prepare_sectors: make biomass transport costs conditional again

rules/build_sector.smk

@@ -295,6 +295,8 @@ rule build_biomass_potentials:
         "../scripts/build_biomass_potentials.py"
 
 
+if config["sector"]["biomass_transport"] or config["sector"]["biomass_spatial"]:
+
     rule build_biomass_transport_costs:
         input:
             transport_cost_data=HTTP.remote(
@@ -315,6 +317,13 @@ rule build_biomass_transport_costs:
         script:
             "../scripts/build_biomass_transport_costs.py"
 
+    build_biomass_transport_costs_output = rules.build_biomass_transport_costs.output
+
+
+if not (config["sector"]["biomass_transport"] or config["sector"]["biomass_spatial"]):
+    # this is effecively an `else` statement which is however not liked by snakefmt
+    build_biomass_transport_costs_output = {}
+
 
 if config["sector"]["regional_co2_sequestration_potential"]["enable"]:
 
@@ -711,7 +720,7 @@ rule prepare_sector_network:
         RDIR=RDIR,
     input:
         **build_retro_cost_output,
-        **rules.build_biomass_transport_costs.output,
+        **build_biomass_transport_costs_output,
         **gas_infrastructure,
         **build_sequestration_potentials_output,
         network=RESOURCES + "networks/elec_s{simpl}_{clusters}_ec_l{ll}_{opts}.nc",
@@ -772,7 +781,7 @@ rule prepare_sector_network:
         + "prenetworks/elec_s{simpl}_{clusters}_l{ll}_{opts}_{sector_opts}_{planning_horizons}.nc",
     threads: 1
     resources:
-        mem_mb=20000,
+        mem_mb=2000,
     log:
         LOGS
         + "prepare_sector_network_elec_s{simpl}_{clusters}_l{ll}_{opts}_{sector_opts}_{planning_horizons}.log",