| Notation | Description | 
|---|
| $x_{d,z,t}^{\textrm{C,DAC}}$ | this term represents CO2 captured by DAC resource $d$ in zone $z$ at time period $t$ | 
| $x_{k,z,t}^{\textrm{C,COMP}}$ | this term represents DAC-captured CO2 compressed by CO2 compression generation resource $k$ in zone $z$ at time period $t$ | 
| $x_{s,z,t}^{\textrm{C,INJ}}$ | this term represents CO2 injected into the CO2 storage resource $s$ in zone $z$ at time period $t$ | 
| $x_{i,z \rightarrow z^{\prime},t}^{\textrm{C,PIP}}$ | the CO2 pipeline flow decision variable representing CO2 flow via pipeline of type $i$ through path $z \rightarrow z^{\prime}$ at time period $t$ | 
| $y_{d,z}^{\textrm{C,DAC}}$ | capacity of DAC resources in the CO2 supply chain | 
| $y_{k,z}^{\textrm{C,COMP}}$ | capacity of CO2 compression resources in the CO2 supply chain | 
| $y_{s,z}^{\textrm{C,STO}}$ | capacity of CO2 storage in the CO2 supply chain | 
| $y_{i,z \rightarrow z^{\prime}}^{\textrm{C,PIP}}$ | the CO2 pipeline construction decision variable representing newly constructed CO2 pipeline of type $i$ through path $z \rightarrow z^{\prime}$ | 
| $U_{i,z \rightarrow z^{\prime},t}^{\textrm{C,PIP}}$ | the CO2 pipeline storage level decision variable representing CO2 stored in pipeline of type $i$ through path $z \rightarrow z^{\prime}$ at time period $t$ | 
| Notation | Description | 
|---|
| $\textrm{c}_{d}^{\textrm{DAC,INV}}$ | investment cost per tonne of DAC capture capacity | 
| $\textrm{c}_{d}^{\textrm{DAC,FOM}}$ | fixed operation cost per tonne of DAC capture capacity | 
| $\textrm{c}_{d}^{\textrm{DAC,VOM}}$ | variable operation cost per tonne of CO2 captured by DAC | 
| $\textrm{c}_{g}^{\textrm{DAC,FUEL}}$ | fuel cost per tonne of CO2 captured by DAC | 
| $\textrm{c}_{k}^{\textrm{COMP,INV}}$ | investment cost per tonne of CO2 compression capacity | 
| $\textrm{c}_{k}^{\textrm{COMP,FOM}}$ | fixed operation cost per tonne of CO2 compression capacity | 
| $\textrm{c}_{s}^{\textrm{STO,INV}}$ | investment cost per tonne of CO2 storage capacity | 
| $\textrm{c}_{s}^{\textrm{STO,FOM}}$ | fixed operation cost per tonne of CO2 storage capacity | 
| $\textrm{c}_{s}^{\textrm{INJ,VOM}}$ | variable operation cost per tonne of CO2 injected into CO2 storage by DAC | 
| $\overline{y}_{d}^{\textrm{\textrm{C,DAC}}}$ | upper bound of capacity is defined,then we impose constraints on maximum DAC capacity | 
| $\underline{y}_{d}^{\textrm{\textrm{C,DAC}}}$ | lower bound of capacity is defined,then we impose constraints on minimum DAC capacity | 
| $\overline{y}_{k}^{\textrm{\textrm{C,COMP}}}$ | upper bound of capacity is defined,then we impose constraints on maximum CO2 compression capacity | 
| $\underline{y}_{k}^{\textrm{\textrm{C,COMP}}}$ | lower bound of capacity is defined,then we impose constraints on minimum CO2 compression capacity | 
| $\overline{y}_{s}^{\textrm{\textrm{C,STO}}}$ | upper bound of capacity is defined,then we impose constraints on maximum CO2 storage capacity | 
| $\underline{y}_{s}^{\textrm{\textrm{C,STO}}}$ | lower bound of capacity is defined,then we impose constraints on minimum CO2 storage capacity | 
| $\overline{x}_{s}^{\textrm{\textrm{C,INJ}}}$ | upper bound of rate is defined,then we impose constraints on maximum CO2 injection rate | 
| $\overline{\textrm{R}}_{d,z,t}^{\textrm{C,DAC}}$ | For DAC where upper bound operation is defined, then we impose constraints on maximum operating capacity rate | 
| $\underline{\textrm{R}}_{d,z}^{\textrm{C,DAC}}$ | For DAC where lower bound operation is defined, then we impose constraints on minimum operating capacity rate | 
| $\overline{\textrm{R}}_{k,z}^{\textrm{C,COMP}}$ | For CO2 compression where upper bound operation is defined, then we impose constraints on maximum operating capacity rate | 
| $\underline{\textrm{R}}_{k,z}^{\textrm{C,COMP}}$ | For CO2 compression where lower bound operation is defined, then we impose constraints on minimum operating capacity rate | 
| $\overline{\textrm{R}}_{k,z}^{\textrm{C,INJ}}$ | For CO2 injection where upper bound operation is defined, then we impose constraints on maximum injection rate | 
| $\underline{\textrm{R}}_{k,z}^{\textrm{C,INJ}}$ | For CO2 injection where lower bound operation is defined, then we impose constraints on minimum injection rate |