Update of Hydrogen Modeling: Flexibility Tax and Electrolysis Tax

[fschreyer]

Purpose of this PR

This PR mainly updates our green hydrogen modeling. It extends and reparameterizes the flexibility tax for electrolysis and adds a SE electricity tax on electricity used by electrolysis. The electrolysis technology elh2 is therefore to be seen as grid electrolysis, which is now noted in the technology description.

It addresses several issues relevant to the ongoing validation:

• high synfuel usage in NPi
• Npi coal power revival in some regions
• hydrogen use for DAC heating

Note: A quick review would be great as this is supposed to feature the next release version and @LaviniaBaumstark wants to start validation runs as soon as possible.

Details:

1.) flexibility tax update

• Flexibility tax (i.e. reduction of electricity price for electrolysis) now depends not only on VRE share but also on the share of electrolysis in total electricity demand. This captures the effect observed in power system models that with increasing green hydrogen production in the power system less hours in the year with low electricity prices will be available.
• Flexibility tax is (re)parameterized based on data from the Enertile model of the German Langfristszenarien.

2.) SE electrolysis tax

• an SE electrolysis tax was added to tax electricity used by (grid) electrolysis. The tax rate is the sum of the FE industry electricity tax and the levelized grid cost (from the tdels technology) to capture that electrolysis also needs to pay for grid maintenance / expansion. However, as in the real world it may make sense to (partially) free electrolysis from taxes at low levels of production since, for example, electrolysis provides balancing services to the grid of a high-VRE power system, the tax is low at low shares and only increases at higher shares. The relationsship is assumed to be a logistic curve with its inflection point at 10% electrolysis share in electricity demand, that is, taxes for electrolysis will get quite high once this threshold is crossed.

3.) Other Changes

• Gas-to-Liquids (gasftrec, gasftcrec) technologies were activated again. This was done in the context of this issue to avoid the model to produce blue hydrogen and use it for synfuels as in reality this would correspond to a GtL process.
• Improve documentation of flexibility tax implementation.

Type of change

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

• New feature

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
• I adjusted the reporting in remind2 where it was needed

See this remind2 PR

• I adjusted forbiddenColumnNames in readCheckScenarioConfig.R in case the PR leads to deprecated switches
• 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?):

Before and after H2 Update (different ramp-up rates for SE tax):

/p/tmp/schreyer/Modeling/remind/Current/compScen-H2Update_vs_original-2024-03-05_09.26.34-H12.pdf

Npi runs at different stages of the incoming changes:

/p/tmp/schreyer/Modeling/remind/Current/compScen-Npi_H2Update-2024-03-01_12.05.50-H12.pdf

[aodenweller]

Thanks, Felix! As we all discussed, let's go ahead with this.

[FalkoUeckerdt]

Based on the discussions and plots on mattermost, I approve this. Thanks Felix!

[fschreyer]

My test runs on this branch did not converge (for instance /p/tmp/schreyer/Modeling/remind/remind_330/output/default_2024-03-13_15.56.02). However, this is most likely due to issues of the current trunk version and not related to this PR. I checked that the taxes I added converge well. Otherwise, there were no infeasibilities and the reporting update worked well. As agreed with @LaviniaBaumstark, I will proceed to merge this to be included in the upcoming validation runs. Recalibration of the CES parameters is recommended after this merge.