add option to limit maximum extension per line/link; linemaxext

config/config.default.yaml

@@ -264,12 +264,14 @@ lines:
     380.: "Al/St 240/40 4-bundle 380.0"
   s_max_pu: 0.7
   s_nom_max: .inf
+  max_extension: .inf
   length_factor: 1.25
   under_construction: 'zero' # 'zero': set capacity to zero, 'remove': remove, 'keep': with full capacity
 
 links:
   p_max_pu: 1.0
   p_nom_max: .inf
+  max_extension: .inf
   include_tyndp: true
   under_construction: 'zero' # 'zero': set capacity to zero, 'remove': remove, 'keep': with full capacity
 

doc/configtables/lines.csv

@@ -2,5 +2,6 @@
 types,--,"Values should specify a `line type in PyPSA <https://pypsa.readthedocs.io/en/latest/components.html#line-types>`_. Keys should specify the corresponding voltage level (e.g. 220., 300. and 380. kV)","Specifies line types to assume for the different voltage levels of the ENTSO-E grid extraction. Should normally handle voltage levels 220, 300, and 380 kV"
 s_max_pu,--,"Value in [0.,1.]","Correction factor for line capacities (``s_nom``) to approximate :math:`N-1` security and reserve capacity for reactive power flows"
 s_nom_max,MW,"float","Global upper limit for the maximum capacity of each extendable line."
+max_extension,MW,"float","Upper limit for the extended capacity of each extendable line."
 length_factor,--,float,"Correction factor to account for the fact that buses are *not* connected by lines through air-line distance."
 under_construction,--,"One of {'zero': set capacity to zero, 'remove': remove completely, 'keep': keep with full capacity}","Specifies how to handle lines which are currently under construction."

doc/configtables/links.csv

@@ -1,5 +1,6 @@
 ,Unit,Values,Description
 p_max_pu,--,"Value in [0.,1.]","Correction factor for link capacities ``p_nom``."
 p_nom_max,MW,"float","Global upper limit for the maximum capacity of each extendable DC link."
+max_extension,MW,"float","Upper limit for the extended capacity of each extendable DC link."
 include_tyndp,bool,"{'true', 'false'}","Specifies whether to add HVDC link projects from the `TYNDP 2018 <https://tyndp.entsoe.eu/tyndp2018/projects/>`_ which are at least in permitting."
 under_construction,--,"One of {'zero': set capacity to zero, 'remove': remove completely, 'keep': keep with full capacity}","Specifies how to handle lines which are currently under construction."

doc/release_notes.rst

@@ -32,6 +32,10 @@ Upcoming Release
 
 * Remove ``vresutils`` dependency.
 
+* Added configuration option ``lines: max_extension:`` and ``links:
+  max_extension:``` to control the maximum capacity addition per line or link in
+  MW.
+
 * Add option to include a piecewise linear approximation of transmission losses,
   e.g. by setting ``solving: options: transmission_losses: 2`` for an
   approximation with two tangents.

scripts/prepare_network.py

@@ -233,7 +233,22 @@ def enforce_autarky(n, only_crossborder=False):
     n.mremove("Link", links_rm)
 
 
-def set_line_nom_max(n, s_nom_max_set=np.inf, p_nom_max_set=np.inf):
+def set_line_nom_max(
+    n,
+    s_nom_max_set=np.inf,
+    p_nom_max_set=np.inf,
+    s_nom_max_ext=np.inf,
+    p_nom_max_ext=np.inf,
+):
+    if np.isfinite(s_nom_max_ext) and s_nom_max_ext > 0:
+        logger.info(f"Limiting line extensions to {s_nom_max_ext} MW")
+        n.lines["s_nom_max"] = n.lines["s_nom"] + s_nom_max_ext
+
+    if np.isfinite(p_nom_max_ext) and p_nom_max_ext > 0:
+        logger.info(f"Limiting line extensions to {p_nom_max_ext} MW")
+        hvdc = n.links.index[n.links.carrier == "DC"]
+        n.links.loc[hvdc, "p_nom_max"] = n.links.loc[hvdc, "p_nom"] + p_nom_max_ext
+
     n.lines.s_nom_max.clip(upper=s_nom_max_set, inplace=True)
     n.links.p_nom_max.clip(upper=p_nom_max_set, inplace=True)
 
@@ -332,8 +347,10 @@ def set_line_nom_max(n, s_nom_max_set=np.inf, p_nom_max_set=np.inf):
 
     set_line_nom_max(
         n,
-        s_nom_max_set=snakemake.params.lines.get("s_nom_max,", np.inf),
-        p_nom_max_set=snakemake.params.links.get("p_nom_max,", np.inf),
+        s_nom_max_set=snakemake.params.lines.get("s_nom_max", np.inf),
+        p_nom_max_set=snakemake.params.links.get("p_nom_max", np.inf),
+        s_nom_max_ext=snakemake.params.lines.get("max_extension", np.inf),
+        p_nom_max_ext=snakemake.params.links.get("max_extension", np.inf),
     )
 
     if "ATK" in opts:

scripts/prepare_sector_network.py

@@ -3056,7 +3056,6 @@ def maybe_adjust_costs_and_potentials(n, opts):
             logger.info(f"changing {attr} for {carrier} by factor {factor}")
 
 
-# TODO this should rather be a config no wildcard
 def limit_individual_line_extension(n, maxext):
     logger.info(f"Limiting new HVAC and HVDC extensions to {maxext} MW")
     n.lines["s_nom_max"] = n.lines["s_nom"] + maxext