diff --git a/rules/build_electricity.smk b/rules/build_electricity.smk
index ad9c12fc..d0ad72c0 100644
--- a/rules/build_electricity.smk
+++ b/rules/build_electricity.smk
@@ -420,6 +420,7 @@ rule prepare_network:
         RESOURCES + "networks/elec_s{simpl}_{gb_regions}_ec.nc",
         overrides="data/override_component_attrs",
         tech_costs=COSTS,
+        capacity_constraints=RESOURCES + "fes_capacity_constraints_{fes_scenario}_{planning_horizons}.csv",
         heat_profile="data/heat_load_profile_BDEW.csv",
         co2_price=RESOURCES + "CO2_price_2022.csv",
         heat_demand=RESOURCES + "heat_demand_total_elec_s{simpl}_{gb_regions}.nc",
diff --git a/scripts/build_fes_constraints.py b/scripts/build_fes_constraints.py
index d42a0c68..183472b3 100644
--- a/scripts/build_fes_constraints.py
+++ b/scripts/build_fes_constraints.py
@@ -14,7 +14,7 @@
 
 import pandas as pd
 
-from _fes_helper import get_data_point
+from _fes_helpers import get_data_point
 from _helpers import configure_logging
 
 
diff --git a/scripts/prepare_network.py b/scripts/prepare_network.py
index ae15e99d..3e279b36 100755
--- a/scripts/prepare_network.py
+++ b/scripts/prepare_network.py
@@ -289,6 +289,34 @@ def remove_elec_base_techs(n):
         # n.carriers.drop(to_remove, inplace=True, errors="ignore")
 
 
+def scale_generation_capacity(n, capacity_file):
+    
+    generation_mapper = {
+        "gas": ["OCGT", "CCGT"],
+        "coal": ["coal", "lignite"],
+        "nuclear": ["nuclear"],
+        "biomass": ["biomass"],
+    }
+
+    constraints = pd.read_csv(capacity_file, index_col=1)["value"]
+
+    gb_gen = n.generators.loc[n.generators.bus.str.contains("GB")]
+
+    for fes_gen, target in generation_mapper.items():
+        index = gb_gen[gb_gen.carrier.isin(target)].index
+
+        if not fes_gen in constraints.index:
+            n.generators.drop(index, inplace=True)
+            continue
+
+        adapted = n.generators.loc[index, "p_nom"].copy()
+        adapted *= constraints.loc[fes_gen] / adapted.sum() 
+
+        n.generators.loc[index, "p_nom"] = adapted
+        n.generators.loc[index, "p_nom_min"] = adapted
+
+
+
 def convert_generators_to_links(n, costs):
 
     logger.info("Converting generators to links")
@@ -300,7 +328,7 @@ def convert_generators_to_links(n, costs):
                      "lignite": "lignite"}
 
     for generator, carrier in conventionals.items(): 
-        
+
         if not f"GB_{carrier}_bus" in n.buses.index:
             n.add("Bus",
                 f"GB_{carrier}_bus",
@@ -314,6 +342,9 @@ def convert_generators_to_links(n, costs):
                   marginal_cost=costs.at[carrier, "fuel"],
                   )
 
+        if not generator in gb_generation.carrier.unique():
+            continue
+
         gens = gb_generation.loc[gb_generation.carrier == generator]
 
         n.madd(
@@ -624,10 +655,9 @@ def add_dac(n, costs):
         1.,
     )
 
-    interesting = ["CCGT", "direct air capture", "coal CCS", "gas CCS"]
-
+    scale_generation_capacity(n, snakemake.input.capacity_constraints)
     convert_generators_to_links(n, other_costs)
-    
+
     import sys
     sys.exit()