feat: layered ptes model by amos-schledorn · Pull Request #2129 · PyPSA/pypsa-eur

amos-schledorn · 2026-03-26T09:33:40Z

Closes # (if applicable).

Changes proposed in this Pull Request

Checklist

Required:

Changes are tested locally and behave as expected.
Code and workflow changes are documented.
A release note entry is added to doc/release_notes.rst.

If applicable:

Changes in configuration options are reflected in scripts/lib/validation.
For new data sources or versions, these instructions have been followed.
New rules are documented in the appropriate doc/*.rst files.

(operational for hard-coded layers, dummy heat transfer coef and resistive boosting)

…or heat sources

Copilot

Pull request overview

This PR introduces a layered PTES (Pit Thermal Energy Storage) model by precomputing PTES operational parameters into a single dataset, wiring per-layer PTES components into the sector network, and adding custom solver constraints for layered PTES behavior.

Changes:

Replace multiple PTES profile outputs with a unified ptes_operations dataset built via a new PtesApproximator.
Extend sector-network building to create per-layer PTES buses/stores/charger-discharger links and inter-layer links.
Add layered-PTES constraints in solve_network.py and propagate the new PTES operations input through Snakemake rules.

Reviewed changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
scripts/solve_network.py	Excludes layered PTES from generic TES constraints; adds layered PTES custom constraints and loads `ptes_operations` in extra_functionality.
scripts/prepare_sector_network.py	Builds layered PTES components from `ptes_operations` and adjusts PTES boosting/HP handling.
scripts/definitions/heat_system.py	Extends heat pump cost mapping for PTES layers and updates waste-heat enum member references.
scripts/definitions/heat_source.py	Adds PTES layer heat sources and treats them as `STORAGE` across helper logic.
scripts/build_ptes_operations/run.py	Switches PTES operational profile building to the new `PtesApproximator` and writes unified dataset.
scripts/build_ptes_operations/ptes_temperature_approximator.py	Removes legacy PTES temperature/profile approximator implementation.
scripts/build_ptes_operations/ptes_approximator.py	Adds new approximator producing layered parameters (weights, availability, boost ratios, interlayer coefficients).
scripts/build_heat_source_utilisation_profiles.py	Uses `ptes_operations` for PTES(-layer) temperatures and cooling assumptions; closes dataset when enabled.
scripts/build_cop_profiles/run.py	Uses `ptes_operations` for PTES(-layer) source temperatures; closes dataset when enabled.
rules/solve_perfect.smk	Adds conditional PTES operations input to solve rule.
rules/solve_overnight.smk	Adds conditional PTES operations input to solve rule.
rules/solve_myopic.smk	Adds conditional PTES operations input to solve rule.
rules/build_sector.smk	Replaces PTES temp/bottom inputs with unified PTES operations input; wires through dependent rules.
data/custom_costs.csv	Adjusts PTES charger marginal cost and adds PTES discharger marginal cost entry.
config/config.default.yaml	Adds layered PTES config stanza (num_layers, heat_transfer_coefficient).

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Copilot · 2026-03-26T09:40:48Z

scripts/build_ptes_operations/run.py

+    top_temp = float(snakemake.params.top_temperature)
+    bottom_temp = float(snakemake.params.bottom_temperature)



top_temperature/bottom_temperature are cast to float, but config validation allows the literals 'forward'/'return'. With such a config this will crash before any helpful error is raised. Either keep support for these string options, or validate early and raise a clear error if only constant temperatures are supported now.

Suggested change

top_temp = float(snakemake.params.top_temperature)

bottom_temp = float(snakemake.params.bottom_temperature)

top_temperature_param = snakemake.params.top_temperature

bottom_temperature_param = snakemake.params.bottom_temperature

unsupported_temperature_refs = {"forward", "return"}

for param_name, param_value in (

("top_temperature", top_temperature_param),

("bottom_temperature", bottom_temperature_param),

):

if isinstance(param_value, str) and param_value in unsupported_temperature_refs:

raise ValueError(

f"PTES configuration for '{param_name}' uses the unsupported value "

f"'{param_value}'. This script currently only supports constant "

"temperatures (numeric values). Please specify a fixed temperature "

"in degrees Celsius in the configuration."

)

top_temp = float(top_temperature_param)

bottom_temp = float(bottom_temperature_param)

Copilot · 2026-03-26T09:40:48Z

scripts/prepare_sector_network.py

+            ptes_ds = xr.open_dataset(ptes_operations_file)
+            num_layers = int(ptes_ds.attrs["num_layers"])



ptes_ds is opened but never closed in this code path, which can leak file handles (especially when add_heat is called repeatedly). Use a context manager (with xr.open_dataset(...) as ptes_ds:) or ensure ptes_ds.close() is called once all PTES-related components (including resistive boosting) are added.

Copilot · 2026-03-26T09:40:48Z

scripts/solve_network.py

+    For each interlayer link:
+        p_{l→l+1, t}  =  -Ψ_{l,l+1} · e_{l, t}   ∀ t
+
+    where Ψ is the interlayer transfer coefficient and e_{l,t} is the
+    state-of-energy of the upper layer store.
+    """
+    interlayer_links = n.links.index[
+        n.links.carrier.str.contains("water pits interlayer")
+    ]
+
+    if interlayer_links.empty:
+        return
+
+    constraints = []
+    for link_name in interlayer_links:
+        # Extract pair index from link name (e.g., "... inter layer 0-layer 1" → 0)
+        pair_str = link_name.split("inter ")[-1]
+        pair_idx = int(pair_str.split("layer ")[1].split("-")[0])
+        heat_transfer_coef = float(
+            ptes_ds["interlayer_heat_transfer_coefficients"]
+            .sel(layer_pair=pair_idx)
+            .item()
+        )
+
+        upper_bus = n.links.at[link_name, "bus0"]
+        # Find the store on the upper bus
+        upper_store = n.stores.index[n.stores.bus == upper_bus]
+        if upper_store.empty:
+            continue
+        upper_store = upper_store[0]
+
+        link_p = n.model["Link-p"].loc[:, link_name]
+        store_e = n.model["Store-e"].loc[:, upper_store]
+        # p = Ψ · e
+        constraints.append(link_p - heat_transfer_coef * store_e)
+


The interlayer flow docstring states p = -Ψ · e but the implementation constrains Link-p - Ψ·Store-e == 0 (no minus sign). Please align the sign convention (either update the constraint or correct the documentation) so that the interlayer link direction matches the intended heat diffusion direction.

Copilot · 2026-03-26T09:40:49Z

scripts/definitions/heat_system.py

        # Check if this is an excess-heat-sourced heat pump
        if heat_source in [
            HeatSource.PTES,
+            HeatSource.PTES_LAYER_0,
+            HeatSource.PTES_LAYER_1,
+            HeatSource.PTES_LAYER_2,
            HeatSource.GEOTHERMAL,
            HeatSource.SEA_WATER,
            HeatSource.RIVER_WATER,
-            HeatSource.ELECTROLYSIS_waste,
-            HeatSource.FISCHER_TROPSCH_waste,
-            HeatSource.SABATIER_waste,
-            HeatSource.HABER_BOSCH_waste,
-            HeatSource.METHANOLISATION_waste,
-            HeatSource.FUEL_CELL_waste,
+            HeatSource.ELECTROLYSIS_WASTE,
+            HeatSource.FISCHER_TROPSCH_WASTE,
+            HeatSource.SABATIER_WASTE,
+            HeatSource.HABER_BOSCH_WASTE,
+            HeatSource.METHANOLISATION_WASTE,
+            HeatSource.FUEL_CELL_WASTE,


HeatSource members for waste heat were renamed to *_WASTE, but other parts of the codebase still reference the old names (e.g. scripts/lib/validation/config/sector.py uses HeatSource.ELECTROLYSIS_waste, etc.). This will raise AttributeError when loading config validation. Please update those remaining references (or provide backwards-compatible aliases) as part of this PR to avoid breaking imports.

Copilot · 2026-03-26T09:40:49Z

scripts/build_heat_source_utilisation_profiles.py

+    heat_source = HeatSource(heat_source_name)
+    if heat_source.source_type == HeatSourceType.STORAGE:
        if return_temperature is None:
            raise ValueError(
                "PTES heat source requires return_temperature to calculate heat pump cooling."
            )


The error message in get_heat_pump_cooling says "PTES heat source" but the condition is now heat_source.source_type == STORAGE, so it will also trigger for ptes layer *. Consider making the message generic (e.g. "Storage heat source requires return_temperature...") to avoid confusion when debugging layered PTES configs.

Copilot · 2026-03-26T09:40:49Z

scripts/build_ptes_operations/run.py

+        num_layers=layered_config["num_layers"],
+        design_top_temperature=snakemake.params.design_top_temperature,
+        design_bottom_temperature=snakemake.params.design_bottom_temperature,
+        design_standing_losses=0.0,  # placeholder; actual value set from costs data


PtesApproximator is instantiated without the required interlayer_heat_transfer_coefficient argument, which will raise a TypeError at runtime. Either pass the value from sector.district_heating.ptes.layered.heat_transfer_coefficient (or similar) or make the constructor parameter optional with a default and document the default.

Suggested change

design_standing_losses=0.0, # placeholder; actual value set from costs data

design_standing_losses=0.0, # placeholder; actual value set from costs data

interlayer_heat_transfer_coefficient=layered_config["heat_transfer_coefficient"],

Copilot · 2026-03-26T09:40:49Z

scripts/prepare_sector_network.py

+                heat_source = HeatSource(f"ptes{layer_suffix}")
+                n.add(
+                    "Bus",
+                    heat_source.resource_bus(nodes, heat_system),
+                    location=nodes,
+                    carrier=f"{heat_system} ptes heat",
+                    unit="MWh_th",
                )
-            else:
-                e_max_pu = 1

-            n.add(
-                "Store",
-                nodes,
-                suffix=f" {heat_system} water pits",
-                bus=nodes + f" {heat_system} water pits",
-                e_cyclic=True,
-                e_nom_extendable=True,
-                e_max_pu=e_max_pu,
-                carrier=f"{heat_system} water pits",
-                standing_loss=costs.at["central water pit storage", "standing_losses"]
-                / 100,  # convert %/hour into unit/hour
-                capital_cost=costs.at["central water pit storage", "capital_cost"],
-                lifetime=costs.at["central water pit storage", "lifetime"],
-            )
+                n.add(
+                    "Link",
+                    nodes,
+                    suffix=f" {heat_system} water pits discharger{layer_suffix}",
+                    bus0=nodes + f" {heat_system} water pits{layer_suffix}",
+                    bus1=heat_source.resource_bus(nodes, heat_system),
+                    carrier=f"{heat_system} water pits discharger",
+                    efficiency=costs.at[


Layer discharge is wired to heat_source.resource_bus(...) where heat_source is ptes layer X, creating buses like <node> urban central ptes layer 0 heat. Unless those layer heat sources are also included in params.heat_sources (and have utilisation/COP profiles built), these buses will be disconnected from the main <node> urban central heat bus. Either keep all PTES layer discharge on the aggregate ptes resource bus, or ensure the config/params and profile-building rules automatically include the per-layer PTES heat sources when num_layers > 1.

Copilot · 2026-03-26T09:40:50Z

scripts/prepare_sector_network.py

+                    in [
+                        HeatSource.PTES_LAYER_0,
+                        HeatSource.PTES_LAYER_1,
+                        HeatSource.PTES_LAYER_2,


The special-casing for layered PTES heat pump capital_cost only covers PTES_LAYER_0..2, but the enum defines PTES_LAYER_3 and PTES_LAYER_4 as well. If num_layers > 3, the extra layers will incorrectly receive full heat pump capex. Consider handling all ptes layer * sources (or all HeatSourceType.STORAGE except the aggregate PTES) consistently.

Suggested change

HeatSource.PTES_LAYER_2,

HeatSource.PTES_LAYER_2,

HeatSource.PTES_LAYER_3,

HeatSource.PTES_LAYER_4,

Copilot · 2026-03-26T09:40:50Z

scripts/definitions/heat_system.py

        # Check if this is an excess-heat-sourced heat pump
        if heat_source in [
            HeatSource.PTES,
+            HeatSource.PTES_LAYER_0,
+            HeatSource.PTES_LAYER_1,
+            HeatSource.PTES_LAYER_2,
            HeatSource.GEOTHERMAL,
            HeatSource.SEA_WATER,
            HeatSource.RIVER_WATER,
-            HeatSource.ELECTROLYSIS_waste,
-            HeatSource.FISCHER_TROPSCH_waste,
-            HeatSource.SABATIER_waste,
-            HeatSource.HABER_BOSCH_waste,
-            HeatSource.METHANOLISATION_waste,
-            HeatSource.FUEL_CELL_waste,
+            HeatSource.ELECTROLYSIS_WASTE,
+            HeatSource.FISCHER_TROPSCH_WASTE,
+            HeatSource.SABATIER_WASTE,
+            HeatSource.HABER_BOSCH_WASTE,
+            HeatSource.METHANOLISATION_WASTE,
+            HeatSource.FUEL_CELL_WASTE,
        ]:
            return f"{self.central_or_decentral} excess-heat-sourced heat pump"


heat_pump_costs_name special-cases PTES layers only up to PTES_LAYER_2, but HeatSource now defines PTES_LAYER_3 and PTES_LAYER_4 as well. If additional layers are configured, they will fall through to the non-excess-heat heat pump cost category. Extend the list (or use heat_source.source_type == HeatSourceType.STORAGE/string matching) so all PTES layers map consistently.

amos-schledorn added 8 commits March 11, 2026 11:50

feat: first draft of layered PTES model

44ea1cd

(operational for hard-coded layers, dummy heat transfer coef and resistive boosting)

refactor: remove expand_ptes_layers function and related validation f…

b6727d0

…or heat sources

feat: add layered PTES heat pump capacity constraint function

9bc232e

introduce HP boosting and cost ptes discharging

1d2d5d8

fix volume capacity weights

30fc522

use conducive heat transfer for interlayer transfer

bf30c43

fix: update marginal cost for central water pit charger

12ce641

feat: add additional PTES layers to heat source enumeration

d6c377a

Copilot AI review requested due to automatic review settings March 26, 2026 09:33

amos-schledorn changed the title ~~Feat layered ptes model~~ feat: layered ptes model Mar 26, 2026

Copilot started reviewing on behalf of amos-schledorn March 26, 2026 09:34 View session

Copilot AI reviewed Mar 26, 2026

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feat: layered ptes model#2129

feat: layered ptes model#2129
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		top_temp = float(snakemake.params.top_temperature)
		bottom_temp = float(snakemake.params.bottom_temperature)

-    top_temp = float(snakemake.params.top_temperature)
-    bottom_temp = float(snakemake.params.bottom_temperature)
+    top_temperature_param = snakemake.params.top_temperature
+    bottom_temperature_param = snakemake.params.bottom_temperature
+    unsupported_temperature_refs = {"forward", "return"}
+    for param_name, param_value in (
+        ("top_temperature", top_temperature_param),
+        ("bottom_temperature", bottom_temperature_param),
+    ):
+        if isinstance(param_value, str) and param_value in unsupported_temperature_refs:
+            raise ValueError(
+                f"PTES configuration for '{param_name}' uses the unsupported value "
+                f"'{param_value}'. This script currently only supports constant "
+                "temperatures (numeric values). Please specify a fixed temperature "
+                "in degrees Celsius in the configuration."
+            )
+    top_temp = float(top_temperature_param)
+    bottom_temp = float(bottom_temperature_param)

		ptes_ds = xr.open_dataset(ptes_operations_file)
		num_layers = int(ptes_ds.attrs["num_layers"])

	design_standing_losses=0.0, # placeholder; actual value set from costs data
	design_standing_losses=0.0, # placeholder; actual value set from costs data
	interlayer_heat_transfer_coefficient=layered_config["heat_transfer_coefficient"],

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amos-schledorn commented Mar 26, 2026

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