diff --git a/scripts/prepare_sector_network.py b/scripts/prepare_sector_network.py
index 35d98657..3be2bdac 100755
--- a/scripts/prepare_sector_network.py
+++ b/scripts/prepare_sector_network.py
@@ -1325,6 +1325,22 @@ def add_storage_and_grids(n, costs):
             n, "H2 pipeline ", carriers=["DC", "gas pipeline"]
         )
 
+        h2_pipes["p_nom"] = 0.0
+
+        if "custom_h2_pipelines" in snakemake.input:
+            fn = snakemake.input.custom_h2_pipelines
+            custom_pipes = pd.read_csv(fn, index_col=0)
+
+            h2_pipes = pd.concat([h2_pipes, custom_pipes])
+
+            # drop duplicates according to buses (order can be different) and keep pipe with highest p_nom
+            h2_pipes["buses_sorted"] = h2_pipes[["bus0", "bus1"]].apply(sorted, axis=1)
+            h2_pipes = (
+                h2_pipes.sort_values("p_nom")
+                .drop_duplicates(subset=["buses_sorted"], keep="last")
+                .drop(columns="buses_sorted")
+            )
+
         # TODO Add efficiency losses
         n.madd(
             "Link",
@@ -1333,6 +1349,7 @@ def add_storage_and_grids(n, costs):
             bus1=h2_pipes.bus1.values + " H2",
             p_min_pu=-1,
             p_nom_extendable=True,
+            p_nom_min=h2_pipes.p_nom.values,
             length=h2_pipes.length.values,
             capital_cost=costs.at["H2 (g) pipeline", "fixed"] * h2_pipes.length.values,
             carrier="H2 pipeline",