diff --git a/scripts/make_summary.py b/scripts/make_summary.py
index 150c159e..c831fb9d 100644
--- a/scripts/make_summary.py
+++ b/scripts/make_summary.py
@@ -62,6 +62,13 @@ idx = pd.IndexSlice
 
 opt_name = {"Store": "e", "Line" : "s", "Transformer" : "s"}
 
+def _add_indexed_rows(df, raw_index):
+    new_index = df.index|pd.MultiIndex.from_product(raw_index)
+    if isinstance(new_index, pd.Index):
+        new_index = pd.MultiIndex.from_tuples(new_index)
+
+    return df.reindex(new_index)
+
 def assign_carriers(n):
 
     if "carrier" not in n.loads:
@@ -82,16 +89,17 @@ def assign_carriers(n):
     if "EU gas store" in n.stores.index and n.stores.loc["EU gas Store","carrier"] == "":
         n.stores.loc["EU gas Store","carrier"] = "gas Store"
 
-
 def calculate_costs(n,label,costs):
 
     for c in n.iterate_components(n.branch_components|n.controllable_one_port_components^{"Load"}):
         capital_costs = c.df.capital_cost*c.df[opt_name.get(c.name,"p") + "_nom_opt"]
         capital_costs_grouped = capital_costs.groupby(c.df.carrier).sum()
+        
+        # Index tuple(s) indicating the newly to-be-added row(s)
+        raw_index = tuple([[c.list_name],["capital"],list(capital_costs_grouped.index)])
+        costs = _add_indexed_rows(costs, raw_index)
 
-        costs = costs.reindex(costs.index|pd.MultiIndex.from_product([[c.list_name],["capital"],capital_costs_grouped.index]))
-
-        costs.loc[idx[c.list_name,"capital",list(capital_costs_grouped.index)],label] = capital_costs_grouped.values
+        costs.loc[idx[raw_index],label] = capital_costs_grouped.values
 
         if c.name == "Link":
             p = c.pnl.p0.multiply(n.snapshot_weightings,axis=0).sum()
@@ -137,8 +145,12 @@ def calculate_energy(n,label,energy):
     return energy
 
 def include_in_summary(summary, multiindexprefix, label, item):
-    summary = summary.reindex(summary.index | pd.MultiIndex.from_product([[p] for p in multiindexprefix] + [item.index]))
-    summary.loc[idx[tuple(multiindexprefix + [list(item.index)])], label] = item.values
+
+    # Index tuple(s) indicating the newly to-be-added row(s)
+    raw_index = tuple([multiindexprefix,list(item.index)])
+    summary = _add_indexed_rows(summary, raw_index)
+    
+    summary.loc[idx[raw_index], label] = item.values
     return summary
 
 def calculate_capacity(n,label,capacity):
@@ -179,9 +191,12 @@ def calculate_supply(n,label,supply):
                 continue
 
             s = c.pnl.p[items].max().multiply(c.df.loc[items,'sign']).groupby(c.df.loc[items,'carrier']).sum()
-
-            supply = supply.reindex(supply.index|pd.MultiIndex.from_product([[i],[c.list_name],s.index]))
-            supply.loc[idx[i,c.list_name,list(s.index)],label] = s.values
+            
+            # Index tuple(s) indicating the newly to-be-added row(s)
+            raw_index = tuple([[i],[c.list_name],list(s.index)])
+            supply = _add_indexed_rows(supply, raw_index)
+            
+            supply.loc[idx[raw_index],label] = s.values
 
 
         for c in n.iterate_components(n.branch_components):
@@ -222,9 +237,12 @@ def calculate_supply_energy(n,label,supply_energy):
                 continue
 
             s = c.pnl.p[items].sum().multiply(c.df.loc[items,'sign']).groupby(c.df.loc[items,'carrier']).sum()
-
-            supply_energy = supply_energy.reindex(supply_energy.index|pd.MultiIndex.from_product([[i],[c.list_name],s.index]))
-            supply_energy.loc[idx[i,c.list_name,list(s.index)],label] = s.values
+          
+            # Index tuple(s) indicating the newly to-be-added row(s)
+            raw_index = tuple([[i],[c.list_name],list(s.index)])
+            supply_energy = _add_indexed_rows(supply_energy, raw_index)
+            
+            supply_energy.loc[idx[raw_index],label] = s.values
 
 
         for c in n.iterate_components(n.branch_components):
@@ -473,7 +491,7 @@ if __name__ == "__main__":
                      for opts in expand_from_wildcard("opts")}
 
     print(networks_dict)
-
+    
     dfs = make_summaries(networks_dict, country=snakemake.wildcards.country)
 
     to_csv(dfs)