Managing named new-entrant projects in templater: BOTN - Cethana

[EllieKallmier]

The new-entrant set is almost entirely generic technology archetypes: Pumped Hydro (Nhrs storage), CCGT, Wind, etc. that can be built anywhere.

BOTN - Cethana is the exception: named, site-specific PHES project (fixed 750 MW, 20h/80% design, in TAS) that the IASR workbook gives its own row in nearly every property table, keyed by project name rather than by technology archetype. In most property tables, the values that it is assigned match those given to 'Pumped Hydro (24hrs storage)', which is the 'Technology Type' assigned to BOTN in the summary table; but there are some instances where it doesn't (e.g., build and connection costs, pumping efficiency).

It's also spelled two ways across the v7.5 tables, either 'BOTN - Cethana' or 'BOTN - Cethana - 20h'

Current handling:

• New-entrant storage templater (src/ispypsa/templater/new_entrants.py): BOTN keeps technology = "Pumped Hydro (24hrs storage)" (so purpose of 'technology' column - grouping - is preserved). Helper function _phes_lookup_key manages the one table merge where this matters, for pumped_hydro_new_entrant_properties, where BOTN differs from the generic 24h PHES.
• **Connection costs ** (src/ispypsa/templater/connection_and_build_costs.py): BOTN is dropped via _NON_VRE_EXCLUDED_TECHNOLOGIES in _canonicalise_non_vre_technologies. Its connection cost in the forecast is $0.0.

Thoughts:

• To me makes most sense to explicitly handle BOTN as a special case as needed; just need to decide how to do that in each situation
• Dropping, merging and then adding back in BOTN rows? Re-keying temporarily (as done in the new_entrants templater atm)? Overriding 'technology' value for templating process, then manually re-setting after all templating finished? TBD...