ReEDS-Model · patrickbrown4 · Apr 15, 2026 · Apr 20, 2026 · Apr 20, 2026 · May 5, 2026
diff --git a/cases.csv b/cases.csv
@@ -317,6 +317,7 @@ GSw_TCPhaseout_trigger_f,The fraction of emissions from the ref year used to det
 GSw_TransCapMaxEachType,[GW] maximum transmission capacity allowed across each individual BA-BA interface for each trtype (constraint is off if set to 0; must be 0 or >= existing capacity (26.13 for AC)),N/A,0,
 GSw_TransCapMaxAllTypes,[GW] maximum transmission capacity allowed across each individual BA-BA interface for all trtypes together (constraint is off if set to 0; must be 0 or >= existing capacity (26.13 for AC)),N/A,0,
 GSw_TransCapMaxTypes,Transmission types to limit according to GSw_TransCapMaxEachType and GSw_TransCapMaxAllTypes [0 = none; 1 = all; 2 = VSC; 3 = all DC],0; 1; 2; 3,1,
+GSw_TransConductor,Which conductor to assume for new AC transmission ('acss' is a mix of ACSS and ACSR as specified by the MISO Transmission Cost Estimation Guide; 'acsr' is just ACSR),^(acss|acsr)$,acsr,
 GSw_TransIntraCost,[USD2004/kW] intra-zone network reinforcement cost for all technologies (100 USD2022/kW using gas cost from slide 14 of https://emp.lbl.gov/publications/generator-interconnection-costs),N/A,65,
 GSw_TransInvMaxLongTerm,[TW-mile/year] maximum transmission capacity investment per year IN/AFTER firstyear_trans_longterm (constraint is OFF if set to 0 meaning unlimited trans investment; annual max since 2009 is ~3.64),N/A,0,
 GSw_TransInvMaxNearTerm,[TW-mile/year] maximum transmission capacity investment per year BEFORE firstyear_trans_longterm (constraint is OFF if set to 0 meaning unlimited trans investment; annual mean since 2009 is ~1.4),float,1.4,
@@ -329,9 +330,9 @@ GSw_TransHurdleLevel2,Apply hurdle rates from inputs/transmission/cost_hurdle_in
 GSw_TransHurdleRate,Turn on (1) or off (0) hurdle rates between hierarchy regions as defined by GSw_TransHurdleLevel1/GSw_TransHurdleLevel2 and inputs/transmission/cost_hurdle_intra.csv,0; 1,0,
 GSw_TransNetworkSource,Network source for the initial transmission network used in the model,NARIS2024,NARIS2024,
 GSw_TransRestrict,hierarchy level within which to allow new transmission lines,r; nercr; transreg; transgrp; cendiv; st; interconnect; country; usda_region,country,
-GSw_TransScen,Transmission expansion scenario (options in inputs/transmission),N/A,default,
-GSw_TransSquiggliness,Transmission distance multiplier to approximate the squigglier paths followed by actual lines (only applied to NEW lines),float,1,
-GSw_TransUpgradeMethod,Method for calculating AC transmission upgrade costs,500kv,500kv,
+GSw_TransScen,Additional candidate interfaces for transmission expansion between zones,^(none|NTP_(MT|P2P))$,none,
+GSw_TransSquigglinessMin,Minimum squiggliness (straight-line length multiplier) to apply for interzonal transmission; the default value is from the MISO Transmission Cost Estimation Guide (https://www.misoenergy.org/planning/transmission-planning/mtep),float,1.3,
+GSw_TransUpgradeMethod,Method for calculating interzonal AC transmission expansion costs,^(greenfield|500kv)$,greenfield,
 GSw_TransGroupContraint,Indicate whether to apply flow constraint on groups of transmission interfaces,0; 1,1,
 GSw_TransGroupDerate,[fraction] amount by which to derate the capacity of grouped transmission flows for new transmission additions (0 = no derate),float,0.15,
 GSw_Upgrades,Switch to turn upgrades on or off - not to be used with water constraints - value of 2 indicates persistent upgrades,0; 1; 2,1,

diff --git a/cases_examples.csv b/cases_examples.csv
@@ -6,7 +6,6 @@ GSw_ZoneSet,,,,,,,z69,z54,z54,z3109,PJMcounty,z3109
 GSw_GasCurve,,2,2,2,2,,,,,2,2,2
 GSw_HourlyType,,,wek,year,,,,,,,,
 GSw_OpRes,,,,0,,,,,0,,,
-GSw_TransSquiggliness,,,,,,,1.07,1.07,1.07,,,
 GSw_HourlyNumClusters,,,,,,20,,,20,,,
 GSw_PRM_CapCredit,,,,,1,,,,,,,
 GSw_StartCost,,,,,,,,,0,,,

diff --git a/cases_standardscenarios.csv b/cases_standardscenarios.csv
@@ -44,6 +44,6 @@ GSw_TransHurdleLevel2,Region whose hurdle rate rate2 is applied to (defined in c
 GSw_TransHurdleRate,Turn on / off hurdle rate,1,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
 GSw_TransInvMaxLongTerm,[TW-mile/year] maximum transmission capacity investment per year IN/AFTER firstyear_trans_longterm (constraint is OFF if set to 0 meaning unlimited trans investment; annual max since 2009 is ~3.64),0,,,,,,,,,,,,,,1.07,,,,,,,,,,,,,,,,,,,,,,,,1.07,,,,,,,,,,,,,,,,,,,,,,,,,,1.07,,,,,,,,
 GSw_TransRestrict,hierarchy level within which to allow new transmission lines,country,,,,,,,,,,,,,,transreg,,,,,,,,,,,,,,,,,,,,,,,,transreg,,,,,,,,,,,,,,,,,,,,,,,,,,transreg,,,,,,,,
-GSw_TransScen,"Select Transmission Scenario [default, LCC_all, LCC_SeamsD3_certain, etc]",default,,,,,,,,,,,,,VSC_all,,,,,,,,,,,,,,,,,,,,,,,,VSC_all,,,,,,,,,,,,,,,,,,,,,,,,,,VSC_all,,,,,,,,,
+GSw_TransScen,"Select Transmission Scenario [default, LCC_all, LCC_SeamsD3_certain, etc]",default,,,,,,,,,,,,,NTP_MT,,,,,,,,,,,,,,,,,,,,,,,,NTP_MT,,,,,,,,,,,,,,,,,,,,,,,,,,NTP_MT,,,,,,,,,
 GSw_UpgradeCost_Mult,CCS upgrade cost scenario: 0=mid 1=adv 2=con,0,,,,,,,,,,,2,1,,,,,,,,,,,,,,,,,,,,,,,2,1,,,,,,,,,,,,,,,,,,,,,,,,,2,1,,,,,,,,,,
 GSw_Upgrades,Turn on/off upgrades,1,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,0
diff --git a/cases_test.csv b/cases_test.csv
@@ -35,7 +35,7 @@ GSw_ReducedResource,,,,,,,1,,,,,,,,,,,,,,,1,,,,,,,,
 GSw_SitingUPV,,,,,,limited,limited,limited,,,,,,,,,,,,,,limited,,,,,,,,
 GSw_SitingWindOfs,,,,,,limited,limited,limited,,,,,,,,,,,,,,open,,,,,,,,
 GSw_SitingWindOns,,,,,,limited,limited,limited,,,,,,,,,,,,,,limited,,,,,,,,
-GSw_TransScen,,,,,,,VSC_all,,,,,,,,,,,,,,,VSC_all,,,,,,,,
+GSw_TransScen,,,,,,,NTP_MT,,,,,,,,,,,,,,,NTP_MT,,,,,,,,
 GSw_CO2_Detail,,,,,,,1,,,,,,,,,,,,,,,1,,,,,,,,
 GSw_DAC,,,,,,,1,,,,,,,,,,,,,,,1,,,,,,,,
 GSw_NoFossilOffsetCDR,,,,,,,1,,,,,,,,,,,,,,,1,,,,,,,,

diff --git a/docs/source/figs/docs/interconnection-cost-distribution.png b/docs/source/figs/docs/interconnection-cost-distribution.png
diff --git a/docs/source/figs/docs/lcp-p134.png b/docs/source/figs/docs/lcp-p134.png
diff --git a/docs/source/figs/docs/local-generation-interconnection-components.png b/docs/source/figs/docs/local-generation-interconnection-components.png
diff --git a/docs/source/figs/docs/new-ac-transmission-cost-assumptions.png b/docs/source/figs/docs/new-ac-transmission-cost-assumptions.png
diff --git a/docs/source/figs/docs/supplycurve-cost.png b/docs/source/figs/docs/supplycurve-cost.png
diff --git a/docs/source/figs/docs/transmission-cost-ac.png b/docs/source/figs/docs/transmission-cost-ac.png
diff --git a/docs/source/figs/docs/transmission-cost-input-data.png b/docs/source/figs/docs/transmission-cost-input-data.png
diff --git a/docs/source/figs/docs/transmission-hvdc_b2b.png b/docs/source/figs/docs/transmission-hvdc_b2b.png
diff --git a/docs/source/figs/docs/transmission-land-terrain.png b/docs/source/figs/docs/transmission-land-terrain.png