added import export balance based on FES

scripts/_fes_helpers.py

@@ -484,3 +484,22 @@ def get_commercial_demand(scenario, year):
     reference = df.loc[scenario_mapper[scenario], 2022] * 1e-3
 
     return reference, value
+
+
+def get_import_export_balance(scenario, year):
+    """Get GB trade balance with mainland Europe, Norway, Ireland through interconnectors"""
+
+    col = string.ascii_uppercase.index("O")
+
+    df = (
+        pd.read_excel(data_file,
+            sheet_name="FL.15",
+            header=4,
+            index_col=0,
+            usecols=[col+i for i in range(31)],
+            )
+        ).iloc[1:5]
+
+    df.columns = range(2022, 2052)
+
+    return df.loc[scenario_mapper[scenario], year] * 1e6

scripts/prepare_network.py

@@ -83,6 +83,7 @@
     get_battery_capacity,
     get_industrial_demand,
     get_commercial_demand,
+    get_import_export_balance,
     )
 
 from pypsa.descriptors import expand_series
@@ -1159,28 +1160,31 @@ def add_batteries(n, costs=None, opts=[]):
     )
 
 
-def add_import_export_balance(n):
-
-    n.add(
-        "Bus",
-        "import export tracker",
-        carrier="import export tracker",
-    )
+def add_import_export_balance(n, fes, year):
 
     cc = pd.read_csv(snakemake.input["capacity_constraints"], index_col=1)
     total_p_nom = cc.at["DC", "value"]
     max_hours = snakemake.config["flexibility"]["balance_link_max_hours"]
 
+    balance = get_import_export_balance(fes, year)
+    e_nom = abs(balance)
+
     e_max_pu = pd.Series(1., n.snapshots) 
     e_max_pu.iloc[0] = 0.
-    e_max_pu.iloc[-1] = 0.
+    e_max_pu.iloc[-1] = balance / max(max_hours * total_p_nom, e_nom)
+
+    n.add(
+        "Bus",
+        "import export tracker",
+        carrier="import export tracker",
+    )
 
     n.add(
         "Store",
         "import export tracker",
         bus="import export tracker",
         carrier="import export tracker",
-        e_nom=max_hours * total_p_nom,
+        e_nom=max(max_hours * total_p_nom, e_nom),
         e_max_pu=e_max_pu,
         e_min_pu=-e_max_pu,
         )