Transition from stores to storage units for LTES, introducing energy-to-power ratio

config/config.default.yaml

@@ -1215,6 +1215,8 @@ plotting:
     residential urban decentral water tanks discharger: '#baac9e'
     services rural water tanks discharger: '#bbc2b8'
     services urban decentral water tanks discharger: '#bdd8d3'
+    water pits: '#cc826a'
+    urban central hot water pits: '#d96f4c'
     # heat demand
     Heat load: '#cc1f1f'
     heat: '#cc1f1f'

doc/release_notes.rst

@@ -11,6 +11,8 @@ Release Notes
 Upcoming Release
 ================
 
+* Added PTES and transitioned LTES stores to storage units to implement an energy-to-power ratio in ``prepare_sector_network``.
+
 * Feature: Introduce geothermal district heating (direct utilisation and heat pumps). Potentials are based on `Manz et al. 2024: Spatial analysis of renewable and excess heat potentials for climate-neutral district heating in Europe <https://www.sciencedirect.com/science/article/pii/S0960148124001769>`.
 
 * Feature: Allow CHPs to use different fuel sources such as gas, oil, coal, and methanol. Note that the cost assumptions are based on a gas CHP (except for solid biomass-fired CHP).

scripts/prepare_sector_network.py

@@ -2261,54 +2261,67 @@ def add_heat(
         if options["tes"]:
             n.add("Carrier", f"{heat_system} water tanks")
 
-            n.add(
-                "Bus",
-                nodes + f" {heat_system} water tanks",
-                location=nodes,
-                carrier=f"{heat_system} water tanks",
-                unit="MWh_th",
-            )
-
-            n.add(
-                "Link",
-                nodes + f" {heat_system} water tanks charger",
-                bus0=nodes + f" {heat_system} heat",
-                bus1=nodes + f" {heat_system} water tanks",
-                efficiency=costs.at["water tank charger", "efficiency"],
-                carrier=f"{heat_system} water tanks charger",
-                p_nom_extendable=True,
-            )
-
-            n.add(
-                "Link",
-                nodes + f" {heat_system} water tanks discharger",
-                bus0=nodes + f" {heat_system} water tanks",
-                bus1=nodes + f" {heat_system} heat",
-                carrier=f"{heat_system} water tanks discharger",
-                efficiency=costs.at["water tank discharger", "efficiency"],
-                p_nom_extendable=True,
-            )
-
             tes_time_constant_days = options["tes_tau"][
                 heat_system.central_or_decentral
             ]
 
             n.add(
-                "Store",
+                "StorageUnit",
                 nodes + f" {heat_system} water tanks",
-                bus=nodes + f" {heat_system} water tanks",
-                e_cyclic=True,
-                e_nom_extendable=True,
+                bus=nodes + f" {heat_system} heat",
                 carrier=f"{heat_system} water tanks",
+                efficiency_store=costs.at[
+                    heat_system.central_or_decentral + " water tank charger",
+                    "efficiency",
+                ],
+                max_hours=costs.at[
+                    heat_system.central_or_decentral + " water tank storage",
+                    "energy to power ratio",
+                ],
+                efficiency_dispatch=costs.at[
+                    heat_system.central_or_decentral + " water tank discharger",
+                    "efficiency",
+                ],
+                p_nom_extendable=True,
                 standing_loss=1 - np.exp(-1 / 24 / tes_time_constant_days),
                 capital_cost=costs.at[
                     heat_system.central_or_decentral + " water tank storage", "fixed"
+                ]
+                * costs.at[
+                    heat_system.central_or_decentral + " water tank storage",
+                    "energy to power ratio",
                 ],
                 lifetime=costs.at[
                     heat_system.central_or_decentral + " water tank storage", "lifetime"
                 ],
+                cyclic_state_of_charge=True,
             )
 
+            if heat_system == HeatSystem.URBAN_CENTRAL:
+                n.add("Carrier", f"{heat_system} water pits")
+
+                n.add(
+                    "StorageUnit",
+                    nodes + f" {heat_system} water pits",
+                    bus=nodes + f" {heat_system} heat",
+                    carrier=f"{heat_system} water pits",
+                    efficiency_store=costs.at[
+                        "central water pit charger", "efficiency"
+                    ],
+                    max_hours=costs.at[
+                        "central water pit storage", "energy to power ratio"
+                    ],
+                    efficiency_dispatch=costs.at[
+                        "central water pit discharger", "efficiency"
+                    ],
+                    p_nom_extendable=True,
+                    standing_loss=1 - np.exp(-1 / 24 / tes_time_constant_days),
+                    capital_cost=costs.at["central water pit storage", "fixed"]
+                    * costs.at["central water pit storage", "energy to power ratio"],
+                    lifetime=costs.at["central water pit storage", "lifetime"],
+                    cyclic_state_of_charge=True,
+                )
+
         if options["resistive_heaters"]:
             key = f"{heat_system.central_or_decentral} resistive heater"
 
@@ -4250,7 +4263,7 @@ def define_clustering(attributes, aggregate_dict):
         return agg
 
     logger.info("Cluster residential and service heat buses.")
-    components = ["Bus", "Carrier", "Generator", "Link", "Load", "Store"]
+    components = ["Bus", "Carrier", "Generator", "Link", "Load", "Store", "StorageUnit"]
 
     for c in n.iterate_components(components):
         df = c.df