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Open-TYNDP Capacity Trajectories

Motivation

PyPSA-Eur allows the optimizer to freely expand any extendable technology up to whatever capacity minimizes total system cost. For variable renewable energy sources (wind, solar) and storage this freedom is often over-optimistic: the model can install far more capacity than real-world supply chains, political constraints, or regulatory processes would ever permit within a given time period.

The Open-TYNDP project uses the capacity trajectories from ENTSO-E's Ten-Year Network Development Plan (TYNDP). These trajectories encode the minimum and maximum buildout that European Transmission System Operators (TSOs) report per technology, country, and year. PyPSA-AT ingests these trajectories and enforces them as p_nom_min / p_nom_max bounds for EU country regions.

Austria and Germany are excluded

Austria (AT) and Germany (DE) receive their dedicated calibration functions in PyPSA-AT and -DE, respectively. instead of Open-TYNDP. They are excluded via the skip_countries configuration key.

Covered Technologies

The following PyPSA carriers are constrained by TYNDP trajectories:

PyPSA-Eur carrier Component Constraint mechanism
onwind Generator p_nom_min / p_nom_max set directly
solar rooftop Generator p_nom_min / p_nom_max set directly
solar + solar-hsat Generator Combined linopy constraint (see below)
battery discharger Link (port 1) p_nom_min / p_nom_max set directly
home battery discharger Link (port 1) p_nom_min / p_nom_max set directly
H2 Electrolysis Link (port 0) p_nom_min / p_nom_max set directly
nuclear Link (port 1) Extendable Link synthesized first, then bounded — myopic years only (see below)

Utility scale Solar PV: flat-panel and single-axis tracking (hsat)

The TYNDP solar-pv-utility trajectory covers the combined deployment of solar (flat-panel) and solar-hsat (single-axis horizontal tracking). Rather than forcing a fixed split, PyPSA-AT adds a linopy constraint that enforces the joint floor and ceiling over both technologies, leaving the optimal technology mix to the solver:

p_nom_opt[solar @ loc] + p_nom_opt[solar-hsat @ loc] >= floor
p_nom_opt[solar @ loc] + p_nom_opt[solar-hsat @ loc] <= ceiling

Implementation Assumptions

Brownfield deduction

For planning horizons beyond 2025, existing brownfield capacity is subtracted from the trajectory bounds so that the bounds represent the additional capacity still available to build:

effective_p_nom_min = max(0, traj_p_nom_min - existing_brownfield)
effective_p_nom_max = max(0, traj_p_nom_max - existing_brownfield)

End-of-life assets are removed by the upstream add_brownfield step before the trajectories are applied, so existing_brownfield reflects only assets that remain economically active.

For the 2025 base year p_nom_min is set to zero for all non-nuclear carriers. The 2025 investment optimum should not be pre-determined by a floor constraint.

Nuclear: a conventional carrier

Unlike wind, solar, and storage, nuclear is a conventional carrier in PyPSA-Eur. It is represented by one or more non-extendable vintage Links per location (bus0="EU uranium", bus1 = electricity bus, bus2="co2 atmosphere"), all created by add_existing_baseyear. Because no extendable variant exists, the trajectory bounds would have nothing to attach to.

register_extendable_nuclear (in mods/network/potentials.py) closes this gap. For each location it synthesizes the missing component — a single extendable Link whose newest vintage supplies the full attribute row (buses, efficiency, capital_cost, ramp limits, …), with p_nom reset to zero and build_year set to the current horizon. apply_trajectories then writes the p_nom_min / p_nom_max bounds onto it at port 1 (electricity output), exactly as for the other Link carriers. The vintages are left untouched and carry the brownfield as a fixed floor.

Myopic years only

Nuclear stays non-extendable in the 2025 base year, mirroring PyPSA-Eur's treatment of conventional technologies. The extendable Link is synthesized and bounded only in myopic horizons (2030 onward); no extendable nuclear is created and no nuclear trajectory is applied for the base year.

Because an unbounded extendable nuclear Link would let the solver build unlimited nuclear, register_extendable_nuclear fails fast rather than leaving a stray component. It raises if the network contains no nuclear vintages, if a non-skipped nuclear location lacks a trajectory, or if the synthesized name collides with an existing component — guaranteeing every created Link is bounded by the subsequent apply_trajectories call.

Geographic aggregation

TYNDP uses its own bus codes (e.g. ITA0, ITN1, SE01). PyPSA-AT maps these to PyPSA-AT location codes via an explicit dictionary in mods/pemmdb_overwrites.py. Key rules:

  • Sub-national TYNDP zones are resolved to the corresponding PyPSA-AT cluster code (e.g. ITSI → IT1 for Sicily, GBNI → GB1 for Northern Ireland).
  • Multiple TYNDP buses that collapse to the same location have their p_nom_min and p_nom_max summed.
  • Kosovo (XK) has no TYNDP entry; it inherits Serbia's (RS) trajectory as a proxy.
  • Cyprus (CY) is not modeled in PyPSA-AT and is excluded from the aggregated trajectories.
  • Northern Ireland (GB1) has no H2 Electrolysis trajectory; its bounds are set to zero.

Backward extrapolation for 2025

The TYNDP source data starts at 2030. A synthetic 2025 row is created with zero values and then extrapolated backward using the slope between the two earliest non-zero data points per group. The extrapolated p_nom_min is clipped to zero and can never exceed p_nom_max.

TYNDP scenario

The default scenario is All, which is the only scenario in the current dataset that covers every technology. Selecting DE, GA, or NT will cause a runtime error due to missing technology entries.

Nuclear is the exception: TYNDP provides it per scenario (DE/GA/NT) rather than under All. Since downstream readers do not filter by scenario, collapse_nuclear_scenarios (in scripts/open-tyndp/build_tyndp_trajectories.py) reduces nuclear to one row per (bus, pyear): when All is selected it takes the smallest p_nom_min and largest p_nom_max across the three scenarios (the widest band); when a concrete scenario is selected it keeps that scenario's values.

Example Data

The table below shows raw TYNDP trajectory data for France (FR00). Nuclear is absent here because it has no native All entry — TYNDP provides it only per scenario (DE/GA/NT), which PyPSA-AT reconciles into the All set via collapse_nuclear_scenarios (see TYNDP scenario above).

Technology Scenario Year p_nom_min (MW) p_nom_max (MW)
H2 Electrolysis All 2025 0.0 0.0
H2 Electrolysis All 2030 0.0 9 999.0
H2 Electrolysis All 2035 0.0 19 999.0
H2 Electrolysis All 2040 0.0 29 999.0
H2 Electrolysis All 2045 0.0 39 999.0
H2 Electrolysis All 2050 0.0 49 999.0
battery discharger All 2025 0.0 0.0
battery discharger All 2030 2 203.7 4 298.0
battery discharger All 2035 6 358.4 13 423.8
battery discharger All 2040 10 513.1 22 549.6
battery discharger All 2045 17 037.9 39 687.2
battery discharger All 2050 24 460.8 59 107.0
home battery discharger All 2025 0.0 0.0
home battery discharger All 2030 0.0 0.0
home battery discharger All 2035 4 418.6 9 328.4
home battery discharger All 2040 10 100.9 21 665.3
home battery discharger All 2045 15 109.1 35 194.4
home battery discharger All 2050 19 219.2 46 441.2
onwind All 2025 0.0 28 000.0
onwind All 2030 28 000.0 39 000.0
onwind All 2035 29 250.0 50 000.0
onwind All 2040 30 500.0 61 000.0
onwind All 2045 35 250.0 70 500.0
onwind All 2050 40 000.0 80 000.0
solar rooftop All 2025 0.0 0.0
solar rooftop All 2030 5 670.0 12 340.0
solar rooftop All 2035 14 350.0 41 205.0
solar rooftop All 2040 23 030.0 70 070.0
solar rooftop All 2045 29 845.0 92 355.0
solar rooftop All 2050 35 200.0 110 000.0
solar(-hsat) All 2025 0.0 32 025.0
solar(-hsat) All 2030 17 330.0 45 660.0
solar(-hsat) All 2035 20 650.0 59 295.0
solar(-hsat) All 2040 23 970.0 72 930.0
solar(-hsat) All 2045 33 655.0 104 145.0
solar(-hsat) All 2050 44 800.0 140 000.0

Configuration

The feature is controlled under mods.PEMMDB_trajectories in config/config.at.yaml:

mods:
  PEMMDB_trajectories:
    enable: true
    tyndp_scenario: All  # All is the only complete scenario
    skip_countries: [ "AT", "DE" ]  # use PyPSA-DE/AT calibrations instead

Set enable: false to revert to unconstrained PyPSA-Eur behavior for all covered carriers.