refactor: refactor input definitions to use conditional input files

doc/release_notes.md

@@ -66,6 +66,8 @@
 
 * chore: Drop the `grpcio < 1.78` pin and add a temporary `python < 3.14` pin ([#2244](https://github.com/PyPSA/pypsa-eur/pull/2244)). The upper bound on python will be lifted once [#2245](https://github.com/PyPSA/pypsa-eur/issues/2245) is resolved.
 
+* refactor: Refactor some input definitions to use conditional input files ([#2248](https://github.com/PyPSA/pypsa-eur/pull/2248)).
+
 ## PyPSA-Eur v2026.02.0 (18th February 2026)
 
 **Features**

rules/build_electricity.smk

@@ -804,7 +804,21 @@ rule add_electricity:
             f"costs_{config_provider('costs', 'year')(w)}_processed.csv"
         ),
         regions=resources("regions_onshore_base_s_{clusters}.geojson"),
-        powerplants=resources("powerplants_s_{clusters}.csv"),
+        powerplants=branch(
+            lambda w: config_provider("electricity", "conventional_carriers")(w)
+            or config_provider("electricity", "extendable_carriers", "Generator")(w)
+            or (
+                config_provider(
+                    "electricity", "estimate_renewable_capacities", "enable"
+                )(w)
+                and config_provider(
+                    "electricity",
+                    "estimate_renewable_capacities",
+                    "from_powerplantmatching",
+                )(w)
+            ),
+            resources("powerplants_s_{clusters}.csv"),
+        ),
         hydro_capacities=ancient("data/hydro_capacities.csv"),
         unit_commitment="data/unit_commitment.csv",
         fuel_price=lambda w: (

rules/build_sector.smk

@@ -819,7 +819,9 @@ rule build_swiss_energy_balances:
 rule build_energy_totals:
     input:
         nuts3_shapes=resources("nuts3_shapes.geojson"),
-        co2=rules.retrieve_ghg_emissions.output["csv"],
+        co2=branch(
+            config_provider("co2_budget"), rules.retrieve_ghg_emissions.output["csv"]
+        ),
         swiss=resources("switzerland_energy_balances.csv"),
         swiss_transport=f"{BFS_ROAD_VEHICLE_STOCK_DATASET['folder']}/vehicle_stock.csv",
         idees=rules.retrieve_jrc_idees.output["directory"],
@@ -1562,12 +1564,33 @@ def input_heat_source_power(w):
     }
 
 
+def input_gas_network(w):
+    inputs = {}
+
+    gas_network = config_provider("sector", "gas_network")(w)
+    h2_retrofit = config_provider("sector", "H2_retrofit")(w)
+    imports_enabled = config_provider("sector", "imports", "enable")(w)
+    import_carriers = config_provider("sector", "imports", "carriers")(w)
+
+    if gas_network or h2_retrofit:
+        inputs["clustered_gas_network"] = resources("gas_network_base_s_{clusters}.csv")
+
+    gas_imports = imports_enabled and "gas" in import_carriers
+    h2_imports = imports_enabled and "H2" in import_carriers
+
+    if gas_network or gas_imports or h2_imports:
+        inputs["gas_input_nodes_simplified"] = resources(
+            "gas_input_locations_s_{clusters}_simplified.csv"
+        )
+
+    return inputs
+
+
 rule prepare_sector_network:
     input:
         unpack(input_profile_offwind),
         unpack(input_heat_source_power),
-        **rules.cluster_gas_network.output,
-        **rules.build_gas_input_locations.output,
+        unpack(input_gas_network),
         snapshot_weightings=resources(
             "snapshot_weightings_base_s_{clusters}_elec_{opts}_{sector_opts}.csv"
         ),
@@ -1599,7 +1622,10 @@ rule prepare_sector_network:
         pop_weighted_energy_totals=resources(
             "pop_weighted_energy_totals_s_{clusters}.csv"
         ),
-        pop_weighted_heat_totals=resources("pop_weighted_heat_totals_s_{clusters}.csv"),
+        pop_weighted_heat_totals=branch(
+            config_provider("sector", "heating"),
+            resources("pop_weighted_heat_totals_s_{clusters}.csv"),
+        ),
         shipping_demand=resources("shipping_demand_s_{clusters}.csv"),
         transport_demand=resources("transport_demand_s_{clusters}.csv"),
         transport_data=resources("transport_data_s_{clusters}.csv"),
@@ -1608,8 +1634,12 @@ rule prepare_sector_network:
         heat_dsm_profile=resources(
             "residential_heat_dsm_profile_total_base_s_{clusters}.csv"
         ),
-        co2_totals_name=resources("co2_totals.csv"),
-        co2=rules.retrieve_ghg_emissions.output["csv"],
+        co2_totals_name=branch(
+            config_provider("co2_budget"), resources("co2_totals.csv")
+        ),
+        co2=branch(
+            config_provider("co2_budget"), rules.retrieve_ghg_emissions.output["csv"]
+        ),
         biomass_potentials=resources(
             "biomass_potentials_s_{clusters}_{planning_horizons}.csv"
         ),
@@ -1618,7 +1648,10 @@ rule prepare_sector_network:
             if config_provider("foresight")(w) == "overnight"
             else resources("costs_{planning_horizons}_processed.csv")
         ),
-        h2_cavern=resources("salt_cavern_potentials_s_{clusters}.csv"),
+        h2_cavern=branch(
+            config_provider("sector", "h2_topology_tyndp"),
+            otherwise=resources("salt_cavern_potentials_s_{clusters}.csv"),
+        ),
         busmap_s=resources("busmap_base_s.csv"),
         busmap=resources("busmap_base_s_{clusters}.csv"),
         clustered_pop_layout=resources("pop_layout_base_s_{clusters}.csv"),

rules/postprocess.smk

@@ -437,7 +437,9 @@ rule plot_summary:
         energy=RESULTS + "csvs/energy.csv",
         balances=RESULTS + "csvs/energy_balance.csv",
         eurostat=resources("eurostat_energy_balances.csv"),
-        co2=rules.retrieve_ghg_emissions.output["csv"],
+        co2=branch(
+            config_provider("co2_budget"), rules.retrieve_ghg_emissions.output["csv"]
+        ),
     output:
         costs=RESULTS + "graphs/costs.pdf",
         energy=RESULTS + "graphs/energy.pdf",

rules/solve_myopic.smk

@@ -8,7 +8,11 @@ rule add_existing_baseyear:
         network=resources(
             "networks/base_s_{clusters}_{opts}_{sector_opts}_{planning_horizons}.nc"
         ),
-        powerplants=resources("powerplants_s_{clusters}.csv"),
+        powerplants=branch(
+            lambda w: config_provider("electricity", "conventional_carriers")(w)
+            or config_provider("electricity", "extendable_carriers", "Generator")(w),
+            resources("powerplants_s_{clusters}.csv"),
+        ),
         costs=lambda w: resources(
             f"costs_{config_provider('scenario', 'planning_horizons',0)(w)}_processed.csv"
         ),

rules/solve_perfect.smk

@@ -6,7 +6,11 @@ rule add_existing_baseyear:
         network=resources(
             "networks/base_s_{clusters}_{opts}_{sector_opts}_{planning_horizons}.nc"
         ),
-        powerplants=resources("powerplants_s_{clusters}.csv"),
+        powerplants=branch(
+            lambda w: config_provider("electricity", "conventional_carriers")(w)
+            or config_provider("electricity", "extendable_carriers", "Generator")(w),
+            resources("powerplants_s_{clusters}.csv"),
+        ),
         busmap_s=resources("busmap_base_s.csv"),
         busmap=resources("busmap_base_s_{clusters}.csv"),
         clustered_pop_layout=resources("pop_layout_base_s_{clusters}.csv"),

scripts/add_electricity.py

@@ -609,6 +609,9 @@ def attach_conventional_generators(
     fuel_price : pd.DataFrame, optional
         DataFrame containing fuel price data, by default None.
     """
+    if ppl.empty:
+        return
+
     carriers = list(
         set(conventional_carriers)
         | set(extendable_carriers["Generator"]) - set(renewable_carriers)
@@ -700,6 +703,9 @@ def attach_existing_batteries(
     ppl: pd.DataFrame,
 ) -> None:
     """Attach existing battery storage units from the power plant dataset."""
+    if ppl.empty:
+        return
+
     batt = ppl.query('carrier == "battery"')
     if batt.empty:
         return
@@ -760,6 +766,9 @@ def attach_hydro(
     **params :
         Additional parameters for hydro units.
     """
+    if ppl.empty:
+        return
+
     add_missing_carriers(n, carriers)
     add_co2_emissions(n, costs, carriers)
 
@@ -1215,13 +1224,16 @@ def attach_stores(
 
     costs = load_costs(snakemake.input.costs)
 
-    ppl = load_and_aggregate_powerplants(
-        snakemake.input.powerplants,
-        costs,
-        params.consider_efficiency_classes,
-        params.aggregation_strategies,
-        params.exclude_carriers,
-    )
+    if ppl_fn := snakemake.input.powerplants:
+        ppl = load_and_aggregate_powerplants(
+            ppl_fn,
+            costs,
+            params.consider_efficiency_classes,
+            params.aggregation_strategies,
+            params.exclude_carriers,
+        )
+    else:
+        ppl = pd.DataFrame()
 
     attach_load(
         n,

scripts/add_existing_baseyear.py

@@ -190,6 +190,9 @@ def add_power_capacities_installed_before_baseyear(
     """
     logger.debug(f"Adding power capacities installed before {baseyear}")
 
+    if not powerplants_file:
+        return
+
     df_agg = pd.read_csv(powerplants_file, index_col=0)
 
     rename_fuel = {

scripts/build_energy_totals.py

@@ -1331,13 +1331,16 @@ def build_heating_efficiencies(
     )
     district_heat_share.to_csv(snakemake.output.district_heat_share)
 
-    base_year_emissions = params["base_emissions_year"]
-    emissions_scope = snakemake.params.energy["emissions"]
-    eea_co2 = build_eea_co2(snakemake.input.co2, base_year_emissions, emissions_scope)
-    eurostat_co2 = build_eurostat_co2(eurostat, base_year_emissions)
-
-    co2 = build_co2_totals(countries, eea_co2, eurostat_co2)
-    co2.to_csv(snakemake.output.co2_name)
+    if co2_fn := snakemake.input.co2:
+        base_year_emissions = params["base_emissions_year"]
+        emissions_scope = snakemake.params.energy["emissions"]
+        eea_co2 = build_eea_co2(co2_fn, base_year_emissions, emissions_scope)
+        eurostat_co2 = build_eurostat_co2(eurostat, base_year_emissions)
+
+        co2 = build_co2_totals(countries, eea_co2, eurostat_co2)
+        co2.to_csv(snakemake.output.co2_name)
+    else:
+        pd.DataFrame().to_csv(snakemake.output.co2_name)
 
     transport = build_transport_data(countries, population, idees)
     transport.to_csv(snakemake.output.transport_name)

scripts/prepare_sector_network.py

@@ -6314,13 +6314,14 @@ def add_import_options(
     pop_weighted_energy_totals = (
         pd.read_csv(snakemake.input.pop_weighted_energy_totals, index_col=0) * nyears
     )
-    pop_weighted_heat_totals = (
-        pd.read_csv(snakemake.input.pop_weighted_heat_totals, index_col=0) * nyears
-    )
-    pop_weighted_energy_totals.update(pop_weighted_heat_totals)
+    if options["heating"]:
+        pop_weighted_heat_totals = (
+            pd.read_csv(snakemake.input.pop_weighted_heat_totals, index_col=0) * nyears
+        )
+        pop_weighted_energy_totals.update(pop_weighted_heat_totals)
 
-    fn = snakemake.input.gas_input_nodes_simplified
-    gas_input_nodes = pd.read_csv(fn, index_col=0)
+    fn = snakemake.input.get("gas_input_nodes_simplified")
+    gas_input_nodes = pd.read_csv(fn, index_col=0) if fn else None
 
     carriers_to_keep = snakemake.params.pypsa_eur
     profiles = {
@@ -6388,7 +6389,7 @@ def add_import_options(
         pop_layout=pop_layout,
         h2_cavern_file=snakemake.input.h2_cavern,
         cavern_types=snakemake.params.sector["hydrogen_underground_storage_locations"],
-        clustered_gas_network_file=snakemake.input.clustered_gas_network,
+        clustered_gas_network_file=snakemake.input.get("clustered_gas_network"),
         gas_input_nodes=gas_input_nodes,
         spatial=spatial,
         options=options,
@@ -6584,8 +6585,8 @@ def add_import_options(
     add_co2limit(
         n,
         options,
-        snakemake.input.co2_totals_name,
-        snakemake.params.countries,
+        snakemake.input.get("co2_totals_name"),
+        snakemake.params.get("countries"),
         nyears,
         limit,
     )