diff --git a/base/addons/combtech/bb4/combtech_balbase4.inc b/base/addons/combtech/bb4/combtech_balbase4.inc
index 5b9e0da4..4d7d2c73 100644
--- a/base/addons/combtech/bb4/combtech_balbase4.inc
+++ b/base/addons/combtech/bb4/combtech_balbase4.inc
@@ -1,4 +1,4 @@
-* Equations for addon combtech used in Balbase3 model definition
+* Equations for addon combtech used in Balbase4 model definition
 
 QCOMBFUP
 
@@ -24,3 +24,4 @@ QHCOMBGSHAREK1
 QHCOMBGSHAREK12
 QCOMBFSHAREK1
 QCOMBFSHAREK12
+QGKE_UP_ADD
diff --git a/base/addons/combtech/bb4/combtech_eqndecdef.inc b/base/addons/combtech/bb4/combtech_eqndecdef.inc
index 01988635..c58d6155 100644
--- a/base/addons/combtech/bb4/combtech_eqndecdef.inc
+++ b/base/addons/combtech/bb4/combtech_eqndecdef.inc
@@ -182,10 +182,10 @@ QCOMBFSHAREK12(IY411,IA,IGCOMB1,IGCOMB2,IS3,T)$(IAGK_HASORPOT(IY411,IA,IGCOMB2)
 ;
 
 *"Capacity adjustment constraint on electricity generation from biogas upgraded plants (MW)"
-QGKE_UP_ADD(IY411,IA,IGCOMB1,IS3,T)..
+QGKE_UP_ADD(IY411,IA,IGCOMB1,IS3,T)$(IAGK_HASORPOT(IY411,IA,IGCOMB1))..
 
   VGE_T(IY411,IA,IGCOMB1,IS3,T)+ SUM(IGCOMB2$GGCOMB(IGCOMB1,IGCOMB2),(VGE_T(IY411,IA,IGCOMB2,IS3,T)*(1+HYDROGEN_H2TOF(IGCOMB2))))
   =L=
   GKFX(IY411,IA,IGCOMB1)+VGKNACCUMNET(IY411,IA,IGCOMB1)
 
-;
\ No newline at end of file
+;
diff --git a/base/addons/hydrogen/bb4/hydrogen_balbase4.inc b/base/addons/hydrogen/bb4/hydrogen_balbase4.inc
index ec1d4869..b4e6a4d7 100644
--- a/base/addons/hydrogen/bb4/hydrogen_balbase4.inc
+++ b/base/addons/hydrogen/bb4/hydrogen_balbase4.inc
@@ -2,6 +2,7 @@
    QHYDROGEN_HGETOH2
    QHYDROGEN_GGEHTOH2
    QHYDROGEN_HGEHTOH2
+   QHYDROGEN_H2TOEH
    QHYDROGEN_EQ
    QHYDROGEN_EQ_AREA
    QHYDROGEN_STOMAXCON
diff --git a/base/addons/hydrogen/bb4/hydrogen_eqndecdef.inc b/base/addons/hydrogen/bb4/hydrogen_eqndecdef.inc
index cbc62086..cf7633af 100644
--- a/base/addons/hydrogen/bb4/hydrogen_eqndecdef.inc
+++ b/base/addons/hydrogen/bb4/hydrogen_eqndecdef.inc
@@ -61,7 +61,6 @@ QHYDROGEN_EQ(IY411,IR,IS3,T)..
    IHYDROGEN_DH2_REGION_T_Y(IY411,IR,IS3,T)+
    SUM(IA$RRRAAA(IR,IA),IHYDROGEN_DH2_AREA_T_Y(IY411,IA,IS3,T))
    + SUM(IAGK_HASORPOT(IY411,IA,IHYDROGEN_GH2FUEL) $(RRRAAA(IR,IA)),VGE_T(IY411,IA,IHYDROGEN_GH2FUEL,IS3,T)/GDATA(IHYDROGEN_GH2FUEL,'GDFE'))
-*IDA new additions
    + SUM(IAGK_HASORPOT(IY411,IA,IHYDROGEN_GH2UP) $(RRRAAA(IR,IA)),HYDROGEN_H2TOF(IHYDROGEN_GH2UP)*VGF_T(IY411,IA,IHYDROGEN_GH2UP,IS3,T))
          - VHYDROGEN_QH2EQ(IY411,IR,IS3,T,'IMINUS') + VHYDROGEN_QH2EQ(IY411,IR,IS3,T,'IPLUS')
 ;
@@ -77,6 +76,8 @@ QHYDROGEN_EQ_AREA(IY411,IA,IS3,T)$(IHYDROGEN_DH2_AREA_T_Y(IY411,IA,IS3,T))..
    - SUM(IHYDROGEN_GH2STO$(IAGK_HASORPOT(IY411,IA,IHYDROGEN_GH2STO)),VHYDROGEN_STOLOADT(IY411,IA,IHYDROGEN_GH2STO,IS3,T))
    =G=
    IHYDROGEN_DH2_AREA_T_Y(IY411,IA,IS3,T)
+   + SUM(IHYDROGEN_GH2FUEL$IAGK_HASORPOT(IY411,IA,IHYDROGEN_GH2FUEL),VGE_T(IY411,IA,IHYDROGEN_GH2FUEL,IS3,T)/GDATA(IHYDROGEN_GH2FUEL,'GDFE'))
+   + SUM(IHYDROGEN_GH2UP$IAGK_HASORPOT(IY411,IA,IHYDROGEN_GH2UP),HYDROGEN_H2TOF(IHYDROGEN_GH2UP)*VGF_T(IY411,IA,IHYDROGEN_GH2UP,IS3,T))
          - VHYDROGEN_QH2EQ(IY411,IA,IS3,T,'IMINUS') + VHYDROGEN_QH2EQ(IY411,IA,IS3,T,'IPLUS')
 ;