diff --git a/Snakefile b/Snakefile
index f4ee4c2b..ad50ff97 100644
--- a/Snakefile
+++ b/Snakefile
@@ -173,9 +173,9 @@ if config['enable'].get('retrieve_cost_data', True):
         params:
             year = config['costs']['year'],
             version = config['costs']['version'],
-        input: HTTP.remote("raw.githubusercontent.com/PyPSA/technology-data/{params.version}/outputs/costs_{params.year}.csv", keep_local=True)
+        input: HTTP.remote(f"raw.githubusercontent.com/PyPSA/technology-data/{params.version}/outputs/costs_{params.year}.csv", keep_local=True)
         output: COSTS
-        shell: 'mv {input} {output}'
+        run: move(input[0], output[0])
 
 rule build_renewable_profiles:
     input:
diff --git a/config.tutorial.yaml b/config.tutorial.yaml
index 89f04324..ecfeff6b 100755
--- a/config.tutorial.yaml
+++ b/config.tutorial.yaml
@@ -159,7 +159,7 @@ load:
 costs:
   year: 2030
   version: v0.1.0
-  rooftop_share: 0.5
+  rooftop_share: 0.14
   fill_values:
     FOM: 0
     VOM: 0
diff --git a/doc/costs.rst b/doc/costs.rst
index f56e40d3..ef0b4d37 100644
--- a/doc/costs.rst
+++ b/doc/costs.rst
@@ -7,9 +7,9 @@
 Cost Assumptions
 ##################
 
-The database of cost assumptions is retrieved from the repository `PyPSA/technology-data <https://github.com/pypsa/technology-data>`_ and then saved to``resources/costs.csv``.
+The database of cost assumptions is retrieved from the repository `PyPSA/technology-data <https://github.com/pypsa/technology-data>`_ and then saved to``resources/costs.csv``. Cost assumptions of previous PyPSA-Eur versions can be restored by setting in the ``Snakefile``: ``COSTS="data/costs.csv".
 
-The ``config.yaml` provides options to choose a reference year (``costs: year:``) and use a specific version of the repository ``costs: version:``.
+The ``config.yaml`` provides options to choose a reference year (``costs: year:``) and use a specific version of the repository ``costs: version:``.
 
 It includes cost assumptions for all included technologies for specific
 years from various sources, namely for
diff --git a/scripts/add_electricity.py b/scripts/add_electricity.py
index c0701c6f..5351bba9 100755
--- a/scripts/add_electricity.py
+++ b/scripts/add_electricity.py
@@ -169,7 +169,7 @@ def load_costs(tech_costs, config, elec_config, Nyears=1.):
         costs_for_storage(costs.loc["battery storage"], costs.loc["battery inverter"],
                           max_hours=max_hours['battery'])
     costs.loc["H2"] = \
-        costs_for_storage(costs.loc["hydrogen storage tank"], costs.loc["fuel cell"],
+        costs_for_storage(costs.loc["hydrogen storage underground"], costs.loc["fuel cell"],
                           costs.loc["electrolysis"], max_hours=max_hours['H2'])
 
     for attr in ('marginal_cost', 'capital_cost'):
diff --git a/scripts/add_extra_components.py b/scripts/add_extra_components.py
index 72e90e3b..bf5c4175 100644
--- a/scripts/add_extra_components.py
+++ b/scripts/add_extra_components.py
@@ -76,28 +76,19 @@ def attach_storageunits(n, costs, elec_opts):
     lookup_dispatch = {"H2": "fuel cell", "battery": "battery inverter"}
 
     for carrier in carriers:
-        if carrier=="battery":
-            n.madd("StorageUnit", buses_i, ' ' + carrier,
-                   bus=buses_i,
-                   carrier=carrier,
-                   p_nom_extendable=True,
-                   capital_cost=costs.at[carrier, 'capital_cost'],
-                   marginal_cost=costs.at[carrier, 'marginal_cost'],
-                   efficiency_store=costs.at[lookup_store[carrier], 'efficiency']**0.5,
-                   efficiency_dispatch=costs.at[lookup_dispatch[carrier], 'efficiency']**0.5,
-                   max_hours=max_hours[carrier],
-                   cyclic_state_of_charge=True)
-        else:
-            n.madd("StorageUnit", buses_i, ' ' + carrier,
-                   bus=buses_i,
-                   carrier=carrier,
-                   p_nom_extendable=True,
-                   capital_cost=costs.at[carrier, 'capital_cost'],
-                   marginal_cost=costs.at[carrier, 'marginal_cost'],
-                   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)
+        roundtrip_correction = 0.5 if carrier == "battery" else 1
+        
+        n.madd("StorageUnit", buses_i, ' ' + carrier,
+               bus=buses_i,
+               carrier=carrier,
+               p_nom_extendable=True,
+               capital_cost=costs.at[carrier, 'capital_cost'],
+               marginal_cost=costs.at[carrier, 'marginal_cost'],
+               efficiency_store=costs.at[lookup_store[carrier], 'efficiency']**roundtrip_correction,
+               efficiency_dispatch=costs.at[lookup_dispatch[carrier], 'efficiency']**roundtrip_correction,
+               max_hours=max_hours[carrier],
+               cyclic_state_of_charge=True
+        )
 
 
 def attach_stores(n, costs, elec_opts):
diff --git a/test/config.test1.yaml b/test/config.test1.yaml
index 2a6bb26a..efd2bc12 100755
--- a/test/config.test1.yaml
+++ b/test/config.test1.yaml
@@ -157,7 +157,7 @@ load:
 costs:
   year: 2030
   version: v0.1.0
-  rooftop_share: 0.5
+  rooftop_share: 0.14
   fill_values:
     FOM: 0
     VOM: 0