Added new PV node and improved documentation.

[Zetison]

This PR adds a PV node to the package, which provides sampling routines for photovoltaic power generation using PVGIS which is more in line with the WindPower node requiring lat-lon coordinates.

[Copilot]

Pull request overview

This PR introduces a new PV node that can sample photovoltaic generation profiles via the PVGIS seriescalc API, aligning PV sampling with the lat/lon workflow used by WindPower, and adds documentation + tests around the new node.

Changes:

• Added PV / PVParameters types and a PVGIS-backed constructor that builds an OperationalProfile from PVGIS hourly output.
• Implemented pvgis_profile(...) with local CSV caching and added PV-specific node checks.
• Added PV documentation and test coverage, and enabled JuliaFormatter checks in the test run.

Reviewed changes

Copilot reviewed 11 out of 12 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
src/datastructures.jl	Adds PVParameters and PV node types plus a PVGIS-sampling constructor.
src/utils.jl	Adds pvgis_profile(...) to call PVGIS, parse JSON, and cache results to CSV.
src/checks.jl	Adds EMB.check_node(::PV, ...) to enforce profile bounds.
src/EnergyModelsLanguageInterfaces.jl	Imports PVGIS-related deps and exports PV / PVParameters.
docs/src/nodes/pv.md	New documentation page for the PV node.
test/utils.jl	Adds simple_graph_pv(...) helper to build a minimal PV test case.
test/test_checks.jl	Adds validation tests for PV input checks.
test/test_PV.jl	Adds a PV node integration test.
test/runtests.jl	Enables JuliaFormatter test and includes test_PV.jl.
test/test_CSPandPV.jl	Minor formatting change to an assertion line.
Project.toml	Adds PVGIS-related dependencies and compat constraints.
NEWS.md	Updates release notes with the new PV node.

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[JulStraus]

I like the idea in general. There are however some structural points within the sampling which I would like you to address. Specifically, I think it would be good to have a hard coded test profile as well to see if there is stuff changing at the source. Note that I think it is also important to check that existing functions are working.

Important

JSON3.jl is deprecated as written in its README.md: https://github.com/quinnj/JSON3.jl. This implies we should use JSON.jl from the start.

[Zetison]

Thanks for your feedback! I have adjusted for most of your input.

[JulStraus]

There are minor things to be adjusted. I think we are soon there.

Important

We have to allow the user to specify the unit for the capacity in PVParameters. Currently, we assume it to be kW while potential users would be more interested in other units. It seems to me that PVGIS requires kW for peakpower, but it would be beneficial for us to have a different approach

[Zetison]

I made some suggestions to accomidate the review in a new commit.

[JulStraus]

I think we are soon there. I have no comments regarding your changes as you pretty much implemented what I asked for.

There are however two things I would like you to include in the test set (and which I unfortunately forgot the last time...):

1. We should test that our checks in the internal constructor for PVParameters are working. In addition, we should test that the constructor is working. The latter could be similar to the approaches I chose in, e.g., EnergyModelsFlex.
2. We do not test that the reading of local profile files is working, at least I do not see it. It is in my opinion however an important point to test it.

Both tests should be within the file test_PV.jl in my opinion.

[JulStraus]

Correction to my self, we actually test the local profile version due to running the test loop twice.

[JulStraus]

Looks good to me now.