Add enum for thermal to electric conversion model types and update us…

[chris-ashe]

…age in power calculations

Description

Checklist

I confirm that I have completed the following checks:

• My changes follow the PROCESS style guide
• I have justified any large differences in the regression tests caused by this pull request in the comments.
• I have added new tests where appropriate for the changes I have made.
• If I have had to change any existing unit or integration tests, I have justified this change in the pull request comments.
• If I have made documentation changes, I have checked they render correctly.
• I have added documentation for my change, if appropriate.

[Copilot]

Pull request overview

This PR introduces a typed IntEnum for the thermal→electric conversion model switch (i_thermal_electric_conversion) and updates the power model logic (and documentation) to use the named enum values instead of raw integers.

Changes:

• Add ElectricConversionModelTypes (IntEnum) in process/models/power.py.
• Refactor component_thermal_powers() and plant_thermal_efficiency() to compare against enum members.
• Fix documentation: “User input” corresponds to i_thermal_electric_conversion = 2.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
process/models/power.py	Adds enum and updates conversion-model branching logic to use enum members.
documentation/source/eng-models/power-requirements.md	Corrects the documented value for the “User input” conversion model.

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[Copilot]

There don’t appear to be unit tests covering the i_thermal_electric_conversion steam Rankine (3) / s-CO2 (4) paths in plant_thermal_efficiency(). Adding focused tests for these options would help catch enum/branch regressions like this one and validate the temperature→efficiency correlations.

[Copilot]

ElectricConversionModelTypes defines SUPERCRITICAL_CO2_BRAYTON_CYCLE, but this branch compares against ElectricConversionModelTypes.SUPERCRITICAL_CO2_CYCLE, which will raise AttributeError at runtime when i_thermal_electric_conversion == 4. Rename the enum member or update this comparison to use the defined name (and keep naming consistent with the docs: “Supercritical CO2 Brayton Cycle”).

Suggested change

	== ElectricConversionModelTypes.SUPERCRITICAL_CO2_CYCLE
	== ElectricConversionModelTypes.SUPERCRITICAL_CO2_BRAYTON_CYCLE

[Copilot]

Casting fwbs_variables.i_thermal_electric_conversion to ElectricConversionModelTypes will raise a ValueError for out-of-range values, so the final else branch that logs an out-of-range message can never execute. Either remove that else branch (since input is validated elsewhere) or wrap the enum conversion in try/except ValueError and handle/log invalid values there.

Suggested change

	i_thermal_electric_conversion = ElectricConversionModelTypes(
	fwbs_variables.i_thermal_electric_conversion
	)
	try:
	i_thermal_electric_conversion = ElectricConversionModelTypes(
	fwbs_variables.i_thermal_electric_conversion
	)
	except ValueError as exc:
	logger.error(
	"i_thermal_electric_conversion=%s is out of range for "
	"ElectricConversionModelTypes",
	fwbs_variables.i_thermal_electric_conversion,
	)
	raise ProcessValueError(
	"Invalid i_thermal_electric_conversion: "
	f"{fwbs_variables.i_thermal_electric_conversion}"
	) from exc

[codecov-commenter]

Codecov Report

❌ Patch coverage is 46.66667% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 52.11%. Comparing base (25b9f07) to head (8217e95).

Files with missing lines	Patch %	Lines
process/models/power.py	46.66%	8 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4209   +/-   ##
=======================================
  Coverage   52.10%   52.11%           
=======================================
  Files         148      148           
  Lines       30389    30398    +9     
=======================================
+ Hits        15835    15842    +7     
- Misses      14554    14556    +2     

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