Robust modelling

config/config.de.yaml

@@ -4,7 +4,7 @@
 
 # docs in https://pypsa-eur.readthedocs.io/en/latest/configuration.html#run
 run:
-  prefix: 20260422_small_changes
+  prefix: 20260710-elec-grid-limitations-test
   name:
   # - ExPol
   - KN2045_Mix
@@ -15,6 +15,15 @@ run:
   # - KN2045_H2
   # - KN2045_NFniedrig
   # - KN2045_NFhoch
+  # - KN2045_Mix_no_grid
+  - KN2045_Mix_transmission_limit_1.0
+  - KN2045_Mix_transmission_limit_1.1
+  # - KN2045_Mix_transmission_limit_1.2
+  # - KN2045_Mix_transmission_limit_1.3
+  - KN2045_Mix_transmission_limit_DE_1.0
+  # - KN2045_Mix_transmission_limit_DE_1.1
+  # - KN2045_Mix_transmission_limit_DE_1.2
+  - KN2045_Mix_transmission_limit_DE_1.3
   scenarios:
     enable: true
     manual_file: config/scenarios.manual.yaml
@@ -70,12 +79,13 @@ scenario:
   sector_opts:
   - none
   planning_horizons:
+  # - 2020
   - 2025
-  - 2030
+  # - 2030
   - 2035
-  - 2040
+  # - 2040
   - 2045
-  - 2050
+  # - 2050
 
 existing_capacities:
   grouping_years_power: [1920, 1950, 1955, 1960, 1965, 1970, 1975, 1980, 1985, 1990, 1995, 2000, 2005, 2010, 2015, 2020, 2025]
@@ -341,7 +351,7 @@ sector:
   regional_gas_demand: true
   regional_co2_sequestration_potential:
     enable: false
-  H2_retrofit: true
+  H2_retrofit: false
   hydrogen_turbine: false
   biogas_upgrading_cc: true
   biomass_to_liquid: true
@@ -378,6 +388,7 @@ sector:
     2040: 0.299
     2045: 0.149
 
+
 # docs in https://pypsa-eur.readthedocs.io/en/latest/configuration.html#industry
 industry:
   steam_biomass_fraction: 0.4
@@ -731,3 +742,5 @@ data:
   costs:
     source: primary
     version: latest
+
+remove_electricity_grid: false

config/config.default.yaml

@@ -183,6 +183,11 @@ electricity:
     enable: false
     by_country: false
   transmission_limit: vopt
+  transmission_limit_countries:
+    enable: false
+    country: DE
+    internal: v1.0
+    interconnector: v1.0
 
 # docs in https://pypsa-eur.readthedocs.io/en/latest/configuration.html#atlite
 atlite:

config/scenarios.manual.yaml

@@ -249,3 +249,67 @@ KN2045_NFhoch:
       2040: 0.24
       2045: 0.29
       2050: 0.33
+
+
+KN2045_Mix_no_grid:
+
+  remove_electricity_grid: true
+
+KN2045_Mix_transmission_limit_1.0:
+
+  electricity:
+    transmission_limit: v1.0
+
+KN2045_Mix_transmission_limit_1.1:
+
+  electricity:
+    transmission_limit: v1.1
+
+KN2045_Mix_transmission_limit_1.2:
+
+  electricity:
+    transmission_limit: v1.2
+
+KN2045_Mix_transmission_limit_1.3:
+
+  electricity:
+    transmission_limit: v1.3
+
+KN2045_Mix_transmission_limit_DE_1.0:
+# Like KN2045_Mix_transmission_limit_1.0, but the expansion limit only
+# applies to Germany's internal grid and its interconnectors; the rest of
+# the European grid stays at the default (unconstrained, vopt).
+
+  electricity:
+    transmission_limit_countries:
+      enable: true
+      country: DE
+      internal: v1.0
+      interconnector: v1.0
+
+KN2045_Mix_transmission_limit_DE_1.1:
+
+  electricity:
+    transmission_limit_countries:
+      enable: true
+      country: DE
+      internal: v1.1
+      interconnector: v1.1
+
+KN2045_Mix_transmission_limit_DE_1.2:
+
+  electricity:
+    transmission_limit_countries:
+      enable: true
+      country: DE
+      internal: v1.2
+      interconnector: v1.2
+
+KN2045_Mix_transmission_limit_DE_1.3:
+
+  electricity:
+    transmission_limit_countries:
+      enable: true
+      country: DE
+      internal: v1.3
+      interconnector: v1.3

pixi.toml

@@ -174,6 +174,10 @@ all-tests = {depends-on = ["integration-tests", "clean-tests", "unit-tests"]}
 [feature.test.dependencies]
 pytest = ">=8.4.2"
 
+[feature.jupyter-kernel.dependencies]
+ipykernel = ">=6,<7"
+
 [environments]
 doc = { features = ["doc"], no-default-feature = true }
 test = ["test"]
+jupyter = ["jupyter-kernel"]

rules/build_electricity.smk

@@ -872,6 +872,9 @@ rule prepare_network:
         autarky=config_provider("electricity", "autarky", default={}),
         drop_leap_day=config_provider("enable", "drop_leap_day"),
         transmission_limit=config_provider("electricity", "transmission_limit"),
+        transmission_limit_countries=config_provider(
+            "electricity", "transmission_limit_countries", default={}
+        ),
     message:
         "Preparing network for model with {wildcards.clusters} clusters and options {wildcards.opts}"
     script:

rules/pypsa-de/modifications.smk

@@ -260,6 +260,7 @@ rule modify_prenetwork:
         limit_cross_border_flows_ac=config_provider(
             "pypsa-de", "limit_cross_border_flows_ac"
         ),
+        remove_electricity_grid=config_provider("pypsa-de", "remove_electricity_grid"),
     script:
         scripts("pypsa-de/modify_prenetwork.py")
 

scripts/_helpers.py

@@ -301,6 +301,60 @@ def handle_exception(exc_type, exc_value, exc_traceback):
     sys.excepthook = handle_exception
 
 
+def get_transmission_country_subsets(n: pypsa.Network, country: str) -> dict:
+    """
+    Split AC lines and DC links into three disjoint groups relative to `country`.
+
+    Used to apply separate transmission expansion limits to a country's
+    internal grid and its cross-border interconnectors (see
+    ``electricity.transmission_limit_countries``).
+
+    Parameters
+    ----------
+    n : pypsa.Network
+    country : str
+        ISO2 country code (must match values in ``n.buses.country``).
+
+    Returns
+    -------
+    dict
+        Keys "internal" (both buses in `country`), "interconnector" (exactly
+        one bus in `country`) and "rest" (neither bus in `country`). Each maps
+        to a dict with keys "lines" and "links" (pandas Index).
+    """
+    dc_i = (
+        n.links.index[n.links.carrier == "DC"] if not n.links.empty else n.links.index
+    )
+
+    lines_c0 = n.lines.bus0.map(n.buses.country)
+    lines_c1 = n.lines.bus1.map(n.buses.country)
+    links_c0 = n.links.bus0.map(n.buses.country)
+    links_c1 = n.links.bus1.map(n.buses.country)
+
+    lines_internal = lines_c0.eq(country) & lines_c1.eq(country)
+    links_internal = links_c0.eq(country) & links_c1.eq(country)
+
+    lines_cross_border = lines_c0.eq(country) ^ lines_c1.eq(country)
+    links_cross_border = links_c0.eq(country) ^ links_c1.eq(country)
+
+    return {
+        "internal": {
+            "lines": n.lines.index[lines_internal],
+            "links": dc_i.intersection(n.links.index[links_internal]),
+        },
+        "interconnector": {
+            "lines": n.lines.index[lines_cross_border],
+            "links": dc_i.intersection(n.links.index[links_cross_border]),
+        },
+        "rest": {
+            "lines": n.lines.index[~(lines_internal | lines_cross_border)],
+            "links": dc_i.intersection(
+                n.links.index[~(links_internal | links_cross_border)]
+            ),
+        },
+    }
+
+
 def update_p_nom_max(n):
     # if extendable carriers (solar/onwind/...) have capacity >= 0,
     # e.g. existing assets from GEM are included to the network,

scripts/add_brownfield.py

@@ -15,6 +15,7 @@
 from scripts._helpers import (
     configure_logging,
     get_snapshots,
+    get_transmission_country_subsets,
     sanitize_custom_columns,
     set_scenario_config,
     update_config_from_wildcards,
@@ -173,7 +174,7 @@ def add_brownfield(
             n.links.loc[gas_pipes_i, "p_nom_max"] = remaining_capacity
 
 
-def disable_grid_expansion_if_limit_hit(n):
+def disable_grid_expansion_if_limit_hit(n, transmission_limit_countries=None):
     """
     Check if transmission expansion limit is already reached; then turn off.
 
@@ -183,45 +184,72 @@ def disable_grid_expansion_if_limit_hit(n):
     n.global_constraints. If so, the nominal capacities are set to the
     minimum and extendable is turned off; the corresponding global
     constraint is then dropped.
+
+    This acts as a ratchet across myopic planning horizons: since
+    ``prepare_network.py`` re-adds the same (absolute) limit at every
+    horizon and brownfield carries forward built capacity as ``s_nom_min``/
+    ``p_nom_min``, expansion is automatically frozen for all later horizons
+    once a cap is reached, without needing a per-horizon budget.
+
+    Parameters
+    ----------
+    transmission_limit_countries : dict, optional
+        The ``electricity.transmission_limit_countries`` config. When
+        enabled, the DE-internal and DE-interconnector limits (added as
+        custom ``GlobalConstraint`` types by ``prepare_network.py``, see
+        ``scripts.solve_network.add_country_transmission_limit_constraints``)
+        are each checked against their own line/link subset, while the plain
+        (unsuffixed) limit is checked only against the remaining lines/links.
     """
     types = {"expansion_cost": "capital_cost", "volume_expansion": "length"}
-    for limit_type in types:
-        glcs = n.global_constraints.query(f"type == 'transmission_{limit_type}_limit'")
-
-        for name, glc in glcs.iterrows():
-            total_expansion = (
-                (
-                    n.lines.query("s_nom_extendable")
-                    .eval(f"s_nom_min * {types[limit_type]}")
-                    .sum()
-                )
-                + (
-                    n.links.query("carrier == 'DC' and p_nom_extendable")
-                    .eval(f"p_nom_min * {types[limit_type]}")
-                    .sum()
-                )
-            ).sum()
 
-            # Allow small numerical differences
-            if np.abs(glc.constant - total_expansion) / glc.constant < 1e-6:
-                logger.info(
-                    f"Transmission expansion {limit_type} is already reached, disabling expansion and limit"
+    dc_i = (
+        n.links.index[n.links.carrier == "DC"] if not n.links.empty else n.links.index
+    )
+    country_cfg = transmission_limit_countries or {}
+    if country_cfg.get("enable", False):
+        subsets = get_transmission_country_subsets(n, country_cfg["country"])
+        country = country_cfg["country"].lower()
+        suffix_scopes = {
+            "": subsets["rest"],
+            f"_{country}_internal": subsets["internal"],
+            f"_{country}_interconnector": subsets["interconnector"],
+        }
+    else:
+        suffix_scopes = {"": {"lines": n.lines.index, "links": dc_i}}
+
+    for limit_type, attr in types.items():
+        for suffix, scope in suffix_scopes.items():
+            glc_type = f"transmission_{limit_type}_limit{suffix}"
+            glcs = n.global_constraints.query("type == @glc_type")
+            if glcs.empty:
+                continue
+
+            ext_lines = n.lines.loc[scope["lines"]].query("s_nom_extendable")
+            ext_links = n.links.loc[scope["links"]].query("p_nom_extendable")
+
+            for name, glc in glcs.iterrows():
+                total_expansion = (
+                    ext_lines.eval(f"s_nom_min * {attr}").sum()
+                    + ext_links.eval(f"p_nom_min * {attr}").sum()
                 )
-                extendable_acs = n.lines.query("s_nom_extendable").index
-                n.lines.loc[extendable_acs, "s_nom_extendable"] = False
-                n.lines.loc[extendable_acs, "s_nom"] = n.lines.loc[
-                    extendable_acs, "s_nom_min"
-                ]
 
-                extendable_dcs = n.links.query(
-                    "carrier == 'DC' and p_nom_extendable"
-                ).index
-                n.links.loc[extendable_dcs, "p_nom_extendable"] = False
-                n.links.loc[extendable_dcs, "p_nom"] = n.links.loc[
-                    extendable_dcs, "p_nom_min"
-                ]
+                # Allow small numerical differences
+                if np.abs(glc.constant - total_expansion) / glc.constant < 1e-6:
+                    logger.info(
+                        f"Transmission expansion {limit_type}{suffix} is already reached, disabling expansion and limit"
+                    )
+                    n.lines.loc[ext_lines.index, "s_nom_extendable"] = False
+                    n.lines.loc[ext_lines.index, "s_nom"] = n.lines.loc[
+                        ext_lines.index, "s_nom_min"
+                    ]
+
+                    n.links.loc[ext_links.index, "p_nom_extendable"] = False
+                    n.links.loc[ext_links.index, "p_nom"] = n.links.loc[
+                        ext_links.index, "p_nom_min"
+                    ]
 
-                n.global_constraints.drop(name, inplace=True)
+                    n.global_constraints.drop(name, inplace=True)
 
 
 def adjust_renewable_profiles(n, input_profiles, params, year):
@@ -386,7 +414,9 @@ def update_dynamic_ptes_capacity(
         capacity_threshold=snakemake.params.threshold_capacity,
     )
 
-    disable_grid_expansion_if_limit_hit(n)
+    disable_grid_expansion_if_limit_hit(
+        n, snakemake.config["electricity"].get("transmission_limit_countries")
+    )
 
     n.meta = dict(snakemake.config, **dict(wildcards=dict(snakemake.wildcards)))