From 8f70a9f41943aef0076dc17fdecf8010a5bb260c Mon Sep 17 00:00:00 2001
From: amerfort <amerfort@pik-potsdam.de>
Date: Fri, 26 Apr 2024 17:41:12 +0200
Subject: [PATCH 1/7] add separate 2050 CO2 targets for emissions and removals

---
 core/declarations.gms                         | 24 ++++++
 core/equations.gms                            | 77 ++++++++++++++++---
 core/postsolve.gms                            | 57 ++++++++++++++
 core/sets.gms                                 | 32 ++++++++
 modules/21_tax/on/declarations.gms            |  4 +
 modules/21_tax/on/equations.gms               | 11 ++-
 modules/21_tax/on/postsolve.gms               |  5 +-
 modules/21_tax/on/preloop.gms                 |  3 +
 modules/21_tax/on/presolve.gms                |  1 +
 modules/37_industry/subsectors/equations.gms  | 16 +++-
 .../SeparateMarketsExpo2Const/datainput.gms   | 32 ++++++++
 .../SeparateMarketsExpo2Const/not_used.txt    | 29 +++++++
 .../SeparateMarketsExpo2Const/realization.gms | 13 ++++
 modules/45_carbonprice/module.gms             |  1 +
 14 files changed, 291 insertions(+), 14 deletions(-)
 create mode 100644 modules/45_carbonprice/SeparateMarketsExpo2Const/datainput.gms
 create mode 100644 modules/45_carbonprice/SeparateMarketsExpo2Const/not_used.txt
 create mode 100644 modules/45_carbonprice/SeparateMarketsExpo2Const/realization.gms

diff --git a/core/declarations.gms b/core/declarations.gms
index 754128dc8e..646ba96b7a 100644
--- a/core/declarations.gms
+++ b/core/declarations.gms
@@ -33,6 +33,11 @@ p_taxCO2eq_iteration(iteration,ttot,all_regi)       "save CO2eq tax used in iter
 pm_taxCO2eq_iterationdiff(ttot,all_regi)              "help parameter for iterative adjustment of taxes"
 pm_taxCO2eq_iterationdiff_tmp(ttot,all_regi)          "help parameter for iterative adjustment of taxes"
 o_taxCO2eq_iterDiff_Itr(iteration,all_regi) "track p_taxCO2eq_iterationdiff over iterations"
+*ACM* parameters for separate markets on emissions and removals
+pm_taxCDR(ttot,all_regi)                             "CDR tax path in T$/GtC = $/kgC. To get $/tCO2, multiply with 272 [T$/GtC]"
+p_taxcdr_iterationdiff(ttot,all_regi)                "helper parameter for cdr revenue level adjustment"
+o_taxCDR_iterDiff_Itr(iteration,all_regi)            "output parameter for manual checking of CDR revenue development"
+
 pm_taxemiMkt(ttot,all_regi,all_emiMkt)                "CO2 or CO2eq region and emission market specific emission tax"
 pm_taxemiMkt_iteration(iteration,ttot,all_regi,all_emiMkt) "CO2 or CO2eq region and emission market specific emission tax per iteration"
 pm_emissionsForeign(tall,all_regi,all_enty)          "total emissions of other regions (nash relevant)"
@@ -122,6 +127,8 @@ pm_dataeta(tall,all_regi,all_te)                            "regional eta data"
 p_emi_quan_conv_ar4(all_enty)                               "conversion factor for various gases to GtCeq"
 pm_emifac(tall,all_regi,all_enty,all_enty,all_te,all_enty)  "emission factor by technology for all types of emissions in emiTe"
 pm_emifacNonEnergy(ttot,all_regi,all_enty,all_enty,emi_sectors,all_enty)                "emission factor for non-energy fedstocks. For now only for Chemicals Industry [GtC per TWa]"
+*** ACM tail pipe emission factor for industry emissions
+pm_emifac_tailpipe(tall,all_regi,all_enty,all_enty)         "tail pipe emissions in industry fuel combustion, necessary to calculate industry cdr"
 pm_incinerationRate(ttot,all_regi)                          "share of plastic waste that gets incinerated [fraction]"
 pm_omeg (all_regi,opTimeYr,all_te)                          "technical depreciation parameter, gives the share of a capacity that is still usable after tlt. [none/share, value between 0 and 1]"
 p_aux_lifetime(all_regi,all_te)                             "auxiliary parameter for calculating life times, calculated externally in excel sheet"
@@ -434,6 +441,13 @@ v_priceOfSpecificGoods(ttot, all_regi,all_te)        "Price in in tril$/TWa for
 vm_revenueFromSpecificGoods(ttot, all_regi)          "Revenue in tril$ from products modelled that are not yet demanded elsewhere in the model, e.g. biochar, carbon fibre products"
 
 
+*** Variables needed to calculate Industry CDR
+vm_IndCDR(ttot,all_regi)                             "Industry CDR" 
+vm_IndstShareco2neutrcarbs(ttot,all_regi,entyFE)             "Share of hydrocarbon fuels with atmospheric carbon in Industry FE demand"
+vm_FracCCS(ttot,all_regi)                             "share of geologically stored co2 from captured co2"
+v_shareAtmCO2inSynfuels(ttot,all_regi)               "Share of atmospheric co2 from all captured co2"
+
+
 ;
 ***----------------------------------------------------------------------------------------
 ***                                   EQUATIONS
@@ -558,6 +572,11 @@ q_demSpecificGoodsCalculation(ttot,all_regi,all_enty,all_te) "derivation for the
 q_priceOfSpecificGoods(ttot, all_regi, all_enty,all_te)   "e"
 qm_revenueOfSpecificGoods(ttot,all_regi)                      "e"
 
+* equations needed to calculate Industry CDR
+q_IndstShareco2neutrcarbs(ttot,all_regi,entyFE)             "Share of hydrocarbon fuels with atmospheric carbon in Industry FE demand"
+q_FracCCS(ttot,all_regi)                             "share of geologically stored co2 from captured co2"
+q_shareAtmCO2inSynfuels(ttot,all_regi)               "Share of atmospheric co2 from all captured co2"
+
 ***----------------------------------------------------------------------------------------
 ***----------------------------------------------trade module------------------------------
 
@@ -618,6 +637,11 @@ p_emi_budget1_gdx                                     "budget for global energy-
 s_actualbudgetco2                                     "actual level of 2020-2100 cumulated emissions, including all CO2 for last iteration"
 s_actualbudgetco2_last                                "actual level of 2020-2100 cumulated emissions for previous iteration" /0/
 
+
+s_actual2050co2                                       "current iterations actual global co2 emissions in 2050 needed to adjust co2 tax until 2050"
+s_actual2050cdr                                       "current iterations actual global cdr amount in 2050 needed to adjust cdr revenues until 2050"
+
+
 sm_globalBudget_dev                                   "actual level of global cumulated emissions budget divided by target budget"
 
 sm_eps                                                "small number: 1e-9 "  /1e-9/
diff --git a/core/equations.gms b/core/equations.gms
index 4bbd3bfff2..1217326343 100644
--- a/core/equations.gms
+++ b/core/equations.gms
@@ -760,26 +760,81 @@ q_emiMac(t,regi,emiMac) ..
   )
 ;
 
+*** Equations for separate carbon markets on emissions and removals
 ***--------------------------------------------------
-*' All CDR emissions summed up
+*' Share of atmospheric carbon in captured carbon
+***--------------------------------------------------
+q_ShareAtmCO2inSynfuels(t,regi)..
+  v_shareAtmCO2inSynfuels(t,regi)
+  =e=
+  !!Atmospheric CO2 (TODO: actually slightly higher, to be accurate atmospheric Industry carbon capture has to be added)
+  (sum(emiBECCS2te(enty,enty2,te,enty3),vm_emiTeDetail(t,regi,enty,enty2,te,enty3)) !!BECC
+  + sum(teCCS2rlf(te,rlf), vm_ccs_cdr(t,regi,"cco2","ico2","ccsinje",rlf))  !!DACC + OAE
+  !! - excluding carbon from fossil and synthetic fegas from DAC heating
+  -  0.9 * pm_emifac(t,regi,"segafos","fegas","tdfosgas","co2") * vm_demFeSector_afterTax(t,regi,"segafos","fegas","CDR","ETS")
+  -  0.9 * pm_emifac(t,regi,"segafos","fegas","tdfosgas","co2") * vm_demFeSector_afterTax(t,regi,"segasyn","fegas","CDR","ETS"))
+  /
+  !! Divided by all captured CO2 (TODO: To be accurate exclude captured carbon from synfuels in DAC and Industry)
+    (sum(teCCS2rlf(te,rlf),
+        vm_co2capture(t,regi,"cco2","ico2","ccsinje",rlf))+sm_eps
+    )
+    ;
+
+***--------------------------------------------------
+*' Share of atmospheric carbon in industry fuels
+***--------------------------------------------------
+q_IndstShareco2neutrcarbs(t,regi,entyFE)..
+  vm_IndstShareco2neutrcarbs(t,regi,entyFE)
+  =e=
+  (sum(entySeBio(entySE),
+    sum(emiMkt$(sector2emiMkt("indst",emiMkt)), vm_demFeSector_afterTax(t,regi,entySE,entyFE,"indst",emiMkt)) * pm_emifac_tailpipe(t,regi,entySE,entyFE))
+  + sum(entySeSyn(entySE),
+    sum(emiMkt$(sector2emiMkt("indst",emiMkt)), vm_demFeSector_afterTax(t,regi,entySE,entyFE,"indst",emiMkt)) * pm_emifac_tailpipe(t,regi,entySE,entyFE) * v_shareAtmCO2inSynfuels(t,regi)$((sameas(entySE,"seliqsyn")) OR (sameas(entySE,"segasyn"))))) 
+    /
+  sum(se_carbs(entySE),
+    sum(emiMkt$(sector2emiMkt("indst",emiMkt)), vm_demFeSector_afterTax(t,regi,entySE,entyFE,"indst",emiMkt)) * pm_emifac_tailpipe(t,regi,entySE,entyFE)
+    + sm_eps)
+;
+
+***--------------------------------------------------
+*' Fraction of captured emissions that get stored geologically
+***--------------------------------------------------
+q_FracCCS(t,regi)..
+  vm_FracCCS(t,regi)
+  =e=
+  (sum(teCCS2rlf(te,rlf),
+        vm_co2CCS(t,regi,"cco2","ico2",te,rlf)) /
+  (sum(teCCS2rlf(te,rlf),
+        vm_co2capture(t,regi,"cco2","ico2","ccsinje",rlf))+sm_eps))
+;
+
+
+***--------------------------------------------------
+*' All novel CDR emissions summed up, negative land-use-change emissions are not included
 ***--------------------------------------------------
 q_emiCdrAll(t,regi)..
   vm_emiCdrAll(t,regi)
-       =e= !! BECC + DACC
+       =e= !! BECC 
   (sum(emiBECCS2te(enty,enty2,te,enty3),vm_emiTeDetail(t,regi,enty,enty2,te,enty3))
-  + sum(teCCS2rlf(te,rlf), vm_ccs_cdr(t,regi,"cco2","ico2","ccsinje",rlf)))
+  !! + DACC + OAE process calcination emissions (that are carbon neutral as they are overcompensated by ocean uptake)
+  + sum(teCCS2rlf(te,rlf), vm_ccs_cdr(t,regi,"cco2","ico2","ccsinje",rlf))
+  !! - fossil CCS from DAC with fegas
+  -  0.9 * pm_emifac(t,regi,"segafos","fegas","tdfosgas","co2") * vm_demFeSector_afterTax(t,regi,"segafos","fegas","CDR","ETS"))
   !! scaled by the fraction that gets stored geologically
-  * (sum(teCCS2rlf(te,rlf),
-        vm_co2CCS(t,regi,"cco2","ico2",te,rlf)) /
-  (sum(teCCS2rlf(te,rlf),
-        vm_co2capture(t,regi,"cco2","ico2","ccsinje",rlf))+sm_eps))
-  !! net negative emissions from co2luc
-  -  p_macBaseMagpieNegCo2(t,regi)
-       !! negative emissions from the cdr module that are not stored geologically
-       -       (vm_emiCdr(t,regi,"co2") + sum(teCCS2rlf(te,rlf), vm_ccs_cdr(t,regi,"cco2","ico2","ccsinje",rlf)))
+  * vm_FracCCS(t,regi)
+  !! OAE net ocean 
+  + (1 - s33_OAE_chem_decomposition) * vm_emiCdrTeDetail(t, regi, "oae")
+  !! CDR from enhanced weathering
+  + vm_emiCdrTeDetail(t, regi, "weathering")
+  !! Biochar
+  + !! negative emissions from biochar
+  -   sum(emiBiochar2te(enty,enty2,te,enty3), vm_emiTeDetail(t,regi,enty,enty2,te,enty3))
+  !! Industry CDR (CCS from carbon neutral fuels)
+  + vm_IndCDR(t,regi)
 ;
 
 
+
 ***------------------------------------------------------
 *' Total regional emissions are the sum of emissions from technologies, MAC-curves, CDR-technologies and emissions that are exogenously given for REMIND.
 ***------------------------------------------------------
diff --git a/core/postsolve.gms b/core/postsolve.gms
index bef3e33997..3c795645ad 100644
--- a/core/postsolve.gms
+++ b/core/postsolve.gms
@@ -493,6 +493,63 @@ if (cm_iterative_target_adj eq 9,
   ); !! if cm_emiscen eq 9,
 );   !! if cm_iterative_target_adj eq 9,
 
+
+
+*Anne* Seperate CO2 emissions and CDR removal prices with seperate year targets (c_peakBudgYr), exponential hotelling prices with adjusted starting points until target year and constant prices afterwards.
+if(cm_iterative_target_adj eq 13,
+  if(cm_emiscen eq 9,
+*last iteration's emissions
+    s_actual2050co2 = sum(ttot$(ttot.val eq c_peakBudgYr),sum(regi,(vm_emiAll.l(ttot,regi,"co2") + vm_emiCdrAll.l(ttot,regi))))*sm_c_2_co2; !! Gross CO2 
+    if(s_actual2050co2 < 0, s_actual2050co2 = sm_eps); 
+    s_actual2050cdr = sum(ttot$(ttot.val eq c_peakBudgYr),sum(regi, vm_emiCdrAll.l(ttot,regi))) *sm_c_2_co2;  !! CDR 
+*** budget calculated as 2015-2095 + 2100*5.5 + 2010*2 in Gt CO2; 
+s_actualbudgetco2 =           sum(ttot$(ttot.val < 2100 AND ttot.val > 2010), (sum(regi, (vm_emiTe.l(ttot,regi,"co2") + vm_emiCdr.l(ttot,regi,"co2") + vm_emiMac.l(ttot,regi,"co2"))) * sm_c_2_co2 * pm_ts(ttot)))
+$if not setglobal test_TS     + sum(regi, (vm_emiTe.l("2100",regi,"co2") + vm_emiCdr.l("2100",regi,"co2") + vm_emiMac.l("2100",regi,"co2")))*sm_c_2_co2 * 5.5
+                              + sum(regi, (vm_emiTe.l("2010",regi,"co2") + vm_emiCdr.l("2010",regi,"co2") + vm_emiMac.l("2010",regi,"co2")))*sm_c_2_co2 * 2;
+*** calculation of peak budget for diagnostics
+  p_actualbudgetco2(ttot)$(ttot.val > 2020) = sum(ttot2$(ttot2.val < ttot.val AND ttot2.val > 2020), (sum(regi, (vm_emiTe.l(ttot2,regi,"co2") + vm_emiCdr.l(ttot2,regi,"co2") + vm_emiMac.l(ttot2,regi,"co2"))) * sm_c_2_co2 * pm_ts(ttot2)))
+                       + sum(regi, (vm_emiTe.l(ttot,regi,"co2") + vm_emiCdr.l(ttot,regi,"co2") + vm_emiMac.l(ttot,regi,"co2"))) * sm_c_2_co2 * ((pm_ttot_val(ttot)-pm_ttot_val(ttot-1))/2 + 0.5)
+                       + sum(regi, (vm_emiTe.l("2020",regi,"co2") + vm_emiCdr.l("2020",regi,"co2") + vm_emiMac.l("2020",regi,"co2"))) * sm_c_2_co2 * (pm_ts("2020")/2 + 0.5);
+  s_actualbudgetco2 = smax(t$(t.val le c_peakBudgYr),p_actualbudgetco2(t));
+display s_actualbudgetco2;
+    display s_actualbudgetco2, s_actual2050co2, s_actual2050cdr;
+    !! Target 2050 CO2 
+    if(o_modelstat eq 2 AND ord(iteration)<cm_iteration_max AND abs(c_target2050co2 - s_actual2050co2) ge 0.3 AND c_target2050co2 gt 0,   !!only for optimal iterations, and not after the last one, and only if target not yet reached
+      pm_taxCO2eq_iterationdiff(t,regi)$(t.val le c_peakBudgYr) = pm_taxCO2eq(t,regi)$(t.val le c_peakBudgYr) * min(max((s_actual2050co2/(c_target2050co2))** (10/(2 * iteration.val + 23)),0.5+iteration.val/208),2 - iteration.val/102)  - pm_taxCO2eq(t,regi)$(t.val le c_peakBudgYr);
+      pm_taxCO2eq(t,regi)$(t.val le c_peakBudgYr) = pm_taxCO2eq(t,regi)$(t.val le c_peakBudgYr) + pm_taxCO2eq_iterationdiff(t,regi)$(t.val le c_peakBudgYr) ;
+      o_taxCO2eq_iterDiff_Itr(iteration,regi) = pm_taxCO2eq_iterationdiff("2030",regi);
+      display o_taxCO2eq_iterDiff_Itr;
+      else
+        !! if model was not optimal, or if target already reached, keep tax constant
+        pm_taxCO2eq(t,regi)$(t.val le c_peakBudgYr) = pm_taxCO2eq(t,regi)$(t.val le c_peakBudgYr);
+        if((c_target2050co2 eq 0 AND c_target2050cdr gt 0),
+          pm_taxCO2eq(t,regi) = 0;
+        );
+      );	
+    !! Target at net-zero CDR (in target year c_peakBudgYr)
+    if(o_modelstat eq 2 AND ord(iteration)<cm_iteration_max AND abs(c_target2050cdr - s_actual2050cdr) ge 0.3,   !!only for optimal iterations, and not after the last one, and only if target not yet reached
+      p_taxcdr_iterationdiff(t,regi)$(t.val le c_peakBudgYr) = pm_taxCDR(t,regi)$(t.val le c_peakBudgYr) * min(max((c_target2050cdr/s_actual2050cdr)** (10/(2 * iteration.val + 23)),0.5+iteration.val/208),2 - iteration.val/102)  - pm_taxCDR(t,regi)$(t.val le cm_peakBudgYr);
+      pm_taxCDR(t,regi)$(t.val le c_peakBudgYr) = pm_taxCDR(t,regi)$(t.val le c_peakBudgYr) + p_taxcdr_iterationdiff(t,regi)$(t.val le c_peakBudgYr) ;
+      o_taxCDR_iterDiff_Itr(iteration,regi) = p_taxcdr_iterationdiff("2030",regi);
+      display o_taxCDR_iterDiff_Itr;
+      else
+        !! if model was not optimal, or if target already reached, keep tax constant
+        pm_taxCDR(t,regi)$(t.val le c_peakBudgYr) = pm_taxCDR(t,regi)$(t.val le c_peakBudgYr);
+      );	      
+    if((c_target2050cdr eq 0 AND c_target2050co2 gt 0),
+      pm_taxCDR(t,regi) = 0;
+      );    
+    if((c_target2050co2 eq 0 AND c_target2050cdr gt 0),
+      pm_taxCO2eq(t,regi) = 0;
+    );
+    pm_taxCDR(t,regi)$(t.val gt c_peakBudgYr) = sum(ttot$(ttot.val eq c_peakBudgYr),pm_taxCDR(ttot,regi)); !! Prices are constant after 2050 (year of net carbon neutrality)
+    display pm_taxCDR;
+    pm_taxCO2eq(t,regi)$(t.val gt c_peakBudgYr) = sum(ttot$(ttot.val eq c_peakBudgYr),pm_taxCO2eq(ttot,regi)); !! Prices are constant after 2050 (year of net carbon neutrality)
+    display pm_taxCO2eq;
+  ); !! end if cm_emiscen eq 9
+); !! end if cm_iterative_target_adj eq 13
+
+
 ***------ end of "cm_iterative_target_adj" variants-----------------------------------------
 
 
diff --git a/core/sets.gms b/core/sets.gms
index 149d92359a..0ce0b1fb7c 100755
--- a/core/sets.gms
+++ b/core/sets.gms
@@ -2088,6 +2088,26 @@ entyFe2Sector(all_enty,emi_sectors) "final energy (stationary and transportation
     fedie.cdr
 /
 
+se_co2neutralcarbs(entySE)
+/
+        segabio
+        segasyn
+        seliqbio
+        seliqsyn
+        sesobio
+/
+se_carbs(entySE)
+/
+        segabio
+        segasyn
+        segafos
+        seliqbio
+        seliqsyn
+        seliqfos
+        sesobio
+        sesofos
+/
+
 ppfEn2Sector(all_in,emi_sectors) "primary energy production factors mapping to sectors"
 /
     fegab.build
@@ -2769,6 +2789,18 @@ emi2te(all_enty,all_enty,all_te,all_enty)    " map emissions to technologies"
         segafos.fegat.tdfosgat.co2
 /
 
+map_eqCarbCont(all_enty,all_enty,all_enty,all_te) "map hydrocarbon fuels from fossil or atm. origin to same carbon content"
+/
+        segabio.segafos.fegas.tdfosgas
+        segasyn.segafos.fegas.tdfosgas
+        segafos.segafos.fegas.tdfosgas
+        seliqbio.seliqfos.fehos.tdfoshos
+        seliqsyn.seliqfos.fehos.tdfoshos
+        seliqfos.seliqfos.fehos.tdfoshos
+        sesobio.sesofos.fesos.tdfossos
+        sesofos.sesofos.fesos.tdfossos
+/
+
 emi2fuel(all_enty,all_enty) "map emissions to fuel extraction"
 /
     pecoal.ch4coal
diff --git a/modules/21_tax/on/declarations.gms b/modules/21_tax/on/declarations.gms
index 819025499d..3669f1324d 100644
--- a/modules/21_tax/on/declarations.gms
+++ b/modules/21_tax/on/declarations.gms
@@ -41,6 +41,7 @@ p21_taxrevFlex0(ttot,all_regi)                               "reference level va
 p21_taxrevImport0(ttot,all_regi,all_enty,tax_import_type_21) "tax revenues from import tax in the previous iteration"
 p21_taxrevChProdStartYear0(ttot,all_regi)                    "reference level value of tax to limit changes compared to reference run in cm_startyear"
 p21_taxrevSE0(ttot,all_regi)                                 "reference level value of tax on SE electricity demand"
+p21_taxrevCDR0(ttot,all_regi)                "reference level value of tax which reduces CDR revenues as fraction of CO2 price"
 
 p21_taxrevGHG_iter(iteration,ttot,all_regi)                "reference level value of GHG emission tax revenue"
 p21_taxrevCCS_iter(iteration,ttot,all_regi)                "reference level value of CCS tax revenue"
@@ -58,6 +59,7 @@ p21_taxrevFlex_iter(iteration,ttot,all_regi)               "reference level valu
 p21_taxrevImport_iter(iteration,ttot,all_regi,all_enty)    "reference level value of import tax"
 p21_taxrevChProdStartYear_iter(iteration,ttot,all_regi)    "Difference to tax revenues in last iteration for: tax to limit changes compared to reference run in cm_startyear"
 p21_taxrevSE_iter(iteration,ttot,all_regi)                 "Difference to tax revenues in last iteration for: tax on SE electricity demand"
+p21_taxrevCDR_iter(iteration,ttot,all_regi)                "reference level value of tax which reduces CDR revenues as fraction of CO2 price"
 
 p21_CO2TaxSectorMarkup(ttot,all_regi,emi_sectors)          "CO2 tax markup in building, industry or transport sector"
 
@@ -124,6 +126,7 @@ v21_taxemiMkt(ttot,all_regi,all_emiMkt)         "tax on greenhouse gas emissions
 v21_taxrevImport(ttot,all_regi,all_enty)        "net change vs. last iteration of tax revenues from energy import tax"
 v21_taxrevChProdStartYear(ttot,all_regi)        "tax to limit changes compared to reference run in cm_startyear"
 v21_taxrevSE(ttot,all_regi)                     "tax on SE electricity demand, used for taxes on electrolysis"
+v21_taxrevCDR(ttot,all_regi)                    "tax which reduces CDR revenues as fraction of CO2 price"
 ;
 
 Positive Variable
@@ -156,6 +159,7 @@ q21_taxrevImport(ttot,all_regi,all_enty)        "calculation of import tax"
 q21_taxrevChProdStartYear(ttot,all_regi)        "calculation of tax to limit changes compared to reference run in cm_startyear"
 q21_taxrevSE(ttot,all_regi)                     "calculation of tax on SE electricity demand, used for taxes on electrolysis"
 q21_SeTaxRate(ttot,all_regi,all_te)             "calculation of SE tax rate, used for taxes on electrolysis"
+q21_taxrevCDR(ttot,all_regi)                    "calculation of tax which reduces CDR revenues as fraction of CO2 price"
 ;
 
 $ifthen.importtaxrc "%cm_taxrc_RE%" == "REdirect"
diff --git a/modules/21_tax/on/equations.gms b/modules/21_tax/on/equations.gms
index becc31befe..af6084de3f 100644
--- a/modules/21_tax/on/equations.gms
+++ b/modules/21_tax/on/equations.gms
@@ -31,6 +31,7 @@ q21_taxrev(t,regi)$(t.val ge max(2010,cm_startyear))..
   vm_taxrev(t,regi)
   =e=
     v21_taxrevGHG(t,regi)
+  - v21_taxrevCDR(t,regi)$(cm_iterative_target_adj eq 13)   
   + sum(emi_sectors, v21_taxrevCO2Sector(t,regi,emi_sectors))
   + v21_taxrevCO2luc(t,regi)
   + v21_taxrevCCS(t,regi) 
@@ -66,9 +67,17 @@ $endIf.cm_implicitPePriceTarget
 *'  Documentation of overall tax approach is above at q21_taxrev.
 ***---------------------------------------------------------------------------
 q21_taxrevGHG(t,regi)$(t.val ge max(2010,cm_startyear))..
-v21_taxrevGHG(t,regi) =e= pm_taxCO2eqSum(t,regi) * (vm_co2eq(t,regi) - vm_emiMacSector(t,regi,"co2luc")$(cm_multigasscen ne 3))
+v21_taxrevGHG(t,regi) =e= pm_taxCO2eqSum(t,regi) * (vm_co2eq(t,regi) + vm_emiCdrAll(t,regi)$(cm_iterative_target_adj eq 13) - vm_emiMacSector(t,regi,"co2luc")$(cm_multigasscen ne 3))
                            - pm_taxrevGHG0(t,regi);
 
+***---------------------------------------------------------------------------
+*'  Calculation of CDR revenues: tax rate (defined as fraction of carbon price) times net-negative emissions
+*'  Documentation of overall tax approach is above at q21_taxrev.
+***---------------------------------------------------------------------------
+q21_taxrevCDR(t,regi)..
+v21_taxrevCDR(t,regi) =e= pm_taxCDR(t,regi) * vm_emiCdrAll(t,regi)
+                                 - p21_taxrevCDR0(t,regi);
+
 
 ***---------------------------------------------------------------------------
 *' Calculation of sectoral CO2 taxes as markup to GHG taxes (combination of 4 components)
diff --git a/modules/21_tax/on/postsolve.gms b/modules/21_tax/on/postsolve.gms
index 3a5015b376..35d9975a1f 100644
--- a/modules/21_tax/on/postsolve.gms
+++ b/modules/21_tax/on/postsolve.gms
@@ -60,7 +60,9 @@ p21_taxrevChProdStartYear0(t,regi) = sum(en2en(enty,enty2,te), vm_changeProdStar
 p21_taxrevSE0(t,regi) =     sum(se2se(enty,enty2,te)$(teSeTax(te)), 
                                     v21_tau_SE_tax.l(t,regi,te) 
                                   * vm_demSe.l(t,regi,enty,enty2,te));
-    
+
+p21_taxrevCDR0(ttot,regi) = pm_taxCDR(ttot,regi) * vm_emiCdrAll.l(ttot,regi);
+
 
 *** Save reference level of tax revenues for each iteration
 p21_taxrevGHG_iter(iteration+1,ttot,regi) = v21_taxrevGHG.l(ttot,regi);
@@ -80,6 +82,7 @@ p21_taxrevFlex_iter(iteration+1,ttot,regi) = v21_taxrevFlex.l(ttot,regi);
 p21_taxrevImport_iter(iteration+1,ttot,regi,tradePe) = v21_taxrevImport.l(ttot,regi,tradePe);
 p21_taxrevChProdStartYear_iter(iteration+1,t,regi) = v21_taxrevChProdStartYear.l(t,regi);
 p21_taxrevSE_iter(iteration+1,t,regi) = v21_taxrevSE.l(t,regi);
+p21_taxrevCDR_iter(iteration+1, ttot, regi) = v21_taxrevCDR.l(ttot,regi);
 
 display p21_taxrevFE_iter;
 
diff --git a/modules/21_tax/on/preloop.gms b/modules/21_tax/on/preloop.gms
index 62b81c0014..77855e9634 100644
--- a/modules/21_tax/on/preloop.gms
+++ b/modules/21_tax/on/preloop.gms
@@ -180,4 +180,7 @@ v21_taxrevChProdStartYear.l(t,regi) = 0;
 *** initialize SE tax rate
 v21_tau_SE_tax.l(t,regi,te)=0;
 
+*AM initialize CDR tax
+v21_taxrevCDR.l(ttot,regi) = 0;
+
 *** EOF ./modules/21_tax/on/preloop.gms
diff --git a/modules/21_tax/on/presolve.gms b/modules/21_tax/on/presolve.gms
index 37b204f931..b0fcf858ed 100644
--- a/modules/21_tax/on/presolve.gms
+++ b/modules/21_tax/on/presolve.gms
@@ -56,5 +56,6 @@ p21_taxrevChProdStartYear0(t,regi) = sum(en2en(enty,enty2,te), vm_changeProdStar
 p21_taxrevSE0(t,regi) =     sum(se2se(enty,enty2,te)$(teSeTax(te)), 
                                     v21_tau_SE_tax.l(t,regi,te) 
                                   * vm_demSe.l(t,regi,enty,enty2,te));
+p21_taxrevCDR0(ttot,regi) = pm_taxCDR(ttot,regi) * vm_emiCdrAll.l(ttot,regi);
 
 *** EOF ./modules/21_tax/on/presolve.gms
diff --git a/modules/37_industry/subsectors/equations.gms b/modules/37_industry/subsectors/equations.gms
index beb633006b..2f61b2dc7d 100644
--- a/modules/37_industry/subsectors/equations.gms
+++ b/modules/37_industry/subsectors/equations.gms
@@ -160,7 +160,21 @@ q37_limit_IndCCS_growth(ttot,regi,emiInd37)$( ttot.val ge cm_startyear ) ..
     * pm_ts(ttot)
     )
 ;
-
+***------------------------------------------------------
+*' Calculate industry CDR (i.e. Industry CCS from carbon neutral fuels, primarily bio-based)
+***------------------------------------------------------
+q37_IndCDR(ttot,regi)$(ttot.val ge cm_startyear)..
+  vm_IndCDR(ttot,regi) 
+  =e=
+      sum(emiMac2mac(emiInd37,macInd37),
+        sum(entyFe,
+          sum((secInd37_2_emiINd37(secInd37,emiInd37)),
+            vm_macBaseInd(ttot,regi,entyFE,secInd37))$(NOT SAMEAS (emiInd37,"co2cement_process"))            
+            * vm_IndstShareco2neutrcarbs(ttot,regi,entyFE)
+      )
+    * pm_macSwitch(macInd37)              !! sub-sector CCS available or not
+    * pm_macAbatLev(ttot,regi,macInd37)   !! abatement level at current price
+  ) * vm_FracCCS(ttot,regi);
 ***------------------------------------------------------
 *' Fix cement fuel and cement process emissions to the same abatement level.
 ***------------------------------------------------------
diff --git a/modules/45_carbonprice/SeparateMarketsExpo2Const/datainput.gms b/modules/45_carbonprice/SeparateMarketsExpo2Const/datainput.gms
new file mode 100644
index 0000000000..032f3d7c3c
--- /dev/null
+++ b/modules/45_carbonprice/SeparateMarketsExpo2Const/datainput.gms
@@ -0,0 +1,32 @@
+*** |  (C) 2006-2022 Potsdam Institute for Climate Impact Research (PIK)
+*** |  authors, and contributors see CITATION.cff file. This file is part
+*** |  of REMIND and licensed under AGPL-3.0-or-later. Under Section 7 of
+*** |  AGPL-3.0, you are granted additional permissions described in the
+*** |  REMIND License Exception, version 1.0 (see LICENSE file).
+*** |  Contact: remind@pik-potsdam.de
+*** SOF ./modules/45_carbonprice/SeparateMarketsExpo2Const/datainput.gms
+***----------------------------
+*** CO2 Tax level
+***----------------------------
+
+*** CO2 tax level is calculated at an initial 5% exponential increase from the 2020 tax level exogenously defined
+
+*GL: tax path in 10^12$/GtC = 1000 $/tC
+*** according to Asian Modeling Excercise tax case setup, 30$/t CO2eq in 2020 = 0.110 k$/tC
+
+if(cm_co2_tax_2020 lt 0,
+abort "please choose a valid cm_co2_tax_2020"
+elseif cm_co2_tax_2020 ge 0,
+*** convert tax value from $/t CO2eq to T$/GtC
+pm_taxCO2eq("2025",regi)= cm_co2_tax_2020 * sm_DptCO2_2_TDpGtC;
+);
+
+pm_taxCO2eq(ttot,regi)$(ttot.val ge 2025 AND ttot.val le c_peakBudgYr) = pm_taxCO2eq("2025",regi)*cm_co2_tax_growth**(ttot.val-2025);
+pm_taxCO2eq(ttot,regi)$(ttot.val gt c_peakBudgYr) =sum(t$(t.val eq c_peakBudgYr),pm_taxCO2eq(t,regi)); !! keep taxes constant after cm_peakBudgYr
+
+pm_taxCDR(ttot,regi) = pm_taxCO2eq(ttot,regi)
+
+
+display pm_taxCDR, pm_taxCO2eq;
+
+*** EOF ./modules/45_carbonprice/SeparateMarketsExpo2Const/datainput.gms
diff --git a/modules/45_carbonprice/SeparateMarketsExpo2Const/not_used.txt b/modules/45_carbonprice/SeparateMarketsExpo2Const/not_used.txt
new file mode 100644
index 0000000000..88edac1a4c
--- /dev/null
+++ b/modules/45_carbonprice/SeparateMarketsExpo2Const/not_used.txt
@@ -0,0 +1,29 @@
+# |  (C) 2006-2022 Potsdam Institute for Climate Impact Research (PIK)
+# |  authors, and contributors see CITATION.cff file. This file is part
+# |  of REMIND and licensed under AGPL-3.0-or-later. Under Section 7 of
+# |  AGPL-3.0, you are granted additional permissions described in the
+# |  REMIND License Exception, version 1.0 (see LICENSE file).
+# |  Contact: remind@pik-potsdam.de
+name,type,reason
+sm_c_2_co2,input,questionnaire
+vm_co2eq,input,questionnaire
+vm_emiFgas,input,questionnaire
+pm_pvp,input,questionnaire
+pm_globalMeanTemperature,input,questionnaire
+pm_temperatureImpulseResponseCO2,input,questionnaire
+pm_GDPGross,input,questionnaire
+pm_ttot_val,input,questionnaire
+pm_ts,input,questionnaire
+pm_ttot_2_tall,input,questionnaire
+cm_emiscen,input,questionnaire
+cm_iterative_target_adj,input,questionnaire
+cm_expoLinear_yearStart,input,questionnaire
+cm_carbonprice_temperatureLimit,input,questionnaire
+cm_taxCO2inc_after_peakBudgYr,input,questionnaire
+cm_NDC_version,input,questionnaire
+cm_NDC_divergentScenario,input,questionnaire
+vm_cesIO,input,questionnaire
+pm_consPC,input,questionnaire
+pm_prtp,input,questionnaire
+vm_demFeSector,input,questionnaire
+pm_emifac,input,questionnaire
diff --git a/modules/45_carbonprice/SeparateMarketsExpo2Const/realization.gms b/modules/45_carbonprice/SeparateMarketsExpo2Const/realization.gms
new file mode 100644
index 0000000000..1c38f3e18b
--- /dev/null
+++ b/modules/45_carbonprice/SeparateMarketsExpo2Const/realization.gms
@@ -0,0 +1,13 @@
+*** |  (C) 2006-2022 Potsdam Institute for Climate Impact Research (PIK)
+*** |  authors, and contributors see CITATION.cff file. This file is part
+*** |  of REMIND and licensed under AGPL-3.0-or-later. Under Section 7 of
+*** |  AGPL-3.0, you are granted additional permissions described in the
+*** |  REMIND License Exception, version 1.0 (see LICENSE file).
+*** |  Contact: remind@pik-potsdam.de
+*** SOF ./modules/45_carbonprice/SeparateMarketsExpo2Const/realization.gms
+
+*####################### R SECTION START (PHASES) ##############################
+$Ifi "%phase%" == "datainput" $include "./modules/45_carbonprice/SeparateMarketsExpo2Const/datainput.gms"
+*######################## R SECTION END (PHASES) ###############################
+
+*** EOF ./modules/45_carbonprice/SeparateMarketsExpo2Const/realization.gms
diff --git a/modules/45_carbonprice/module.gms b/modules/45_carbonprice/module.gms
index 7642cceba0..ae95f0e5ed 100644
--- a/modules/45_carbonprice/module.gms
+++ b/modules/45_carbonprice/module.gms
@@ -30,5 +30,6 @@ $Ifi "%carbonprice%" == "exponential" $include "./modules/45_carbonprice/exponen
 $Ifi "%carbonprice%" == "linear" $include "./modules/45_carbonprice/linear/realization.gms"
 $Ifi "%carbonprice%" == "none" $include "./modules/45_carbonprice/none/realization.gms"
 $Ifi "%carbonprice%" == "temperatureNotToExceed" $include "./modules/45_carbonprice/temperatureNotToExceed/realization.gms"
+$Ifi "%carbonprice%" == "SeparateMarketsExpo2Const" $include "./modules/45_carbonprice/SeparateMarketsExpo2Const/realization.gms"
 *###################### R SECTION END (MODULETYPES) ############################
 *** EOF ./modules/45_carbonprice/module.gms

From e3641504fa1fbf02a3be673cbe86eba890ded45d Mon Sep 17 00:00:00 2001
From: amerfort <amerfort@pik-potsdam.de>
Date: Fri, 26 Apr 2024 19:20:01 +0200
Subject: [PATCH 2/7] add more code for separate markets and bug fixes

---
 core/datainput.gms                               | 12 ++++++++++++
 core/equations.gms                               |  3 +--
 core/postsolve.gms                               |  2 +-
 main.gms                                         | 16 +++++++++++++++-
 modules/37_industry/subsectors/declarations.gms  |  1 +
 modules/37_industry/subsectors/equations.gms     |  2 +-
 modules/45_carbonprice/NPi/datainput.gms         |  2 ++
 .../diffCurvPhaseIn2Lin/datainput.gms            |  2 ++
 modules/45_carbonprice/module.gms                |  2 +-
 modules/45_carbonprice/none/datainput.gms        |  2 ++
 scripts/input/exoGAINSAirpollutants.R            |  2 +-
 scripts/input/prepare_NDC.R                      |  4 ++--
 scripts/output/single/reporting.R                |  2 +-
 scripts/start/prepare.R                          |  2 +-
 14 files changed, 43 insertions(+), 11 deletions(-)

diff --git a/core/datainput.gms b/core/datainput.gms
index db8d3e334c..9af95d5d50 100644
--- a/core/datainput.gms
+++ b/core/datainput.gms
@@ -1450,6 +1450,18 @@ pm_emifac(ttot,regi,"seliqfos","fepet","tdfospet","co2") = p_ef_dem(regi,"fepet"
 pm_emifac(ttot,regi,"seliqfos","fedie","tdfosdie","co2") = p_ef_dem(regi,"fedie") / (sm_c_2_co2*1000*sm_EJ_2_TWa); !! GtC/TWa
 pm_emifac(ttot,regi,"segafos","fegat","tdfosgat","co2") = p_ef_dem(regi,"fegas") / (sm_c_2_co2*1000*sm_EJ_2_TWa); !! GtC/TWa
 
+pm_emifac_tailpipe(t,regi,"seliqfos","fehos") = p_ef_dem(regi,"fehos") / (sm_c_2_co2*1000*sm_EJ_2_TWa); !! GtC/TWa
+pm_emifac_tailpipe(t,regi,"seliqbio","fehos") = p_ef_dem(regi,"fehos") / (sm_c_2_co2*1000*sm_EJ_2_TWa); !! GtC/TWa
+pm_emifac_tailpipe(t,regi,"seliqsyn","fehos") = p_ef_dem(regi,"fehos") / (sm_c_2_co2*1000*sm_EJ_2_TWa); !! GtC/TWa
+
+pm_emifac_tailpipe(t,regi,"segafos","fegas") = p_ef_dem(regi,"fegas") / (sm_c_2_co2*1000*sm_EJ_2_TWa); !! GtC/TWa
+pm_emifac_tailpipe(t,regi,"segabio","fegas") = p_ef_dem(regi,"fegas") / (sm_c_2_co2*1000*sm_EJ_2_TWa); !! GtC/TWa
+pm_emifac_tailpipe(t,regi,"segasyn","fegas") = p_ef_dem(regi,"fegas") / (sm_c_2_co2*1000*sm_EJ_2_TWa); !! GtC/TWa
+
+pm_emifac_tailpipe(t,regi,"sesofos","fesos") = p_ef_dem(regi,"fesos") / (sm_c_2_co2*1000*sm_EJ_2_TWa); !! GtC/TWa
+pm_emifac_tailpipe(t,regi,"sesobio","fesos") = p_ef_dem(regi,"fesos") / (sm_c_2_co2*1000*sm_EJ_2_TWa); !! GtC/TWa
+
+
 ***------ Read in emission factors for process emissions in chemicals sector---
 *** calculated using IEA data on feedstocks flows and UNFCCC data on chem sector process emissions
 *** these emission factors are for the chemical industry only
diff --git a/core/equations.gms b/core/equations.gms
index 1217326343..97170a4e84 100644
--- a/core/equations.gms
+++ b/core/equations.gms
@@ -826,8 +826,7 @@ q_emiCdrAll(t,regi)..
   + (1 - s33_OAE_chem_decomposition) * vm_emiCdrTeDetail(t, regi, "oae")
   !! CDR from enhanced weathering
   + vm_emiCdrTeDetail(t, regi, "weathering")
-  !! Biochar
-  + !! negative emissions from biochar
+  !! negative emissions from biochar
   -   sum(emiBiochar2te(enty,enty2,te,enty3), vm_emiTeDetail(t,regi,enty,enty2,te,enty3))
   !! Industry CDR (CCS from carbon neutral fuels)
   + vm_IndCDR(t,regi)
diff --git a/core/postsolve.gms b/core/postsolve.gms
index 3c795645ad..42e1309611 100644
--- a/core/postsolve.gms
+++ b/core/postsolve.gms
@@ -528,7 +528,7 @@ display s_actualbudgetco2;
       );	
     !! Target at net-zero CDR (in target year c_peakBudgYr)
     if(o_modelstat eq 2 AND ord(iteration)<cm_iteration_max AND abs(c_target2050cdr - s_actual2050cdr) ge 0.3,   !!only for optimal iterations, and not after the last one, and only if target not yet reached
-      p_taxcdr_iterationdiff(t,regi)$(t.val le c_peakBudgYr) = pm_taxCDR(t,regi)$(t.val le c_peakBudgYr) * min(max((c_target2050cdr/s_actual2050cdr)** (10/(2 * iteration.val + 23)),0.5+iteration.val/208),2 - iteration.val/102)  - pm_taxCDR(t,regi)$(t.val le cm_peakBudgYr);
+      p_taxcdr_iterationdiff(t,regi)$(t.val le c_peakBudgYr) = pm_taxCDR(t,regi)$(t.val le c_peakBudgYr) * min(max((c_target2050cdr/s_actual2050cdr)** (10/(2 * iteration.val + 23)),0.5+iteration.val/208),2 - iteration.val/102)  - pm_taxCDR(t,regi)$(t.val le c_peakBudgYr);
       pm_taxCDR(t,regi)$(t.val le c_peakBudgYr) = pm_taxCDR(t,regi)$(t.val le c_peakBudgYr) + p_taxcdr_iterationdiff(t,regi)$(t.val le c_peakBudgYr) ;
       o_taxCDR_iterDiff_Itr(iteration,regi) = p_taxcdr_iterationdiff("2030",regi);
       display o_taxCDR_iterDiff_Itr;
diff --git a/main.gms b/main.gms
index ddbc273b32..9d019fb463 100755
--- a/main.gms
+++ b/main.gms
@@ -866,7 +866,7 @@ parameter
 parameter
   cm_iterative_target_adj   "settings on iterative adjustment for CO2 tax based on in-iteration emission or forcing level. Allow iteratively generated endogenous global CO2 tax under peak budget constraint."
 ;
-  cm_iterative_target_adj = 0;      !! def = 0  !! regexp = 0|2|3|4|5|6|7|9
+  cm_iterative_target_adj = 0;      !! def = 0  !! regexp = 0|2|3|4|5|6|7|9|13
 *' * (0): no iterative adjustment of CO2 tax (terminology: CO2 price and CO2 tax in REMIND is used interchangeably)
 *' * (2): iterative adjustment of CO2 tax or cumulative emission based on climate forcing calculated by climate model magicc, for runs with budget or CO2 tax constraints. See ./modules/45_carbonprice/NDC/postsolve.gms for direct algorithm
 *' * (3): [requires 45_carbonprice = NDC and emiscen = 9] iterative adjustment of CO2 tax based on 2025 or 2030 regionally differentiated emissions, for runs with emission budget or CO2 tax constraints. See ./modules/45_carbonprice/NDC/postsolve.gms for direct algorithm
@@ -1034,6 +1034,20 @@ parameter
 *' * (0.5) Halves the effective CO2 price when regional net CO2 emissions turn negative.
 *' * (1)   No effective CO2 tax once regional emissions turn net-negative. Hence regions never become net-negative.
 
+
+parameter
+  c_target2050co2     "global co2 emission year target in 2050"
+;
+  c_target2050co2      = -1; !! def =-1
+*' -1 indicates no target, otherwise number indicates global gross emission target for 2050 in GtCO2 per y
+
+
+parameter
+  c_target2050cdr     "global cdr emission year target in 2050"
+;
+  c_target2050cdr      = -1; !! def =-1
+*' -1 indicates no target, otherwise number indicates global cdr emission target for 2050 in GtCO2 per y
+
 parameter
   cm_DiscRateScen          "Scenario for the implicit discount rate applied to the energy efficiency capital"
 ;
diff --git a/modules/37_industry/subsectors/declarations.gms b/modules/37_industry/subsectors/declarations.gms
index 1592ee2132..090c83598b 100644
--- a/modules/37_industry/subsectors/declarations.gms
+++ b/modules/37_industry/subsectors/declarations.gms
@@ -112,6 +112,7 @@ $endif.no_calibration
   q37_nonIncineratedPlastics(ttot,all_regi,all_enty,all_enty,all_emiMkt)            "calculate carbon contained in plastics that are not incinerated [GtC]"
   q37_feedstockEmiUnknownFate(ttot,all_regi,all_enty,all_enty,all_emiMkt)           "calculate carbon contained in chemical feedstock with unknown fate [GtC]"
   q37_feedstocksLimit(ttot,all_regi,all_enty,all_enty,all_in,all_emiMkt)            "restrict feedstocks flow to total energy flows into industry"
+  q37_IndCDR(ttot,all_regi)                                                         "Industry CDR"
 
   !! process-based implementation
   q37_demMatPrc(tall,all_regi,mat)                                                  "Material demand of processes"
diff --git a/modules/37_industry/subsectors/equations.gms b/modules/37_industry/subsectors/equations.gms
index 2f61b2dc7d..24bc84a902 100644
--- a/modules/37_industry/subsectors/equations.gms
+++ b/modules/37_industry/subsectors/equations.gms
@@ -169,7 +169,7 @@ q37_IndCDR(ttot,regi)$(ttot.val ge cm_startyear)..
       sum(emiMac2mac(emiInd37,macInd37),
         sum(entyFe,
           sum((secInd37_2_emiINd37(secInd37,emiInd37)),
-            vm_macBaseInd(ttot,regi,entyFE,secInd37))$(NOT SAMEAS (emiInd37,"co2cement_process"))            
+                vm_emiIndBase(ttot,regi,entyFE,secInd37))$(NOT SAMEAS (emiInd37,"co2cement_process"))            
             * vm_IndstShareco2neutrcarbs(ttot,regi,entyFE)
       )
     * pm_macSwitch(macInd37)              !! sub-sector CCS available or not
diff --git a/modules/45_carbonprice/NPi/datainput.gms b/modules/45_carbonprice/NPi/datainput.gms
index fababf7641..c85dbb714f 100644
--- a/modules/45_carbonprice/NPi/datainput.gms
+++ b/modules/45_carbonprice/NPi/datainput.gms
@@ -20,6 +20,8 @@ pm_taxCO2eq(ttot,regi)$( (ttot.val ge 2025) AND (ttot.val le 2100)) =
 ;
 pm_taxCO2eq(ttot,regi)$(ttot.val gt 2100) = pm_taxCO2eq("2100",regi);
 
+pm_taxCDR(ttot,regi) = 0;
+
 display pm_taxCO2eq;
 
 *** EOF ./modules/45_carbonprice/NPi/datainput.gms
diff --git a/modules/45_carbonprice/diffCurvPhaseIn2Lin/datainput.gms b/modules/45_carbonprice/diffCurvPhaseIn2Lin/datainput.gms
index f7f2f48bdf..b27ebd6d62 100644
--- a/modules/45_carbonprice/diffCurvPhaseIn2Lin/datainput.gms
+++ b/modules/45_carbonprice/diffCurvPhaseIn2Lin/datainput.gms
@@ -61,6 +61,8 @@ p45_regCO2priceFactor(ttot,regi)$(ttot.val ge cm_CO2priceRegConvEndYr) = 1;
 *** transition to global price - starting point depends on GDP/cap
 pm_taxCO2eq(t,regi) = p45_regCO2priceFactor(t,regi) * p45_CO2priceTrajDeveloped(t);
 
+pm_taxCDR(ttot,regi) = 0;
+
 
 display p45_regCO2priceFactor, p45_CO2priceTrajDeveloped, pm_taxCO2eq;
 
diff --git a/modules/45_carbonprice/module.gms b/modules/45_carbonprice/module.gms
index ae95f0e5ed..31672fab9e 100644
--- a/modules/45_carbonprice/module.gms
+++ b/modules/45_carbonprice/module.gms
@@ -23,6 +23,7 @@
 *###################### R SECTION START (MODULETYPES) ##########################
 $Ifi "%carbonprice%" == "NDC" $include "./modules/45_carbonprice/NDC/realization.gms"
 $Ifi "%carbonprice%" == "NPi" $include "./modules/45_carbonprice/NPi/realization.gms"
+$Ifi "%carbonprice%" == "SeparateMarketsExpo2Const" $include "./modules/45_carbonprice/SeparateMarketsExpo2Const/realization.gms"
 $Ifi "%carbonprice%" == "diffCurvPhaseIn2Lin" $include "./modules/45_carbonprice/diffCurvPhaseIn2Lin/realization.gms"
 $Ifi "%carbonprice%" == "exogenous" $include "./modules/45_carbonprice/exogenous/realization.gms"
 $Ifi "%carbonprice%" == "expoLinear" $include "./modules/45_carbonprice/expoLinear/realization.gms"
@@ -30,6 +31,5 @@ $Ifi "%carbonprice%" == "exponential" $include "./modules/45_carbonprice/exponen
 $Ifi "%carbonprice%" == "linear" $include "./modules/45_carbonprice/linear/realization.gms"
 $Ifi "%carbonprice%" == "none" $include "./modules/45_carbonprice/none/realization.gms"
 $Ifi "%carbonprice%" == "temperatureNotToExceed" $include "./modules/45_carbonprice/temperatureNotToExceed/realization.gms"
-$Ifi "%carbonprice%" == "SeparateMarketsExpo2Const" $include "./modules/45_carbonprice/SeparateMarketsExpo2Const/realization.gms"
 *###################### R SECTION END (MODULETYPES) ############################
 *** EOF ./modules/45_carbonprice/module.gms
diff --git a/modules/45_carbonprice/none/datainput.gms b/modules/45_carbonprice/none/datainput.gms
index 7e41e15f79..78b7f6e46d 100644
--- a/modules/45_carbonprice/none/datainput.gms
+++ b/modules/45_carbonprice/none/datainput.gms
@@ -11,5 +11,7 @@
 
 *** CO2 tax level is set to zero
 pm_taxCO2eq(ttot,regi)$(ttot.val ge 2005) = 0;
+pm_taxCDR(ttot,regi) = 0;
+
 
 *** EOF ./modules/45_carbonprice/none/datainput.gms
diff --git a/scripts/input/exoGAINSAirpollutants.R b/scripts/input/exoGAINSAirpollutants.R
index c89e9fa7ff..b03372a134 100644
--- a/scripts/input/exoGAINSAirpollutants.R
+++ b/scripts/input/exoGAINSAirpollutants.R
@@ -22,7 +22,7 @@ for (pkg in c('madrat', 'dplyr', 'luscale', 'gdx')) {
   suppressPackageStartupMessages(require(pkg, character.only = TRUE))
 }
 
-devtools::load_all("/p/tmp/katarkow/remind2/rebased-cdr-portfolio-oae")
+devtools::load_all("/p/tmp/tabeado/SynTra_lowRisk/remind2")
 
 # stop madrat reporting its default settings _every damn time_
 invisible(getConfig(option = NULL, verbose = firstIteration))
diff --git a/scripts/input/prepare_NDC.R b/scripts/input/prepare_NDC.R
index e76a999c36..f36e70a7e0 100644
--- a/scripts/input/prepare_NDC.R
+++ b/scripts/input/prepare_NDC.R
@@ -11,8 +11,8 @@ prepare_NDC<-function(gdx, cfg){
   library(luplot,quietly=TRUE,warn.conflicts =FALSE)
   library(lucode2,quietly=TRUE,warn.conflicts =FALSE)
   library(gdx,quietly=TRUE,warn.conflicts =FALSE)
-  devtools::load_all("/p/tmp/katarkow/remind2/rebased-cdr-portfolio-oae")
-
+  devtools::load_all("/p/tmp/tabeado/SynTra_lowRisk/remind2")
+  
   ############################# BASIC CONFIGURATION #############################
 
   #Define arguments that can be read from command line
diff --git a/scripts/output/single/reporting.R b/scripts/output/single/reporting.R
index e0ea42bbfb..2551c11260 100644
--- a/scripts/output/single/reporting.R
+++ b/scripts/output/single/reporting.R
@@ -7,7 +7,7 @@
 
 library(magclass)
 # library(remind2)
-devtools::load_all("/p/tmp/katarkow/remind2/rebased-cdr-portfolio-oae")
+devtools::load_all("/p/tmp/tabeado/SynTra_lowRisk/remind2")
 library(lucode2)
 library(gms)
 library(methods)
diff --git a/scripts/start/prepare.R b/scripts/start/prepare.R
index fc7e531678..e9e9ef548a 100644
--- a/scripts/start/prepare.R
+++ b/scripts/start/prepare.R
@@ -13,7 +13,7 @@ prepare <- function() {
   #require(lucode, quietly = TRUE,warn.conflicts =FALSE)
   require(magclass, quietly = TRUE,warn.conflicts =FALSE)
   require(tools, quietly = TRUE,warn.conflicts =FALSE)
-  devtools::load_all("/p/tmp/katarkow/remind2/rebased-cdr-portfolio-oae")
+  devtools::load_all("/p/tmp/tabeado/SynTra_lowRisk/remind2")
   # require(remind2)
   require(mrremind)
   require(mrvalidation)

From aa063852d1c23e562a3c9e01194ef4b3e7b23ec2 Mon Sep 17 00:00:00 2001
From: amerfort <amerfort@pik-potsdam.de>
Date: Tue, 30 Apr 2024 14:18:27 +0200
Subject: [PATCH 3/7] Add separate EUR specific GHG neutrality targets for 2050
 and differentiated separate C-prices

---
 core/datainput.gms                            | 29 ++++++++
 core/declarations.gms                         |  4 +-
 core/postsolve.gms                            | 39 ++++++++++-
 main.gms                                      |  8 +++
 modules/21_tax/on/postsolve.gms               |  2 +-
 modules/21_tax/on/presolve.gms                |  2 +-
 .../SepMarkdiffCurv2const/datainput.gms       | 69 +++++++++++++++++++
 .../SepMarkdiffCurv2const/declarations.gms    | 22 ++++++
 .../SepMarkdiffCurv2const/not_used.txt        | 25 +++++++
 .../SepMarkdiffCurv2const/postsolve.gms       | 41 +++++++++++
 .../SepMarkdiffCurv2const/realization.gms     | 15 ++++
 .../SeparateMarketsExpo2Const/datainput.gms   |  2 +-
 modules/45_carbonprice/module.gms             |  1 +
 .../47_regipol/regiCarbonPrice/datainput.gms  | 22 ------
 .../regiCarbonPrice/declarations.gms          |  2 +-
 .../47_regipol/regiCarbonPrice/postsolve.gms  | 12 ++--
 16 files changed, 261 insertions(+), 34 deletions(-)
 create mode 100644 modules/45_carbonprice/SepMarkdiffCurv2const/datainput.gms
 create mode 100644 modules/45_carbonprice/SepMarkdiffCurv2const/declarations.gms
 create mode 100644 modules/45_carbonprice/SepMarkdiffCurv2const/not_used.txt
 create mode 100644 modules/45_carbonprice/SepMarkdiffCurv2const/postsolve.gms
 create mode 100644 modules/45_carbonprice/SepMarkdiffCurv2const/realization.gms

diff --git a/core/datainput.gms b/core/datainput.gms
index 9af95d5d50..8c57af9806 100644
--- a/core/datainput.gms
+++ b/core/datainput.gms
@@ -6,6 +6,8 @@
 *** |  Contact: remind@pik-potsdam.de
 *** SOF ./core/datainput.gms
 
+
+
 *AJS* technical. initialize parameters so that they are read from gdx
 vm_co2eq.l(ttot,regi) = 0;
 vm_emiAll.l(ttot,regi,enty) = 0;
@@ -1604,5 +1606,32 @@ p_prodAllReference(t,regi,te) =
 *' initialize vm_changeProdStartyearCost for tax calculation
 vm_changeProdStartyearCost.l(t,regi,te) = 0;
 
+
+
+*** p_EmiLULUCFCountryAcc contains historic LULUCF emissions from UNFCCC, 
+*** used for rescaling land-use change emissions for emissions targets based on national accounting
+parameter pm_EmiLULUCFCountryAcc(tall,all_regi)                "historic co2 emissions from landuse change based on country accounting [Mt CO2/yr]"
+/
+$ondelim
+$include "./modules/47_regipol/regiCarbonPrice/input/p_EmiLULUCFCountryAcc.cs4r"
+$offdelim
+/
+;
+
+*** difference between 2020 land-use change emissions from Magpie and UNFCCC 2015 and 2020 moving average land-use change emissions
+pm_LULUCFEmi_GrassiShift(t,regi)$(pm_EmiLULUCFCountryAcc("2020",regi)) = 
+  pm_macBaseMagpie("2020",regi,"co2luc") 
+  - 
+  (
+    (
+      ((pm_EmiLULUCFCountryAcc("2013",regi) + pm_EmiLULUCFCountryAcc("2014",regi) + pm_EmiLULUCFCountryAcc("2015",regi) + pm_EmiLULUCFCountryAcc("2016",regi) + pm_EmiLULUCFCountryAcc("2017",regi))/5)
+      +
+      ((pm_EmiLULUCFCountryAcc("2018",regi) + pm_EmiLULUCFCountryAcc("2019",regi) + pm_EmiLULUCFCountryAcc("2020",regi) + pm_EmiLULUCFCountryAcc("2021",regi))/4)
+    )/2
+    * 1e-3/sm_c_2_co2
+  )
+;
+
+
 *** EOF ./core/datainput.gms
 
diff --git a/core/declarations.gms b/core/declarations.gms
index 646ba96b7a..d7c8e43824 100644
--- a/core/declarations.gms
+++ b/core/declarations.gms
@@ -101,6 +101,7 @@ p_adj_coeff(ttot,all_regi,all_te)                    "coefficient for adjustment
 p_adj_coeff_glob(all_te)                             "coefficient for adjustment costs - global scale"
 p_switch_cement(ttot,all_regi)                       "describes an s-curve to provide a smooth switching from the short-term behavior (depending on per capita capital investments) to the long-term behavior (constant per capita emissions) of CO2 emissions from cement production"
 p_cint(all_regi,all_enty,all_enty,rlf)               "additional emissions of GHG from mining, on top of emissions from combustion"
+pm_LULUCFEmi_GrassiShift(ttot,all_regi)              "difference between Magpie land-use change emissions and UNFCCC emissions in 2015 to correct for national accounting in emissions targets"
 
 $IFTHEN.agricult_base_shift not "%c_agricult_base_shift%" == "off"
 p_agricult_base_shift(ext_regi)                      "fraction by which to scale agricultural emissions of baseline up or down, positive values increase emissions, negative values decrease emissions" / %c_agricult_base_shift% /
@@ -640,7 +641,8 @@ s_actualbudgetco2_last                                "actual level of 2020-2100
 
 s_actual2050co2                                       "current iterations actual global co2 emissions in 2050 needed to adjust co2 tax until 2050"
 s_actual2050cdr                                       "current iterations actual global cdr amount in 2050 needed to adjust cdr revenues until 2050"
-
+s_actual2050ghgEUR                                    "current iterations actual EUR ghg emissions including land-use cdr in 2050 needed to adjust co2 tax until 2050"
+s_actual2050cdrEUR                                    "current iterations actual EUR novel cdr amount in 2050 needed to adjust cdr revenues until 2050"
 
 sm_globalBudget_dev                                   "actual level of global cumulated emissions budget divided by target budget"
 
diff --git a/core/postsolve.gms b/core/postsolve.gms
index 42e1309611..eecead20c5 100644
--- a/core/postsolve.gms
+++ b/core/postsolve.gms
@@ -542,6 +542,44 @@ display s_actualbudgetco2;
     if((c_target2050co2 eq 0 AND c_target2050cdr gt 0),
       pm_taxCO2eq(t,regi) = 0;
     );
+***-----------------------------------------------
+*AM* Additional targets for EUR
+***-----------------------------------------------
+    if(c_target2050cdrEUR > 0,
+    s_actual2050ghgEUR = sum(ttot$(ttot.val eq c_peakBudgYr),sum(regi$sameas(regi,"EUR"),
+        !! Gross CO2 emissions excluding novel CDR in GtCO2 but including land use and managed forests (with Grassi shift)
+        ((vm_emiAll.l(ttot,regi,"co2") + vm_emiCdrAll.l(ttot,regi) - pm_LULUCFEmi_GrassiShift(ttot,regi)) * sm_c_2_co2
+        !! CH4 emissions in GtCO2eq with GWP100
+        +vm_emiAll.l(ttot,regi,"ch4") * s_gwpCH4
+        !! N"O emissions in GtCO2eq with GWP100
+        +vm_emiAll.l(ttot,regi,"n2o") * s_gwpN2O
+        )));
+    s_actual2050cdrEUR = sum(ttot$(ttot.val eq c_peakBudgYr),sum(regi$(sameas(regi,"EUR")), vm_emiCdrAll.l(ttot,regi))) *sm_c_2_co2;  !! CDR     
+    !! Target 2050 GHG in Europe
+    display s_actual2050ghgEUR, s_actual2050cdrEUR;
+    if(o_modelstat eq 2 AND ord(iteration)<cm_iteration_max AND abs(c_target2050cdrEUR - s_actual2050ghgEUR) ge 0.05 ,   !!only for optimal iterations, and not after the last one, and only if target not yet reached
+      pm_taxCO2eq_iterationdiff(t,regi)$(t.val le c_peakBudgYr AND sameas(regi,"EUR")) = pm_taxCO2eq(t,regi)$(t.val le c_peakBudgYr AND sameas(regi,"EUR")) * min(max((s_actual2050ghgEUR/(c_target2050cdrEUR))** (10/(2 * iteration.val + 23)),0.5+iteration.val/208),2 - iteration.val/102)  - pm_taxCO2eq(t,regi)$(t.val le c_peakBudgYr AND sameas(regi,"EUR"));
+      pm_taxCO2eq(t,regi)$(t.val le c_peakBudgYr AND sameas(regi,"EUR")) = pm_taxCO2eq(t,regi)$(t.val le c_peakBudgYr AND sameas(regi,"EUR")) + pm_taxCO2eq_iterationdiff(t,regi)$(t.val le c_peakBudgYr AND sameas(regi,"EUR")) ;
+      !!o_taxCO2eq_iterDiff_Itr(iteration,regi) = pm_taxCO2eq_iterationdiff("2030",regi);
+      !!display o_taxCO2eq_iterDiff_Itr;
+      !!else
+        !!!! if model was not optimal, or if target already reached, keep tax constant
+        !!pm_taxCO2eq(t,regi)$(t.val le c_peakBudgYr) = pm_taxCO2eq(t,regi)$(t.val le c_peakBudgYr);
+        !!if((c_target2050co2 eq 0 AND c_target2050cdr gt 0),
+          !!pm_taxCO2eq(t,regi) = 0;
+        !!);
+      );	
+    !! Target at net-zero CDR (in target year c_peakBudgYr)
+    if(o_modelstat eq 2 AND ord(iteration)<cm_iteration_max AND abs(c_target2050cdr - s_actual2050cdr) ge 0.3,   !!only for optimal iterations, and not after the last one, and only if target not yet reached
+      p_taxcdr_iterationdiff(t,regi)$(t.val le c_peakBudgYr AND sameas(regi,"EUR")) = pm_taxCDR(t,regi)$(t.val le c_peakBudgYr AND sameas(regi,"EUR")) * min(max((c_target2050cdrEUR/s_actual2050cdrEUR)** (10/(2 * iteration.val + 23)),0.5+iteration.val/208),2 - iteration.val/102)  - pm_taxCDR(t,regi)$(t.val le c_peakBudgYr AND sameas(regi,"EUR"));
+      pm_taxCDR(t,regi)$(t.val le c_peakBudgYr AND sameas(regi,"EUR")) = pm_taxCDR(t,regi)$(t.val le c_peakBudgYr AND sameas(regi,"EUR")) + p_taxcdr_iterationdiff(t,regi)$(t.val le c_peakBudgYr AND sameas(regi,"EUR")) ;
+      !!o_taxCDR_iterDiff_Itr(iteration,regi) = p_taxcdr_iterationdiff("2030",regi);
+      !!display o_taxCDR_iterDiff_Itr;
+      !!else
+        !! if model was not optimal, or if target already reached, keep tax constant
+        !!pm_taxCDR(t,regi)$(t.val le c_peakBudgYr) = pm_taxCDR(t,regi)$(t.val le c_peakBudgYr);
+      );	          
+    ); !! end of additional EUR GHG neutrality with limited CDR condition
     pm_taxCDR(t,regi)$(t.val gt c_peakBudgYr) = sum(ttot$(ttot.val eq c_peakBudgYr),pm_taxCDR(ttot,regi)); !! Prices are constant after 2050 (year of net carbon neutrality)
     display pm_taxCDR;
     pm_taxCO2eq(t,regi)$(t.val gt c_peakBudgYr) = sum(ttot$(ttot.val eq c_peakBudgYr),pm_taxCO2eq(ttot,regi)); !! Prices are constant after 2050 (year of net carbon neutrality)
@@ -550,7 +588,6 @@ display s_actualbudgetco2;
 ); !! end if cm_iterative_target_adj eq 13
 
 
-***------ end of "cm_iterative_target_adj" variants-----------------------------------------
 
 
 *** for having it available in next iteration, too:
diff --git a/main.gms b/main.gms
index 9d019fb463..7a78a7ff49 100755
--- a/main.gms
+++ b/main.gms
@@ -1048,6 +1048,14 @@ parameter
   c_target2050cdr      = -1; !! def =-1
 *' -1 indicates no target, otherwise number indicates global cdr emission target for 2050 in GtCO2 per y
 
+
+parameter
+  c_target2050cdrEUR     "Novel cdr target for H12 EUR GHG neutrality in 2050"
+;
+  c_target2050cdrEUR      = -1; !! def =-1
+*' -1 indicates no target, otherwise number indicates novel CDR to be reached for GHG neutrality in 2050 in GtCO2 per y
+
+
 parameter
   cm_DiscRateScen          "Scenario for the implicit discount rate applied to the energy efficiency capital"
 ;
diff --git a/modules/21_tax/on/postsolve.gms b/modules/21_tax/on/postsolve.gms
index 35d9975a1f..477b549561 100644
--- a/modules/21_tax/on/postsolve.gms
+++ b/modules/21_tax/on/postsolve.gms
@@ -18,7 +18,7 @@ OPTION decimals =3;
 *GL* save reference level value of taxes for revenue recycling
 *JH* !!Warning!! The same allocation block exists in presolve.gms.
 ***                Do not forget to update the other file.
-pm_taxrevGHG0(t,regi) = pm_taxCO2eqSum(t,regi) * (vm_co2eq.l(t,regi) - vm_emiMacSector.l(t,regi,"co2luc")$(cm_multigasscen ne 3));
+pm_taxrevGHG0(t,regi) = pm_taxCO2eqSum(t,regi) * (vm_co2eq.l(t,regi) + vm_emiCdrAll.l(t,regi)$(cm_iterative_target_adj eq 13) - vm_emiMacSector.l(t,regi,"co2luc")$(cm_multigasscen ne 3));
 pm_taxrevCO2Sector0(ttot,regi,emi_sectors) = p21_CO2TaxSectorMarkup(ttot,regi,emi_sectors) * pm_taxCO2eqSum(ttot,regi) * vm_emiCO2Sector.l(ttot,regi,emi_sectors);
 pm_taxrevCO2LUC0(t,regi) = pm_taxCO2eqSum(t,regi) * vm_emiMacSector.l(t,regi,"co2luc")$(cm_multigasscen ne 3);
 p21_taxrevCCS0(ttot,regi) = cm_frac_CCS * pm_data(regi,"omf","ccsinje") * pm_inco0_t(ttot,regi,"ccsinje") 
diff --git a/modules/21_tax/on/presolve.gms b/modules/21_tax/on/presolve.gms
index b0fcf858ed..a98bf71730 100644
--- a/modules/21_tax/on/presolve.gms
+++ b/modules/21_tax/on/presolve.gms
@@ -16,7 +16,7 @@ p21_tau_so2_tax(ttot,regi)$(ttot.val>2100)=p21_tau_so2_tax("2100",regi);
 *JH* !!Warning!! The same allocation block exists in postsolve.gms. 
 ***                Do not forget to update the other file.
 *** save level value of all taxes
-pm_taxrevGHG0(t,regi) = pm_taxCO2eqSum(t,regi) * (vm_co2eq.l(t,regi) - vm_emiMacSector.l(t,regi,"co2luc")$(cm_multigasscen ne 3));
+pm_taxrevGHG0(t,regi) = pm_taxCO2eqSum(t,regi) * (vm_co2eq.l(t,regi) + vm_emiCdrAll.l(t,regi)$(cm_iterative_target_adj eq 13) - vm_emiMacSector.l(t,regi,"co2luc")$(cm_multigasscen ne 3));
 pm_taxrevCO2Sector0(ttot,regi,emi_sectors) = p21_CO2TaxSectorMarkup(ttot,regi,emi_sectors) * pm_taxCO2eqSum(ttot,regi) * vm_emiCO2Sector.l(ttot,regi,emi_sectors);
 pm_taxrevCO2LUC0(t,regi) = pm_taxCO2eqSum(t,regi) * vm_emiMacSector.l(t,regi,"co2luc")$(cm_multigasscen ne 3);
 p21_taxrevCCS0(ttot,regi) = cm_frac_CCS * pm_data(regi,"omf","ccsinje") * pm_inco0_t(ttot,regi,"ccsinje") 
diff --git a/modules/45_carbonprice/SepMarkdiffCurv2const/datainput.gms b/modules/45_carbonprice/SepMarkdiffCurv2const/datainput.gms
new file mode 100644
index 0000000000..35718c02be
--- /dev/null
+++ b/modules/45_carbonprice/SepMarkdiffCurv2const/datainput.gms
@@ -0,0 +1,69 @@
+*** |  (C) 2006-2023 Potsdam Institute for Climate Impact Research (PIK)
+*** |  authors, and contributors see CITATION.cff file. This file is part
+*** |  of REMIND and licensed under AGPL-3.0-or-later. Under Section 7 of
+*** |  AGPL-3.0, you are granted additional permissions described in the
+*** |  REMIND License Exception, version 1.0 (see LICENSE file).
+*** |  Contact: remind@pik-potsdam.de
+*** SOF ./modules/45_carbonprice/diffCurvPhaseIn2Lin/datainput.gms
+***------------------------------------------------------------------------------------------------------------------------
+*** *BS* 20190930 linear convergence with starting points differentiated by GDP/capita, global price from 2040
+***-----------------------------------------------------------------------------------------------------------------------
+
+
+*** convergence to global CO2 price depends on GDP per capita (in 1e3 $ PPP 2005).
+p45_gdppcap2015_PPP(regi) = pm_gdp("2015",regi)/pm_shPPPMER(regi) / pm_pop("2015",regi);
+display p45_gdppcap2015_PPP;
+
+p45_phasein_2025ratio(regi)$(p45_gdppcap2015_PPP(regi) le 3) = 0.1;
+p45_phasein_2025ratio(regi)$(p45_gdppcap2015_PPP(regi) gt 3 and p45_gdppcap2015_PPP(regi) le 5) = 0.2;
+p45_phasein_2025ratio(regi)$(p45_gdppcap2015_PPP(regi) gt 5 and p45_gdppcap2015_PPP(regi) le 8) = 0.3;
+p45_phasein_2025ratio(regi)$(p45_gdppcap2015_PPP(regi) gt 8 and p45_gdppcap2015_PPP(regi) le 11) = 0.5;
+p45_phasein_2025ratio(regi)$(p45_gdppcap2015_PPP(regi) gt 11 and p45_gdppcap2015_PPP(regi) le 14) = 0.65;
+p45_phasein_2025ratio(regi)$(p45_gdppcap2015_PPP(regi) gt 14 and p45_gdppcap2015_PPP(regi) le 19) = 0.8;
+p45_phasein_2025ratio(regi)$(p45_gdppcap2015_PPP(regi) gt 19 and p45_gdppcap2015_PPP(regi) le 24) = 0.9;
+p45_phasein_2025ratio(regi)$(p45_gdppcap2015_PPP(regi) gt 24) = 1;
+display p45_phasein_2025ratio;
+
+
+*** for the current implementation, use the following trajectory for rich countries:
+*** global price is linear from 2010 until the pkBudgYr, then increases with c_taxCO2inc_after_peakBudgYr
+if(cm_co2_tax_2020 lt 0,
+  abort "please choose a valid cm_co2_tax_2020"
+elseif cm_co2_tax_2020 ge 0,
+*** convert tax value from $/t CO2eq to T$/GtC
+  p45_CO2priceTrajDeveloped("2040")= 3 * cm_co2_tax_2020 * sm_DptCO2_2_TDpGtC;  !! shifted to 2040 to make sure that even in delay scenarios the fixpoint of the linear price path is inside the "t" range, otherwise the CO2 prices from reference run may be overwritten
+*** The factor 3 comes from shifting the 2020 value 20 years into the future at linear increase of 10% of 2020 value per year.
+);
+
+
+
+p45_CO2priceTrajDeveloped(ttot)$((ttot.val gt 2005) AND (ttot.val ge cm_startyear)) = p45_CO2priceTrajDeveloped("2040")*( 1 + 0.1/3 * (ttot.val-2040)); !! no CO2 price in 2005 and only change CO2 prices after ; 
+*** annual increase by (10/3)% of the 2040 value is the same as a 10% increase of the 2020 value is the same as a linear increase from 0 in 2010 to the 2020/2040 value
+
+
+*** Then create regional phase-in:
+loop(ttot$((ttot.val ge cm_startyear) AND (ttot.val le cm_CO2priceRegConvEndYr) ),
+  p45_regCO2priceFactor(ttot,regi) = 
+   min(1,
+       max(0, 
+	        p45_phasein_2025ratio(regi) + (1 - p45_phasein_2025ratio(regi)) 
+			                               * Power( 
+										       ( (ttot.val - 2025) + (cm_CO2priceRegConvEndYr - 2025) * 0.1 ) 
+                                               / ( (cm_CO2priceRegConvEndYr - 2025) * 1.1 )
+											   , 2
+											 ) !! use Power instead of ** to allow ttot be smaller than 2025, and thus the base to be negative
+       )											 
+   );
+);
+p45_regCO2priceFactor(ttot,regi)$(ttot.val ge cm_CO2priceRegConvEndYr) = 1;
+
+
+*** transition to global price - starting point depends on GDP/cap
+pm_taxCO2eq(t,regi) = p45_regCO2priceFactor(t,regi) * p45_CO2priceTrajDeveloped(t);
+
+pm_taxCDR(ttot,regi) = pm_taxCO2eq(ttot,regi);
+
+
+display p45_regCO2priceFactor, p45_CO2priceTrajDeveloped, pm_taxCO2eq;
+
+*** EOF ./modules/45_carbonprice/diffCurvPhaseIn2Lin/datainput.gms
diff --git a/modules/45_carbonprice/SepMarkdiffCurv2const/declarations.gms b/modules/45_carbonprice/SepMarkdiffCurv2const/declarations.gms
new file mode 100644
index 0000000000..c953139446
--- /dev/null
+++ b/modules/45_carbonprice/SepMarkdiffCurv2const/declarations.gms
@@ -0,0 +1,22 @@
+*** |  (C) 2006-2023 Potsdam Institute for Climate Impact Research (PIK)
+*** |  authors, and contributors see CITATION.cff file. This file is part
+*** |  of REMIND and licensed under AGPL-3.0-or-later. Under Section 7 of
+*** |  AGPL-3.0, you are granted additional permissions described in the
+*** |  REMIND License Exception, version 1.0 (see LICENSE file).
+*** |  Contact: remind@pik-potsdam.de
+*** SOF ./modules/45_carbonprice/diffCurvPhaseIn2Lin/declarations.gms
+***------------------------------------------------------------------------------------------------------------------------
+*** *BS* 20190930 linear convergence with starting points differentiated by GDP/capita, global price from 2040
+***-----------------------------------------------------------------------------------------------------------------------
+
+parameters
+p45_tauCO2_ref(ttot, all_regi)              "CO2 tax path of reference policy (NDC)"
+p45_gdppcap2015_PPP(all_regi)               "2015 GDP per capita (k $ PPP 2005)"
+p45_phasein_2025ratio(all_regi)             "ratio of CO2 price to that of developed region in 2025"
+
+p45_regCO2priceFactor(ttot,all_regi)                    "regional multiplicative factor to the CO2 price of the developed countries"
+p45_CO2priceTrajDeveloped(ttot)                         "CO2 price trajectory for developed/rich countries"
+;
+
+
+*** EOF ./modules/45_carbonprice/diffCurvPhaseIn2Lin/declarations.gms
diff --git a/modules/45_carbonprice/SepMarkdiffCurv2const/not_used.txt b/modules/45_carbonprice/SepMarkdiffCurv2const/not_used.txt
new file mode 100644
index 0000000000..6d7ccb5555
--- /dev/null
+++ b/modules/45_carbonprice/SepMarkdiffCurv2const/not_used.txt
@@ -0,0 +1,25 @@
+# |  (C) 2006-2023 Potsdam Institute for Climate Impact Research (PIK)
+# |  authors, and contributors see CITATION.cff file. This file is part
+# |  of REMIND and licensed under AGPL-3.0-or-later. Under Section 7 of
+# |  AGPL-3.0, you are granted additional permissions described in the
+# |  REMIND License Exception, version 1.0 (see LICENSE file).
+# |  Contact: remind@pik-potsdam.de
+name,type,reason
+sm_c_2_co2,input,questionnaire
+vm_co2eq,input,questionnaire
+vm_emiFgas,input,questionnaire
+pm_globalMeanTemperature,input,questionnaire
+pm_temperatureImpulseResponseCO2,input,questionnaire
+pm_GDPGross,input,questionnaire
+pm_ttot_val,input,questionnaire
+pm_ttot_2_tall,input,questionnaire
+cm_emiscen,input,questionnaire
+cm_co2_tax_growth,input,questionnaire
+cm_iterative_target_adj,input,questionnaire
+cm_expoLinear_yearStart,input,questionnaire
+cm_carbonprice_temperatureLimit,input,questionnaire
+cm_NDC_divergentScenario,input,questionnaire
+pm_consPC,input,questionnaire
+pm_prtp,input,questionnaire
+vm_demFeSector,input,questionnaire
+pm_emifac,input,questionnaire
diff --git a/modules/45_carbonprice/SepMarkdiffCurv2const/postsolve.gms b/modules/45_carbonprice/SepMarkdiffCurv2const/postsolve.gms
new file mode 100644
index 0000000000..c730453354
--- /dev/null
+++ b/modules/45_carbonprice/SepMarkdiffCurv2const/postsolve.gms
@@ -0,0 +1,41 @@
+*** |  (C) 2006-2023 Potsdam Institute for Climate Impact Research (PIK)
+*** |  authors, and contributors see CITATION.cff file. This file is part
+*** |  of REMIND and licensed under AGPL-3.0-or-later. Under Section 7 of
+*** |  AGPL-3.0, you are granted additional permissions described in the
+*** |  REMIND License Exception, version 1.0 (see LICENSE file).
+*** |  Contact: remind@pik-potsdam.de
+*** SOF ./modules/45_carbonprice/diffCurvPhaseIn2Lin/postsolve.gms
+***------------------------------------------------------------------------------------------------------------------------
+*** *BS* 20190930 linear convergence with starting points differentiated by GDP/capita, global price from 2040
+***-----------------------------------------------------------------------------------------------------------------------
+
+***   *** updated constant global price as scalar (regional prices are the same anyway)
+***   s45_constantCO2price = sum((ttot,regi)$(ttot.val eq s45_stageend), pm_taxCO2eq(ttot,regi))/card(regi) ;
+***   *** entire path has been shifted in update, so have to set these again
+***   pm_taxCO2eq(ttot,regi)$(ttot.val le s45_stagestart) = p45_tauCO2_ref(ttot, regi);
+***   pm_taxCO2eq(ttot,regi)$(ttot.val gt s45_stagestart and ttot.val lt s45_stageend)
+***     = s45_constantCO2price * (ttot.val - p45_phasein_zeroyear(regi))/(s45_stageend - p45_phasein_zeroyear(regi));
+***   *** price trajectory should be constant anyway but let's be explicit here
+***   pm_taxCO2eq(ttot,regi)$(ttot.val ge s45_stageend) = s45_constantCO2price;
+
+
+*** re-create the regional differentation, use path from developed countries as the basis.
+*** This doesn't need to be a loop, but it will be correct for any cycle of the loop, so also for the last cycle.
+loop(regi$(p45_gdppcap2015_PPP(regi) gt 30),
+  p45_CO2priceTrajDeveloped(t) = pm_taxCO2eq(t,regi);
+);
+
+*** linear transition to global price - starting point depends on GDP/cap
+pm_taxCO2eq(t,regi) = p45_regCO2priceFactor(t,regi) * p45_CO2priceTrajDeveloped(t);
+
+
+*** same procedure for CDR subsidy (shamelessly reusing the CO2 price helper parameter for temporary storage)
+loop(regi$(p45_gdppcap2015_PPP(regi) gt 30),
+  p45_CO2priceTrajDeveloped(t) = pm_taxCDR(t,regi);
+);
+
+*** linear transition to global price - starting point depends on GDP/cap
+pm_taxCDR(t,regi) = p45_regCO2priceFactor(t,regi) * p45_CO2priceTrajDeveloped(t);
+
+display pm_taxCO2eq, pm_taxCDR;
+*** EOF ./modules/45_carbonprice/diffCurvPhaseIn2Lin/postsolve.gms
diff --git a/modules/45_carbonprice/SepMarkdiffCurv2const/realization.gms b/modules/45_carbonprice/SepMarkdiffCurv2const/realization.gms
new file mode 100644
index 0000000000..ca62d0101e
--- /dev/null
+++ b/modules/45_carbonprice/SepMarkdiffCurv2const/realization.gms
@@ -0,0 +1,15 @@
+*** |  (C) 2006-2023 Potsdam Institute for Climate Impact Research (PIK)
+*** |  authors, and contributors see CITATION.cff file. This file is part
+*** |  of REMIND and licensed under AGPL-3.0-or-later. Under Section 7 of
+*** |  AGPL-3.0, you are granted additional permissions described in the
+*** |  REMIND License Exception, version 1.0 (see LICENSE file).
+*** |  Contact: remind@pik-potsdam.de
+*** SOF ./modules/45_carbonprice/diffCurvPhaseIn2Lin/realization.gms
+
+*####################### R SECTION START (PHASES) ##############################
+$Ifi "%phase%" == "declarations" $include "./modules/45_carbonprice/SepMarkdiffCurv2const/declarations.gms"
+$Ifi "%phase%" == "datainput" $include "./modules/45_carbonprice/SepMarkdiffCurv2const/datainput.gms"
+$Ifi "%phase%" == "postsolve" $include "./modules/45_carbonprice/SepMarkdiffCurv2const/postsolve.gms"
+*######################## R SECTION END (PHASES) ###############################
+
+*** EOF ./modules/45_carbonprice/diffCurvPhaseIn2Lin/realization.gms
diff --git a/modules/45_carbonprice/SeparateMarketsExpo2Const/datainput.gms b/modules/45_carbonprice/SeparateMarketsExpo2Const/datainput.gms
index 032f3d7c3c..61997a351d 100644
--- a/modules/45_carbonprice/SeparateMarketsExpo2Const/datainput.gms
+++ b/modules/45_carbonprice/SeparateMarketsExpo2Const/datainput.gms
@@ -24,7 +24,7 @@ pm_taxCO2eq("2025",regi)= cm_co2_tax_2020 * sm_DptCO2_2_TDpGtC;
 pm_taxCO2eq(ttot,regi)$(ttot.val ge 2025 AND ttot.val le c_peakBudgYr) = pm_taxCO2eq("2025",regi)*cm_co2_tax_growth**(ttot.val-2025);
 pm_taxCO2eq(ttot,regi)$(ttot.val gt c_peakBudgYr) =sum(t$(t.val eq c_peakBudgYr),pm_taxCO2eq(t,regi)); !! keep taxes constant after cm_peakBudgYr
 
-pm_taxCDR(ttot,regi) = pm_taxCO2eq(ttot,regi)
+pm_taxCDR(ttot,regi) = pm_taxCO2eq(ttot,regi);
 
 
 display pm_taxCDR, pm_taxCO2eq;
diff --git a/modules/45_carbonprice/module.gms b/modules/45_carbonprice/module.gms
index 31672fab9e..0cdeb1d077 100644
--- a/modules/45_carbonprice/module.gms
+++ b/modules/45_carbonprice/module.gms
@@ -23,6 +23,7 @@
 *###################### R SECTION START (MODULETYPES) ##########################
 $Ifi "%carbonprice%" == "NDC" $include "./modules/45_carbonprice/NDC/realization.gms"
 $Ifi "%carbonprice%" == "NPi" $include "./modules/45_carbonprice/NPi/realization.gms"
+$Ifi "%carbonprice%" == "SepMarkdiffCurv2const" $include "./modules/45_carbonprice/SepMarkdiffCurv2const/realization.gms"
 $Ifi "%carbonprice%" == "SeparateMarketsExpo2Const" $include "./modules/45_carbonprice/SeparateMarketsExpo2Const/realization.gms"
 $Ifi "%carbonprice%" == "diffCurvPhaseIn2Lin" $include "./modules/45_carbonprice/diffCurvPhaseIn2Lin/realization.gms"
 $Ifi "%carbonprice%" == "exogenous" $include "./modules/45_carbonprice/exogenous/realization.gms"
diff --git a/modules/47_regipol/regiCarbonPrice/datainput.gms b/modules/47_regipol/regiCarbonPrice/datainput.gms
index 08942b838c..d5b03fcd68 100644
--- a/modules/47_regipol/regiCarbonPrice/datainput.gms
+++ b/modules/47_regipol/regiCarbonPrice/datainput.gms
@@ -239,29 +239,7 @@ loop(te$sameas(te,"spv"),
 );
 
 
-*** p_EmiLULUCFCountryAcc contains historic LULUCF emissions from UNFCCC, 
-*** used for rescaling land-use change emissions for emissions targets based on national accounting
-parameter p47_EmiLULUCFCountryAcc(tall,all_regi)                "historic co2 emissions from landuse change based on country accounting [Mt CO2/yr]"
-/
-$ondelim
-$include "./modules/47_regipol/regiCarbonPrice/input/p_EmiLULUCFCountryAcc.cs4r"
-$offdelim
-/
-;
 
-*** difference between 2020 land-use change emissions from Magpie and UNFCCC 2015 and 2020 moving average land-use change emissions
-p47_LULUCFEmi_GrassiShift(t,regi)$(p47_EmiLULUCFCountryAcc("2020",regi)) = 
-  pm_macBaseMagpie("2020",regi,"co2luc") 
-  - 
-  (
-    (
-      ((p47_EmiLULUCFCountryAcc("2013",regi) + p47_EmiLULUCFCountryAcc("2014",regi) + p47_EmiLULUCFCountryAcc("2015",regi) + p47_EmiLULUCFCountryAcc("2016",regi) + p47_EmiLULUCFCountryAcc("2017",regi))/5)
-      +
-      ((p47_EmiLULUCFCountryAcc("2018",regi) + p47_EmiLULUCFCountryAcc("2019",regi) + p47_EmiLULUCFCountryAcc("2020",regi) + p47_EmiLULUCFCountryAcc("2021",regi))/4)
-    )/2
-    * 1e-3/sm_c_2_co2
-  )
-;
 
 *** -------------------------Primary Energy Tax--------------------------
 
diff --git a/modules/47_regipol/regiCarbonPrice/declarations.gms b/modules/47_regipol/regiCarbonPrice/declarations.gms
index f788051086..cb802e84c8 100644
--- a/modules/47_regipol/regiCarbonPrice/declarations.gms
+++ b/modules/47_regipol/regiCarbonPrice/declarations.gms
@@ -13,7 +13,7 @@
 Parameter
   s47_firstFreeYear                                  "value of first free year for the carbon price trajectory"
   s47_prefreeYear                                    "value of the last non-free year for the carbon price trajectory"
-  p47_LULUCFEmi_GrassiShift(ttot,all_regi)           "difference between Magpie land-use change emissions and UNFCCC emissions in 2015 to correct for national accounting in emissions targets"
+  !!p47_LULUCFEmi_GrassiShift(ttot,all_regi)           "difference between Magpie land-use change emissions and UNFCCC emissions in 2015 to correct for national accounting in emissions targets"
   pm_emiMktTarget_dev(ttot,ttot2,ext_regi,emiMktExt) "deviation of emissions of current iteration from target emissions, for budget target this is the difference normalized by target emissions, while for year targets this is the difference normalized by 2005 emissions [%]"
 
 *** RR this should be replaced as soon as non-energy is treated endogenously in the model
diff --git a/modules/47_regipol/regiCarbonPrice/postsolve.gms b/modules/47_regipol/regiCarbonPrice/postsolve.gms
index b13fda54ac..e6d999b62a 100644
--- a/modules/47_regipol/regiCarbonPrice/postsolve.gms
+++ b/modules/47_regipol/regiCarbonPrice/postsolve.gms
@@ -96,27 +96,27 @@ p47_emiTargetMkt(ttot,regi, emiMktExt,"netGHG_noLULUCF_noBunkers") =
 *** net CO2 per Mkt with Grassi LULUCF shift
 p47_emiTargetMkt(ttot,regi, emiMktExt,"netCO2_LULUCFGrassi") =
   p47_emiTargetMkt(ttot,regi, emiMktExt,"netCO2")
-  - ( p47_LULUCFEmi_GrassiShift(ttot,regi) )$(sameas(emiMktExt,"other") or sameas(emiMktExt,"all"));
+  - ( pm_LULUCFEmi_GrassiShift(ttot,regi) )$(sameas(emiMktExt,"other") or sameas(emiMktExt,"all"));
 
 *** net CO2 per Mkt without bunkers and with Grassi LULUCF shift
 p47_emiTargetMkt(ttot,regi, emiMktExt,"netCO2_LULUCFGrassi_noBunkers") =
   p47_emiTargetMkt(ttot,regi, emiMktExt,"netCO2_noBunkers")
-  - ( p47_LULUCFEmi_GrassiShift(ttot,regi) )$(sameas(emiMktExt,"other") or sameas(emiMktExt,"all"));
+  - ( pm_LULUCFEmi_GrassiShift(ttot,regi) )$(sameas(emiMktExt,"other") or sameas(emiMktExt,"all"));
 
 *** net GHG per Mkt with Grassi LULUCF shift
 p47_emiTargetMkt(ttot,regi, emiMktExt,"netGHG_LULUCFGrassi") =
   p47_emiTargetMkt(ttot,regi, emiMktExt,"netGHG")
-  - ( p47_LULUCFEmi_GrassiShift(ttot,regi) )$(sameas(emiMktExt,"other") or sameas(emiMktExt,"all"));
+  - ( pm_LULUCFEmi_GrassiShift(ttot,regi) )$(sameas(emiMktExt,"other") or sameas(emiMktExt,"all"));
 
 *** net GHG per Mkt without bunkers and with Grassi LULUCF shift
 p47_emiTargetMkt(ttot,regi, emiMktExt,"netGHG_LULUCFGrassi_noBunkers") =
   p47_emiTargetMkt(ttot,regi, emiMktExt,"netGHG_noBunkers")
-  - ( p47_LULUCFEmi_GrassiShift(ttot,regi) )$(sameas(emiMktExt,"other") or sameas(emiMktExt,"all"));
+  - ( pm_LULUCFEmi_GrassiShift(ttot,regi) )$(sameas(emiMktExt,"other") or sameas(emiMktExt,"all"));
 
 *** net CO2 per Mkt without bunkers and with Grassi LULUCF shift
 p47_emiTargetMkt(ttot,regi, emiMktExt,"netCO2_LULUCFGrassi_intraRegBunker") =
   p47_emiTargetMkt(ttot,regi, emiMktExt,"netCO2_noBunkers")
-  - ( p47_LULUCFEmi_GrassiShift(ttot,regi) )$(sameas(emiMktExt,"other") or sameas(emiMktExt,"all"))
+  - ( pm_LULUCFEmi_GrassiShift(ttot,regi) )$(sameas(emiMktExt,"other") or sameas(emiMktExt,"all"))
   + (
     sum(se2fe(enty,enty2,te),
       pm_emifac(ttot,regi,enty,enty2,te,"co2")
@@ -127,7 +127,7 @@ p47_emiTargetMkt(ttot,regi, emiMktExt,"netCO2_LULUCFGrassi_intraRegBunker") =
 *** net GHG per Mkt without bunkers and with Grassi LULUCF shift
 p47_emiTargetMkt(ttot,regi, emiMktExt,"netGHG_LULUCFGrassi_intraRegBunker") =
   p47_emiTargetMkt(ttot,regi, emiMktExt,"netGHG_noBunkers")
-  - ( p47_LULUCFEmi_GrassiShift(ttot,regi) )$(sameas(emiMktExt,"other") or sameas(emiMktExt,"all"))
+  - ( pm_LULUCFEmi_GrassiShift(ttot,regi) )$(sameas(emiMktExt,"other") or sameas(emiMktExt,"all"))
   + (
     sum(se2fe(enty,enty2,te),
       pm_emifac(ttot,regi,enty,enty2,te,"co2")

From ace54f92dc792c1b41f3f8cebb094b8c6e53a953 Mon Sep 17 00:00:00 2001
From: amerfort <amerfort@pik-potsdam.de>
Date: Tue, 30 Apr 2024 17:16:01 +0200
Subject: [PATCH 4/7] bug fix on dedicated EUR tax

---
 .../SepMarkdiffCurv2const/postsolve.gms          | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/modules/45_carbonprice/SepMarkdiffCurv2const/postsolve.gms b/modules/45_carbonprice/SepMarkdiffCurv2const/postsolve.gms
index c730453354..f80076f488 100644
--- a/modules/45_carbonprice/SepMarkdiffCurv2const/postsolve.gms
+++ b/modules/45_carbonprice/SepMarkdiffCurv2const/postsolve.gms
@@ -21,21 +21,27 @@
 
 *** re-create the regional differentation, use path from developed countries as the basis.
 *** This doesn't need to be a loop, but it will be correct for any cycle of the loop, so also for the last cycle.
-loop(regi$(p45_gdppcap2015_PPP(regi) gt 30),
+loop(regi$(p45_gdppcap2015_PPP(regi) gt 30 AND (not(sameas (regi,"EUR")))),
   p45_CO2priceTrajDeveloped(t) = pm_taxCO2eq(t,regi);
 );
 
-*** linear transition to global price - starting point depends on GDP/cap
-pm_taxCO2eq(t,regi) = p45_regCO2priceFactor(t,regi) * p45_CO2priceTrajDeveloped(t);
 
+*** linear transition to global price - starting point depends on GDP/cap
+pm_taxCO2eq(t,regi)$(not(sameas (regi,"EUR"))) = p45_regCO2priceFactor(t,regi)(not(sameas (regi,"EUR"))) * p45_CO2priceTrajDeveloped(t);
+if(c_target2050cdrEUR < 0,
+  pm_taxCO2eq(t,regi)$(sameas (regi,"EUR")) = p45_regCO2priceFactor(t,regi)$(sameas (regi,"USA")) * p45_CO2priceTrajDeveloped(t);
+)
 
 *** same procedure for CDR subsidy (shamelessly reusing the CO2 price helper parameter for temporary storage)
-loop(regi$(p45_gdppcap2015_PPP(regi) gt 30),
+loop(regi$(p45_gdppcap2015_PPP(regi) gt 30AND (not(sameas (regi,"EUR")))),
   p45_CO2priceTrajDeveloped(t) = pm_taxCDR(t,regi);
 );
 
 *** linear transition to global price - starting point depends on GDP/cap
-pm_taxCDR(t,regi) = p45_regCO2priceFactor(t,regi) * p45_CO2priceTrajDeveloped(t);
+pm_taxCDR(t,regi)$(not(sameas (regi,"EUR"))) = p45_regCO2priceFactor(t,regi)(not(sameas (regi,"EUR"))) * p45_CO2priceTrajDeveloped(t);
+if(c_target2050cdrEUR < 0,
+  pm_taxCDR(t,regi)$(sameas (regi,"EUR")) = p45_regCO2priceFactor(t,regi)$(sameas (regi,"USA")) * p45_CO2priceTrajDeveloped(t);
+)
 
 display pm_taxCO2eq, pm_taxCDR;
 *** EOF ./modules/45_carbonprice/diffCurvPhaseIn2Lin/postsolve.gms

From 7d92b65cbcd24c04b05aeac0825c14da3b55ef53 Mon Sep 17 00:00:00 2001
From: amerfort <amerfort@pik-potsdam.de>
Date: Tue, 30 Apr 2024 17:26:43 +0200
Subject: [PATCH 5/7] another bug fix

---
 core/postsolve.gms | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/core/postsolve.gms b/core/postsolve.gms
index eecead20c5..640d597689 100644
--- a/core/postsolve.gms
+++ b/core/postsolve.gms
@@ -570,7 +570,7 @@ display s_actualbudgetco2;
         !!);
       );	
     !! Target at net-zero CDR (in target year c_peakBudgYr)
-    if(o_modelstat eq 2 AND ord(iteration)<cm_iteration_max AND abs(c_target2050cdr - s_actual2050cdr) ge 0.3,   !!only for optimal iterations, and not after the last one, and only if target not yet reached
+    if(o_modelstat eq 2 AND ord(iteration)<cm_iteration_max AND abs(c_target2050cdrEUR - s_actual2050cdrEUR) ge 0.05,   !!only for optimal iterations, and not after the last one, and only if target not yet reached
       p_taxcdr_iterationdiff(t,regi)$(t.val le c_peakBudgYr AND sameas(regi,"EUR")) = pm_taxCDR(t,regi)$(t.val le c_peakBudgYr AND sameas(regi,"EUR")) * min(max((c_target2050cdrEUR/s_actual2050cdrEUR)** (10/(2 * iteration.val + 23)),0.5+iteration.val/208),2 - iteration.val/102)  - pm_taxCDR(t,regi)$(t.val le c_peakBudgYr AND sameas(regi,"EUR"));
       pm_taxCDR(t,regi)$(t.val le c_peakBudgYr AND sameas(regi,"EUR")) = pm_taxCDR(t,regi)$(t.val le c_peakBudgYr AND sameas(regi,"EUR")) + p_taxcdr_iterationdiff(t,regi)$(t.val le c_peakBudgYr AND sameas(regi,"EUR")) ;
       !!o_taxCDR_iterDiff_Itr(iteration,regi) = p_taxcdr_iterationdiff("2030",regi);

From 0fefba35d475c8dbc895acf83741503310266ad8 Mon Sep 17 00:00:00 2001
From: amerfort <amerfort@pik-potsdam.de>
Date: Tue, 30 Apr 2024 17:42:56 +0200
Subject: [PATCH 6/7] one more bug

---
 modules/45_carbonprice/SepMarkdiffCurv2const/postsolve.gms | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/modules/45_carbonprice/SepMarkdiffCurv2const/postsolve.gms b/modules/45_carbonprice/SepMarkdiffCurv2const/postsolve.gms
index f80076f488..06e46415d5 100644
--- a/modules/45_carbonprice/SepMarkdiffCurv2const/postsolve.gms
+++ b/modules/45_carbonprice/SepMarkdiffCurv2const/postsolve.gms
@@ -27,18 +27,18 @@ loop(regi$(p45_gdppcap2015_PPP(regi) gt 30 AND (not(sameas (regi,"EUR")))),
 
 
 *** linear transition to global price - starting point depends on GDP/cap
-pm_taxCO2eq(t,regi)$(not(sameas (regi,"EUR"))) = p45_regCO2priceFactor(t,regi)(not(sameas (regi,"EUR"))) * p45_CO2priceTrajDeveloped(t);
+pm_taxCO2eq(t,regi)$(not(sameas (regi,"EUR"))) = p45_regCO2priceFactor(t,regi)$(not(sameas (regi,"EUR"))) * p45_CO2priceTrajDeveloped(t);
 if(c_target2050cdrEUR < 0,
   pm_taxCO2eq(t,regi)$(sameas (regi,"EUR")) = p45_regCO2priceFactor(t,regi)$(sameas (regi,"USA")) * p45_CO2priceTrajDeveloped(t);
 )
 
 *** same procedure for CDR subsidy (shamelessly reusing the CO2 price helper parameter for temporary storage)
-loop(regi$(p45_gdppcap2015_PPP(regi) gt 30AND (not(sameas (regi,"EUR")))),
+loop(regi$(p45_gdppcap2015_PPP(regi) gt 30 AND (not(sameas (regi,"EUR")))),
   p45_CO2priceTrajDeveloped(t) = pm_taxCDR(t,regi);
 );
 
 *** linear transition to global price - starting point depends on GDP/cap
-pm_taxCDR(t,regi)$(not(sameas (regi,"EUR"))) = p45_regCO2priceFactor(t,regi)(not(sameas (regi,"EUR"))) * p45_CO2priceTrajDeveloped(t);
+pm_taxCDR(t,regi)$(not(sameas (regi,"EUR"))) = p45_regCO2priceFactor(t,regi)$(not(sameas (regi,"EUR"))) * p45_CO2priceTrajDeveloped(t);
 if(c_target2050cdrEUR < 0,
   pm_taxCDR(t,regi)$(sameas (regi,"EUR")) = p45_regCO2priceFactor(t,regi)$(sameas (regi,"USA")) * p45_CO2priceTrajDeveloped(t);
 )

From 2ccfb45063fdc9d3ee9398631a9e07dcef5354ed Mon Sep 17 00:00:00 2001
From: amerfort <amerfort@pik-potsdam.de>
Date: Thu, 2 May 2024 16:27:24 +0200
Subject: [PATCH 7/7] bug fix in unit conversion

---
 core/postsolve.gms | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/core/postsolve.gms b/core/postsolve.gms
index 640d597689..6cd36d998b 100644
--- a/core/postsolve.gms
+++ b/core/postsolve.gms
@@ -547,14 +547,15 @@ display s_actualbudgetco2;
 ***-----------------------------------------------
     if(c_target2050cdrEUR > 0,
     s_actual2050ghgEUR = sum(ttot$(ttot.val eq c_peakBudgYr),sum(regi$sameas(regi,"EUR"),
-        !! Gross CO2 emissions excluding novel CDR in GtCO2 but including land use and managed forests (with Grassi shift)
-        ((vm_emiAll.l(ttot,regi,"co2") + vm_emiCdrAll.l(ttot,regi) - pm_LULUCFEmi_GrassiShift(ttot,regi)) * sm_c_2_co2
-        !! CH4 emissions in GtCO2eq with GWP100
-        +vm_emiAll.l(ttot,regi,"ch4") * s_gwpCH4
-        !! N"O emissions in GtCO2eq with GWP100
-        +vm_emiAll.l(ttot,regi,"n2o") * s_gwpN2O
-        )));
-    s_actual2050cdrEUR = sum(ttot$(ttot.val eq c_peakBudgYr),sum(regi$(sameas(regi,"EUR")), vm_emiCdrAll.l(ttot,regi))) *sm_c_2_co2;  !! CDR     
+        !! Gross CO2 emissions excluding novel CDR in GtC but including land use and managed forests (with Grassi shift)
+        ((vm_emiAll.l(ttot,regi,"co2") + vm_emiCdrAll.l(ttot,regi) - pm_LULUCFEmi_GrassiShift(ttot,regi)) 
+        !! CH4 emissions in GtCeq with GWP100
+        +vm_emiAll.l(ttot,regi,"ch4") * sm_tgch4_2_pgc
+        !! N2O emissions in GtCeq with GWP100
+        +vm_emiAll.l(ttot,regi,"n2o") * sm_tgn_2_pgc
+        !! Conversion to GtCO2eq
+        ))) * sm_c_2_co2;
+    s_actual2050cdrEUR = sum(ttot$(ttot.val eq c_peakBudgYr),sum(regi$(sameas(regi,"EUR")), vm_emiCdrAll.l(ttot,regi))) *sm_c_2_co2;  !! CDR in GtCO2    
     !! Target 2050 GHG in Europe
     display s_actual2050ghgEUR, s_actual2050cdrEUR;
     if(o_modelstat eq 2 AND ord(iteration)<cm_iteration_max AND abs(c_target2050cdrEUR - s_actual2050ghgEUR) ge 0.05 ,   !!only for optimal iterations, and not after the last one, and only if target not yet reached