add cyclic lifetime param

peakshaving_analyzer/PSA.py

@@ -184,7 +184,7 @@ def add_storage(self):
                 commodity="stored_energy",
                 locationalEligibility=pd.Series([1, 0], index=["consumption_site", "grid"]),
                 hasCapacityVariable=True,
-                cyclicLifetime=10000,
+                cyclicLifetime=self.config.storage_cyclic_lifetime,
                 chargeEfficiency=self.storage_charge_efficiency,
                 dischargeEfficiency=self.storage_discharge_efficiency,
                 capacityMax=self.max_storage_size_kwh,

peakshaving_analyzer/input.py

@@ -51,6 +51,7 @@ class Config(IOHandler):
     storage_charge_efficiency: float = 0.95
     storage_discharge_efficiency: float = 0.95
     storage_charge_rate: float = 5
+    storage_cyclic_lifetime: float = 10000
     storage_discharge_rate: float = 5
     inverter_efficiency: float = 0.95
     max_pv_system_size_kwp: float | None = None

tests/test_psa.py

@@ -103,3 +103,33 @@ def test_add_solar():
         + results.inverter_annuity_eur
         + results.storage_annuity_eur
     )
+
+
+def test_storage_only():
+    # 4 cheap hours, one expensive hour
+    # adding a storage of 1 kwh reduces cost here
+    config = Config(
+        "test_config",
+        consumption_timeseries=[1] * 6,
+        hours_per_timestep=1,
+        n_timesteps=6,
+        price_timeseries=pd.DataFrame({"grid": [0.3] * 4 + [1] + [0.3], "consumption_site": [0] * 6}),
+        storage_charge_rate=10,
+        storage_discharge_rate=10,
+        # cyclic lifetime must be increased, otherwise we are building much more storage
+        storage_cyclic_lifetime=1e5,
+        interest_rate=2,
+        storage_charge_efficiency=1,
+        storage_discharge_efficiency=1,
+    )
+    psa = PeakShavingAnalyzer(config=config)
+    results = psa.optimize()
+    ts = results.timeseries_to_df()
+    # we need to charge in the first few hours
+    assert (ts["grid_usage_kw"][0:4] >= 1).all()
+    # but do not charge in the last hour
+    assert (ts["grid_usage_kw"][4] == 0).all()
+
+    assert results.inverter_capacity_kw == 1
+    results.storage_capacity_kwh
+    assert results.storage_capacity_kwh == 1