Add more options for temporal aggregation

doc/release_notes.rst

@@ -57,11 +57,13 @@ incorporates retrofitting options to hydrogen.
 **New features and functionality**
 
 
+* Add option to aggregate network temporally using representative snapshots or segments (with tsam package)
+
 * Add option for biomass boilers (wood pellets) for decentral heating
 
-* Add option for BioSNG (methane from biomass) with and without CC 
+* Add option for BioSNG (methane from biomass) with and without CC
 
-* Add option for BtL (Biomass to liquid fuel/oil) with and without CC 
+* Add option for BtL (Biomass to liquid fuel/oil) with and without CC
 
 * Units are assigned to the buses. These only provide a better understanding. The specifications of the units are not taken into account in the optimisation, which means that no automatic conversion of units takes place.
 

scripts/prepare_sector_network.py

@@ -2413,6 +2413,88 @@ def limit_individual_line_extension(n, maxext):
     hvdc = n.links.index[n.links.carrier == 'DC']
     n.links.loc[hvdc, 'p_nom_max'] = n.links.loc[hvdc, 'p_nom'] + maxext
 
+
+def apply_time_segmentation(n, segments, solver_name="cbc",
+                            overwrite_time_dependent=True):
+    """Aggregating time series to segments with different lengths
+
+    Input:
+        n: pypsa Network
+        segments: (int) number of segments in which the typical period should be
+                  subdivided
+        solver_name: (str) name of solver
+        overwrite_time_dependent: (bool) overwrite time dependent data of pypsa network
+        with typical time series created by tsam
+    """
+    try:
+        import tsam.timeseriesaggregation as tsam
+    except:
+        raise ModuleNotFoundError("Optional dependency 'tsam' not found."
+                                  "Install via 'pip install tsam'")
+
+    # get all time-dependent data
+    columns = pd.MultiIndex.from_tuples([],names=['component', 'key', 'asset'])
+    raw = pd.DataFrame(index=n.snapshots,columns=columns)
+    for c in n.iterate_components():
+        for attr, pnl in c.pnl.items():
+            # exclude e_min_pu which is used for SOC of EVs in the morning
+            if not pnl.empty and attr != 'e_min_pu':
+                df = pnl.copy()
+                df.columns = pd.MultiIndex.from_product([[c.name], [attr], df.columns])
+                raw = pd.concat([raw, df], axis=1)
+
+    # normalise all time-dependent data
+    annual_max = raw.max().replace(0,1)
+    raw = raw.div(annual_max, level=0)
+
+    # get representative segments
+    agg = tsam.TimeSeriesAggregation(raw, hoursPerPeriod=len(raw),
+                                     noTypicalPeriods=1, noSegments=int(segments),
+                                     segmentation=True, solver=solver_name)
+    segmented = agg.createTypicalPeriods()
+
+
+    weightings = segmented.index.get_level_values("Segment Duration")
+    offsets = np.insert(np.cumsum(weightings[:-1]), 0, 0)
+    timesteps = [raw.index[0] + pd.Timedelta(f"{offset}h") for offset in offsets]
+    snapshots =  pd.DatetimeIndex(timesteps)
+    sn_weightings = pd.Series(weightings, index=snapshots, name="weightings", dtype="float64")
+
+    n.set_snapshots(sn_weightings.index)
+    n.snapshot_weightings = n.snapshot_weightings.mul(sn_weightings, axis=0)
+
+    # overwrite time-dependent data with timeseries created by tsam
+    if overwrite_time_dependent:
+        values_t = segmented.mul(annual_max).set_index(snapshots)
+        for component, key in values_t.columns.droplevel(2).unique():
+            n.pnl(component)[key] = values_t[component, key]
+
+    return n
+
+def set_temporal_aggregation(n, opts, solver_name):
+    """Aggregate network temporally."""
+    for o in opts:
+        # temporal averaging
+        m = re.match(r"^\d+h$", o, re.IGNORECASE)
+        if m is not None:
+            n = average_every_nhours(n, m.group(0))
+            break
+        # representive snapshots
+        m = re.match(r"(^\d+)sn$", o, re.IGNORECASE)
+        if m is not None:
+            sn = int(m[1])
+            logger.info(f"use every {sn} snapshot as representative")
+            n.set_snapshots(n.snapshots[::sn])
+            n.snapshot_weightings *= sn
+            break
+        # segments with package tsam
+        m = re.match(r"^(\d+)seg$", o, re.IGNORECASE)
+        if m is not None:
+            segments = int(m[1])
+            logger.info(f"use temporal segmentation with {segments} segments")
+            n = apply_time_segmentation(n, segments, solver_name=solver_name)
+            break
+    return n
 #%%
 if __name__ == "__main__":
     if 'snakemake' not in globals():
@@ -2514,11 +2596,8 @@ def limit_individual_line_extension(n, maxext):
     if options["co2_network"]:
         add_co2_network(n, costs)
 
-    for o in opts:
-        m = re.match(r'^\d+h$', o, re.IGNORECASE)
-        if m is not None:
-            n = average_every_nhours(n, m.group(0))
-            break
+    solver_name = snakemake.config["solving"]["solver"]["name"]
+    n = set_temporal_aggregation(n, opts, solver_name)
 
     limit_type = "config"
     limit = get(snakemake.config["co2_budget"], investment_year)