From 904d2d0338f246aa3222f0781a7c3774165ae92f Mon Sep 17 00:00:00 2001
From: tabeado <tabea.dorndorf@pik-potsdam.de>
Date: Thu, 16 Jul 2026 10:31:53 +0200
Subject: [PATCH 01/11] ERW unit documentation

---
 core/datainput.gms              | 6 +++---
 core/input/generisdata_tech.prn | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/core/datainput.gms b/core/datainput.gms
index f1b5a31686..7e746e0d36 100644
--- a/core/datainput.gms
+++ b/core/datainput.gms
@@ -290,9 +290,9 @@ fm_dataglob("inco0", "oae_ng") = fm_dataglob("inco0", "oae_ng") / (cm_33_OAE_eff
 fm_dataglob("inco0", "oae_el") = fm_dataglob("inco0", "oae_el") / (cm_33_OAE_eff / sm_c_2_co2);
 
 *** convert inco0, floorcost and omv to REMIND units by applying a factor 0.001
-***   category          energy technology   ccs technology    process-based industry 
-***   input data unit   $/kW                $/(tC/a)          $/(t/a)
-***   REMIND unit       T$/TW               T$/(GtC/a)        T$/(Gt/a)
+***   category          energy technology   ccs technology    process-based industry            weathering
+***   input data unit   $/kW                $/(tC/a)          $/(t/a)                         $/(t rocks/a)
+***   REMIND unit       T$/TW               T$/(GtC/a)        T$/(Gt/a)                       T$/(Gt rocks/a)
 fm_dataglob("inco0",te)        = s_DpKW_2_TDpTW   * fm_dataglob("inco0",te);
 fm_dataglob("floorcost",te)    = s_DpKW_2_TDpTW   * fm_dataglob("floorcost",te);
 fm_dataglob("omv",te)          = s_DpKWa_2_TDpTWa * fm_dataglob("omv",te);
diff --git a/core/input/generisdata_tech.prn b/core/input/generisdata_tech.prn
index 689d68f66d..f731e7e457 100644
--- a/core/input/generisdata_tech.prn
+++ b/core/input/generisdata_tech.prn
@@ -1,7 +1,7 @@
 *** SOF ./core/input/generisdata_tech.prn
 $ontext
 tech_stat   technology status: how close a technology is to market readiness. Scale: 0-3, with 0 'I can go out and build a GW plant today' to 3 'Still some research necessary'
-inco0       Initial investment costs given in $[2015] / kW[output] capacity; for dac/prc cc: $[2015] / (tC[captured]/a); for other indutry prc: $[2015]/(t[output]/a)
+inco0       Initial investment costs given in $[2015] / kW[output] capacity; for dac/prc cc: $[2015] / (tC[captured]/a); for other indutry prc: $[2015]/(t[output]/a); for weathering:  $[2015]/(t rock/a)
 floorcost   Floor investment costs, given in $[2015] / kW[output]; for dac: $[2015] / (tC[captured]/a)
 constrTme   Construction time in years, needed to calculate turn-key cost premium compared to overnight costs
 lifetime    Average lifetime of a technology, given in years. Effective maximum lifetime is longer than that.

From 814ed21c19ad0f6cb184de454bbe51774758a4e6 Mon Sep 17 00:00:00 2001
From: tabeado <tabea.dorndorf@pik-potsdam.de>
Date: Tue, 21 Jul 2026 11:58:34 +0200
Subject: [PATCH 02/11] remove global rock limit switch

---
 main.gms                                            |  5 ++---
 modules/33_carbonRemoval/portfolio/datainput.gms    |  5 +----
 modules/33_carbonRemoval/portfolio/declarations.gms |  2 --
 modules/33_carbonRemoval/portfolio/equations.gms    | 10 ----------
 modules/33_carbonRemoval/portfolio/realization.gms  |  3 +--
 standalone/MOFEX/MOFEX.gms                          |  2 --
 standalone/template.gms                             |  2 --
 standalone/trade/trade.gms                          |  2 --
 8 files changed, 4 insertions(+), 27 deletions(-)

diff --git a/main.gms b/main.gms
index 31538296af..0de13db480 100755
--- a/main.gms
+++ b/main.gms
@@ -1086,10 +1086,9 @@ parameter
 ;
   cm_gs_ew                 = 20;     !! def = 20  !! regexp = is.numeric
 *'
+
 parameter
-  cm_LimRock                "limit amount of rock spread each year [Gt]"
-;
-  cm_LimRock               = 1000;   !! def = 1000
+
 *'
 parameter
   cm_33_EW_upScalingRateLimit    "Annual growth rate limit on upscaling of mining & spreading rocks on fields"
diff --git a/modules/33_carbonRemoval/portfolio/datainput.gms b/modules/33_carbonRemoval/portfolio/datainput.gms
index 755deccb6f..90c52ca256 100644
--- a/modules/33_carbonRemoval/portfolio/datainput.gms
+++ b/modules/33_carbonRemoval/portfolio/datainput.gms
@@ -54,9 +54,6 @@ p33_rock_weath_rate("2") = s33_rock_weath_rate_ambientT * 0.29;
 p33_fedem("weathering", "feels") = 6.62 * cm_gs_ew**(-1.16);
 p33_fedem("weathering", "fedie") = 0.3;
 
-*' Factor distributing the global rock limit across regions according to population
-p33_LimRock(regi) = pm_pop("2005",regi) / sum(regi2,pm_pop("2005",regi2));
-
 *' Annual growth rate limit on upscaling of mining & spreading rocks on fields
 p33_EW_upScalingLimit(ttot) = cm_33_EW_upScalingRateLimit;
 
@@ -64,7 +61,7 @@ p33_EW_upScalingLimit(ttot) = cm_33_EW_upScalingRateLimit;
 p33_EW_shortTermEW_Limit(regi) = cm_33_EW_shortTermLimit * sum(rlf, f33_maxProdGradeRegiWeathering(regi, rlf));
 
 *' Narrative switch: what share of cropland can be used for EW?
-parameter f33_EW_maxShareOfCropland(ext_regi) "Maximum share of cropland available for enhanced weathering by region" / %cm_33_EW_maxShareOfCropland% /;
+parameter f33_EW_maxShareOfCropland(ext_regi) "Maximum share of suitable cropland available for enhanced weathering by region" / %cm_33_EW_maxShareOfCropland% /;
 p33_EW_maxShareOfCropland(regi) = 1; !! if no value is assigned to GLO, the default share is set to 100%
 p33_EW_maxShareOfCropland(regi) = f33_EW_maxShareOfCropland("GLO"); !! if a value is assigned to GLO, this value is set for all regions
 loop(ext_regi$f33_EW_maxShareOfCropland(ext_regi),
diff --git a/modules/33_carbonRemoval/portfolio/declarations.gms b/modules/33_carbonRemoval/portfolio/declarations.gms
index 2614d4d8c5..972d7d1552 100644
--- a/modules/33_carbonRemoval/portfolio/declarations.gms
+++ b/modules/33_carbonRemoval/portfolio/declarations.gms
@@ -24,7 +24,6 @@ parameters
 *** Multiple options
 p33_fedem(all_te,all_enty)               "final energy demand of each technology [EJ/GtC] (for EW the unit is [EJ/Gt stone])"
 *** EW
-p33_LimRock(all_regi)                    "regional share of EW limit [fraction], calculated ex ante for a maximal annual amount of 8 Gt rock in D:\projects\CEMICS\paper_technical\supply_curve_transport_remind_regions.m"
 p33_rock_weath_rate(rlf)                 "fraction of stone weathering per year depending on climate grade (warm or temperate)"
 p33_EW_upScalingLimit(ttot)              "Annual growth rate limit on upscaling of mining & spreading rocks on fields"
 p33_EW_shortTermEW_Limit(all_regi)       "Limit on 2030 potential for enhanced weathering, defined in Gt rocks, based on % of land on which EW is applied"
@@ -89,7 +88,6 @@ q33_EW_omcosts(ttot,all_regi)  "calculates O&M costs for spreading ground rocks
 q33_EW_FEdemand(ttot,all_regi,all_enty)  "calculates final energy demand from enhanced weathering"
 q33_EW_potential(ttot,all_regi,rlf)  "limits the total potential of EW per region and grade"
 q33_EW_emi(ttot,all_regi)  "calculates amount of carbon captured by EW"
-q33_EW_LimEmi(ttot,all_regi)  "limits EW to a maximal annual amount of ground rock of cm_LimRock"
 q33_EW_upscaling_rate(ttot, all_regi) "limits spreading of rock to a steep but credible upscaling rate"
 q33_EW_ShortTermBound(ttot,all_regi)   "Limits short term potential for enhanced weathering"
 
diff --git a/modules/33_carbonRemoval/portfolio/equations.gms b/modules/33_carbonRemoval/portfolio/equations.gms
index b53f78255b..902b27582d 100644
--- a/modules/33_carbonRemoval/portfolio/equations.gms
+++ b/modules/33_carbonRemoval/portfolio/equations.gms
@@ -189,16 +189,6 @@ q33_EW_potential(t,regi,rlf_cz33)..
     ;
 
 
-***---------------------------------------------------------------------------
-*'  An annual limit for the maximum global amount of rocks spread [Gt] can be set via cm_LimRock,
-*'  e.g. due to sustainability concerns.
-***---------------------------------------------------------------------------
-q33_EW_LimEmi(t,regi)..
-    sum((rlf_cz33, rlf), v33_EW_onfield(t,regi,rlf_cz33,rlf))
-    =l=
-    cm_LimRock * p33_LimRock(regi)
-    ;
-
 ***---------------------------------------------------------------------------
 *' Short term bound on spreading of rock
 ***---------------------------------------------------------------------------
diff --git a/modules/33_carbonRemoval/portfolio/realization.gms b/modules/33_carbonRemoval/portfolio/realization.gms
index a36706d8af..5c60d42e47 100644
--- a/modules/33_carbonRemoval/portfolio/realization.gms
+++ b/modules/33_carbonRemoval/portfolio/realization.gms
@@ -19,8 +19,7 @@
 *' on crop fields where it weathers in reaction with water and atmospheric CO2. Electricity is needed to grind the
 *' rocks and diesel is needed for transportation and spreading on crop fields. The weathering process leads to an exponential
 *' decay over time of the spread rocks. There is an upper limit on the amount of rock that can be on the fields, so that
-*' in equilibrium only the part that decays in one timestep can be replaced in the next. In addition, an arbitrary
-*' limit of the amount of rock spread each year can be set in cm_LimRock. Costs consist of costs for capital, O&M,
+*' in equilibrium only the part that decays in one timestep can be replaced in the next. Costs consist of costs for capital, O&M,
 *' distribution and transport (grades depend on region specific transport distance from mine to fields).
 *'
 *' (OAE) Ocean alkalinity enhancement via ocean liming draws down CO2 from the atmosphere by adding (hydrated) lime
diff --git a/standalone/MOFEX/MOFEX.gms b/standalone/MOFEX/MOFEX.gms
index 78266bd2c4..e41aacdfda 100644
--- a/standalone/MOFEX/MOFEX.gms
+++ b/standalone/MOFEX/MOFEX.gms
@@ -170,7 +170,6 @@ c_export_tax_scen    "choose which oil export tax is used in the model. 0 = none
 cm_iterative_target_adj "whether or not a tax or a budget target should be iteratively adjusted depending on actual emission or forcing level"
 cm_gdximport_target   "whether or not the starting value for iteratively adjusted budgets, tax scenarios, or forcing targets (emiscen 5,6,8,9) should be read in from the input.gdx"
 cm_gs_ew              "grain size (for enhanced weathering, CDR module) [micrometre]"
-cm_LimRock             "limit amount of rock spread each year [Gt]"
 cm_expoLinear_yearStart "time at which carbon price increases linearly instead of exponentially"
 
 c_budgetCO2FFI        "carbon budget for CO2 emissions from FFI (in GtCO2)"
@@ -299,7 +298,6 @@ cm_iterative_target_adj  = 0;      !! def = 0
 cm_gdximport_target      = 0;      !! def = 0
 $setglobal c_SSP_forcing_adjust  forcing_SSP2   !! def = forcing_SSP2
 cm_gs_ew                 = 20;     !! def = 20
-cm_LimRock               = 1000;   !! def = 1000
 cm_expoLinear_yearStart  = 2050;   !! def = 2050
 c_budgetCO2FFI           = 1000;   !! def = 1000
 c_abtrdy                 = 2010;   !! def = 2010
diff --git a/standalone/template.gms b/standalone/template.gms
index 36e48f195b..32843c7795 100644
--- a/standalone/template.gms
+++ b/standalone/template.gms
@@ -166,7 +166,6 @@ c_export_tax_scen    "choose which oil export tax is used in the model. 0 = none
 cm_iterative_target_adj "whether or not a tax or a budget target should be iteratively adjusted depending on actual emission or forcing level"
 cm_gdximport_target   "whether or not the starting value for iteratively adjusted budgets, tax scenarios, or forcing targets (emiscen 5,6,8,9) should be read in from the input.gdx"
 cm_gs_ew              "grain size (for enhanced weathering, CDR module) [micrometre]"
-cm_LimRock             "limit amount of rock spread each year [Gt]"
 cm_expoLinear_yearStart "time at which carbon price increases linearly instead of exponentially"
 
 c_budgetCO2FFI        "carbon budget for CO2 emissions from FFI (in GtCO2)"
@@ -253,7 +252,6 @@ cm_iterative_target_adj  = 0;      !! def = 0
 cm_gdximport_target      = 0;      !! def = 0
 $setglobal c_SSP_forcing_adjust  forcing_SSP2   !! def = forcing_SSP2
 cm_gs_ew                 = 20;     !! def = 20
-cm_LimRock               = 1000;   !! def = 1000
 cm_expoLinear_yearStart  = 2050;   !! def = 2050
 c_budgetCO2FFI           = 1000;   !! def = 1000
 c_abtrdy                 = 2010;   !! def = 2010
diff --git a/standalone/trade/trade.gms b/standalone/trade/trade.gms
index 68ae9acc91..d5be04c038 100644
--- a/standalone/trade/trade.gms
+++ b/standalone/trade/trade.gms
@@ -174,7 +174,6 @@ c_export_tax_scen    "choose which oil export tax is used in the model. 0 = none
 cm_iterative_target_adj "whether or not a tax or a budget target should be iteratively adjusted depending on actual emission or forcing level"
 cm_gdximport_target   "whether or not the starting value for iteratively adjusted budgets, tax scenarios, or forcing targets (emiscen 5,6,8,9) should be read in from the input.gdx"
 cm_gs_ew              "grain size (for enhanced weathering, CDR module) [micrometre]"
-cm_LimRock             "limit amount of rock spread each year [Gt]"
 cm_expoLinear_yearStart "time at which carbon price increases linearly instead of exponentially"
 
 c_budgetCO2FFI        "carbon budget for CO2 emissions from FFI (in GtCO2)"
@@ -304,7 +303,6 @@ cm_iterative_target_adj  = 0;      !! def = 0
 cm_gdximport_target      = 0;      !! def = 0
 $setglobal c_SSP_forcing_adjust  forcing_SSP2   !! def = forcing_SSP2
 cm_gs_ew                 = 20;     !! def = 20
-cm_LimRock               = 1000;   !! def = 1000
 cm_expoLinear_yearStart  = 2050;   !! def = 2050
 c_budgetCO2FFI           = 1000;   !! def = 1000
 c_abtrdy                 = 2010;   !! def = 2010

From 33324f26574b54d5f6aac96e59086bc29f9c6b3a Mon Sep 17 00:00:00 2001
From: tabeado <tabea.dorndorf@pik-potsdam.de>
Date: Wed, 22 Jul 2026 12:29:52 +0200
Subject: [PATCH 03/11] adjust weathering cost + documentation

---
 core/input/generisdata_tech.prn | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/core/input/generisdata_tech.prn b/core/input/generisdata_tech.prn
index f731e7e457..9a6595dea2 100644
--- a/core/input/generisdata_tech.prn
+++ b/core/input/generisdata_tech.prn
@@ -162,7 +162,7 @@ constrTme           3            5
 lifetime           40           40            20          20          25          25
 mix0             1.00         1.00
 eta              1.00         1.00          1.00        1.00        1.00        1.00
-omf              0.06         0.12          0.84       0.025        0.35        0.17
+omf              0.06         0.12          0.59       0.025        0.35        0.17
 ccap0                                                 0.0008
 learn                                                   0.15
 
@@ -303,6 +303,13 @@ Ocean Liming - oae
     Costs per tC removed is calculated in the code as it depends on the efficiency (tCO2/tCaO; exogenous):
         cost (USD/tC) = inco0 (USD/tCaO) / ( efficiency (tCO2/tCaO) / 3.66 (tCO2/tC) )
 
+Enhanced Rock Weathering - weathering
+    Parameterization based on Strefler et al (2018) doi.org/10.1088/1748-9326/aaa9c4
+    annuity factor = 0.08 for lifetime of 20 years and r = 0.05; capacity factor = 0.69
+    inco0: 5 (USD/t rock) * 0.69 / 0.08 = 43 USD/t rock/a for mining and production
+    omf: O&M cost from rock mining & production (25 USD/t rock) and transportation & distribution (12 USD/t rock), i.e. 37/(43/0.69) = 0.86
+    To use the upper Capital Cost estimate from Strefler et al, 15 USD/t rock, set inco0 = 129 and omf = 0.2
+
 Gas to Liquids (GtL) Fischer-Tropsch Process - gasftrec/gasftcrec
     efficiency eta = 0.60 (0.57 with capture), estimation at higher end of efficiency spectrum
     Details in Issue 518/PR 2034

From eb4eacf49481eb2b634925e73512bc6f6881b5ec Mon Sep 17 00:00:00 2001
From: tabeado <tabea.dorndorf@pik-potsdam.de>
Date: Wed, 22 Jul 2026 15:37:30 +0200
Subject: [PATCH 04/11] add cm_33_EW_rockRemPot, documentation, fixes

---
 core/input/generisdata_tech.prn                     |  4 ++--
 main.gms                                            | 10 +++++++++-
 modules/33_carbonRemoval/portfolio/datainput.gms    |  4 +++-
 modules/33_carbonRemoval/portfolio/declarations.gms |  2 +-
 modules/33_carbonRemoval/portfolio/equations.gms    |  2 +-
 5 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/core/input/generisdata_tech.prn b/core/input/generisdata_tech.prn
index 9a6595dea2..3b7b833bcf 100644
--- a/core/input/generisdata_tech.prn
+++ b/core/input/generisdata_tech.prn
@@ -155,8 +155,8 @@ lifetime               30        30          45          45          45
 
 *** carbon management
 +           ccsinjeon   ccsinjeoff    weathering         dac      oae_ng      oae_el
-tech_stat           0            0                         4
-inco0             350          525          0.01       18800         200         400
+tech_stat           0            0             1           4 
+inco0             350          525            43        18800        200         400
 floorcost                                               4800
 constrTme           3            5
 lifetime           40           40            20          20          25          25
diff --git a/main.gms b/main.gms
index 0de13db480..cf90c2ef13 100755
--- a/main.gms
+++ b/main.gms
@@ -1088,7 +1088,15 @@ parameter
 *'
 
 parameter
-
+  cm_33_EW_rockRemPot             "Maximum CO2 removal potential per ton of rock."
+;
+  cm_33_EW_rockRemPot            = 0.3;   !! def = 0.3 t CO2 / t basalt
+*' Theoretical potential is influenced by the chemical composition of the rock, in particular calcium and magnesium content. 
+*' * (0.3): 0.3 t CO2 / t basalt is the commonly used average, see e.g. Strefler et al 2018 (SI-A Table A-1)
+*' * (0.2-0.4): 0.2 and 0.4 t CO2 / t basalt are a lower and upper bound in Strefler et al 2018 (SI-A Table A-1) 
+*' The theoretical potential may not be reached due to different loss pathways (dissolution through strong acids;
+*' secondary mineral formation (esp. clays); secondary carbonate formation (where carbon retention is only temporary)) which 
+*' strongly depend on the local soil conditions. Reduction below 50% of the theoretical potential is well possible. 
 *'
 parameter
   cm_33_EW_upScalingRateLimit    "Annual growth rate limit on upscaling of mining & spreading rocks on fields"
diff --git a/modules/33_carbonRemoval/portfolio/datainput.gms b/modules/33_carbonRemoval/portfolio/datainput.gms
index 90c52ca256..76b49a11e3 100644
--- a/modules/33_carbonRemoval/portfolio/datainput.gms
+++ b/modules/33_carbonRemoval/portfolio/datainput.gms
@@ -39,7 +39,9 @@ s33_step = 2.5;
 *' @code
 *' fix costs [T$/Gt stone]. Data from strefler et al. in $/t stone: mining, crushing, grinding (5.0 investment costs, 25.1 O&M costs), spreading (12.1 O&M costs)
 s33_costs_fix = 0.0422;
-s33_co2_rem_pot = 0.3 * 12/44;       !! default for basalt, for Olivine 1.1
+s33_rockRemPot = cm_33_EW_rockRemPot * 12/44;       !! default for basalt is 0.3 t CO2/t rock, for Olivine 1.1 t CO2/t rock. Converted to t C/t rock.
+*' Sources for loss pathways that would reduce the total removal potential per ton rock: 
+*' https://www.carbon-drawdown.de/blog/2026-7-18-where-does-the-co-removal-potential-of-enhanced-weathering-actually-go; https://cdrxiv.org/preprint/417
 
 *' rock weathering rate (i.e. fraction of rock weathering per year) at ambient temperature (25 degree C), based on 
 *' eq 2 in strefler, amann et al. (2018): 
diff --git a/modules/33_carbonRemoval/portfolio/declarations.gms b/modules/33_carbonRemoval/portfolio/declarations.gms
index 972d7d1552..bfbacca902 100644
--- a/modules/33_carbonRemoval/portfolio/declarations.gms
+++ b/modules/33_carbonRemoval/portfolio/declarations.gms
@@ -9,7 +9,7 @@ scalars
 *** Multiple options
 sm_capture_rate_cdrmodule       "CO2 capture rate for CDR energy and process emissions, i.e. fegas use in OAE and DAC and for calcination emissions in oae" / 0.9 /
 *** EW
-s33_co2_rem_pot                 "specific carbon removal potential [Gt C per Gt ground rock]"
+s33_rockRemPot                 "specific carbon removal potential [Gt C per Gt ground rock]"
 s33_rock_weath_rate_ambientT    "fraction of stone weathering per year at ambient temperature (25 degree C)"
 s33_costs_fix                   "fixed costs for mining, grinding, spreading [T$/Gt stone]"
 s33_step                        "size of bins in v33_weathering_onfield [Gt stone]"
diff --git a/modules/33_carbonRemoval/portfolio/equations.gms b/modules/33_carbonRemoval/portfolio/equations.gms
index 902b27582d..d3a59c993e 100644
--- a/modules/33_carbonRemoval/portfolio/equations.gms
+++ b/modules/33_carbonRemoval/portfolio/equations.gms
@@ -154,7 +154,7 @@ q33_EW_emi(t,regi)..
     vm_emiCdrTeDetail(t,regi, "weathering")
     =e=
     sum((rlf_cz33, rlf),
-        - v33_EW_onfield_tot(t,regi,rlf_cz33,rlf) * s33_co2_rem_pot * p33_rock_weath_rate(rlf_cz33)
+        - v33_EW_onfield_tot(t,regi,rlf_cz33,rlf) * s33_rockRemPot * p33_rock_weath_rate(rlf_cz33)
         )
     ;
 

From 031af72144ab514703902d8215529472137c8e87 Mon Sep 17 00:00:00 2001
From: Tabea Dorndorf <117268634+tabeado@users.noreply.github.com>
Date: Wed, 22 Jul 2026 16:47:25 +0200
Subject: [PATCH 05/11] bugfix in description

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
---
 core/input/generisdata_tech.prn | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/core/input/generisdata_tech.prn b/core/input/generisdata_tech.prn
index 3b7b833bcf..0b973768a8 100644
--- a/core/input/generisdata_tech.prn
+++ b/core/input/generisdata_tech.prn
@@ -307,7 +307,7 @@ Enhanced Rock Weathering - weathering
     Parameterization based on Strefler et al (2018) doi.org/10.1088/1748-9326/aaa9c4
     annuity factor = 0.08 for lifetime of 20 years and r = 0.05; capacity factor = 0.69
     inco0: 5 (USD/t rock) * 0.69 / 0.08 = 43 USD/t rock/a for mining and production
-    omf: O&M cost from rock mining & production (25 USD/t rock) and transportation & distribution (12 USD/t rock), i.e. 37/(43/0.69) = 0.86
+    omf: O&M cost from rock mining & production (25 USD/t rock) and transportation & distribution (12 USD/t rock), i.e. 37/(43/0.69) = 0.59
     To use the upper Capital Cost estimate from Strefler et al, 15 USD/t rock, set inco0 = 129 and omf = 0.2
 
 Gas to Liquids (GtL) Fischer-Tropsch Process - gasftrec/gasftcrec

From d54eac80c757d13c4e07e4e84bfca4be8be699e9 Mon Sep 17 00:00:00 2001
From: tabeado <tabea.dorndorf@pik-potsdam.de>
Date: Mon, 27 Jul 2026 12:19:24 +0200
Subject: [PATCH 06/11] remove old ERW cost calculation in module 33 + renaming

---
 core/equations.gms                                  | 2 +-
 modules/33_carbonRemoval/portfolio/bounds.gms       | 4 ++--
 modules/33_carbonRemoval/portfolio/datainput.gms    | 2 --
 modules/33_carbonRemoval/portfolio/declarations.gms | 3 +--
 modules/33_carbonRemoval/portfolio/equations.gms    | 4 ++--
 5 files changed, 6 insertions(+), 9 deletions(-)

diff --git a/core/equations.gms b/core/equations.gms
index 2ed65dd7dd..ccf1e94836 100644
--- a/core/equations.gms
+++ b/core/equations.gms
@@ -106,7 +106,7 @@ q_costOM(t,regi)..
              vm_costTeCapital(t,regi,te) * vm_cap(t,regi,te,rlf)
             )
   )
-  + vm_omcosts_cdr(t,regi)
+  + vm_EW_transport_costs(t,regi)
 ;
 
 ***---------------------------------------------------------------------------
diff --git a/modules/33_carbonRemoval/portfolio/bounds.gms b/modules/33_carbonRemoval/portfolio/bounds.gms
index 25474693d3..495d8e453f 100644
--- a/modules/33_carbonRemoval/portfolio/bounds.gms
+++ b/modules/33_carbonRemoval/portfolio/bounds.gms
@@ -30,7 +30,7 @@ vm_co2emi_cdrFE_beforeCapture.fx(t,regi,te_all33)$(not te_ccs33(te_all33)) = 0;
 vm_emiCdrTeDetail.fx(t,regi,te_used33)$(t.val lt 2025) = 0.0;
 v33_FEdemand.fx(t,regi,entyFe,entyFe2,te_used33)$(fe2cdr(entyFe,entyFe2,te_used33) AND (t.val lt 2025)) = 0.0;
 vm_emiCdr.fx(t,regi,"co2")$(t.val lt 2025) = 0;
-vm_omcosts_cdr.fx(t,regi)$((t.val lt 2025)) = 0;
+vm_EW_transport_costs.fx(t,regi)$((t.val lt 2025)) = 0;
 vm_cap.fx(t,regi,"weathering",rlf)$(t.val lt 2025) = 0;
 vm_co2emi_cdrFE_beforeCapture.fx(t,regi,te_used33)$(t.val lt 2025) = 0;
 v33_co2emi_non_atm_calcination.fx(t,regi,te_oae33)$(t.val lt 2025) = 0;
@@ -61,7 +61,7 @@ if(te_used33("weathering"),
     v33_EW_onfield_tot.fx(ttot,regi,rlf_cz33,rlf)$(ttot.val lt max(2025,cm_startyear)) = 0.0; !! 
     vm_emiCdrTeDetail.up(ttot,regi,"weathering")$(ttot.val gt 2040) = - sm_eps; !! force some minimum amount of EW to help the solver see it 
 else
-    vm_omcosts_cdr.fx(t,regi) = 0;
+    vm_EW_transport_costs.fx(t,regi) = 0;
     vm_cap.fx(t,regi,"weathering",rlf) = 0;
 );
 
diff --git a/modules/33_carbonRemoval/portfolio/datainput.gms b/modules/33_carbonRemoval/portfolio/datainput.gms
index 76b49a11e3..5a090b1eb9 100644
--- a/modules/33_carbonRemoval/portfolio/datainput.gms
+++ b/modules/33_carbonRemoval/portfolio/datainput.gms
@@ -37,8 +37,6 @@ display p33_EW_transport_costs;
 s33_step = 2.5;
 
 *' @code
-*' fix costs [T$/Gt stone]. Data from strefler et al. in $/t stone: mining, crushing, grinding (5.0 investment costs, 25.1 O&M costs), spreading (12.1 O&M costs)
-s33_costs_fix = 0.0422;
 s33_rockRemPot = cm_33_EW_rockRemPot * 12/44;       !! default for basalt is 0.3 t CO2/t rock, for Olivine 1.1 t CO2/t rock. Converted to t C/t rock.
 *' Sources for loss pathways that would reduce the total removal potential per ton rock: 
 *' https://www.carbon-drawdown.de/blog/2026-7-18-where-does-the-co-removal-potential-of-enhanced-weathering-actually-go; https://cdrxiv.org/preprint/417
diff --git a/modules/33_carbonRemoval/portfolio/declarations.gms b/modules/33_carbonRemoval/portfolio/declarations.gms
index bfbacca902..46f774c2c0 100644
--- a/modules/33_carbonRemoval/portfolio/declarations.gms
+++ b/modules/33_carbonRemoval/portfolio/declarations.gms
@@ -11,7 +11,6 @@ sm_capture_rate_cdrmodule       "CO2 capture rate for CDR energy and process emi
 *** EW
 s33_rockRemPot                 "specific carbon removal potential [Gt C per Gt ground rock]"
 s33_rock_weath_rate_ambientT    "fraction of stone weathering per year at ambient temperature (25 degree C)"
-s33_costs_fix                   "fixed costs for mining, grinding, spreading [T$/Gt stone]"
 s33_step                        "size of bins in v33_weathering_onfield [Gt stone]"
 *JeS* GJ/tCO2 = EJ/Gt CO2 = 44/12 EJ/Gt C.
 *** OAE
@@ -41,7 +40,7 @@ p33_GDP_NetNeg_share(all_regi)                    "Upper bound on share of expen
 ;
 
 variables
-vm_omcosts_cdr(tall,all_regi)                        "O&M costs for spreading grinded rocks on fields [T$]"
+vm_EW_transport_costs(tall,all_regi)     "O&M costs for spreading grinded rocks on fields [T$]"
 ;
 
 positive variables
diff --git a/modules/33_carbonRemoval/portfolio/equations.gms b/modules/33_carbonRemoval/portfolio/equations.gms
index d3a59c993e..c926a638f7 100644
--- a/modules/33_carbonRemoval/portfolio/equations.gms
+++ b/modules/33_carbonRemoval/portfolio/equations.gms
@@ -172,10 +172,10 @@ q33_EW_FEdemand(t,regi,entyFe2)$sum(entyFe, fe2cdr(entyFe,entyFe2,"weathering"))
 *'  O&M costs of EW, consisting of fix costs for mining, grinding and spreading, and transportation costs.
 ***---------------------------------------------------------------------------
 q33_EW_omcosts(t,regi)..
-    vm_omcosts_cdr(t,regi)
+    vm_EW_transport_costs(t,regi)
     =e=
     sum((rlf_cz33, rlf),
-        (s33_costs_fix + p33_EW_transport_costs(regi,rlf_cz33,rlf)) * v33_EW_onfield(t,regi,rlf_cz33,rlf)
+        (p33_EW_transport_costs(regi,rlf_cz33,rlf)) * v33_EW_onfield(t,regi,rlf_cz33,rlf)
     )
     ;
 

From c4ad69d81612377671f2a98dfa7c18fe90554a8b Mon Sep 17 00:00:00 2001
From: tabeado <tabea.dorndorf@pik-potsdam.de>
Date: Mon, 27 Jul 2026 14:26:13 +0200
Subject: [PATCH 07/11] consistency fixes

---
 core/datainput.gms                                  | 4 ++--
 core/input/generisdata_tech.prn                     | 2 +-
 main.gms                                            | 2 +-
 modules/33_carbonRemoval/portfolio/datainput.gms    | 2 +-
 modules/33_carbonRemoval/portfolio/declarations.gms | 6 +++---
 standalone/MOFEX/MOFEX.gms                          | 2 ++
 standalone/template.gms                             | 2 ++
 standalone/trade/trade.gms                          | 2 ++
 8 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/core/datainput.gms b/core/datainput.gms
index 7e746e0d36..5ced91119c 100644
--- a/core/datainput.gms
+++ b/core/datainput.gms
@@ -291,8 +291,8 @@ fm_dataglob("inco0", "oae_el") = fm_dataglob("inco0", "oae_el") / (cm_33_OAE_eff
 
 *** convert inco0, floorcost and omv to REMIND units by applying a factor 0.001
 ***   category          energy technology   ccs technology    process-based industry            weathering
-***   input data unit   $/kW                $/(tC/a)          $/(t/a)                         $/(t rocks/a)
-***   REMIND unit       T$/TW               T$/(GtC/a)        T$/(Gt/a)                       T$/(Gt rocks/a)
+***   input data unit   $/kW                $/(tC/a)          $/(t/a)                         $/(t rock/a)
+***   REMIND unit       T$/TW               T$/(GtC/a)        T$/(Gt/a)                       T$/(Gt rock/a)
 fm_dataglob("inco0",te)        = s_DpKW_2_TDpTW   * fm_dataglob("inco0",te);
 fm_dataglob("floorcost",te)    = s_DpKW_2_TDpTW   * fm_dataglob("floorcost",te);
 fm_dataglob("omv",te)          = s_DpKWa_2_TDpTWa * fm_dataglob("omv",te);
diff --git a/core/input/generisdata_tech.prn b/core/input/generisdata_tech.prn
index 0b973768a8..3864a4ed21 100644
--- a/core/input/generisdata_tech.prn
+++ b/core/input/generisdata_tech.prn
@@ -1,7 +1,7 @@
 *** SOF ./core/input/generisdata_tech.prn
 $ontext
 tech_stat   technology status: how close a technology is to market readiness. Scale: 0-3, with 0 'I can go out and build a GW plant today' to 3 'Still some research necessary'
-inco0       Initial investment costs given in $[2015] / kW[output] capacity; for dac/prc cc: $[2015] / (tC[captured]/a); for other indutry prc: $[2015]/(t[output]/a); for weathering:  $[2015]/(t rock/a)
+inco0       Initial investment costs given in $[2015] / kW[output] capacity; for dac/prc cc: $[2015] / (tC[captured]/a); for other industry prc: $[2015]/(t[output]/a); for weathering:  $[2015]/(t rock/a)
 floorcost   Floor investment costs, given in $[2015] / kW[output]; for dac: $[2015] / (tC[captured]/a)
 constrTme   Construction time in years, needed to calculate turn-key cost premium compared to overnight costs
 lifetime    Average lifetime of a technology, given in years. Effective maximum lifetime is longer than that.
diff --git a/main.gms b/main.gms
index cf90c2ef13..568aa023b6 100755
--- a/main.gms
+++ b/main.gms
@@ -1088,7 +1088,7 @@ parameter
 *'
 
 parameter
-  cm_33_EW_rockRemPot             "Maximum CO2 removal potential per ton of rock."
+  cm_33_EW_rockRemPot             "Maximum CO2 removal potential per ton of rock (t CO2 / t rock)."
 ;
   cm_33_EW_rockRemPot            = 0.3;   !! def = 0.3 t CO2 / t basalt
 *' Theoretical potential is influenced by the chemical composition of the rock, in particular calcium and magnesium content. 
diff --git a/modules/33_carbonRemoval/portfolio/datainput.gms b/modules/33_carbonRemoval/portfolio/datainput.gms
index 5a090b1eb9..c16a911bb5 100644
--- a/modules/33_carbonRemoval/portfolio/datainput.gms
+++ b/modules/33_carbonRemoval/portfolio/datainput.gms
@@ -37,7 +37,7 @@ display p33_EW_transport_costs;
 s33_step = 2.5;
 
 *' @code
-s33_rockRemPot = cm_33_EW_rockRemPot * 12/44;       !! default for basalt is 0.3 t CO2/t rock, for Olivine 1.1 t CO2/t rock. Converted to t C/t rock.
+s33_rockRemPot = cm_33_EW_rockRemPot / sm_c_2_co2;       !! default for basalt is 0.3 t CO2/t rock, for Olivine 1.1 t CO2/t rock. Converted to t C/t rock.
 *' Sources for loss pathways that would reduce the total removal potential per ton rock: 
 *' https://www.carbon-drawdown.de/blog/2026-7-18-where-does-the-co-removal-potential-of-enhanced-weathering-actually-go; https://cdrxiv.org/preprint/417
 
diff --git a/modules/33_carbonRemoval/portfolio/declarations.gms b/modules/33_carbonRemoval/portfolio/declarations.gms
index 46f774c2c0..b5a37fb0a6 100644
--- a/modules/33_carbonRemoval/portfolio/declarations.gms
+++ b/modules/33_carbonRemoval/portfolio/declarations.gms
@@ -9,9 +9,9 @@ scalars
 *** Multiple options
 sm_capture_rate_cdrmodule       "CO2 capture rate for CDR energy and process emissions, i.e. fegas use in OAE and DAC and for calcination emissions in oae" / 0.9 /
 *** EW
-s33_rockRemPot                 "specific carbon removal potential [Gt C per Gt ground rock]"
+s33_rockRemPot                 "specific carbon removal potential [t C / t rock]"
 s33_rock_weath_rate_ambientT    "fraction of stone weathering per year at ambient temperature (25 degree C)"
-s33_step                        "size of bins in v33_weathering_onfield [Gt stone]"
+s33_step                        "size of bins in v33_weathering_onfield [Gt stone]" / 2.5 /
 *JeS* GJ/tCO2 = EJ/Gt CO2 = 44/12 EJ/Gt C.
 *** OAE
 s33_OAE_efficiency          "the amount of rock required to sequester 1GtC [Gt rock / GtC]"
@@ -21,7 +21,7 @@ s33_OAE_glo_limit           "global limit for OAE [tC / a]"
 
 parameters
 *** Multiple options
-p33_fedem(all_te,all_enty)               "final energy demand of each technology [EJ/GtC] (for EW the unit is [EJ/Gt stone])"
+p33_fedem(all_te,all_enty)               "final energy demand of each technology [EJ/GtC] (for EW the unit is [EJ/Gt rock])"
 *** EW
 p33_rock_weath_rate(rlf)                 "fraction of stone weathering per year depending on climate grade (warm or temperate)"
 p33_EW_upScalingLimit(ttot)              "Annual growth rate limit on upscaling of mining & spreading rocks on fields"
diff --git a/standalone/MOFEX/MOFEX.gms b/standalone/MOFEX/MOFEX.gms
index e41aacdfda..2b7414b8c9 100644
--- a/standalone/MOFEX/MOFEX.gms
+++ b/standalone/MOFEX/MOFEX.gms
@@ -170,6 +170,7 @@ c_export_tax_scen    "choose which oil export tax is used in the model. 0 = none
 cm_iterative_target_adj "whether or not a tax or a budget target should be iteratively adjusted depending on actual emission or forcing level"
 cm_gdximport_target   "whether or not the starting value for iteratively adjusted budgets, tax scenarios, or forcing targets (emiscen 5,6,8,9) should be read in from the input.gdx"
 cm_gs_ew              "grain size (for enhanced weathering, CDR module) [micrometre]"
+cm_33_EW_rockRemPot     "Maximum CO2 removal potential per ton of rock (t CO2 / t rock)."
 cm_expoLinear_yearStart "time at which carbon price increases linearly instead of exponentially"
 
 c_budgetCO2FFI        "carbon budget for CO2 emissions from FFI (in GtCO2)"
@@ -298,6 +299,7 @@ cm_iterative_target_adj  = 0;      !! def = 0
 cm_gdximport_target      = 0;      !! def = 0
 $setglobal c_SSP_forcing_adjust  forcing_SSP2   !! def = forcing_SSP2
 cm_gs_ew                 = 20;     !! def = 20
+cm_33_EW_rockRemPot      = 0.3;    !! def = 0.3
 cm_expoLinear_yearStart  = 2050;   !! def = 2050
 c_budgetCO2FFI           = 1000;   !! def = 1000
 c_abtrdy                 = 2010;   !! def = 2010
diff --git a/standalone/template.gms b/standalone/template.gms
index 32843c7795..f0b001ea63 100644
--- a/standalone/template.gms
+++ b/standalone/template.gms
@@ -166,6 +166,7 @@ c_export_tax_scen    "choose which oil export tax is used in the model. 0 = none
 cm_iterative_target_adj "whether or not a tax or a budget target should be iteratively adjusted depending on actual emission or forcing level"
 cm_gdximport_target   "whether or not the starting value for iteratively adjusted budgets, tax scenarios, or forcing targets (emiscen 5,6,8,9) should be read in from the input.gdx"
 cm_gs_ew              "grain size (for enhanced weathering, CDR module) [micrometre]"
+cm_33_EW_rockRemPot     "Maximum CO2 removal potential per ton of rock (t CO2 / t rock)."
 cm_expoLinear_yearStart "time at which carbon price increases linearly instead of exponentially"
 
 c_budgetCO2FFI        "carbon budget for CO2 emissions from FFI (in GtCO2)"
@@ -252,6 +253,7 @@ cm_iterative_target_adj  = 0;      !! def = 0
 cm_gdximport_target      = 0;      !! def = 0
 $setglobal c_SSP_forcing_adjust  forcing_SSP2   !! def = forcing_SSP2
 cm_gs_ew                 = 20;     !! def = 20
+cm_33_EW_rockRemPot      = 0.3;    !! def = 0.3
 cm_expoLinear_yearStart  = 2050;   !! def = 2050
 c_budgetCO2FFI           = 1000;   !! def = 1000
 c_abtrdy                 = 2010;   !! def = 2010
diff --git a/standalone/trade/trade.gms b/standalone/trade/trade.gms
index d5be04c038..68a7580b20 100644
--- a/standalone/trade/trade.gms
+++ b/standalone/trade/trade.gms
@@ -174,6 +174,7 @@ c_export_tax_scen    "choose which oil export tax is used in the model. 0 = none
 cm_iterative_target_adj "whether or not a tax or a budget target should be iteratively adjusted depending on actual emission or forcing level"
 cm_gdximport_target   "whether or not the starting value for iteratively adjusted budgets, tax scenarios, or forcing targets (emiscen 5,6,8,9) should be read in from the input.gdx"
 cm_gs_ew              "grain size (for enhanced weathering, CDR module) [micrometre]"
+cm_33_EW_rockRemPot     "Maximum CO2 removal potential per ton of rock (t CO2 / t rock)."
 cm_expoLinear_yearStart "time at which carbon price increases linearly instead of exponentially"
 
 c_budgetCO2FFI        "carbon budget for CO2 emissions from FFI (in GtCO2)"
@@ -303,6 +304,7 @@ cm_iterative_target_adj  = 0;      !! def = 0
 cm_gdximport_target      = 0;      !! def = 0
 $setglobal c_SSP_forcing_adjust  forcing_SSP2   !! def = forcing_SSP2
 cm_gs_ew                 = 20;     !! def = 20
+cm_33_EW_rockRemPot      = 0.3;    !! def = 0.3
 cm_expoLinear_yearStart  = 2050;   !! def = 2050
 c_budgetCO2FFI           = 1000;   !! def = 1000
 c_abtrdy                 = 2010;   !! def = 2010

From 49c5700091b7a14442bb3a6e0f3066af34190b30 Mon Sep 17 00:00:00 2001
From: tabeado <tabea.dorndorf@pik-potsdam.de>
Date: Thu, 6 Aug 2026 15:58:49 +0200
Subject: [PATCH 08/11] ERW documentation and removing cm_gs_ew

---
 core/input/generisdata_tech.prn                  |  3 ++-
 main.gms                                         |  5 -----
 modules/33_carbonRemoval/portfolio/datainput.gms |  4 ++--
 .../33_carbonRemoval/portfolio/declarations.gms  |  7 ++++---
 modules/33_carbonRemoval/portfolio/equations.gms |  6 +++---
 .../33_carbonRemoval/portfolio/realization.gms   | 16 ++++++++++++----
 standalone/MOFEX/MOFEX.gms                       |  2 --
 standalone/template.gms                          |  2 --
 standalone/trade/trade.gms                       |  2 --
 tests/testthat/test_01-checkFixCfg.R             |  1 -
 10 files changed, 23 insertions(+), 25 deletions(-)

diff --git a/core/input/generisdata_tech.prn b/core/input/generisdata_tech.prn
index 3864a4ed21..a71219ec18 100644
--- a/core/input/generisdata_tech.prn
+++ b/core/input/generisdata_tech.prn
@@ -307,7 +307,8 @@ Enhanced Rock Weathering - weathering
     Parameterization based on Strefler et al (2018) doi.org/10.1088/1748-9326/aaa9c4
     annuity factor = 0.08 for lifetime of 20 years and r = 0.05; capacity factor = 0.69
     inco0: 5 (USD/t rock) * 0.69 / 0.08 = 43 USD/t rock/a for mining and production
-    omf: O&M cost from rock mining & production (25 USD/t rock) and transportation & distribution (12 USD/t rock), i.e. 37/(43/0.69) = 0.59
+    omf: O&M cost from rock mining & production (25 USD/t rock) and spreading on fields (12 USD/t rock), i.e. 37/(43/0.69) = 0.59
+    Additional transport cost from mine to field are accounted separately in 33_carbonRemoval depending on distance grade.
     To use the upper Capital Cost estimate from Strefler et al, 15 USD/t rock, set inco0 = 129 and omf = 0.2
 
 Gas to Liquids (GtL) Fischer-Tropsch Process - gasftrec/gasftcrec
diff --git a/main.gms b/main.gms
index 568aa023b6..2657fc6835 100755
--- a/main.gms
+++ b/main.gms
@@ -1081,11 +1081,6 @@ parameter
 *'           5 Gt CO2/yr uptake limit corresponds roughly to CaO being distributed in the upper 2m of the entire (!) EEZ
 *'           up to the precipitation avoiding concentration limit, assuming average uptake efficiency. 
 *' 
-parameter
-  cm_gs_ew                  "grain size (for enhanced weathering, CDR module) [micrometre]"
-;
-  cm_gs_ew                 = 20;     !! def = 20  !! regexp = is.numeric
-*'
 
 parameter
   cm_33_EW_rockRemPot             "Maximum CO2 removal potential per ton of rock (t CO2 / t rock)."
diff --git a/modules/33_carbonRemoval/portfolio/datainput.gms b/modules/33_carbonRemoval/portfolio/datainput.gms
index c16a911bb5..79b83f8994 100644
--- a/modules/33_carbonRemoval/portfolio/datainput.gms
+++ b/modules/33_carbonRemoval/portfolio/datainput.gms
@@ -51,8 +51,8 @@ p33_rock_weath_rate("1") = s33_rock_weath_rate_ambientT * 0.94;
 p33_rock_weath_rate("2") = s33_rock_weath_rate_ambientT * 0.29;
 
 *' JeS FE demand fit from Thorben: SI D in strefler, amann et al. (2018)
-p33_fedem("weathering", "feels") = 6.62 * cm_gs_ew**(-1.16);
-p33_fedem("weathering", "fedie") = 0.3;
+p33_fedem("weathering", "feels") = 6.62 * s33_rockGrainSize**(-1.16);    !! electricity for grinding of rocks, depends on the grain size. 
+p33_fedem("weathering", "fedie") = 0.3;                         !! diesel for spreading rocks on fields using tractors
 
 *' Annual growth rate limit on upscaling of mining & spreading rocks on fields
 p33_EW_upScalingLimit(ttot) = cm_33_EW_upScalingRateLimit;
diff --git a/modules/33_carbonRemoval/portfolio/declarations.gms b/modules/33_carbonRemoval/portfolio/declarations.gms
index b5a37fb0a6..9934a4ed86 100644
--- a/modules/33_carbonRemoval/portfolio/declarations.gms
+++ b/modules/33_carbonRemoval/portfolio/declarations.gms
@@ -9,6 +9,7 @@ scalars
 *** Multiple options
 sm_capture_rate_cdrmodule       "CO2 capture rate for CDR energy and process emissions, i.e. fegas use in OAE and DAC and for calcination emissions in oae" / 0.9 /
 *** EW
+s33_rockGrainSize               "grain size of ground rock, influences electricity demand and weathering rate. By default 20 micrometer based on Strefler et al. (2018) [micrometre]" /20/
 s33_rockRemPot                 "specific carbon removal potential [t C / t rock]"
 s33_rock_weath_rate_ambientT    "fraction of stone weathering per year at ambient temperature (25 degree C)"
 s33_step                        "size of bins in v33_weathering_onfield [Gt stone]" / 2.5 /
@@ -40,7 +41,7 @@ p33_GDP_NetNeg_share(all_regi)                    "Upper bound on share of expen
 ;
 
 variables
-vm_EW_transport_costs(tall,all_regi)     "O&M costs for spreading grinded rocks on fields [T$]"
+vm_EW_transport_costs(tall,all_regi)     "O&M costs for transporting ground rocks from mines to fields [T$]"
 ;
 
 positive variables
@@ -83,8 +84,8 @@ q33_DAC_FEdemand(ttot,all_regi,all_enty)  "calculates final energy demand from D
 *** EW
 q33_EW_capconst(ttot,all_regi)  "calculates amount of ground rock spread on fields"
 q33_EW_onfield_tot(ttot,all_regi,rlf,rlf)  "total amount of ground rock on fields"
-q33_EW_omcosts(ttot,all_regi)  "calculates O&M costs for spreading ground rocks on fields"
-q33_EW_FEdemand(ttot,all_regi,all_enty)  "calculates final energy demand from enhanced weathering"
+q33_EW_transportCosts(ttot,all_regi)  "calculates transport costs for transporting ground rocks from mines to fields"
+q33_EW_FEdemand(ttot,all_regi,all_enty)  "calculates final energy demand from enhanced weathering for grinding and spreading rocks on fields"
 q33_EW_potential(ttot,all_regi,rlf)  "limits the total potential of EW per region and grade"
 q33_EW_emi(ttot,all_regi)  "calculates amount of carbon captured by EW"
 q33_EW_upscaling_rate(ttot, all_regi) "limits spreading of rock to a steep but credible upscaling rate"
diff --git a/modules/33_carbonRemoval/portfolio/equations.gms b/modules/33_carbonRemoval/portfolio/equations.gms
index c926a638f7..03b20c9d1c 100644
--- a/modules/33_carbonRemoval/portfolio/equations.gms
+++ b/modules/33_carbonRemoval/portfolio/equations.gms
@@ -160,7 +160,7 @@ q33_EW_emi(t,regi)..
 
 ***---------------------------------------------------------------------------
 *'  Calculation of FE demand for enhanced weathering, i.e., electricity demand for grinding,
-*'  and the diesel demand for transportation and spreading on crop fields.
+*'  and the diesel demand for spreading rocks on crop fields.
 ***---------------------------------------------------------------------------
 q33_EW_FEdemand(t,regi,entyFe2)$sum(entyFe, fe2cdr(entyFe,entyFe2,"weathering"))..
     sum(fe2cdr(entyFe,entyFe2,"weathering"), v33_FEdemand(t,regi,entyFe,entyFe2,"weathering"))
@@ -169,9 +169,9 @@ q33_EW_FEdemand(t,regi,entyFe2)$sum(entyFe, fe2cdr(entyFe,entyFe2,"weathering"))
     ;
 
 ***---------------------------------------------------------------------------
-*'  O&M costs of EW, consisting of fix costs for mining, grinding and spreading, and transportation costs.
+*'  Transport cost for rocks from mine to field
 ***---------------------------------------------------------------------------
-q33_EW_omcosts(t,regi)..
+q33_EW_transportCosts(t,regi)..
     vm_EW_transport_costs(t,regi)
     =e=
     sum((rlf_cz33, rlf),
diff --git a/modules/33_carbonRemoval/portfolio/realization.gms b/modules/33_carbonRemoval/portfolio/realization.gms
index 5c60d42e47..10d7b422b5 100644
--- a/modules/33_carbonRemoval/portfolio/realization.gms
+++ b/modules/33_carbonRemoval/portfolio/realization.gms
@@ -15,12 +15,15 @@
 *' low-temperature heat demand. The heat can be provided via district heat, electricity, gas, or H2. If gas is used,
 *' the resulting CO2 is captured with a capture rate of 90%.
 *'
-*' (EW) Basalt is mined and ground to fine grain sizes (specified in cm_gs_ew, by default 20 µm), and then spread
+*' (EW) Basalt is mined and ground to fine grain sizes (default 20 µm), and then spread
 *' on crop fields where it weathers in reaction with water and atmospheric CO2. Electricity is needed to grind the
-*' rocks and diesel is needed for transportation and spreading on crop fields. The weathering process leads to an exponential
+*' rocks and diesel is needed for spreading on crop fields. Transport costs from mine to fields depend on distance grades.
+*' In addition, capital cost for mining and production, and O&M cost for mining and distribution on fields are added. 
+*' The amount of rock that can be spread on fields is limited by the maximum potential for enhanced weathering, 
+*' which depends on the region and climate grade. The weathering process leads to an exponential
 *' decay over time of the spread rocks. There is an upper limit on the amount of rock that can be on the fields, so that
-*' in equilibrium only the part that decays in one timestep can be replaced in the next. Costs consist of costs for capital, O&M,
-*' distribution and transport (grades depend on region specific transport distance from mine to fields).
+*' in equilibrium only the part that decays in one timestep can be replaced in the next. The share of suitable fields that can be 
+*' used for spreading rocks can be adjusted via cm_33_EW_maxShareOfCropland.
 *'
 *' (OAE) Ocean alkalinity enhancement via ocean liming draws down CO2 from the atmosphere by adding (hydrated) lime
 *' to the coastal or open ocean. Calcination process, which involves heating limestone to typically around 900-1000°C,
@@ -34,6 +37,11 @@
 *' material).
 *'
 *' Equations for each option determine the capacity, emissions, energy demand, costs and limits.
+
+*' (Overarching) This module further limits the amount of final energy that can be used for CDR technologies (via cm_33_maxFeShare), 
+*' and the share of GDP that can be spent on net negative emissions (via cm_33_GDP_netNegCDR_maxShare). It also contains
+*' the biochar material value price assumption and revenue calculation.
+
 ***----------------------------------------------------
 
 *####################### R SECTION START (PHASES) ##############################
diff --git a/standalone/MOFEX/MOFEX.gms b/standalone/MOFEX/MOFEX.gms
index 2b7414b8c9..1dafff636d 100644
--- a/standalone/MOFEX/MOFEX.gms
+++ b/standalone/MOFEX/MOFEX.gms
@@ -169,7 +169,6 @@ c_ccscapratescen      "CCS capture rate"
 c_export_tax_scen    "choose which oil export tax is used in the model. 0 = none, 1 = fix"
 cm_iterative_target_adj "whether or not a tax or a budget target should be iteratively adjusted depending on actual emission or forcing level"
 cm_gdximport_target   "whether or not the starting value for iteratively adjusted budgets, tax scenarios, or forcing targets (emiscen 5,6,8,9) should be read in from the input.gdx"
-cm_gs_ew              "grain size (for enhanced weathering, CDR module) [micrometre]"
 cm_33_EW_rockRemPot     "Maximum CO2 removal potential per ton of rock (t CO2 / t rock)."
 cm_expoLinear_yearStart "time at which carbon price increases linearly instead of exponentially"
 
@@ -298,7 +297,6 @@ c_export_tax_scen     = 0;         !! def = 0
 cm_iterative_target_adj  = 0;      !! def = 0
 cm_gdximport_target      = 0;      !! def = 0
 $setglobal c_SSP_forcing_adjust  forcing_SSP2   !! def = forcing_SSP2
-cm_gs_ew                 = 20;     !! def = 20
 cm_33_EW_rockRemPot      = 0.3;    !! def = 0.3
 cm_expoLinear_yearStart  = 2050;   !! def = 2050
 c_budgetCO2FFI           = 1000;   !! def = 1000
diff --git a/standalone/template.gms b/standalone/template.gms
index f0b001ea63..1eacd1380f 100644
--- a/standalone/template.gms
+++ b/standalone/template.gms
@@ -165,7 +165,6 @@ c_ccscapratescen      "CCS capture rate"
 c_export_tax_scen    "choose which oil export tax is used in the model. 0 = none, 1 = fix"
 cm_iterative_target_adj "whether or not a tax or a budget target should be iteratively adjusted depending on actual emission or forcing level"
 cm_gdximport_target   "whether or not the starting value for iteratively adjusted budgets, tax scenarios, or forcing targets (emiscen 5,6,8,9) should be read in from the input.gdx"
-cm_gs_ew              "grain size (for enhanced weathering, CDR module) [micrometre]"
 cm_33_EW_rockRemPot     "Maximum CO2 removal potential per ton of rock (t CO2 / t rock)."
 cm_expoLinear_yearStart "time at which carbon price increases linearly instead of exponentially"
 
@@ -252,7 +251,6 @@ c_export_tax_scen     = 0;         !! def = 0
 cm_iterative_target_adj  = 0;      !! def = 0
 cm_gdximport_target      = 0;      !! def = 0
 $setglobal c_SSP_forcing_adjust  forcing_SSP2   !! def = forcing_SSP2
-cm_gs_ew                 = 20;     !! def = 20
 cm_33_EW_rockRemPot      = 0.3;    !! def = 0.3
 cm_expoLinear_yearStart  = 2050;   !! def = 2050
 c_budgetCO2FFI           = 1000;   !! def = 1000
diff --git a/standalone/trade/trade.gms b/standalone/trade/trade.gms
index 68a7580b20..c9d0c123e0 100644
--- a/standalone/trade/trade.gms
+++ b/standalone/trade/trade.gms
@@ -173,7 +173,6 @@ c_ccscapratescen      "CCS capture rate"
 c_export_tax_scen    "choose which oil export tax is used in the model. 0 = none, 1 = fix"
 cm_iterative_target_adj "whether or not a tax or a budget target should be iteratively adjusted depending on actual emission or forcing level"
 cm_gdximport_target   "whether or not the starting value for iteratively adjusted budgets, tax scenarios, or forcing targets (emiscen 5,6,8,9) should be read in from the input.gdx"
-cm_gs_ew              "grain size (for enhanced weathering, CDR module) [micrometre]"
 cm_33_EW_rockRemPot     "Maximum CO2 removal potential per ton of rock (t CO2 / t rock)."
 cm_expoLinear_yearStart "time at which carbon price increases linearly instead of exponentially"
 
@@ -303,7 +302,6 @@ c_export_tax_scen     = 0;         !! def = 0
 cm_iterative_target_adj  = 0;      !! def = 0
 cm_gdximport_target      = 0;      !! def = 0
 $setglobal c_SSP_forcing_adjust  forcing_SSP2   !! def = forcing_SSP2
-cm_gs_ew                 = 20;     !! def = 20
 cm_33_EW_rockRemPot      = 0.3;    !! def = 0.3
 cm_expoLinear_yearStart  = 2050;   !! def = 2050
 c_budgetCO2FFI           = 1000;   !! def = 1000
diff --git a/tests/testthat/test_01-checkFixCfg.R b/tests/testthat/test_01-checkFixCfg.R
index 3e3fc37cf2..c162e9a33d 100644
--- a/tests/testthat/test_01-checkFixCfg.R
+++ b/tests/testthat/test_01-checkFixCfg.R
@@ -13,7 +13,6 @@ test_that("checkFixCfg works", {
     "cm_NDC_version" = "2004_cond",
     "cm_emiscen" = "123",
     "cm_nash_autoconverge" = "NA",
-    "cm_gs_ew" = "2.2.2",
     "cm_taxCO2_expGrowth" = "333++",
     "c_macscen" = "-1",
     "cm_keep_presolve_gdxes" = "1.1",

From b1c8868f2bc688f8db31d7c0617f62c8476ec38d Mon Sep 17 00:00:00 2001
From: tabeado <tabea.dorndorf@pik-potsdam.de>
Date: Thu, 6 Aug 2026 15:59:27 +0200
Subject: [PATCH 09/11] change cm_gs_ew to s33_rockGrainSize in datainput

---
 modules/33_carbonRemoval/portfolio/datainput.gms | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/modules/33_carbonRemoval/portfolio/datainput.gms b/modules/33_carbonRemoval/portfolio/datainput.gms
index 79b83f8994..bc1ec91824 100644
--- a/modules/33_carbonRemoval/portfolio/datainput.gms
+++ b/modules/33_carbonRemoval/portfolio/datainput.gms
@@ -44,8 +44,8 @@ s33_rockRemPot = cm_33_EW_rockRemPot / sm_c_2_co2;       !! default for basalt i
 *' rock weathering rate (i.e. fraction of rock weathering per year) at ambient temperature (25 degree C), based on 
 *' eq 2 in strefler, amann et al. (2018): 
 *' wr = grain surface area based weathering rate (10^-10.53 mol m^-2 s^-1) * molar weight of basalt/forsterite (140.7 g/mol) 
-*'      * 3.155^7 s/a * specific surface area(depending on grain size cm_gs_ew)
-s33_rock_weath_rate_ambientT = 10**(-10.53) * 125 * 3.155*10**7 * 69.18*(cm_gs_ew**(-1.24));
+*'      * 3.155^7 s/a * specific surface area(depending on grain size s33_rockGrainSize)
+s33_rock_weath_rate_ambientT = 10**(-10.53) * 125 * 3.155*10**7 * 69.18*(s33_rockGrainSize**(-1.24));
 *' rock weathering rate for different climate grades: SI Tab F-1 of strefler, amann et al. (2018)
 p33_rock_weath_rate("1") = s33_rock_weath_rate_ambientT * 0.94;
 p33_rock_weath_rate("2") = s33_rock_weath_rate_ambientT * 0.29;

From 35fa982da4e017aeca0f6f11bf11ccf5978047cb Mon Sep 17 00:00:00 2001
From: tabeado <tabea.dorndorf@pik-potsdam.de>
Date: Thu, 6 Aug 2026 16:00:16 +0200
Subject: [PATCH 10/11] wording

---
 modules/33_carbonRemoval/portfolio/datainput.gms | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/modules/33_carbonRemoval/portfolio/datainput.gms b/modules/33_carbonRemoval/portfolio/datainput.gms
index bc1ec91824..cbd60af42a 100644
--- a/modules/33_carbonRemoval/portfolio/datainput.gms
+++ b/modules/33_carbonRemoval/portfolio/datainput.gms
@@ -18,14 +18,14 @@ p33_fedem("dac", "fehes") = 21.12; !! FE demand heat for material recovery
 *' #### EW input data
 *------------------------------------------------------------------------------------
 *' @stop
-table f33_maxProdGradeRegiWeathering(all_regi,rlf)  "regional maximum potentials for enhanced weathering in Gt of grinded stone/a for different grades"
+table f33_maxProdGradeRegiWeathering(all_regi,rlf)  "regional maximum potentials for enhanced weathering in Gt of ground rock/a for different grades"
 $ondelim
 $include "./modules/33_carbonRemoval/portfolio/input/f33_maxProdGradeRegiWeathering.cs3r"
 $offdelim
 ;
 display f33_maxProdGradeRegiWeathering;
 
-parameter p33_EW_transport_costs(all_regi,rlf,rlf)    "transport costs [T$/Gt stone]"
+parameter p33_EW_transport_costs(all_regi,rlf,rlf)    "transport costs [T$/Gt rock]"
 /
 $ondelim
 $include "./modules/33_carbonRemoval/portfolio/input/p33_transportCostsWeathering.cs4r"

From 4301cb81479a17e7a8299cfe3a202a436f994d3c Mon Sep 17 00:00:00 2001
From: tabeado <tabea.dorndorf@pik-potsdam.de>
Date: Thu, 6 Aug 2026 16:32:40 +0200
Subject: [PATCH 11/11] s33_step adjustments

---
 modules/33_carbonRemoval/portfolio/datainput.gms    | 2 --
 modules/33_carbonRemoval/portfolio/declarations.gms | 2 +-
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/modules/33_carbonRemoval/portfolio/datainput.gms b/modules/33_carbonRemoval/portfolio/datainput.gms
index cbd60af42a..f1347e5ee8 100644
--- a/modules/33_carbonRemoval/portfolio/datainput.gms
+++ b/modules/33_carbonRemoval/portfolio/datainput.gms
@@ -34,8 +34,6 @@ $offdelim
 ;
 display p33_EW_transport_costs;
 
-s33_step = 2.5;
-
 *' @code
 s33_rockRemPot = cm_33_EW_rockRemPot / sm_c_2_co2;       !! default for basalt is 0.3 t CO2/t rock, for Olivine 1.1 t CO2/t rock. Converted to t C/t rock.
 *' Sources for loss pathways that would reduce the total removal potential per ton rock: 
diff --git a/modules/33_carbonRemoval/portfolio/declarations.gms b/modules/33_carbonRemoval/portfolio/declarations.gms
index 9934a4ed86..22bd351517 100644
--- a/modules/33_carbonRemoval/portfolio/declarations.gms
+++ b/modules/33_carbonRemoval/portfolio/declarations.gms
@@ -12,7 +12,7 @@ sm_capture_rate_cdrmodule       "CO2 capture rate for CDR energy and process emi
 s33_rockGrainSize               "grain size of ground rock, influences electricity demand and weathering rate. By default 20 micrometer based on Strefler et al. (2018) [micrometre]" /20/
 s33_rockRemPot                 "specific carbon removal potential [t C / t rock]"
 s33_rock_weath_rate_ambientT    "fraction of stone weathering per year at ambient temperature (25 degree C)"
-s33_step                        "size of bins in v33_weathering_onfield [Gt stone]" / 2.5 /
+s33_step                        "size of bins in v33_EW_onfield_tot [Gt rock]" / 2.5 /
 *JeS* GJ/tCO2 = EJ/Gt CO2 = 44/12 EJ/Gt C.
 *** OAE
 s33_OAE_efficiency          "the amount of rock required to sequester 1GtC [Gt rock / GtC]"