Increase power sector minimal back-up capacity requirement and reintroduce constraint for minimal electrolysis capacities at a certain VRE share

[fschreyer]

Purpose of this PR

• Back-up capacity constraint: In the course of the Ariadne project, we realized our minimal dispatchable back-up capacity was smaller than from a couple of other more detailed models/scenarios (e.g. German Langfristszenarien). We therefore reparameterize and increase the minimum requirement globally here.

• Electrolysis constraint: We reintroduce a constraint to have some minimal electrolysis capacities at a certain VRE share. Usually, that is not binding as the flexibility tax incentivizes H2 production with increasing VRE share. However, in specific cases with (high) exogenous hydrogen imports, hardly any electrolysis is built which is probably an underestimation in a high-VRE power system. The minimum electrolysis level is 0 before 2030 and then fully phased in until 2040 depending on the level of VRE storage. This phase-in is done to not have too much electrolysis too early inconsistent with project pipeline / upscaling feasibility.

See scenario PDFs below for changes in results on a global level and for Germany.

Tagging @pweigmann who coded the changes.

Type of change

(Make sure to delete from the Type-of-change list the items not relevant to your PR)

• Minor change (default scenarios show only small differences)

Checklist:

• My code follows the coding etiquette
• I performed a self-review of my own code
• I explained my changes within the PR, particularly in hard-to-understand areas
• I checked that the in-code documentation is up-to-date
• All automated model tests pass (FAIL 0 in the output of make test)
• The changelog CHANGELOG.md has been updated correctly

Further information (optional):

• Test runs are here:
• Comparison of results (what changes by this PR?):
  /p/tmp/schreyer/Modeling/remind/remind_330/compScen-PowerSectorUpdate-2024-08-22_09.16.51-AriadneDEU.pdf

and

/p/tmp/schreyer/Modeling/remind/remind_330/compScen-PowerSectorUpdate-2024-08-22_09.16.51-H12.pdf

[robertpietzcker]

I am now back from vacation - will take a look at this tomorrow.

would you mind just posting the 6 most relevant plots from the compscen here? easier for me, but also for future people who might want to understand how large the changes of this PR were.
(I would say H2 supply mix, electricity mix, electricity capacity mix, electrolyzer capacity line plot, hydrogen turbine capacity line plot, Price|SE|H2)

[fschreyer]

Ok, let's continue the discussion here: https://github.com/remindmodel/development_issues/issues/342

[robertpietzcker]

thanks for uploading the images!

looks good