diff --git a/etrago/tools/calc_results.py b/etrago/tools/calc_results.py
index 5c3f3f4c..1605f991 100755
--- a/etrago/tools/calc_results.py
+++ b/etrago/tools/calc_results.py
@@ -355,7 +355,7 @@ def system_costs_germany(self):
 
     """
 
-    network_de = self.german_network
+    network_de = self.german_network()
 
     marginal_cost = 0
     invest_cost = 0
diff --git a/etrago/tools/network.py b/etrago/tools/network.py
index 2ed5aa5e..8e4b57b7 100644
--- a/etrago/tools/network.py
+++ b/etrago/tools/network.py
@@ -40,6 +40,8 @@
     calc_etrago_results,
     dc_export,
     dc_export_per_country,
+    german_network,
+    system_costs_germany,
 )
 from etrago.tools.execute import (
     dispatch_disaggregation,
@@ -246,22 +248,26 @@ def __init__(
 
     calc_results = calc_etrago_results
 
-    calc_ac_export = ac_export()
+    calc_ac_export = ac_export
 
-    calc_ac_export_per_country = ac_export_per_country()
+    calc_ac_export_per_country = ac_export_per_country
 
-    calc_dc_export = dc_export()
+    calc_dc_export = dc_export
 
-    calc_dc_export_per_country = dc_export_per_country()
+    calc_dc_export_per_country = dc_export_per_country
 
     export_to_csv = export_to_csv
 
     filter_links_by_carrier = filter_links_by_carrier
 
+    german_network = german_network
+
     set_line_costs = set_line_costs
 
     set_trafo_costs = set_trafo_costs
 
+    system_costs_germany = system_costs_germany
+
     drop_sectors = drop_sectors
 
     buses_by_country = buses_by_country