StorageUnit correct efficiency_dispatch/store (counter-proposal 2) (#202)

* fix efficiencies of storage units counter proposal

* extra_components: fix roundtrip efficiency

* add_electricity: remove misleading roundtrip efficiency for storageunit

* add release notes

data/costs.csv

@@ -114,7 +114,7 @@ DAC,2030,lifetime,30,years,Fasihi
 DAC,2030,FOM,4,%/year,Fasihi
 battery inverter,2030,investment,411,USD/kWel,budischak2013
 battery inverter,2030,lifetime,20,years,budischak2013
-battery inverter,2030,efficiency,0.81,per unit,budischak2013; Lund and Kempton (2008) http://dx.doi.org/10.1016/j.enpol.2008.06.007
+battery inverter,2030,efficiency,0.9,per unit charge/discharge,budischak2013; Lund and Kempton (2008) http://dx.doi.org/10.1016/j.enpol.2008.06.007
 battery inverter,2030,FOM,3,%/year,budischak2013
 battery storage,2030,investment,192,USD/kWh,budischak2013
 battery storage,2030,lifetime,15,years,budischak2013

doc/release_notes.rst

@@ -42,6 +42,9 @@ Upcoming Release
 
 * The mappings for clustered lines and buses produced by the ``simplify_network`` and ``cluster_network`` rules changed from Hierarchical Data Format (.h5) to Comma-Separated Values format (.csv) (`#198 <https://github.com/PyPSA/pypsa-eur/pull/198>`_)
 
+* Fixed a bug for storage units such that individual store and dispatch efficiencies are correctly taken account of rather than only their round-trip efficiencies.
+  In the cost database (``data/costs.csv``) the efficiency of battery inverters should be stated as per discharge/charge rather than per roundtrip (`#202 <https://github.com/PyPSA/pypsa-eur/pull/202>_).
+
 * Parameter corrections for East-Western and Anglo-Scottish interconnectors (`#206 <https://github.com/PyPSA/pypsa-eur/pull/206>`_)
 
 * Modelling hydrogen and battery storage with Store and Link components is now the default, rather than using StorageUnit components with fixed power-to-energy ratio (`#205 <https://github.com/PyPSA/pypsa-eur/pull/205>`_).

scripts/add_electricity.py

@@ -166,13 +166,10 @@ def load_costs(Nyears=1., tech_costs=None, config=None, elec_config=None):
 
     def costs_for_storage(store, link1, link2=None, max_hours=1.):
         capital_cost = link1['capital_cost'] + max_hours * store['capital_cost']
-        efficiency = link1['efficiency']**0.5
         if link2 is not None:
             capital_cost += link2['capital_cost']
-            efficiency *= link2['efficiency']**0.5
         return pd.Series(dict(capital_cost=capital_cost,
                               marginal_cost=0.,
-                              efficiency=efficiency,
                               co2_emissions=0.))
 
     if elec_config is None:

scripts/add_extra_components.py

@@ -70,6 +70,9 @@ def attach_storageunits(n, costs):
 
     buses_i = n.buses.index
 
+    lookup_store = {"H2": "electrolysis", "battery": "battery inverter"}
+    lookup_dispatch = {"H2": "fuel cell", "battery": "battery inverter"}
+
     for carrier in carriers:
         n.madd("StorageUnit", buses_i, ' ' + carrier,
                bus=buses_i,
@@ -77,8 +80,8 @@ def attach_storageunits(n, costs):
                p_nom_extendable=True,
                capital_cost=costs.at[carrier, 'capital_cost'],
                marginal_cost=costs.at[carrier, 'marginal_cost'],
-               efficiency_store=costs.at[carrier, 'efficiency'],
-               efficiency_dispatch=costs.at[carrier, 'efficiency'],
+               efficiency_store=costs.at[lookup_store[carrier], 'efficiency'],
+               efficiency_dispatch=costs.at[lookup_dispatch[carrier], 'efficiency'],
                max_hours=max_hours[carrier],
                cyclic_state_of_charge=True)
 
@@ -132,7 +135,7 @@ def attach_stores(n, costs):
                bus0=buses_i,
                bus1=b_buses_i,
                carrier='battery charger',
-               efficiency=costs.at['battery inverter', 'efficiency']**0.5,
+               efficiency=costs.at['battery inverter', 'efficiency'],
                capital_cost=costs.at['battery inverter', 'capital_cost'],
                p_nom_extendable=True)
 
@@ -140,7 +143,7 @@ def attach_stores(n, costs):
                bus0=b_buses_i,
                bus1=buses_i,
                carrier='battery discharger',
-               efficiency=costs.at['battery inverter','efficiency']**0.5,
+               efficiency=costs.at['battery inverter','efficiency'],
                capital_cost=costs.at['battery inverter', 'capital_cost'],
                p_nom_extendable=True)