s_max_pu = 1 for some lines despite default config of 0.7

[grecht]

Hi everyone! I noticed that some lines have s_max_pu values of 1 instead of 0.7. These are mostly TYNDP2020 lines and some lines whose names start with "P", see the output below.
If this is intentional, what is the reasoning behind this? I could not find anything in the documentation, and the default config file which I used specifies s_max_pu: 0.7 which should hold for all lines, as I understand it.

What I did

• built the "default" PyPSA-Eur (on commit b328169) in different spatial resolutions using
  snakemake resources/networks/elec_s_{39,128,256,512,1024}.nc -call --configfile config/config.default.yaml
• executed this

import pypsa

nw_path = "resources/networks/elec_s.nc"
nw = pypsa.Network(nw_path)
print(nw.lines.loc[nw.lines["s_max_pu"] == 1].index)

The output:

WARNING:pypsa.io:Importing network from PyPSA version v0.30.1 while current version is v0.30.2. Read the release notes at https://pypsa.readthedocs.io/en/latest/release_notes.html to prepare your network for import.
INFO:pypsa.io:Imported network elec_s.nc has buses, carriers, generators, lines, links, loads, shapes, storage_units
Index(['TYNDP2020_0', 'TYNDP2020_1', 'TYNDP2020_2', 'TYNDP2020_3',
       'TYNDP2020_4', 'TYNDP2020_6', 'TYNDP2020_8', 'TYNDP2020_9',
       'TYNDP2020_11', 'TYNDP2020_13', 'TYNDP2020_14', 'TYNDP2020_15',        
       'TYNDP2020_16', 'TYNDP2020_17', 'TYNDP2020_24', 'TYNDP2020_25',        
       'TYNDP2020_26', 'TYNDP2020_27', 'TYNDP2020_28', 'TYNDP2020_29',        
       'TYNDP2020_30', 'TYNDP2020_31', 'TYNDP2020_32', 'TYNDP2020_33',        
       'TYNDP2020_34', 'TYNDP2020_35', 'TYNDP2020_36', 'TYNDP2020_37',        
       'TYNDP2020_47', 'TYNDP2020_48', 'TYNDP2020_49', 'TYNDP2020_50',        
       'TYNDP2020_51', 'TYNDP2020_53', 'TYNDP2020_54', 'TYNDP2020_56',        
       'TYNDP2020_57', 'TYNDP2020_59', 'TYNDP2020_60', 'TYNDP2020_74',        
       'TYNDP2020_77', 'TYNDP2020_82', 'TYNDP2020_88', 'TYNDP2020_89',        
       'TYNDP2020_90', 'TYNDP2020_92', 'TYNDP2020_94', 'TYNDP2020_97',        
       'TYNDP2020_98', 'TYNDP2020_99', 'TYNDP2020_100', 'TYNDP2020_101',      
       'TYNDP2020_113', 'TYNDP2020_120', 'TYNDP2020_121', 'TYNDP2020_122',    
       'TYNDP2020_123', 'TYNDP2020_124', 'TYNDP2020_125', 'TYNDP2020_132',    
       'TYNDP2020_133', 'TYNDP2020_134', 'TYNDP2020_135', 'P43', 'P71', 'P84',
       'P227', 'P402', 'P470', 'P476', 'P478', 'P485', 'P490', 'P540', 'P625',
       'P627', 'P635', 'P636'],
      dtype='object', name='Line')

[fneum]

No, it's not intended and should indeed be 0.7 also for TYNDP links.

[grecht]

A quick fix would be adding the following line to the main body of build_transmission_projects.py, which worked for me (see 4ee4884)

new_lines_df["s_max_pu"] = snakemake.config["lines"]["s_max_pu"]

But it really makes no sense to put this there instead of a single place where s_max_pu is set for all lines. I think this should probably happen here:

pypsa-eur/scripts/prepare_network.py

Line 346 in e35f651

set_line_s_max_pu(n, snakemake.params.lines["s_max_pu"])

But apparently, this is not applied to the transmission projects, not sure why. Maybe it is due to the order of execution.

[p-glaum]

Hi @grecht , you are right! I thought the line factor would be applied later for all lines but it already happens in base_network. I added your suggestion in PR #1323

Thanks for reporting the bug!

[grecht]

Sure, thanks for fixing it!