Purpose of this PR

This PR prevents a spillover of traditional biomass into other sectors (i.e. the industry sector), by ensuring that not more pebiolc is transformed into sesobio via biotr than there is demand for solid biomass in buildings. This applies only to regions that still have a traditional biomass demand.

In order to do that, the phase-out trajectory of vm_deltaCap(t ,regi, "biotr","1") is relaxed from a fixed value to an upper bound. This works, because biotr is by definition the cheapest and most efficient technology, so REMIND will always use that technology if not constrained otherwise.

The effect is, that IND and SSA now have lower levels of vm_prodSe(t,regi,"pebiolc","sesobio","biotr") and the solids demand is instead fulfilled with coal (coaltr) and modern solid biomass (biotrmod).

Type of change

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

• Bug fix
• Refactoring
• New feature
• Minor change (default scenarios show only small differences)
• Fundamental change
• This change requires a documentation update

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 (not needed)
• I adjusted forbiddenColumnNames in readCheckScenarioConfig.R in case the PR leads to deprecated switches (not needed)
• 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:
  /p/tmp/merfort/REMIND_update_residues/remind
• Comparison of results (what changes by this PR?):
  You find a compare scenarios PDF here:
  /p/tmp/merfort/REMIND_update_residues/remind/compScen-orig_vs_relax_biotr_supply_v2-2024-01-11_08.50.31-H12.pdf
  Differences between the previous version ("orig") and the new version ("relax_biotr_supply_v2") are small. Biggest difference is that some of the solids that came from traditional biomass before is now coming from coal or (modern) biomass in IND and SSA: