diff --git a/rules/postprocess.smk b/rules/postprocess.smk
index d275279e..d1c65ced 100644
--- a/rules/postprocess.smk
+++ b/rules/postprocess.smk
@@ -14,7 +14,8 @@ if config["foresight"] != "perfect":
             plotting=config["plotting"],
         input:
             network=RESOURCES + "networks/elec_s{simpl}_{clusters}.nc",
-            regions_onshore=RESOURCES + "regions_onshore_elec_s{simpl}_{clusters}.geojson",
+            regions_onshore=RESOURCES
+            + "regions_onshore_elec_s{simpl}_{clusters}.geojson",
             rc="matplotlibrc",
         output:
             map=RESULTS + "maps/power-network-{clusters}.pdf",
@@ -28,7 +29,6 @@ if config["foresight"] != "perfect":
         script:
             "../scripts/plot_power_network_clustered.py"
 
-
     rule plot_power_network:
         params:
             plotting=config["plotting"],
diff --git a/scripts/plot_power_network_clustered.py b/scripts/plot_power_network_clustered.py
index e1140fd6..318afbb9 100644
--- a/scripts/plot_power_network_clustered.py
+++ b/scripts/plot_power_network_clustered.py
@@ -6,15 +6,13 @@
 Plot clustered electricity transmission network.
 """
 
-import pypsa
+import cartopy.crs as ccrs
 import geopandas as gpd
 import matplotlib.pyplot as plt
-import cartopy.crs as ccrs
+import pypsa
 from matplotlib.lines import Line2D
-from pypsa.plot import add_legend_lines
-
 from plot_power_network import load_projection
-
+from pypsa.plot import add_legend_lines
 
 if __name__ == "__main__":
     if "snakemake" not in globals():
@@ -23,7 +21,7 @@ if __name__ == "__main__":
         snakemake = mock_snakemake(
             "plot_power_network_clustered",
             clusters=128,
-            configfiles=["../../config/config.test.yaml"]
+            configfiles=["../../config/config.test.yaml"],
         )
 
     plt.style.use(snakemake.input.rc)
@@ -32,16 +30,13 @@ if __name__ == "__main__":
 
     n = pypsa.Network(snakemake.input.network)
 
-    regions = gpd.read_file(snakemake.input.regions_onshore).set_index('name')
+    regions = gpd.read_file(snakemake.input.regions_onshore).set_index("name")
 
     proj = load_projection(snakemake.params.plotting)
 
-    fig, ax = plt.subplots(figsize=(8,8), subplot_kw={"projection": proj})
+    fig, ax = plt.subplots(figsize=(8, 8), subplot_kw={"projection": proj})
     regions.to_crs(proj.proj4_init).plot(
-        ax=ax,
-        facecolor='none',
-        edgecolor='lightgray',
-        linewidth=0.75
+        ax=ax, facecolor="none", edgecolor="lightgray", linewidth=0.75
     )
     n.plot(
         ax=ax,
@@ -50,7 +45,7 @@ if __name__ == "__main__":
         link_colors=n.links.p_nom.apply(
             lambda x: "darkseagreen" if x > 0 else "skyblue"
         ),
-        link_widths=2.,
+        link_widths=2.0,
     )
 
     sizes = [10, 20]
@@ -74,6 +69,12 @@ if __name__ == "__main__":
         Line2D([0], [0], color="darkseagreen", lw=2),
         Line2D([0], [0], color="skyblue", lw=2),
     ]
-    plt.legend(handles, ["HVDC existing", "HVDC planned"], frameon=False, loc=[0., 0.9], fontsize=13)
+    plt.legend(
+        handles,
+        ["HVDC existing", "HVDC planned"],
+        frameon=False,
+        loc=[0.0, 0.9],
+        fontsize=13,
+    )
 
-    plt.savefig(snakemake.output.map, bbox_inches='tight')
+    plt.savefig(snakemake.output.map, bbox_inches="tight")