move calculation of district heating share to its own script

Now the script build_district_heat_share.py does what the old function
create_nodes_for_heating() in prepare_sector_networks.py did.

There is no need to build nodes lists for each heating sector, since
all nodes have district heating now.

rules/build_sector.smk

@@ -726,6 +726,27 @@ rule build_transport_demand:
         "../scripts/build_transport_demand.py"
 
 
+
+
+rule build_district_heat_share:
+    params:
+        sector=config["sector"],
+    input:
+        district_heat_share=RESOURCES + "district_heat_share.csv",
+        clustered_pop_layout=RESOURCES + "pop_layout_elec_s{simpl}_{clusters}.csv",
+    output:
+        district_heat_share=RESOURCES + "district_heat_share_elec_s{simpl}_{clusters}_{planning_horizons}.csv",
+    threads: 1
+    resources:
+        mem_mb=1000,
+    log:
+        LOGS + "build_district_heat_share_s{simpl}_{clusters}_{planning_horizons}.log",
+    conda:
+        "../envs/environment.yaml"
+    script:
+        "../scripts/build_district_heat_share.py"
+
+
 rule prepare_sector_network:
     params:
         co2_budget=config["co2_budget"],
@@ -777,6 +798,7 @@ rule prepare_sector_network:
         industrial_demand=RESOURCES
         + "industrial_energy_demand_elec_s{simpl}_{clusters}_{planning_horizons}.csv",
         hourly_heat_demand_total=RESOURCES + "hourly_heat_demand_total_elec_s{simpl}_{clusters}.nc",
+	district_heat_share=RESOURCES + "district_heat_share_elec_s{simpl}_{clusters}_{planning_horizons}.csv",
         temp_soil_total=RESOURCES + "temp_soil_total_elec_s{simpl}_{clusters}.nc",
         temp_soil_rural=RESOURCES + "temp_soil_rural_elec_s{simpl}_{clusters}.nc",
         temp_soil_urban=RESOURCES + "temp_soil_urban_elec_s{simpl}_{clusters}.nc",

scripts/build_district_heat_share.py

@@ -0,0 +1,77 @@
+# -*- coding: utf-8 -*-
+# SPDX-FileCopyrightText: : 2020-2023 The PyPSA-Eur Authors
+#
+# SPDX-License-Identifier: MIT
+"""
+Build district heat shares at each node, depending on investment year.
+"""
+
+import pandas as pd
+
+from prepare_sector_network import get
+
+import logging
+
+
+logger = logging.getLogger(__name__)
+
+
+if __name__ == "__main__":
+    if "snakemake" not in globals():
+        from _helpers import mock_snakemake
+
+        snakemake = mock_snakemake(
+            "build_heat_demands",
+            simpl="",
+            clusters=48,
+        )
+
+    investment_year = int(snakemake.wildcards.planning_horizons[-4:])
+
+    pop_layout = pd.read_csv(snakemake.input.clustered_pop_layout,
+                             index_col=0)
+
+    district_heat_share = pd.read_csv(snakemake.input.district_heat_share,
+                                      index_col=0).squeeze()
+
+    # make ct-based share nodal
+    district_heat_share = district_heat_share.loc[pop_layout.ct]
+    district_heat_share.index = pop_layout.index
+
+    # total urban population per country
+    ct_urban = pop_layout.urban.groupby(pop_layout.ct).sum()
+
+    # distribution of urban population within a country
+    pop_layout["urban_ct_fraction"] = pop_layout.urban / pop_layout.ct.map(ct_urban.get)
+
+    # fraction of node that is urban
+    urban_fraction = pop_layout.urban / pop_layout[["rural", "urban"]].sum(axis=1)
+
+    # maximum potential of urban demand covered by district heating
+    central_fraction = snakemake.config["sector"]["district_heating"]["potential"]
+
+    # district heating share at each node
+    dist_fraction_node = (
+        district_heat_share * pop_layout["urban_ct_fraction"] / pop_layout["fraction"]
+    )
+
+    # if district heating share larger than urban fraction -> set urban
+    # fraction to district heating share
+    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
+    progress = get(snakemake.config["sector"]["district_heating"]["progress"], investment_year)
+    dist_fraction_node += diff * progress
+    logger.info(
+        f"Increase district heating share by a progress factor of {progress:.2%} "
+        f"resulting in new average share of {dist_fraction_node.mean():.2%}"
+    )
+
+    df = pd.DataFrame(dtype=float)
+
+    df["original district heat share"] = district_heat_share
+    df["district fraction of node"] = dist_fraction_node
+    df["urban fraction"] = urban_fraction
+
+    df.to_csv(snakemake.output.district_heat_share)

scripts/build_energy_totals.py

@@ -571,7 +571,7 @@ def build_energy_totals(countries, eurostat, swiss, idees):
     return df
 
 
-def build_district_heat_share(idees):
+def build_district_heat_share(countries, idees):
 
     # district heating share
     district_heat = idees[
@@ -581,6 +581,8 @@ def build_district_heat_share(idees):
 
     district_heat_share = district_heat/total_heat
 
+    district_heat_share = district_heat_share.reindex(countries)
+
     # Missing district heating share
     dh_share = pd.read_csv(
         snakemake.input.district_heat_share, index_col=0, usecols=[0, 1]
@@ -761,7 +763,7 @@ def build_transport_data(countries, population, idees):
     energy = build_energy_totals(countries, eurostat, swiss, idees)
     energy.to_csv(snakemake.output.energy_name)
 
-    district_heat_share = build_district_heat_share(idees)
+    district_heat_share = build_district_heat_share(countries, idees)
     district_heat_share.to_csv(snakemake.output.district_heat_share)
 
     base_year_emissions = params["base_emissions_year"]

scripts/build_population_weighted_energy_totals.py

@@ -26,9 +26,4 @@
     nodal_energy_totals.index = pop_layout.index
     nodal_energy_totals = nodal_energy_totals.multiply(pop_layout.fraction, axis=0)
 
-    # district heating share should not be divided by population fraction
-    dh_share = energy_totals["district heat share"].loc[pop_layout.ct].fillna(0.0)
-    dh_share.index = pop_layout.index
-    nodal_energy_totals["district heat share"] = dh_share
-
     nodal_energy_totals.to_csv(snakemake.output[0])