diff --git a/rules/build_sector.smk b/rules/build_sector.smk
index 170a25e8..356abdc5 100644
--- a/rules/build_sector.smk
+++ b/rules/build_sector.smk
@@ -295,25 +295,34 @@ rule build_biomass_potentials:
         "../scripts/build_biomass_potentials.py"
 
 
-rule build_biomass_transport_costs:
-    input:
-        transport_cost_data=HTTP.remote(
-            "publications.jrc.ec.europa.eu/repository/bitstream/JRC98626/biomass potentials in europe_web rev.pdf",
-            keep_local=True,
-        ),
-    output:
-        biomass_transport_costs=RESOURCES + "biomass_transport_costs.csv",
-    threads: 1
-    resources:
-        mem_mb=1000,
-    log:
-        LOGS + "build_biomass_transport_costs.log",
-    benchmark:
-        BENCHMARKS + "build_biomass_transport_costs"
-    conda:
-        "../envs/environment.yaml"
-    script:
-        "../scripts/build_biomass_transport_costs.py"
+if config["sector"]["biomass_transport"] or config["sector"]["biomass_spatial"]:
+
+    rule build_biomass_transport_costs:
+        input:
+            transport_cost_data=HTTP.remote(
+                "publications.jrc.ec.europa.eu/repository/bitstream/JRC98626/biomass potentials in europe_web rev.pdf",
+                keep_local=True,
+            ),
+        output:
+            biomass_transport_costs=RESOURCES + "biomass_transport_costs.csv",
+        threads: 1
+        resources:
+            mem_mb=1000,
+        log:
+            LOGS + "build_biomass_transport_costs.log",
+        benchmark:
+            BENCHMARKS + "build_biomass_transport_costs"
+        conda:
+            "../envs/environment.yaml"
+        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",