Fix negative district heating progress (#1168)

* impose minimum district heating progress of 0

* update release_notes

* update configtables

doc/configtables/sector.csv

@@ -5,7 +5,7 @@ biomass,--,"{true, false}",Flag to include biomass sector.
 industry,--,"{true, false}",Flag to include industry sector.
 agriculture,--,"{true, false}",Flag to include agriculture sector.
 district_heating,--,,`prepare_sector_network.py <https://github.com/PyPSA/pypsa-eur-sec/blob/master/scripts/prepare_sector_network.py>`_
--- potential,--,float,maximum fraction of urban demand which can be supplied by district heating
+-- potential,--,float,maximum fraction of urban demand which can be supplied by district heating. Ignored where below current fraction.
 -- progress,--,Dictionary with planning horizons as keys., Increase of today's district heating demand to potential maximum district heating share. Progress = 0 means today's district heating share. Progress = 1 means maximum fraction of urban demand is supplied by district heating
 -- district_heating_loss,--,float,Share increase in district heat demand in urban central due to heat losses
 cluster_heat_buses,--,"{true, false}",Cluster residential and service heat buses in `prepare_sector_network.py <https://github.com/PyPSA/pypsa-eur-sec/blob/master/scripts/prepare_sector_network.py>`_  to one to save memory.

doc/release_notes.rst

@@ -31,6 +31,8 @@ Upcoming Release
 
 * Bugfix: Correctly read in threshold capacity below which to remove components from previous planning horizons in :mod:`add_brownfield`.
 
+* Bugfix: Impose minimum value of zero for district heating progress between current and future market share in :mod:`build_district_heat_share`.
+
 PyPSA-Eur 0.11.0 (25th May 2024)
 =====================================
 

scripts/build_district_heat_share.py

@@ -86,7 +86,7 @@
     urban_fraction = pd.concat([urban_fraction, dist_fraction_node], axis=1).max(axis=1)
 
     # difference of max potential and today's share of district heating
-    diff = (urban_fraction * central_fraction) - dist_fraction_node
+    diff = ((urban_fraction * central_fraction) - dist_fraction_node).clip(lower=0)
     progress = get(
         snakemake.config["sector"]["district_heating"]["progress"], investment_year
     )