From 0c8ad8b356a46334b3f7ac982449b34f51056055 Mon Sep 17 00:00:00 2001
From: Fabian Neumann <fabian.neumann@outlook.de>
Date: Wed, 18 Feb 2026 09:13:05 +0100
Subject: [PATCH 01/16] Add option to specify fixed DC-AC ratio for solar PV

---
 config/config.default.yaml                 |  2 ++
 config/schema.default.json                 | 30 ++++++++++++++++++++++
 scripts/build_renewable_profiles.py        |  6 +++++
 scripts/lib/validation/config/renewable.py |  5 ++++
 4 files changed, 43 insertions(+)

diff --git a/config/config.default.yaml b/config/config.default.yaml
index 9e8e27d8d8..4eb0a95480 100644
--- a/config/config.default.yaml
+++ b/config/config.default.yaml
@@ -368,6 +368,7 @@ renewable:
     natura: true
     excluder_resolution: 100
     clip_p_max_pu: 0.01
+    dc_ac_ratio: 1.3
   "solar-hsat":
     cutout: default
     resource:
@@ -408,6 +409,7 @@ renewable:
     natura: true
     excluder_resolution: 100
     clip_p_max_pu: 0.01
+    dc_ac_ratio: 1.3
   hydro:
     cutout: default
     carriers:
diff --git a/config/schema.default.json b/config/schema.default.json
index 078a459c2b..81b2851446 100644
--- a/config/schema.default.json
+++ b/config/schema.default.json
@@ -3690,6 +3690,12 @@
               "default": 0.01,
               "description": "To avoid too small values in the renewables` per-unit availability time series values below this threshold are set to zero.",
               "type": "number"
+            },
+            "dc_ac_ratio": {
+              "default": 1.3,
+              "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
+              "exclusiveMinimum": 0,
+              "type": "number"
             }
           }
         },
@@ -3814,6 +3820,12 @@
               "default": 0.01,
               "description": "To avoid too small values in the renewables` per-unit availability time series values below this threshold are set to zero.",
               "type": "number"
+            },
+            "dc_ac_ratio": {
+              "default": 1.3,
+              "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
+              "exclusiveMinimum": 0,
+              "type": "number"
             }
           }
         },
@@ -7529,6 +7541,12 @@
           "default": 0.01,
           "description": "To avoid too small values in the renewables` per-unit availability time series values below this threshold are set to zero.",
           "type": "number"
+        },
+        "dc_ac_ratio": {
+          "default": 1.3,
+          "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
+          "exclusiveMinimum": 0,
+          "type": "number"
         }
       }
     },
@@ -9552,6 +9570,12 @@
               "default": 0.01,
               "description": "To avoid too small values in the renewables` per-unit availability time series values below this threshold are set to zero.",
               "type": "number"
+            },
+            "dc_ac_ratio": {
+              "default": 1.3,
+              "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
+              "exclusiveMinimum": 0,
+              "type": "number"
             }
           }
         },
@@ -9676,6 +9700,12 @@
               "default": 0.01,
               "description": "To avoid too small values in the renewables` per-unit availability time series values below this threshold are set to zero.",
               "type": "number"
+            },
+            "dc_ac_ratio": {
+              "default": 1.3,
+              "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
+              "exclusiveMinimum": 0,
+              "type": "number"
             }
           }
         },
diff --git a/scripts/build_renewable_profiles.py b/scripts/build_renewable_profiles.py
index 724d002e16..d17d3041c9 100644
--- a/scripts/build_renewable_profiles.py
+++ b/scripts/build_renewable_profiles.py
@@ -321,6 +321,12 @@
         )
     )
 
+    dc_ac_ratio = params.get("dc_ac_ratio", 1.0)
+    if dc_ac_ratio != 1.0:
+        logger.info(f"Applying DC/AC ratio of {dc_ac_ratio} to solar profiles")
+        ds["profile"] = ds["profile"].clip(max=1 / dc_ac_ratio) * dc_ac_ratio
+        ds["p_nom_max"] = ds["p_nom_max"] / dc_ac_ratio
+
     if "clip_p_max_pu" in params:
         min_p_max_pu = params["clip_p_max_pu"]
         ds["profile"] = ds["profile"].where(ds["profile"] >= min_p_max_pu, 0)
diff --git a/scripts/lib/validation/config/renewable.py b/scripts/lib/validation/config/renewable.py
index 7d549419f3..a4f0134b52 100644
--- a/scripts/lib/validation/config/renewable.py
+++ b/scripts/lib/validation/config/renewable.py
@@ -256,6 +256,11 @@ class _SolarConfig(BaseModel):
         0.01,
         description="To avoid too small values in the renewables` per-unit availability time series values below this threshold are set to zero.",
     )
+    dc_ac_ratio: float = Field(
+        1.3,
+        description="DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
+        gt=0,
+    )
 
 
 class _HydroConfig(BaseModel):

From dc24ebae75b2bdec15d98523326fe2f1d1861f70 Mon Sep 17 00:00:00 2001
From: Michael Lindner <michaellindner@posteo.de>
Date: Fri, 27 Feb 2026 16:26:34 +0100
Subject: [PATCH 02/16] keep dc profiles but clip them correctly

---
 scripts/build_renewable_profiles.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/scripts/build_renewable_profiles.py b/scripts/build_renewable_profiles.py
index d17d3041c9..59f64b41d8 100644
--- a/scripts/build_renewable_profiles.py
+++ b/scripts/build_renewable_profiles.py
@@ -324,8 +324,8 @@
     dc_ac_ratio = params.get("dc_ac_ratio", 1.0)
     if dc_ac_ratio != 1.0:
         logger.info(f"Applying DC/AC ratio of {dc_ac_ratio} to solar profiles")
-        ds["profile"] = ds["profile"].clip(max=1 / dc_ac_ratio) * dc_ac_ratio
-        ds["p_nom_max"] = ds["p_nom_max"] / dc_ac_ratio
+        ds["profile"] = ds["profile"].clip(max=1 / dc_ac_ratio) 
+        ds["p_nom_max"] = ds["p_nom_max"]
 
     if "clip_p_max_pu" in params:
         min_p_max_pu = params["clip_p_max_pu"]

From ca23b65b7b1ec8a8f94c763e000b09be2999482a Mon Sep 17 00:00:00 2001
From: Michael Lindner <michaellindner@posteo.de>
Date: Fri, 27 Feb 2026 17:30:21 +0100
Subject: [PATCH 03/16] add switch if costs are given in DC

---
 scripts/add_electricity.py        |  4 ++++
 scripts/prepare_sector_network.py | 12 +++++++++---
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/scripts/add_electricity.py b/scripts/add_electricity.py
index 0df64d148f..e89a68dc50 100755
--- a/scripts/add_electricity.py
+++ b/scripts/add_electricity.py
@@ -460,6 +460,7 @@ def attach_wind_and_solar(
     extendable_carriers: list | set,
     line_length_factor: float = 1.0,
     landfall_lengths: dict = None,
+    params_renewable: dict = None,
 ) -> None:
     """
     Attach wind and solar generators to the network.
@@ -531,6 +532,8 @@ def attach_wind_and_solar(
                 logger.info(
                     f"Added connection cost of {connection_cost.min():0.0f}-{connection_cost.max():0.0f} Eur/MW/a to {car}"
                 )
+            elif params_renewable[car].get("costs_given_for_ac") and params_renewable[car].get("dc_ac_ratio", 1.0) != 1.0:
+                capital_cost = costs.at[car, "capital_cost"] / params_renewable[car]["dc_ac_ratio"]
             else:
                 capital_cost = costs.at[car, "capital_cost"]
 
@@ -1211,6 +1214,7 @@ def attach_stores(
         extendable_carriers,
         params.line_length_factor,
         landfall_lengths,
+        params.renewable,
     )
 
     if "hydro" in renewable_carriers:
diff --git a/scripts/prepare_sector_network.py b/scripts/prepare_sector_network.py
index d9434ef76e..7824dc9bc8 100755
--- a/scripts/prepare_sector_network.py
+++ b/scripts/prepare_sector_network.py
@@ -427,6 +427,7 @@ def update_wind_solar_costs(
     profiles: dict[str, str],
     landfall_lengths: dict = None,
     line_length_factor: int | float = 1,
+    params_renewable: dict = None,
 ) -> None:
     """
     Update costs for wind and solar generators added with pypsa-eur to those
@@ -445,6 +446,8 @@ def update_wind_solar_costs(
     profiles : dict[str, str]
         Dictionary mapping technology names to profile file paths
         e.g. {'offwind-dc': 'path/to/profile.nc'}
+    params_renewable : dict, optional
+        Dictionary of renewable parameters, by default None
     """
 
     if landfall_lengths is None:
@@ -464,6 +467,9 @@ def update_wind_solar_costs(
         n.generators.loc[n.generators.carrier == carrier, "capital_cost"] = costs.at[
             cost_key, "capital_cost"
         ]
+        if params_renewable[carrier].get("costs_given_for_ac") and params_renewable[carrier].get("dc_ac_ratio", 1.0) != 1.0:
+            n.generators.loc[n.generators.carrier == carrier, "capital_cost"] /= params_renewable[carrier]["dc_ac_ratio"]
+
 
     # for offshore wind, need to calculated connection costs
     for key, fn in profiles.items():
@@ -689,11 +695,11 @@ def remove_non_electric_buses(n):
         n.buses = n.buses[n.buses.carrier.isin(["AC", "DC"])]
 
 
-def patch_electricity_network(n, costs, carriers_to_keep, profiles, landfall_lengths):
+def patch_electricity_network(n, costs, carriers_to_keep, profiles, landfall_lengths, params_renewable=None):
     remove_elec_base_techs(n, carriers_to_keep)
     remove_non_electric_buses(n)
     update_wind_solar_costs(
-        n, costs, landfall_lengths=landfall_lengths, profiles=profiles
+        n, costs, landfall_lengths=landfall_lengths, profiles=profiles, params_renewable=params_renewable   
     )
     n.loads["carrier"] = "electricity"
     n.buses["location"] = n.buses.index
@@ -6287,7 +6293,7 @@ def add_import_options(
         for tech, settings in snakemake.params.renewable.items()
         if "landfall_length" in settings.keys()
     }
-    patch_electricity_network(n, costs, carriers_to_keep, profiles, landfall_lengths)
+    patch_electricity_network(n, costs, carriers_to_keep, profiles, landfall_lengths, snakemake.params.renewable)
 
     fn = snakemake.input.heating_efficiencies
     year = int(snakemake.params["energy_totals_year"])

From c6fdfa7fcc82f2f64b4199cd12592190b43fb373 Mon Sep 17 00:00:00 2001
From: Michael Lindner <michaellindner@posteo.de>
Date: Fri, 27 Feb 2026 17:30:32 +0100
Subject: [PATCH 04/16] scale grid expansion cost to dc

---
 scripts/prepare_sector_network.py | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/scripts/prepare_sector_network.py b/scripts/prepare_sector_network.py
index 7824dc9bc8..7338f48902 100755
--- a/scripts/prepare_sector_network.py
+++ b/scripts/prepare_sector_network.py
@@ -1743,14 +1743,15 @@ def insert_gas_distribution_costs(
     n.links.loc[mchp, "capital_cost"] += capital_cost
 
 
-def add_electricity_grid_connection(n, costs):
+def add_electricity_grid_connection(n, costs, params_renewables):
     carriers = ["onwind", "solar", "solar-hsat"]
-
-    gens = n.generators.index[n.generators.carrier.isin(carriers)]
-
-    n.generators.loc[gens, "capital_cost"] += costs.at[
-        "electricity grid connection", "capital_cost"
-    ]
+    for car in carriers:
+            
+        gens = n.generators.index[n.generators.carrier == car]
+        dc_ac_ratio = params_renewables[car].get("dc_ac_ratio", 1.0)
+        n.generators.loc[gens, "capital_cost"] += costs.at[
+            "electricity grid connection", "capital_cost"
+        ] / dc_ac_ratio
 
 
 def add_h2_gas_infrastructure(
@@ -6576,7 +6577,7 @@ def add_import_options(
         insert_gas_distribution_costs(n, costs, options=options)
 
     if options["electricity_grid_connection"]:
-        add_electricity_grid_connection(n, costs)
+        add_electricity_grid_connection(n, costs, snakemake.param["renewable"])
 
     for k, v in options["transmission_efficiency"].items():
         if k in options["transmission_efficiency"]["enable"]:

From 6dab084f6c98a2fe2f17cecb4b5a8019c00c986e Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Fri, 27 Feb 2026 16:30:51 +0000
Subject: [PATCH 05/16] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 scripts/add_electricity.py          |  9 ++++++--
 scripts/build_renewable_profiles.py |  2 +-
 scripts/prepare_sector_network.py   | 36 +++++++++++++++++++++--------
 3 files changed, 34 insertions(+), 13 deletions(-)

diff --git a/scripts/add_electricity.py b/scripts/add_electricity.py
index e89a68dc50..9a7ac9ba6f 100755
--- a/scripts/add_electricity.py
+++ b/scripts/add_electricity.py
@@ -532,8 +532,13 @@ def attach_wind_and_solar(
                 logger.info(
                     f"Added connection cost of {connection_cost.min():0.0f}-{connection_cost.max():0.0f} Eur/MW/a to {car}"
                 )
-            elif params_renewable[car].get("costs_given_for_ac") and params_renewable[car].get("dc_ac_ratio", 1.0) != 1.0:
-                capital_cost = costs.at[car, "capital_cost"] / params_renewable[car]["dc_ac_ratio"]
+            elif (
+                params_renewable[car].get("costs_given_for_ac")
+                and params_renewable[car].get("dc_ac_ratio", 1.0) != 1.0
+            ):
+                capital_cost = (
+                    costs.at[car, "capital_cost"] / params_renewable[car]["dc_ac_ratio"]
+                )
             else:
                 capital_cost = costs.at[car, "capital_cost"]
 
diff --git a/scripts/build_renewable_profiles.py b/scripts/build_renewable_profiles.py
index 59f64b41d8..186c382e1b 100644
--- a/scripts/build_renewable_profiles.py
+++ b/scripts/build_renewable_profiles.py
@@ -324,7 +324,7 @@
     dc_ac_ratio = params.get("dc_ac_ratio", 1.0)
     if dc_ac_ratio != 1.0:
         logger.info(f"Applying DC/AC ratio of {dc_ac_ratio} to solar profiles")
-        ds["profile"] = ds["profile"].clip(max=1 / dc_ac_ratio) 
+        ds["profile"] = ds["profile"].clip(max=1 / dc_ac_ratio)
         ds["p_nom_max"] = ds["p_nom_max"]
 
     if "clip_p_max_pu" in params:
diff --git a/scripts/prepare_sector_network.py b/scripts/prepare_sector_network.py
index 7338f48902..e7e1c1cdab 100755
--- a/scripts/prepare_sector_network.py
+++ b/scripts/prepare_sector_network.py
@@ -467,9 +467,13 @@ def update_wind_solar_costs(
         n.generators.loc[n.generators.carrier == carrier, "capital_cost"] = costs.at[
             cost_key, "capital_cost"
         ]
-        if params_renewable[carrier].get("costs_given_for_ac") and params_renewable[carrier].get("dc_ac_ratio", 1.0) != 1.0:
-            n.generators.loc[n.generators.carrier == carrier, "capital_cost"] /= params_renewable[carrier]["dc_ac_ratio"]
-
+        if (
+            params_renewable[carrier].get("costs_given_for_ac")
+            and params_renewable[carrier].get("dc_ac_ratio", 1.0) != 1.0
+        ):
+            n.generators.loc[n.generators.carrier == carrier, "capital_cost"] /= (
+                params_renewable[carrier]["dc_ac_ratio"]
+            )
 
     # for offshore wind, need to calculated connection costs
     for key, fn in profiles.items():
@@ -695,11 +699,17 @@ def remove_non_electric_buses(n):
         n.buses = n.buses[n.buses.carrier.isin(["AC", "DC"])]
 
 
-def patch_electricity_network(n, costs, carriers_to_keep, profiles, landfall_lengths, params_renewable=None):
+def patch_electricity_network(
+    n, costs, carriers_to_keep, profiles, landfall_lengths, params_renewable=None
+):
     remove_elec_base_techs(n, carriers_to_keep)
     remove_non_electric_buses(n)
     update_wind_solar_costs(
-        n, costs, landfall_lengths=landfall_lengths, profiles=profiles, params_renewable=params_renewable   
+        n,
+        costs,
+        landfall_lengths=landfall_lengths,
+        profiles=profiles,
+        params_renewable=params_renewable,
     )
     n.loads["carrier"] = "electricity"
     n.buses["location"] = n.buses.index
@@ -1746,12 +1756,11 @@ def insert_gas_distribution_costs(
 def add_electricity_grid_connection(n, costs, params_renewables):
     carriers = ["onwind", "solar", "solar-hsat"]
     for car in carriers:
-            
         gens = n.generators.index[n.generators.carrier == car]
         dc_ac_ratio = params_renewables[car].get("dc_ac_ratio", 1.0)
-        n.generators.loc[gens, "capital_cost"] += costs.at[
-            "electricity grid connection", "capital_cost"
-        ] / dc_ac_ratio
+        n.generators.loc[gens, "capital_cost"] += (
+            costs.at["electricity grid connection", "capital_cost"] / dc_ac_ratio
+        )
 
 
 def add_h2_gas_infrastructure(
@@ -6294,7 +6303,14 @@ def add_import_options(
         for tech, settings in snakemake.params.renewable.items()
         if "landfall_length" in settings.keys()
     }
-    patch_electricity_network(n, costs, carriers_to_keep, profiles, landfall_lengths, snakemake.params.renewable)
+    patch_electricity_network(
+        n,
+        costs,
+        carriers_to_keep,
+        profiles,
+        landfall_lengths,
+        snakemake.params.renewable,
+    )
 
     fn = snakemake.input.heating_efficiencies
     year = int(snakemake.params["energy_totals_year"])

From 6ab77fb5cce51d580938d5b60a98d54d192876f8 Mon Sep 17 00:00:00 2001
From: Michael Lindner <michaellindner@posteo.de>
Date: Mon, 2 Mar 2026 10:20:16 +0100
Subject: [PATCH 06/16] add new config to indicate if solar costs are given in
 ac or in dc

---
 config/config.default.yaml                 |  2 ++
 config/schema.default.json                 | 26 +++++++++++++++++++++-
 scripts/lib/validation/config/renewable.py |  4 ++++
 3 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/config/config.default.yaml b/config/config.default.yaml
index 4eb0a95480..ab2f51bdd1 100644
--- a/config/config.default.yaml
+++ b/config/config.default.yaml
@@ -369,6 +369,7 @@ renewable:
     excluder_resolution: 100
     clip_p_max_pu: 0.01
     dc_ac_ratio: 1.3
+    costs_given_for_ac: true
   "solar-hsat":
     cutout: default
     resource:
@@ -410,6 +411,7 @@ renewable:
     excluder_resolution: 100
     clip_p_max_pu: 0.01
     dc_ac_ratio: 1.3
+    costs_given_for_ac: true
   hydro:
     cutout: default
     carriers:
diff --git a/config/schema.default.json b/config/schema.default.json
index 81b2851446..5de89902c9 100644
--- a/config/schema.default.json
+++ b/config/schema.default.json
@@ -3696,7 +3696,11 @@
               "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
               "exclusiveMinimum": 0,
               "type": "number"
-            }
+            },
+            "costs_given_for_ac": {
+              "default": true,
+              "description": "Switch to indicate that the capital_costs for solar are given for AC capacity. If `false`, costs are given for DC peak capacity.",
+              "type": "boolean"
           }
         },
         "solar-hsat": {
@@ -3826,6 +3830,11 @@
               "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
               "exclusiveMinimum": 0,
               "type": "number"
+            },
+            "costs_given_for_ac": {
+              "default": true,
+              "description": "Switch to indicate that the capital_costs for solar are given for AC capacity. If `false`, costs are given for DC peak capacity.",
+              "type": "boolean"
             }
           }
         },
@@ -7547,6 +7556,11 @@
           "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
           "exclusiveMinimum": 0,
           "type": "number"
+        },
+        "costs_given_for_ac": {
+              "default": true,
+              "description": "Switch to indicate that the capital_costs for solar are given for AC capacity. If `false`, costs are given for DC peak capacity.",
+              "type": "boolean"
         }
       }
     },
@@ -9576,6 +9590,11 @@
               "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
               "exclusiveMinimum": 0,
               "type": "number"
+            },
+            "costs_given_for_ac": {
+              "default": true,
+              "description": "Switch to indicate that the capital_costs for solar are given for AC capacity. If `false`, costs are given for DC peak capacity.",
+              "type": "boolean"
             }
           }
         },
@@ -9706,6 +9725,11 @@
               "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
               "exclusiveMinimum": 0,
               "type": "number"
+            },
+            "costs_given_for_ac": {
+              "default": true,
+              "description": "Switch to indicate that the capital_costs for solar are given for AC capacity. If `false`, costs are given for DC peak capacity.",
+              "type": "boolean"
             }
           }
         },
diff --git a/scripts/lib/validation/config/renewable.py b/scripts/lib/validation/config/renewable.py
index a4f0134b52..46d6fbd546 100644
--- a/scripts/lib/validation/config/renewable.py
+++ b/scripts/lib/validation/config/renewable.py
@@ -261,6 +261,10 @@ class _SolarConfig(BaseModel):
         description="DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
         gt=0,
     )
+    costs_given_for_ac: bool = Field(
+        True,
+        description="Switch to indicate that the capital_costs for solar are given for AC capacity. If `false`, costs are given for DC peak capacity.",
+    )
 
 
 class _HydroConfig(BaseModel):

From 7581116336b7db9eadfbcc34714449f738b019c8 Mon Sep 17 00:00:00 2001
From: Michael Lindner <michaellindner@posteo.de>
Date: Mon, 2 Mar 2026 10:23:14 +0100
Subject: [PATCH 07/16] more reasonable bound for dc/ac ratio

---
 config/schema.default.json                 | 10 +++++-----
 scripts/lib/validation/config/renewable.py |  2 +-
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/config/schema.default.json b/config/schema.default.json
index 5de89902c9..950ad07d54 100644
--- a/config/schema.default.json
+++ b/config/schema.default.json
@@ -3694,7 +3694,7 @@
             "dc_ac_ratio": {
               "default": 1.3,
               "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
-              "exclusiveMinimum": 0,
+              "minimum": 1,
               "type": "number"
             },
             "costs_given_for_ac": {
@@ -3828,7 +3828,7 @@
             "dc_ac_ratio": {
               "default": 1.3,
               "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
-              "exclusiveMinimum": 0,
+              "minimum": 1,
               "type": "number"
             },
             "costs_given_for_ac": {
@@ -7554,7 +7554,7 @@
         "dc_ac_ratio": {
           "default": 1.3,
           "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
-          "exclusiveMinimum": 0,
+          "minimum": 1,
           "type": "number"
         },
         "costs_given_for_ac": {
@@ -9588,7 +9588,7 @@
             "dc_ac_ratio": {
               "default": 1.3,
               "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
-              "exclusiveMinimum": 0,
+              "minimum": 1,
               "type": "number"
             },
             "costs_given_for_ac": {
@@ -9723,7 +9723,7 @@
             "dc_ac_ratio": {
               "default": 1.3,
               "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
-              "exclusiveMinimum": 0,
+              "minimum": 1,
               "type": "number"
             },
             "costs_given_for_ac": {
diff --git a/scripts/lib/validation/config/renewable.py b/scripts/lib/validation/config/renewable.py
index 46d6fbd546..cfb222fb63 100644
--- a/scripts/lib/validation/config/renewable.py
+++ b/scripts/lib/validation/config/renewable.py
@@ -259,7 +259,7 @@ class _SolarConfig(BaseModel):
     dc_ac_ratio: float = Field(
         1.3,
         description="DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
-        gt=0,
+        ge=1,
     )
     costs_given_for_ac: bool = Field(
         True,

From d47c739054df106cf41c175f84e624fa09205a0b Mon Sep 17 00:00:00 2001
From: Michael Lindner <michaellindner@posteo.de>
Date: Mon, 2 Mar 2026 10:27:08 +0100
Subject: [PATCH 08/16] pixi run generate-config

---
 config/schema.default.json | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/config/schema.default.json b/config/schema.default.json
index 950ad07d54..d2eed43b77 100644
--- a/config/schema.default.json
+++ b/config/schema.default.json
@@ -3701,6 +3701,7 @@
               "default": true,
               "description": "Switch to indicate that the capital_costs for solar are given for AC capacity. If `false`, costs are given for DC peak capacity.",
               "type": "boolean"
+            }
           }
         },
         "solar-hsat": {
@@ -7558,9 +7559,9 @@
           "type": "number"
         },
         "costs_given_for_ac": {
-              "default": true,
-              "description": "Switch to indicate that the capital_costs for solar are given for AC capacity. If `false`, costs are given for DC peak capacity.",
-              "type": "boolean"
+          "default": true,
+          "description": "Switch to indicate that the capital_costs for solar are given for AC capacity. If `false`, costs are given for DC peak capacity.",
+          "type": "boolean"
         }
       }
     },

From 0e2fdbeb8bbc9aa4af208eee430a1ce594712586 Mon Sep 17 00:00:00 2001
From: Michael Lindner <michaellindner@posteo.de>
Date: Mon, 2 Mar 2026 11:36:56 +0100
Subject: [PATCH 09/16] fix typo

---
 scripts/prepare_sector_network.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/prepare_sector_network.py b/scripts/prepare_sector_network.py
index e7e1c1cdab..e47ef35c27 100755
--- a/scripts/prepare_sector_network.py
+++ b/scripts/prepare_sector_network.py
@@ -6593,7 +6593,7 @@ def add_import_options(
         insert_gas_distribution_costs(n, costs, options=options)
 
     if options["electricity_grid_connection"]:
-        add_electricity_grid_connection(n, costs, snakemake.param["renewable"])
+        add_electricity_grid_connection(n, costs, snakemake.params["renewable"])
 
     for k, v in options["transmission_efficiency"].items():
         if k in options["transmission_efficiency"]["enable"]:

From 30598769f145b5adfac2af838f59b2d9a9b1b403 Mon Sep 17 00:00:00 2001
From: Michael Lindner <michaellindner@posteo.de>
Date: Mon, 2 Mar 2026 12:45:57 +0100
Subject: [PATCH 10/16] improve logger message

---
 scripts/build_renewable_profiles.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/scripts/build_renewable_profiles.py b/scripts/build_renewable_profiles.py
index 186c382e1b..552ff4b0d5 100644
--- a/scripts/build_renewable_profiles.py
+++ b/scripts/build_renewable_profiles.py
@@ -323,9 +323,8 @@
 
     dc_ac_ratio = params.get("dc_ac_ratio", 1.0)
     if dc_ac_ratio != 1.0:
-        logger.info(f"Applying DC/AC ratio of {dc_ac_ratio} to solar profiles")
+        logger.info(f"Applying DC/AC ratio of {dc_ac_ratio} by clipping solar profiles at {1/dc_ac_ratio:.2f}.")
         ds["profile"] = ds["profile"].clip(max=1 / dc_ac_ratio)
-        ds["p_nom_max"] = ds["p_nom_max"]
 
     if "clip_p_max_pu" in params:
         min_p_max_pu = params["clip_p_max_pu"]

From 78080cfa6261524447b3764d7dfb09075b4b808a Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Mon, 2 Mar 2026 11:46:15 +0000
Subject: [PATCH 11/16] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 scripts/build_renewable_profiles.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/scripts/build_renewable_profiles.py b/scripts/build_renewable_profiles.py
index 552ff4b0d5..f0d3975457 100644
--- a/scripts/build_renewable_profiles.py
+++ b/scripts/build_renewable_profiles.py
@@ -323,7 +323,9 @@
 
     dc_ac_ratio = params.get("dc_ac_ratio", 1.0)
     if dc_ac_ratio != 1.0:
-        logger.info(f"Applying DC/AC ratio of {dc_ac_ratio} by clipping solar profiles at {1/dc_ac_ratio:.2f}.")
+        logger.info(
+            f"Applying DC/AC ratio of {dc_ac_ratio} by clipping solar profiles at {1 / dc_ac_ratio:.2f}."
+        )
         ds["profile"] = ds["profile"].clip(max=1 / dc_ac_ratio)
 
     if "clip_p_max_pu" in params:

From 3647bac5ec1782c61c5cd92af9418ee14935bc06 Mon Sep 17 00:00:00 2001
From: Michael Lindner <michaellindner@posteo.de>
Date: Tue, 3 Mar 2026 09:22:14 +0100
Subject: [PATCH 12/16] apply cost transformation to solar rooftop as well

---
 scripts/prepare_sector_network.py | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/scripts/prepare_sector_network.py b/scripts/prepare_sector_network.py
index e47ef35c27..9181855cc0 100755
--- a/scripts/prepare_sector_network.py
+++ b/scripts/prepare_sector_network.py
@@ -1521,6 +1521,7 @@ def insert_electricity_distribution_grid(
     options: dict,
     pop_layout: pd.DataFrame,
     solar_rooftop_potentials_fn: str,
+    params_renewable: dict,
 ) -> None:
     """
     Insert electricity distribution grid components into the network.
@@ -1545,6 +1546,8 @@ def insert_electricity_distribution_grid(
         Population data per node with at least:
         - 'total' column containing population in thousands
         Index should match network nodes
+    params_renewable : dict
+        Renewable energy parameters
 
     Returns
     -------
@@ -1627,11 +1630,19 @@ def insert_electricity_distribution_grid(
     solar = n.generators.index[n.generators.carrier == "solar"]
     n.generators.loc[solar, "capital_cost"] = costs.at["solar-utility", "capital_cost"]
 
+    dc_ac_ratio = params_renewable["solar"].get("dc_ac_ratio", 1.0)
+    if params_renewable["solar"].get("costs_given_for_ac") and dc_ac_ratio != 1.0:
+        n.generators.loc[solar, "capital_cost"] /= dc_ac_ratio
+
+
     fn = solar_rooftop_potentials_fn
     if len(fn) > 0:
         potential = pd.read_csv(fn, index_col=["bus", "bin"]).squeeze(axis=1)
         potential.index = potential.index.map(flatten) + " solar"
 
+        capital_cost = costs.at["solar rooftop", "capital_cost"]
+        if params_renewable["solar"].get("costs_given_for_ac") and dc_ac_ratio != 1.0:
+            capital_cost /= dc_ac_ratio
         n.add(
             "Generator",
             solar,
@@ -1641,7 +1652,7 @@ def insert_electricity_distribution_grid(
             p_nom_extendable=True,
             p_nom_max=potential.loc[solar],
             marginal_cost=n.generators.loc[solar, "marginal_cost"],
-            capital_cost=costs.at["solar-rooftop", "capital_cost"],
+            capital_cost=capital_cost,
             efficiency=n.generators.loc[solar, "efficiency"],
             p_max_pu=n.generators_t.p_max_pu[solar],
             lifetime=costs.at["solar-rooftop", "lifetime"],
@@ -6571,7 +6582,7 @@ def add_import_options(
 
     if options["electricity_distribution_grid"]:
         insert_electricity_distribution_grid(
-            n, costs, options, pop_layout, snakemake.input.solar_rooftop_potentials
+            n, costs, options, pop_layout, snakemake.input.solar_rooftop_potentials, snakemake.params.renewable
         )
 
     if options["enhanced_geothermal"].get("enable", False):

From 7e2ac5cb0010e9f656816356af65fa5c53ddb008 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Tue, 3 Mar 2026 08:22:34 +0000
Subject: [PATCH 13/16] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 scripts/prepare_sector_network.py | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/scripts/prepare_sector_network.py b/scripts/prepare_sector_network.py
index 9181855cc0..3b184cf7e5 100755
--- a/scripts/prepare_sector_network.py
+++ b/scripts/prepare_sector_network.py
@@ -1634,7 +1634,6 @@ def insert_electricity_distribution_grid(
     if params_renewable["solar"].get("costs_given_for_ac") and dc_ac_ratio != 1.0:
         n.generators.loc[solar, "capital_cost"] /= dc_ac_ratio
 
-
     fn = solar_rooftop_potentials_fn
     if len(fn) > 0:
         potential = pd.read_csv(fn, index_col=["bus", "bin"]).squeeze(axis=1)
@@ -6582,7 +6581,12 @@ def add_import_options(
 
     if options["electricity_distribution_grid"]:
         insert_electricity_distribution_grid(
-            n, costs, options, pop_layout, snakemake.input.solar_rooftop_potentials, snakemake.params.renewable
+            n,
+            costs,
+            options,
+            pop_layout,
+            snakemake.input.solar_rooftop_potentials,
+            snakemake.params.renewable,
         )
 
     if options["enhanced_geothermal"].get("enable", False):

From eb228041f6d4eb87756e3f48b44c5e4d2a9e2246 Mon Sep 17 00:00:00 2001
From: Michael Lindner <michaellindner@posteo.de>
Date: Wed, 4 Mar 2026 13:26:17 +0100
Subject: [PATCH 14/16] set default dc_ac_ratio to DEA value

---
 config/config.default.yaml |  4 ++--
 config/schema.default.json | 16 ++++++++--------
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/config/config.default.yaml b/config/config.default.yaml
index a99c90f450..f006b9283a 100644
--- a/config/config.default.yaml
+++ b/config/config.default.yaml
@@ -364,7 +364,7 @@ renewable:
     natura: true
     excluder_resolution: 100
     clip_p_max_pu: 0.01
-    dc_ac_ratio: 1.3
+    dc_ac_ratio: 1.25
     costs_given_for_ac: true
   "solar-hsat":
     cutout: default
@@ -406,7 +406,7 @@ renewable:
     natura: true
     excluder_resolution: 100
     clip_p_max_pu: 0.01
-    dc_ac_ratio: 1.3
+    dc_ac_ratio: 1.25
     costs_given_for_ac: true
   hydro:
     cutout: default
diff --git a/config/schema.default.json b/config/schema.default.json
index cc4ba544a9..354652d5b7 100644
--- a/config/schema.default.json
+++ b/config/schema.default.json
@@ -3773,7 +3773,7 @@
               "type": "number"
             },
             "dc_ac_ratio": {
-              "default": 1.3,
+              "default": 1.25,
               "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
               "minimum": 1,
               "type": "number"
@@ -3908,7 +3908,7 @@
               "type": "number"
             },
             "dc_ac_ratio": {
-              "default": 1.3,
+              "default": 1.25,
               "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
               "minimum": 1,
               "type": "number"
@@ -5020,7 +5020,7 @@
               "type": "boolean"
             },
             "factor": {
-              "default": 1.3,
+              "default": 1.25,
               "description": "The maximum growth factor of a carrier (e.g. 1.3 allows  30% larger than max historic growth).",
               "type": "number"
             },
@@ -6724,7 +6724,7 @@
           "type": "boolean"
         },
         "factor": {
-          "default": 1.3,
+          "default": 1.25,
           "description": "The maximum growth factor of a carrier (e.g. 1.3 allows  30% larger than max historic growth).",
           "type": "number"
         },
@@ -7633,7 +7633,7 @@
           "type": "number"
         },
         "dc_ac_ratio": {
-          "default": 1.3,
+          "default": 1.25,
           "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
           "minimum": 1,
           "type": "number"
@@ -9685,7 +9685,7 @@
               "type": "number"
             },
             "dc_ac_ratio": {
-              "default": 1.3,
+              "default": 1.25,
               "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
               "minimum": 1,
               "type": "number"
@@ -9820,7 +9820,7 @@
               "type": "number"
             },
             "dc_ac_ratio": {
-              "default": 1.3,
+              "default": 1.25,
               "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
               "minimum": 1,
               "type": "number"
@@ -11341,7 +11341,7 @@
               "type": "boolean"
             },
             "factor": {
-              "default": 1.3,
+              "default": 1.25,
               "description": "The maximum growth factor of a carrier (e.g. 1.3 allows  30% larger than max historic growth).",
               "type": "number"
             },

From ce8863c86002b14178cd389a1623fc2e4fa45487 Mon Sep 17 00:00:00 2001
From: "pypsa[bot]" <181215446+pypsa[bot]@users.noreply.github.com>
Date: Wed, 4 Mar 2026 12:26:35 +0000
Subject: [PATCH 15/16] [pypsa-bot] run `sync-locks` & `generate-config`

- `pixi run sync-locks`
- `pixi run generate-config`
---
 config/config.default.yaml |  4 ++--
 config/schema.default.json | 16 ++++++++--------
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/config/config.default.yaml b/config/config.default.yaml
index f006b9283a..a99c90f450 100644
--- a/config/config.default.yaml
+++ b/config/config.default.yaml
@@ -364,7 +364,7 @@ renewable:
     natura: true
     excluder_resolution: 100
     clip_p_max_pu: 0.01
-    dc_ac_ratio: 1.25
+    dc_ac_ratio: 1.3
     costs_given_for_ac: true
   "solar-hsat":
     cutout: default
@@ -406,7 +406,7 @@ renewable:
     natura: true
     excluder_resolution: 100
     clip_p_max_pu: 0.01
-    dc_ac_ratio: 1.25
+    dc_ac_ratio: 1.3
     costs_given_for_ac: true
   hydro:
     cutout: default
diff --git a/config/schema.default.json b/config/schema.default.json
index 354652d5b7..cc4ba544a9 100644
--- a/config/schema.default.json
+++ b/config/schema.default.json
@@ -3773,7 +3773,7 @@
               "type": "number"
             },
             "dc_ac_ratio": {
-              "default": 1.25,
+              "default": 1.3,
               "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
               "minimum": 1,
               "type": "number"
@@ -3908,7 +3908,7 @@
               "type": "number"
             },
             "dc_ac_ratio": {
-              "default": 1.25,
+              "default": 1.3,
               "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
               "minimum": 1,
               "type": "number"
@@ -5020,7 +5020,7 @@
               "type": "boolean"
             },
             "factor": {
-              "default": 1.25,
+              "default": 1.3,
               "description": "The maximum growth factor of a carrier (e.g. 1.3 allows  30% larger than max historic growth).",
               "type": "number"
             },
@@ -6724,7 +6724,7 @@
           "type": "boolean"
         },
         "factor": {
-          "default": 1.25,
+          "default": 1.3,
           "description": "The maximum growth factor of a carrier (e.g. 1.3 allows  30% larger than max historic growth).",
           "type": "number"
         },
@@ -7633,7 +7633,7 @@
           "type": "number"
         },
         "dc_ac_ratio": {
-          "default": 1.25,
+          "default": 1.3,
           "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
           "minimum": 1,
           "type": "number"
@@ -9685,7 +9685,7 @@
               "type": "number"
             },
             "dc_ac_ratio": {
-              "default": 1.25,
+              "default": 1.3,
               "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
               "minimum": 1,
               "type": "number"
@@ -9820,7 +9820,7 @@
               "type": "number"
             },
             "dc_ac_ratio": {
-              "default": 1.25,
+              "default": 1.3,
               "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
               "minimum": 1,
               "type": "number"
@@ -11341,7 +11341,7 @@
               "type": "boolean"
             },
             "factor": {
-              "default": 1.25,
+              "default": 1.3,
               "description": "The maximum growth factor of a carrier (e.g. 1.3 allows  30% larger than max historic growth).",
               "type": "number"
             },

From c50201520ac950e975d90a0b2fd6418378ac74c6 Mon Sep 17 00:00:00 2001
From: Michael Lindner <michaellindner@posteo.de>
Date: Wed, 4 Mar 2026 13:51:24 +0100
Subject: [PATCH 16/16] set default dc_ac_ratio to DEA value (second try)

---
 config/config.default.yaml                 |  4 ++--
 config/schema.default.json                 | 10 +++++-----
 scripts/lib/validation/config/renewable.py |  2 +-
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/config/config.default.yaml b/config/config.default.yaml
index a99c90f450..f006b9283a 100644
--- a/config/config.default.yaml
+++ b/config/config.default.yaml
@@ -364,7 +364,7 @@ renewable:
     natura: true
     excluder_resolution: 100
     clip_p_max_pu: 0.01
-    dc_ac_ratio: 1.3
+    dc_ac_ratio: 1.25
     costs_given_for_ac: true
   "solar-hsat":
     cutout: default
@@ -406,7 +406,7 @@ renewable:
     natura: true
     excluder_resolution: 100
     clip_p_max_pu: 0.01
-    dc_ac_ratio: 1.3
+    dc_ac_ratio: 1.25
     costs_given_for_ac: true
   hydro:
     cutout: default
diff --git a/config/schema.default.json b/config/schema.default.json
index cc4ba544a9..adc8a872d6 100644
--- a/config/schema.default.json
+++ b/config/schema.default.json
@@ -3773,7 +3773,7 @@
               "type": "number"
             },
             "dc_ac_ratio": {
-              "default": 1.3,
+              "default": 1.25,
               "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
               "minimum": 1,
               "type": "number"
@@ -3908,7 +3908,7 @@
               "type": "number"
             },
             "dc_ac_ratio": {
-              "default": 1.3,
+              "default": 1.25,
               "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
               "minimum": 1,
               "type": "number"
@@ -7633,7 +7633,7 @@
           "type": "number"
         },
         "dc_ac_ratio": {
-          "default": 1.3,
+          "default": 1.25,
           "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
           "minimum": 1,
           "type": "number"
@@ -9685,7 +9685,7 @@
               "type": "number"
             },
             "dc_ac_ratio": {
-              "default": 1.3,
+              "default": 1.25,
               "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
               "minimum": 1,
               "type": "number"
@@ -9820,7 +9820,7 @@
               "type": "number"
             },
             "dc_ac_ratio": {
-              "default": 1.3,
+              "default": 1.25,
               "description": "DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
               "minimum": 1,
               "type": "number"
diff --git a/scripts/lib/validation/config/renewable.py b/scripts/lib/validation/config/renewable.py
index 7202646abc..0a6a4707d0 100644
--- a/scripts/lib/validation/config/renewable.py
+++ b/scripts/lib/validation/config/renewable.py
@@ -257,7 +257,7 @@ class _SolarConfig(BaseModel):
         description="To avoid too small values in the renewables` per-unit availability time series values below this threshold are set to zero.",
     )
     dc_ac_ratio: float = Field(
-        1.3,
+        1.25,
         description="DC/AC ratio for solar PV. Capacity factors are clipped at 1/dc_ac_ratio and rescaled to express output as a fraction of AC capacity.",
         ge=1,
     )