CAPEX documentation issue

[Alex-Neve]

Checklist

• [ X] I am using the current master branch or the latest release. Please indicate:

Describe the Bug

• The CSV files of generators, lines, links, storage_units, stores and transformers stored under the "component_attrs" folder incorrectly state in the "description" column that the "capital_cost" attribute is the "Capital cost of extending p_nom by 1 MW."
• However, as pointed out in the PyPSA article "Power System Optimization", "the capital_cost of the assets is now the fixed annual costs, including annuity and FOM."
• I suggest replacing the "capital_cost" attribute description with "Fixed annual costs, including investment costs annuity and Fixed O&M costs." (This is done in the attached CSV files)
  transformers.csv
  generators.csv
  lines.csv
  links.csv
  storage_units.csv
  stores.csv

[FabianHofmann]

Hey @Alex-Neve, thank you for your suggestion. I am not sure whether the proposed description is general enough. Assume you have a time horizon of less or more than one year. Then the term annualized costs is not correct any more, right?

[Alex-Neve]

Hi @FabianHofmann ,

Would you prefer "periodized costs"? This would leave it to the user to pick his/her preferred time-scale.

In my sector of the industry we use annualized costs because the investment periods are so long that monthly discounting of the costs would not make sense, but other users may work at different time-scales.

If you prefer "periodized costs", I might leave an indication in the CSV files that if periods are defined as years, these periodized costs are identical to annualized costs.

Kr,
Alex

[Alex-Neve]

Here are the CSV files that I have reworded to avoid the terms "annual" and "annualized".
FYI, I cannot create a branch to propose this change myself in a pull request.

generators.csv
lines.csv
links.csv
storage_units.csv
stores.csv
transformers.csv

[fneum]

You can via a fork.