Cluster network replace pyomo

[FabianHofmann]

Changes proposed in this Pull Request

To determine the optimal topology to meet the number of clusters, the workflow used pyomo in combination with ipopt or gurobi. This dependency has been replaced by using linopy in combination with scipopt or gurobi. The environment file has been updated accordingly.

It seems that scipopt works better than ipopt. In my local test, scipopt always meets the same optimum as gurobi, whereas ipopt does not.

Checklist

• I tested my contribution locally and it seems to work fine.
• Code and workflow changes are sufficiently documented.
• Changed dependencies are added to envs/environment.yaml.
• Changes in configuration options are added in all of config.default.yaml.
• Changes in configuration options are also documented in doc/configtables/*.csv.
• A release note doc/release_notes.rst is added.

[FabianHofmann]

CI fails because environment is not build/cashed correctly. Don't know how to fix that yet. @fneum any idea?

[fneum]

       │  ├─ pyscipopt [4.0.0|4.1.0|4.2.0] would require
      │  │  ├─ python_abi 3.10.* *_cp310, which can be installed;
      │  │  └─ scip >=8.0.0,<9.0a0  but there are no viable options
      │  │     ├─ scip 8.0.0 would require
      │  │     │  └─ ipopt >=3.14.6,<3.14.7.0a0 , which conflicts with any installable versions previously reported;
      │  │     ├─ scip 8.0.0 would require
      │  │     │  └─ ipopt >=3.14.4,<3.14.5.0a0 , which conflicts with any installable versions previously reported;
      │  │     ├─ scip 8.0.1 would require
      │  │     │  └─ ipopt >=3.14.9,<3.14.10.0a0 , which conflicts with any installable versions previously reported;
      │  │     ├─ scip 8.0.1 would require
      │  │     │  └─ ipopt >=3.14.7,<3.14.8.0a0 , which conflicts with any installable versions previously reported;
      │  │     ├─ scip [8.0.1|8.0.2] would require
      │  │     │  └─ ipopt >=3.14.8,<3.14.9.0a0 , which conflicts with any installable versions previously reported;
      │  │     ├─ scip [8.0.2|8.0.3] would require
      │  │     │  └─ ipopt >=3.14.10,<3.14.11.0a0 , which conflicts with any installable versions previously reported;
      │  │     ├─ scip [8.0.3|8.0.4|8.1.0] would require
      │  │     │  └─ ipopt >=3.14.12,<3.14.13.0a0 , which conflicts with any installable versions previously reported;
      │  │     ├─ scip 8.0.3 would require
      │  │     │  └─ ipopt >=3.14.11,<3.14.12.0a0 , which conflicts with any installable versions previously reported;
      │  │     ├─ scip 8.1.0 would require
      │  │     │  └─ ipopt >=3.14.14,<3.14.15.0a0 , which conflicts with any installable versions previously reported;
      │  │     └─ scip 8.1.0 would require
      │  │        └─ ipopt >=3.14.13,<3.14.14.0a0 , which conflicts with any installable versions previously reported;

I think the version constraint on ipopt causes the issue.

[fneum]

We can try to simplify:

https://github.com/PyPSA/pypsa-eur/blob/cb00f42476f8fdb9dd6db58f88ee19594763b028/.github/workflows/ci.yaml#L48C1-L57C47

    - name: Add solver to environment
      run: |
        echo -e "- glpk" >> envs/environment.yaml

Or even include glpk or highspy directly in the envs/environment.yaml.