add option for retrofitted pipe capacity per CH4 capacity

config.default.yaml

@@ -222,6 +222,7 @@ sector:
   electricity_grid_connection: true  # only applies to onshore wind and utility PV
   gas_network: true
   H2_retrofit: true  # if set to True existing gas pipes can be retrofitted to H2 pipes
+  H2_retrofit_capacity_per_CH4: 0.6  # ratio for H2 capacity per original CH4 capacity of retrofitted pipelines
   gas_distribution_grid: true
   gas_distribution_grid_cost_factor: 1.0  #multiplies cost in data/costs.csv
   conventional_generation: # generator : carrier

scripts/prepare_sector_network.py

@@ -1050,7 +1050,7 @@ def add_storage(n, costs):
             bus0=h2_pipes.bus0 + " H2",
             bus1=h2_pipes.bus1 + " H2",
             p_min_pu=-1.,  # allow that all H2 pipelines can be used in other direction
-            p_nom_max=h2_pipes.pipe_capacity_MW,
+            p_nom_max=h2_pipes.pipe_capacity_MW * options["H2_retrofit_capacity_per_CH4"],
             p_nom_extendable=True,
             length=h2_pipes.length_km,
             capital_cost=costs.at['H2 (g) pipeline','fixed'] * h2_pipes.length_km * 0.3,   # TODO