure trajectories, a maturity-based filtering approach is applied. Not all projects in the collection are included in all horizons; rather, infrastructure is incorporated into a given target year only when its commissioning can be considered plausible based on the project’s maturity status at the time of data collection. This methodology is grounded in the principle that scenario credibility requires alignment between assumed infrastructure and the realistic pace of project development, permitting, and construction.

The maturity classification applied to the TYNDP 2026 project set follows the categories defined in the ENTSO-E CBA Guidelines (4^th edition), which establish a standardised taxonomy for assessing transmission project readiness. These categories reflect the progressive stages of infrastructure development, from initial conceptual planning through to active construction. The framework ensures a consistent, transparent, and reproducible basis for determining which projects are sufficiently advanced to be included in each modelling horizon.

This taxonomy provides the analytical basis for the horizon-­dependent inclusion logic. By linking infrastructure assumptions to observable, documented milestones in the project development cycle, the methodology minimises the risk of over- or under-estimating future grid capacity in any given scenario.

The application of the maturity framework yields a ­structured, horizon-dependent selection logic that governs which projects are incorporated into the scenario grid for each target year. This tiered approach reflects the increasing uncertainty associated with longer planning horizons: near-term horizons require a higher level of project ­maturity, while more distant horizons accommodate projects at earlier stages of development.

For projects in the Planned – Not Yet in Permitting category, additional supporting evidence is assessed to determine the plausibility of inclusion. Relevant indications that may support a project’s progression include, but are not limited to:

These indicators are evaluated collectively; no single criterion is deterministic, and the assessment is intended to capture a rounded view of each project’s development trajectory.

Following the maturity screening, the resulting project set for each target year is translated into NTC values for use in market scenario modelling. NTC values represent the maximum commercial exchange capacity available at each cross-border boundary under normal system conditions and constitute the primary interface between the infrastructure assumptions and the market simulation toolchain.

In the context of the TYNDP 2026 Scenario market modelling framework, NTC values define the upper limit of energy that can be traded between bidding zones in each direction at any given time step.

These values are applied exogenously to the market model and directly constrain the optimisation of dispatch and trade flows. It is important to clarify that NTC values do not represent the physical or thermal capacity of the transmission assets. Instead, they reflect a commercial transfer limit derived from system security considerations and coordinated capacity calculation methodologies (including N 1 security criteria and related operational margins). As such, they are a reduced representation of grid capabilities, already internalising operational constraints such as security margins, contingencies, and stability requirements. Within the market simulation, NTC constraints are fully available to the optimisation algorithm at all time steps, without additional endogenous operational limitations. The model can therefore utilise up to 100 % of the NTC value in any given direction whenever economically efficient, based on relative prices, generation dispatch patterns, and demand conditions across bidding zones. No explicit modelling of real-time operational constraints – such as dynamic security limits, redispatch actions, phase-shifting transformers, or flow-based allocation mechanisms – is implemented in the market simulations. Consequently, the use of NTC in the model should be understood as a simplified, zonal representation of cross-border exchange capabilities, consistent with long-term scenario analysis rather than detailed operational modelling.

The 2050 target year warrants specific methodological consideration due to its position at the outer boundary of the planning timeframe. At this distance, infrastructure planning is inherently more speculative, and the project collection alone may not fully capture the grid evolution required to support long-term decarbonisation pathways, energy security objectives, or the integration of emerging energy vectors such as offshore renewable energy and cross-sectoral coupling.

To address this, the 2050 scenarios grid incorporates two additional categories of infrastructure beyond the standard maturity-filtered project set:

Selected “Under Consideration” projects: projects at an early stage of development that, while not yet in permitting, have been identified as strategically relevant for long-term grid development. Their inclusion is conditional on alignment with the scenario narratives and the system needs identified in the TYNDP 2026 Scenario modelling framework.

Long-term conceptual projects: submitted by project ­promoters during the concept project collection window, these represent forward-looking infrastructure concepts that extend beyond the current project pipeline. They may include novel interconnection corridors, offshore grid ­topologies, or reinforcements linked to emerging ­generation centres.

The inclusion of these categories in the 2050 horizon ­reflects the need for scenario-driven, rather than purely project-driven, grid assumptions at longer time scales. It also acknowledges that the realisation of ambitious climate and energy policy targets, as embedded in the scenario ­narratives, may require infrastructure investments that are not yet reflected in formal project pipelines.