From 98d2c4dd911b6d0157ea11691b057f32837a1760 Mon Sep 17 00:00:00 2001
From: Thomas Gilon <tgi@climact.com>
Date: Thu, 11 Apr 2024 10:54:25 +0200
Subject: [PATCH] Fix p_nom_min of renewables generators for myopic approach
 and add check of existing capacities in add_land_use_constraint_m

---
 doc/release_notes.rst    |  2 ++
 scripts/solve_network.py | 16 ++++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/doc/release_notes.rst b/doc/release_notes.rst
index d42b149f8..d9c692449 100644
--- a/doc/release_notes.rst
+++ b/doc/release_notes.rst
@@ -181,6 +181,8 @@ Upcoming Release
 
 * Fix custom busmap read in `cluster_network`.
 
+* Fix p_nom_min of renewables generators for myopic approach and add check of existing capacities in `add_land_use_constraint_m`.
+
 PyPSA-Eur 0.10.0 (19th February 2024)
 =====================================
 
diff --git a/scripts/solve_network.py b/scripts/solve_network.py
index 0f6725c70..b8819a19b 100644
--- a/scripts/solve_network.py
+++ b/scripts/solve_network.py
@@ -159,6 +159,9 @@ def _add_land_use_constraint_m(n, planning_horizons, config):
     current_horizon = snakemake.wildcards.planning_horizons
 
     for carrier in ["solar", "onwind", "offwind-ac", "offwind-dc"]:
+        extendable_i = (n.generators.carrier == carrier) & n.generators.p_nom_extendable
+        n.generators.loc[extendable_i, "p_nom_min"] = 0
+
         existing = n.generators.loc[n.generators.carrier == carrier, "p_nom"]
         ind = list(
             {i.split(sep=" ")[0] + " " + i.split(sep=" ")[1] for i in existing.index}
@@ -180,6 +183,19 @@ def _add_land_use_constraint_m(n, planning_horizons, config):
                 sel_p_year
             ].rename(lambda x: x[:-4] + current_horizon)
 
+    # check if existing capacities are larger than technical potential
+    existing_large = n.generators[
+        n.generators["p_nom_min"] > n.generators["p_nom_max"]
+    ].index
+    if len(existing_large):
+        logger.warning(
+            f"Existing capacities larger than technical potential for {existing_large},\
+                        adjust technical potential to existing capacities"
+        )
+        n.generators.loc[existing_large, "p_nom_max"] = n.generators.loc[
+            existing_large, "p_nom_min"
+        ]
+
     n.generators.p_nom_max.clip(lower=0, inplace=True)