507 add cross border flows to scenarios

[tiernan-buckley-ufr]

Pull Request

Related Issue

Closes #507

Description

This update adds a new type of unit, "Exchanges", corresponding to the commercial exchanges (imports/exports), allowing imports and exports to be added to the market dynamics.

Exports are treated as a form of demand and are set as a bid just below the (price-inelastic) demand bid price to ensure they are realised, and imports are treated as a form of generation set near to the min. bid price to ensure they are realised.

In example 1a, an "exchanges_df.csv" is added to the inputs containing import and export values that are fractions of the demand_df values. A corresponding "exchanges_units.csv" is made configuring how the exchanges participate in the market.

In example 3, "exchanges_df.csv" contains German commercial exchanges for the year 2019, and "exchanges_units.csv" configures how the exchanges participate in the market.

Changes Proposed

• Create new unit type "Exchanges", to allow imports and exports to participate in the market.
• Add exchanges data to examples 1a and 3.
• Make ramp variables optional in Unit class declarations.

Testing

• For example 3, the accepted bid prices with and without exchanges were modelled and compared with historical prices for 2019 to see if including exchanges improves the accuracy of the model.

• For January:

• • Modelled Average without Exchanges: 32.60
• • Modelled Average with Exchanges: 37.80
• • Actual Average Price: 49.40

• For April:

• • Modelled Average without Exchanges: 29.50
• • Modelled Average with Exchanges: 31.70
• • Actual Average Price: 36.96

• For July:

• • Modelled Average without Exchanges: 31.30
• • Modelled Average with Exchanges: 30.70
• • Actual Average Price: 39.68

For January a significant increase in accuracy is seen, for April a marginal increase, and for July a slight decrease is seen.

Checklist

Please check all applicable items:

• Code changes are sufficiently documented (docstrings, inline comments, doc folder updates)
• New unit tests added for new features or bug fixes
• Existing tests pass with the changes
• Reinforcement learning examples are operational (for DRL-related changes)
• Code tested with both local and Docker databases
• Code follows project style guidelines and best practices
• [] Changes are backwards compatible, or deprecation notices added
• New dependencies added to pyproject.toml
• A note for the release notes doc/release_notes.rst of the upcoming release is included
• Consent to release this PR's code under the GNU Affero General Public License v3.0

[nick-harder]

@tiernan-buckley-ufr in the future run the pre-commit run --all-files command as described in the development section of the readme file to avoid errors during checks

[codecov]

Codecov Report

Attention: Patch coverage is 89.13043% with 5 lines in your changes missing coverage. Please review.

Project coverage is 77.62%. Comparing base (be4b849) to head (7493466).

Files with missing lines	Patch %	Lines
assume/units/exchanges.py	86.20%	4 Missing ⚠️
assume/scenario/loader_csv.py	87.50%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #522      +/-   ##
==========================================
+ Coverage   77.51%   77.62%   +0.10%     
==========================================
  Files          50       51       +1     
  Lines        6792     6832      +40     
==========================================
+ Hits         5265     5303      +38     
- Misses       1527     1529       +2     

Flag	Coverage Δ
pytest	77.62% <89.13%> (+0.10%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.